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diff --git a/jpgd.cpp b/jpgd.cpp
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--- /dev/null
+++ b/jpgd.cpp
@@ -0,0 +1,3230 @@
+// jpgd.cpp - C++ class for JPEG decompression. Written by Richard Geldreich <richgel99@gmail.com> between 1994-2020.
+// Supports progressive and baseline sequential JPEG image files, and the most common chroma subsampling factors: Y, H1V1, H2V1, H1V2, and H2V2.
+// Supports box and linear chroma upsampling.
+//
+// Released under two licenses. You are free to choose which license you want:
+// License 1:
+// Public Domain
+//
+// License 2:
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Alex Evans: Linear memory allocator (taken from jpge.h).
+// v1.04, May. 19, 2012: Code tweaks to fix VS2008 static code analysis warnings
+// v2.00, March 20, 2020: Fuzzed with zzuf and afl. Fixed several issues, converted most assert()'s to run-time checks. Added chroma upsampling. Removed freq. domain upsampling. gcc/clang warnings.
+//
+
+#ifdef _MSC_VER
+#ifndef BASISU_NO_ITERATOR_DEBUG_LEVEL
+#if defined(_DEBUG) || defined(DEBUG)
+#define _ITERATOR_DEBUG_LEVEL 1
+#define _SECURE_SCL 1
+#else
+#define _SECURE_SCL 0
+#define _ITERATOR_DEBUG_LEVEL 0
+#endif
+#endif
+#endif
+
+#include "jpgd.h"
+#include <string.h>
+#include <algorithm>
+#include <assert.h>
+
+#ifdef _MSC_VER
+#pragma warning (disable : 4611) // warning C4611: interaction between '_setjmp' and C++ object destruction is non-portable
+#endif
+
+#define JPGD_TRUE (1)
+#define JPGD_FALSE (0)
+
+#define JPGD_MAX(a,b) (((a)>(b)) ? (a) : (b))
+#define JPGD_MIN(a,b) (((a)<(b)) ? (a) : (b))
+
+namespace jpgd {
+
+ static inline void* jpgd_malloc(size_t nSize) { return malloc(nSize); }
+ static inline void jpgd_free(void* p) { free(p); }
+
+ // DCT coefficients are stored in this sequence.
+ static int g_ZAG[64] = { 0,1,8,16,9,2,3,10,17,24,32,25,18,11,4,5,12,19,26,33,40,48,41,34,27,20,13,6,7,14,21,28,35,42,49,56,57,50,43,36,29,22,15,23,30,37,44,51,58,59,52,45,38,31,39,46,53,60,61,54,47,55,62,63 };
+
+ enum JPEG_MARKER
+ {
+ M_SOF0 = 0xC0, M_SOF1 = 0xC1, M_SOF2 = 0xC2, M_SOF3 = 0xC3, M_SOF5 = 0xC5, M_SOF6 = 0xC6, M_SOF7 = 0xC7, M_JPG = 0xC8,
+ M_SOF9 = 0xC9, M_SOF10 = 0xCA, M_SOF11 = 0xCB, M_SOF13 = 0xCD, M_SOF14 = 0xCE, M_SOF15 = 0xCF, M_DHT = 0xC4, M_DAC = 0xCC,
+ M_RST0 = 0xD0, M_RST1 = 0xD1, M_RST2 = 0xD2, M_RST3 = 0xD3, M_RST4 = 0xD4, M_RST5 = 0xD5, M_RST6 = 0xD6, M_RST7 = 0xD7,
+ M_SOI = 0xD8, M_EOI = 0xD9, M_SOS = 0xDA, M_DQT = 0xDB, M_DNL = 0xDC, M_DRI = 0xDD, M_DHP = 0xDE, M_EXP = 0xDF,
+ M_APP0 = 0xE0, M_APP15 = 0xEF, M_JPG0 = 0xF0, M_JPG13 = 0xFD, M_COM = 0xFE, M_TEM = 0x01, M_ERROR = 0x100, RST0 = 0xD0
+ };
+
+ enum JPEG_SUBSAMPLING { JPGD_GRAYSCALE = 0, JPGD_YH1V1, JPGD_YH2V1, JPGD_YH1V2, JPGD_YH2V2 };
+
+#define CONST_BITS 13
+#define PASS1_BITS 2
+#define SCALEDONE ((int32)1)
+
+#define FIX_0_298631336 ((int32)2446) /* FIX(0.298631336) */
+#define FIX_0_390180644 ((int32)3196) /* FIX(0.390180644) */
+#define FIX_0_541196100 ((int32)4433) /* FIX(0.541196100) */
+#define FIX_0_765366865 ((int32)6270) /* FIX(0.765366865) */
+#define FIX_0_899976223 ((int32)7373) /* FIX(0.899976223) */
+#define FIX_1_175875602 ((int32)9633) /* FIX(1.175875602) */
+#define FIX_1_501321110 ((int32)12299) /* FIX(1.501321110) */
+#define FIX_1_847759065 ((int32)15137) /* FIX(1.847759065) */
+#define FIX_1_961570560 ((int32)16069) /* FIX(1.961570560) */
+#define FIX_2_053119869 ((int32)16819) /* FIX(2.053119869) */
+#define FIX_2_562915447 ((int32)20995) /* FIX(2.562915447) */
+#define FIX_3_072711026 ((int32)25172) /* FIX(3.072711026) */
+
+#define DESCALE(x,n) (((x) + (SCALEDONE << ((n)-1))) >> (n))
+#define DESCALE_ZEROSHIFT(x,n) (((x) + (128 << (n)) + (SCALEDONE << ((n)-1))) >> (n))
+
+#define MULTIPLY(var, cnst) ((var) * (cnst))
+
+#define CLAMP(i) ((static_cast<uint>(i) > 255) ? (((~i) >> 31) & 0xFF) : (i))
+
+ // Compiler creates a fast path 1D IDCT for X non-zero columns
+ template <int NONZERO_COLS>
+ struct Row
+ {
+ static void idct(int* pTemp, const jpgd_block_t* pSrc)
+ {
+ // ACCESS_COL() will be optimized at compile time to either an array access, or 0. Good compilers will then optimize out muls against 0.
+#define ACCESS_COL(x) (((x) < NONZERO_COLS) ? (int)pSrc[x] : 0)
+
+ const int z2 = ACCESS_COL(2), z3 = ACCESS_COL(6);
+
+ const int z1 = MULTIPLY(z2 + z3, FIX_0_541196100);
+ const int tmp2 = z1 + MULTIPLY(z3, -FIX_1_847759065);
+ const int tmp3 = z1 + MULTIPLY(z2, FIX_0_765366865);
+
+ const int tmp0 = (ACCESS_COL(0) + ACCESS_COL(4)) << CONST_BITS;
+ const int tmp1 = (ACCESS_COL(0) - ACCESS_COL(4)) << CONST_BITS;
+
+ const int tmp10 = tmp0 + tmp3, tmp13 = tmp0 - tmp3, tmp11 = tmp1 + tmp2, tmp12 = tmp1 - tmp2;
+
+ const int atmp0 = ACCESS_COL(7), atmp1 = ACCESS_COL(5), atmp2 = ACCESS_COL(3), atmp3 = ACCESS_COL(1);
+
+ const int bz1 = atmp0 + atmp3, bz2 = atmp1 + atmp2, bz3 = atmp0 + atmp2, bz4 = atmp1 + atmp3;
+ const int bz5 = MULTIPLY(bz3 + bz4, FIX_1_175875602);
+
+ const int az1 = MULTIPLY(bz1, -FIX_0_899976223);
+ const int az2 = MULTIPLY(bz2, -FIX_2_562915447);
+ const int az3 = MULTIPLY(bz3, -FIX_1_961570560) + bz5;
+ const int az4 = MULTIPLY(bz4, -FIX_0_390180644) + bz5;
+
+ const int btmp0 = MULTIPLY(atmp0, FIX_0_298631336) + az1 + az3;
+ const int btmp1 = MULTIPLY(atmp1, FIX_2_053119869) + az2 + az4;
+ const int btmp2 = MULTIPLY(atmp2, FIX_3_072711026) + az2 + az3;
+ const int btmp3 = MULTIPLY(atmp3, FIX_1_501321110) + az1 + az4;
+
+ pTemp[0] = DESCALE(tmp10 + btmp3, CONST_BITS - PASS1_BITS);
+ pTemp[7] = DESCALE(tmp10 - btmp3, CONST_BITS - PASS1_BITS);
+ pTemp[1] = DESCALE(tmp11 + btmp2, CONST_BITS - PASS1_BITS);
+ pTemp[6] = DESCALE(tmp11 - btmp2, CONST_BITS - PASS1_BITS);
+ pTemp[2] = DESCALE(tmp12 + btmp1, CONST_BITS - PASS1_BITS);
+ pTemp[5] = DESCALE(tmp12 - btmp1, CONST_BITS - PASS1_BITS);
+ pTemp[3] = DESCALE(tmp13 + btmp0, CONST_BITS - PASS1_BITS);
+ pTemp[4] = DESCALE(tmp13 - btmp0, CONST_BITS - PASS1_BITS);
+ }
+ };
+
+ template <>
+ struct Row<0>
+ {
+ static void idct(int* pTemp, const jpgd_block_t* pSrc)
+ {
+#ifdef _MSC_VER
+ pTemp; pSrc;
+#endif
+ }
+ };
+
+ template <>
+ struct Row<1>
+ {
+ static void idct(int* pTemp, const jpgd_block_t* pSrc)
+ {
+ const int dcval = (pSrc[0] << PASS1_BITS);
+
+ pTemp[0] = dcval;
+ pTemp[1] = dcval;
+ pTemp[2] = dcval;
+ pTemp[3] = dcval;
+ pTemp[4] = dcval;
+ pTemp[5] = dcval;
+ pTemp[6] = dcval;
+ pTemp[7] = dcval;
+ }
+ };
+
+ // Compiler creates a fast path 1D IDCT for X non-zero rows
+ template <int NONZERO_ROWS>
+ struct Col
+ {
+ static void idct(uint8* pDst_ptr, const int* pTemp)
+ {
+ // ACCESS_ROW() will be optimized at compile time to either an array access, or 0.
+#define ACCESS_ROW(x) (((x) < NONZERO_ROWS) ? pTemp[x * 8] : 0)
+
+ const int z2 = ACCESS_ROW(2);
+ const int z3 = ACCESS_ROW(6);
+
+ const int z1 = MULTIPLY(z2 + z3, FIX_0_541196100);
+ const int tmp2 = z1 + MULTIPLY(z3, -FIX_1_847759065);
+ const int tmp3 = z1 + MULTIPLY(z2, FIX_0_765366865);
+
+ const int tmp0 = (ACCESS_ROW(0) + ACCESS_ROW(4)) << CONST_BITS;
+ const int tmp1 = (ACCESS_ROW(0) - ACCESS_ROW(4)) << CONST_BITS;
+
+ const int tmp10 = tmp0 + tmp3, tmp13 = tmp0 - tmp3, tmp11 = tmp1 + tmp2, tmp12 = tmp1 - tmp2;
+
+ const int atmp0 = ACCESS_ROW(7), atmp1 = ACCESS_ROW(5), atmp2 = ACCESS_ROW(3), atmp3 = ACCESS_ROW(1);
+
+ const int bz1 = atmp0 + atmp3, bz2 = atmp1 + atmp2, bz3 = atmp0 + atmp2, bz4 = atmp1 + atmp3;
+ const int bz5 = MULTIPLY(bz3 + bz4, FIX_1_175875602);
+
+ const int az1 = MULTIPLY(bz1, -FIX_0_899976223);
+ const int az2 = MULTIPLY(bz2, -FIX_2_562915447);
+ const int az3 = MULTIPLY(bz3, -FIX_1_961570560) + bz5;
+ const int az4 = MULTIPLY(bz4, -FIX_0_390180644) + bz5;
+
+ const int btmp0 = MULTIPLY(atmp0, FIX_0_298631336) + az1 + az3;
+ const int btmp1 = MULTIPLY(atmp1, FIX_2_053119869) + az2 + az4;
+ const int btmp2 = MULTIPLY(atmp2, FIX_3_072711026) + az2 + az3;
+ const int btmp3 = MULTIPLY(atmp3, FIX_1_501321110) + az1 + az4;
+
+ int i = DESCALE_ZEROSHIFT(tmp10 + btmp3, CONST_BITS + PASS1_BITS + 3);
+ pDst_ptr[8 * 0] = (uint8)CLAMP(i);
+
+ i = DESCALE_ZEROSHIFT(tmp10 - btmp3, CONST_BITS + PASS1_BITS + 3);
+ pDst_ptr[8 * 7] = (uint8)CLAMP(i);
+
+ i = DESCALE_ZEROSHIFT(tmp11 + btmp2, CONST_BITS + PASS1_BITS + 3);
+ pDst_ptr[8 * 1] = (uint8)CLAMP(i);
+
+ i = DESCALE_ZEROSHIFT(tmp11 - btmp2, CONST_BITS + PASS1_BITS + 3);
+ pDst_ptr[8 * 6] = (uint8)CLAMP(i);
+
+ i = DESCALE_ZEROSHIFT(tmp12 + btmp1, CONST_BITS + PASS1_BITS + 3);
+ pDst_ptr[8 * 2] = (uint8)CLAMP(i);
+
+ i = DESCALE_ZEROSHIFT(tmp12 - btmp1, CONST_BITS + PASS1_BITS + 3);
+ pDst_ptr[8 * 5] = (uint8)CLAMP(i);
+
+ i = DESCALE_ZEROSHIFT(tmp13 + btmp0, CONST_BITS + PASS1_BITS + 3);
+ pDst_ptr[8 * 3] = (uint8)CLAMP(i);
+
+ i = DESCALE_ZEROSHIFT(tmp13 - btmp0, CONST_BITS + PASS1_BITS + 3);
+ pDst_ptr[8 * 4] = (uint8)CLAMP(i);
+ }
+ };
+
+ template <>
+ struct Col<1>
+ {
+ static void idct(uint8* pDst_ptr, const int* pTemp)
+ {
+ int dcval = DESCALE_ZEROSHIFT(pTemp[0], PASS1_BITS + 3);
+ const uint8 dcval_clamped = (uint8)CLAMP(dcval);
+ pDst_ptr[0 * 8] = dcval_clamped;
+ pDst_ptr[1 * 8] = dcval_clamped;
+ pDst_ptr[2 * 8] = dcval_clamped;
+ pDst_ptr[3 * 8] = dcval_clamped;
+ pDst_ptr[4 * 8] = dcval_clamped;
+ pDst_ptr[5 * 8] = dcval_clamped;
+ pDst_ptr[6 * 8] = dcval_clamped;
+ pDst_ptr[7 * 8] = dcval_clamped;
+ }
+ };
+
+ static const uint8 s_idct_row_table[] =
+ {
+ 1,0,0,0,0,0,0,0, 2,0,0,0,0,0,0,0, 2,1,0,0,0,0,0,0, 2,1,1,0,0,0,0,0, 2,2,1,0,0,0,0,0, 3,2,1,0,0,0,0,0, 4,2,1,0,0,0,0,0, 4,3,1,0,0,0,0,0,
+ 4,3,2,0,0,0,0,0, 4,3,2,1,0,0,0,0, 4,3,2,1,1,0,0,0, 4,3,2,2,1,0,0,0, 4,3,3,2,1,0,0,0, 4,4,3,2,1,0,0,0, 5,4,3,2,1,0,0,0, 6,4,3,2,1,0,0,0,
+ 6,5,3,2,1,0,0,0, 6,5,4,2,1,0,0,0, 6,5,4,3,1,0,0,0, 6,5,4,3,2,0,0,0, 6,5,4,3,2,1,0,0, 6,5,4,3,2,1,1,0, 6,5,4,3,2,2,1,0, 6,5,4,3,3,2,1,0,
+ 6,5,4,4,3,2,1,0, 6,5,5,4,3,2,1,0, 6,6,5,4,3,2,1,0, 7,6,5,4,3,2,1,0, 8,6,5,4,3,2,1,0, 8,7,5,4,3,2,1,0, 8,7,6,4,3,2,1,0, 8,7,6,5,3,2,1,0,
+ 8,7,6,5,4,2,1,0, 8,7,6,5,4,3,1,0, 8,7,6,5,4,3,2,0, 8,7,6,5,4,3,2,1, 8,7,6,5,4,3,2,2, 8,7,6,5,4,3,3,2, 8,7,6,5,4,4,3,2, 8,7,6,5,5,4,3,2,
+ 8,7,6,6,5,4,3,2, 8,7,7,6,5,4,3,2, 8,8,7,6,5,4,3,2, 8,8,8,6,5,4,3,2, 8,8,8,7,5,4,3,2, 8,8,8,7,6,4,3,2, 8,8,8,7,6,5,3,2, 8,8,8,7,6,5,4,2,
+ 8,8,8,7,6,5,4,3, 8,8,8,7,6,5,4,4, 8,8,8,7,6,5,5,4, 8,8,8,7,6,6,5,4, 8,8,8,7,7,6,5,4, 8,8,8,8,7,6,5,4, 8,8,8,8,8,6,5,4, 8,8,8,8,8,7,5,4,
+ 8,8,8,8,8,7,6,4, 8,8,8,8,8,7,6,5, 8,8,8,8,8,7,6,6, 8,8,8,8,8,7,7,6, 8,8,8,8,8,8,7,6, 8,8,8,8,8,8,8,6, 8,8,8,8,8,8,8,7, 8,8,8,8,8,8,8,8,
+ };
+
+ static const uint8 s_idct_col_table[] =
+ {
+ 1, 1, 2, 3, 3, 3, 3, 3, 3, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+ 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8
+ };
+
+ // Scalar "fast pathing" IDCT.
+ static void idct(const jpgd_block_t* pSrc_ptr, uint8* pDst_ptr, int block_max_zag)
+ {
+ assert(block_max_zag >= 1);
+ assert(block_max_zag <= 64);
+
+ if (block_max_zag <= 1)
+ {
+ int k = ((pSrc_ptr[0] + 4) >> 3) + 128;
+ k = CLAMP(k);
+ k = k | (k << 8);
+ k = k | (k << 16);
+
+ for (int i = 8; i > 0; i--)
+ {
+ *(int*)&pDst_ptr[0] = k;
+ *(int*)&pDst_ptr[4] = k;
+ pDst_ptr += 8;
+ }
+ return;
+ }
+
+ int temp[64];
+
+ const jpgd_block_t* pSrc = pSrc_ptr;
+ int* pTemp = temp;
+
+ const uint8* pRow_tab = &s_idct_row_table[(block_max_zag - 1) * 8];
+ int i;
+ for (i = 8; i > 0; i--, pRow_tab++)
+ {
+ switch (*pRow_tab)
+ {
+ case 0: Row<0>::idct(pTemp, pSrc); break;
+ case 1: Row<1>::idct(pTemp, pSrc); break;
+ case 2: Row<2>::idct(pTemp, pSrc); break;
+ case 3: Row<3>::idct(pTemp, pSrc); break;
+ case 4: Row<4>::idct(pTemp, pSrc); break;
+ case 5: Row<5>::idct(pTemp, pSrc); break;
+ case 6: Row<6>::idct(pTemp, pSrc); break;
+ case 7: Row<7>::idct(pTemp, pSrc); break;
+ case 8: Row<8>::idct(pTemp, pSrc); break;
+ }
+
+ pSrc += 8;
+ pTemp += 8;
+ }
+
+ pTemp = temp;
+
+ const int nonzero_rows = s_idct_col_table[block_max_zag - 1];
+ for (i = 8; i > 0; i--)
+ {
+ switch (nonzero_rows)
+ {
+ case 1: Col<1>::idct(pDst_ptr, pTemp); break;
+ case 2: Col<2>::idct(pDst_ptr, pTemp); break;
+ case 3: Col<3>::idct(pDst_ptr, pTemp); break;
+ case 4: Col<4>::idct(pDst_ptr, pTemp); break;
+ case 5: Col<5>::idct(pDst_ptr, pTemp); break;
+ case 6: Col<6>::idct(pDst_ptr, pTemp); break;
+ case 7: Col<7>::idct(pDst_ptr, pTemp); break;
+ case 8: Col<8>::idct(pDst_ptr, pTemp); break;
+ }
+
+ pTemp++;
+ pDst_ptr++;
+ }
+ }
+
+ // Retrieve one character from the input stream.
+ inline uint jpeg_decoder::get_char()
+ {
+ // Any bytes remaining in buffer?
+ if (!m_in_buf_left)
+ {
+ // Try to get more bytes.
+ prep_in_buffer();
+ // Still nothing to get?
+ if (!m_in_buf_left)
+ {
+ // Pad the end of the stream with 0xFF 0xD9 (EOI marker)
+ int t = m_tem_flag;
+ m_tem_flag ^= 1;
+ if (t)
+ return 0xD9;
+ else
+ return 0xFF;
+ }
+ }
+
+ uint c = *m_pIn_buf_ofs++;
+ m_in_buf_left--;
+
+ return c;
+ }
+
+ // Same as previous method, except can indicate if the character is a pad character or not.
+ inline uint jpeg_decoder::get_char(bool* pPadding_flag)
+ {
+ if (!m_in_buf_left)
+ {
+ prep_in_buffer();
+ if (!m_in_buf_left)
+ {
+ *pPadding_flag = true;
+ int t = m_tem_flag;
+ m_tem_flag ^= 1;
+ if (t)
+ return 0xD9;
+ else
+ return 0xFF;
+ }
+ }
+
+ *pPadding_flag = false;
+
+ uint c = *m_pIn_buf_ofs++;
+ m_in_buf_left--;
+
+ return c;
+ }
+
+ // Inserts a previously retrieved character back into the input buffer.
+ inline void jpeg_decoder::stuff_char(uint8 q)
+ {
+ // This could write before the input buffer, but we've placed another array there.
+ *(--m_pIn_buf_ofs) = q;
+ m_in_buf_left++;
+ }
+
+ // Retrieves one character from the input stream, but does not read past markers. Will continue to return 0xFF when a marker is encountered.
+ inline uint8 jpeg_decoder::get_octet()
+ {
+ bool padding_flag;
+ int c = get_char(&padding_flag);
+
+ if (c == 0xFF)
+ {
+ if (padding_flag)
+ return 0xFF;
+
+ c = get_char(&padding_flag);
+ if (padding_flag)
+ {
+ stuff_char(0xFF);
+ return 0xFF;
+ }
+
+ if (c == 0x00)
+ return 0xFF;
+ else
+ {
+ stuff_char(static_cast<uint8>(c));
+ stuff_char(0xFF);
+ return 0xFF;
+ }
+ }
+
+ return static_cast<uint8>(c);
+ }
+
+ // Retrieves a variable number of bits from the input stream. Does not recognize markers.
+ inline uint jpeg_decoder::get_bits(int num_bits)
+ {
+ if (!num_bits)
+ return 0;
+
+ uint i = m_bit_buf >> (32 - num_bits);
+
+ if ((m_bits_left -= num_bits) <= 0)
+ {
+ m_bit_buf <<= (num_bits += m_bits_left);
+
+ uint c1 = get_char();
+ uint c2 = get_char();
+ m_bit_buf = (m_bit_buf & 0xFFFF0000) | (c1 << 8) | c2;
+
+ m_bit_buf <<= -m_bits_left;
+
+ m_bits_left += 16;
+
+ assert(m_bits_left >= 0);
+ }
+ else
+ m_bit_buf <<= num_bits;
+
+ return i;
+ }
+
+ // Retrieves a variable number of bits from the input stream. Markers will not be read into the input bit buffer. Instead, an infinite number of all 1's will be returned when a marker is encountered.
+ inline uint jpeg_decoder::get_bits_no_markers(int num_bits)
+ {
+ if (!num_bits)
+ return 0;
+
+ assert(num_bits <= 16);
+
+ uint i = m_bit_buf >> (32 - num_bits);
+
+ if ((m_bits_left -= num_bits) <= 0)
+ {
+ m_bit_buf <<= (num_bits += m_bits_left);
+
+ if ((m_in_buf_left < 2) || (m_pIn_buf_ofs[0] == 0xFF) || (m_pIn_buf_ofs[1] == 0xFF))
+ {
+ uint c1 = get_octet();
+ uint c2 = get_octet();
+ m_bit_buf |= (c1 << 8) | c2;
+ }
+ else
+ {
+ m_bit_buf |= ((uint)m_pIn_buf_ofs[0] << 8) | m_pIn_buf_ofs[1];
+ m_in_buf_left -= 2;
+ m_pIn_buf_ofs += 2;
+ }
+
+ m_bit_buf <<= -m_bits_left;
+
+ m_bits_left += 16;
+
+ assert(m_bits_left >= 0);
+ }
+ else
+ m_bit_buf <<= num_bits;
+
+ return i;
+ }
+
+ // Decodes a Huffman encoded symbol.
+ inline int jpeg_decoder::huff_decode(huff_tables* pH)
+ {
+ if (!pH)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ int symbol;
+ // Check first 8-bits: do we have a complete symbol?
+ if ((symbol = pH->look_up[m_bit_buf >> 24]) < 0)
+ {
+ // Decode more bits, use a tree traversal to find symbol.
+ int ofs = 23;
+ do
+ {
+ unsigned int idx = -(int)(symbol + ((m_bit_buf >> ofs) & 1));
+
+ // This should never happen, but to be safe I'm turning these asserts into a run-time check.
+ if ((idx >= JPGD_HUFF_TREE_MAX_LENGTH) || (ofs < 0))
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ symbol = pH->tree[idx];
+ ofs--;
+ } while (symbol < 0);
+
+ get_bits_no_markers(8 + (23 - ofs));
+ }
+ else
+ {
+ assert(symbol < JPGD_HUFF_CODE_SIZE_MAX_LENGTH);
+ get_bits_no_markers(pH->code_size[symbol]);
+ }
+
+ return symbol;
+ }
+
+ // Decodes a Huffman encoded symbol.
+ inline int jpeg_decoder::huff_decode(huff_tables* pH, int& extra_bits)
+ {
+ int symbol;
+
+ if (!pH)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ // Check first 8-bits: do we have a complete symbol?
+ if ((symbol = pH->look_up2[m_bit_buf >> 24]) < 0)
+ {
+ // Use a tree traversal to find symbol.
+ int ofs = 23;
+ do
+ {
+ unsigned int idx = -(int)(symbol + ((m_bit_buf >> ofs) & 1));
+
+ // This should never happen, but to be safe I'm turning these asserts into a run-time check.
+ if ((idx >= JPGD_HUFF_TREE_MAX_LENGTH) || (ofs < 0))
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ symbol = pH->tree[idx];
+ ofs--;
+ } while (symbol < 0);
+
+ get_bits_no_markers(8 + (23 - ofs));
+
+ extra_bits = get_bits_no_markers(symbol & 0xF);
+ }
+ else
+ {
+ if (symbol & 0x8000)
+ {
+ //get_bits_no_markers((symbol >> 8) & 31);
+ assert(((symbol >> 8) & 31) <= 15);
+ get_bits_no_markers((symbol >> 8) & 15);
+ extra_bits = symbol >> 16;
+ }
+ else
+ {
+ int code_size = (symbol >> 8) & 31;
+ int num_extra_bits = symbol & 0xF;
+ int bits = code_size + num_extra_bits;
+
+ if (bits <= 16)
+ extra_bits = get_bits_no_markers(bits) & ((1 << num_extra_bits) - 1);
+ else
+ {
+ get_bits_no_markers(code_size);
+ extra_bits = get_bits_no_markers(num_extra_bits);
+ }
+ }
+
+ symbol &= 0xFF;
+ }
+
+ return symbol;
+ }
+
+ // Tables and macro used to fully decode the DPCM differences.
+ static const int s_extend_test[16] = { 0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080, 0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000 };
+ static const int s_extend_offset[16] = { 0, -1, -3, -7, -15, -31, -63, -127, -255, -511, -1023, -2047, -4095, -8191, -16383, -32767 };
+ static const int s_extend_mask[] = { 0, (1 << 0), (1 << 1), (1 << 2), (1 << 3), (1 << 4), (1 << 5), (1 << 6), (1 << 7), (1 << 8), (1 << 9), (1 << 10), (1 << 11), (1 << 12), (1 << 13), (1 << 14), (1 << 15), (1 << 16) };
+
+#define JPGD_HUFF_EXTEND(x, s) (((x) < s_extend_test[s & 15]) ? ((x) + s_extend_offset[s & 15]) : (x))
+
+ // Unconditionally frees all allocated m_blocks.
+ void jpeg_decoder::free_all_blocks()
+ {
+ m_pStream = nullptr;
+ for (mem_block* b = m_pMem_blocks; b; )
+ {
+ mem_block* n = b->m_pNext;
+ jpgd_free(b);
+ b = n;
+ }
+ m_pMem_blocks = nullptr;
+ }
+
+ // This method handles all errors. It will never return.
+ // It could easily be changed to use C++ exceptions.
+ JPGD_NORETURN void jpeg_decoder::stop_decoding(jpgd_status status)
+ {
+ m_error_code = status;
+ free_all_blocks();
+ longjmp(m_jmp_state, status);
+ }
+
+ void* jpeg_decoder::alloc(size_t nSize, bool zero)
+ {
+ nSize = (JPGD_MAX(nSize, 1) + 3) & ~3;
+ char* rv = nullptr;
+ for (mem_block* b = m_pMem_blocks; b; b = b->m_pNext)
+ {
+ if ((b->m_used_count + nSize) <= b->m_size)
+ {
+ rv = b->m_data + b->m_used_count;
+ b->m_used_count += nSize;
+ break;
+ }
+ }
+ if (!rv)
+ {
+ int capacity = JPGD_MAX(32768 - 256, (nSize + 2047) & ~2047);
+ mem_block* b = (mem_block*)jpgd_malloc(sizeof(mem_block) + capacity);
+ if (!b)
+ {
+ stop_decoding(JPGD_NOTENOUGHMEM);
+ }
+
+ b->m_pNext = m_pMem_blocks;
+ m_pMem_blocks = b;
+ b->m_used_count = nSize;
+ b->m_size = capacity;
+ rv = b->m_data;
+ }
+ if (zero) memset(rv, 0, nSize);
+ return rv;
+ }
+
+ void jpeg_decoder::word_clear(void* p, uint16 c, uint n)
+ {
+ uint8* pD = (uint8*)p;
+ const uint8 l = c & 0xFF, h = (c >> 8) & 0xFF;
+ while (n)
+ {
+ pD[0] = l;
+ pD[1] = h;
+ pD += 2;
+ n--;
+ }
+ }
+
+ // Refill the input buffer.
+ // This method will sit in a loop until (A) the buffer is full or (B)
+ // the stream's read() method reports and end of file condition.
+ void jpeg_decoder::prep_in_buffer()
+ {
+ m_in_buf_left = 0;
+ m_pIn_buf_ofs = m_in_buf;
+
+ if (m_eof_flag)
+ return;
+
+ do
+ {
+ int bytes_read = m_pStream->read(m_in_buf + m_in_buf_left, JPGD_IN_BUF_SIZE - m_in_buf_left, &m_eof_flag);
+ if (bytes_read == -1)
+ stop_decoding(JPGD_STREAM_READ);
+
+ m_in_buf_left += bytes_read;
+ } while ((m_in_buf_left < JPGD_IN_BUF_SIZE) && (!m_eof_flag));
+
+ m_total_bytes_read += m_in_buf_left;
+
+ // Pad the end of the block with M_EOI (prevents the decompressor from going off the rails if the stream is invalid).
+ // (This dates way back to when this decompressor was written in C/asm, and the all-asm Huffman decoder did some fancy things to increase perf.)
+ word_clear(m_pIn_buf_ofs + m_in_buf_left, 0xD9FF, 64);
+ }
+
+ // Read a Huffman code table.
+ void jpeg_decoder::read_dht_marker()
+ {
+ int i, index, count;
+ uint8 huff_num[17];
+ uint8 huff_val[256];
+
+ uint num_left = get_bits(16);
+
+ if (num_left < 2)
+ stop_decoding(JPGD_BAD_DHT_MARKER);
+
+ num_left -= 2;
+
+ while (num_left)
+ {
+ index = get_bits(8);
+
+ huff_num[0] = 0;
+
+ count = 0;
+
+ for (i = 1; i <= 16; i++)
+ {
+ huff_num[i] = static_cast<uint8>(get_bits(8));
+ count += huff_num[i];
+ }
+
+ if (count > 255)
+ stop_decoding(JPGD_BAD_DHT_COUNTS);
+
+ bool symbol_present[256];
+ memset(symbol_present, 0, sizeof(symbol_present));
+
+ for (i = 0; i < count; i++)
+ {
+ const int s = get_bits(8);
+
+ // Check for obviously bogus tables.
+ if (symbol_present[s])
+ stop_decoding(JPGD_BAD_DHT_COUNTS);
+
+ huff_val[i] = static_cast<uint8_t>(s);
+ symbol_present[s] = true;
+ }
+
+ i = 1 + 16 + count;
+
+ if (num_left < (uint)i)
+ stop_decoding(JPGD_BAD_DHT_MARKER);
+
+ num_left -= i;
+
+ if ((index & 0x10) > 0x10)
+ stop_decoding(JPGD_BAD_DHT_INDEX);
+
+ index = (index & 0x0F) + ((index & 0x10) >> 4) * (JPGD_MAX_HUFF_TABLES >> 1);
+
+ if (index >= JPGD_MAX_HUFF_TABLES)
+ stop_decoding(JPGD_BAD_DHT_INDEX);
+
+ if (!m_huff_num[index])
+ m_huff_num[index] = (uint8*)alloc(17);
+
+ if (!m_huff_val[index])
+ m_huff_val[index] = (uint8*)alloc(256);
+
+ m_huff_ac[index] = (index & 0x10) != 0;
+ memcpy(m_huff_num[index], huff_num, 17);
+ memcpy(m_huff_val[index], huff_val, 256);
+ }
+ }
+
+ // Read a quantization table.
+ void jpeg_decoder::read_dqt_marker()
+ {
+ int n, i, prec;
+ uint num_left;
+ uint temp;
+
+ num_left = get_bits(16);
+
+ if (num_left < 2)
+ stop_decoding(JPGD_BAD_DQT_MARKER);
+
+ num_left -= 2;
+
+ while (num_left)
+ {
+ n = get_bits(8);
+ prec = n >> 4;
+ n &= 0x0F;
+
+ if (n >= JPGD_MAX_QUANT_TABLES)
+ stop_decoding(JPGD_BAD_DQT_TABLE);
+
+ if (!m_quant[n])
+ m_quant[n] = (jpgd_quant_t*)alloc(64 * sizeof(jpgd_quant_t));
+
+ // read quantization entries, in zag order
+ for (i = 0; i < 64; i++)
+ {
+ temp = get_bits(8);
+
+ if (prec)
+ temp = (temp << 8) + get_bits(8);
+
+ m_quant[n][i] = static_cast<jpgd_quant_t>(temp);
+ }
+
+ i = 64 + 1;
+
+ if (prec)
+ i += 64;
+
+ if (num_left < (uint)i)
+ stop_decoding(JPGD_BAD_DQT_LENGTH);
+
+ num_left -= i;
+ }
+ }
+
+ // Read the start of frame (SOF) marker.
+ void jpeg_decoder::read_sof_marker()
+ {
+ int i;
+ uint num_left;
+
+ num_left = get_bits(16);
+
+ /* precision: sorry, only 8-bit precision is supported */
+ if (get_bits(8) != 8)
+ stop_decoding(JPGD_BAD_PRECISION);
+
+ m_image_y_size = get_bits(16);
+
+ if ((m_image_y_size < 1) || (m_image_y_size > JPGD_MAX_HEIGHT))
+ stop_decoding(JPGD_BAD_HEIGHT);
+
+ m_image_x_size = get_bits(16);
+
+ if ((m_image_x_size < 1) || (m_image_x_size > JPGD_MAX_WIDTH))
+ stop_decoding(JPGD_BAD_WIDTH);
+
+ m_comps_in_frame = get_bits(8);
+
+ if (m_comps_in_frame > JPGD_MAX_COMPONENTS)
+ stop_decoding(JPGD_TOO_MANY_COMPONENTS);
+
+ if (num_left != (uint)(m_comps_in_frame * 3 + 8))
+ stop_decoding(JPGD_BAD_SOF_LENGTH);
+
+ for (i = 0; i < m_comps_in_frame; i++)
+ {
+ m_comp_ident[i] = get_bits(8);
+ m_comp_h_samp[i] = get_bits(4);
+ m_comp_v_samp[i] = get_bits(4);
+
+ if (!m_comp_h_samp[i] || !m_comp_v_samp[i] || (m_comp_h_samp[i] > 2) || (m_comp_v_samp[i] > 2))
+ stop_decoding(JPGD_UNSUPPORTED_SAMP_FACTORS);
+
+ m_comp_quant[i] = get_bits(8);
+ if (m_comp_quant[i] >= JPGD_MAX_QUANT_TABLES)
+ stop_decoding(JPGD_DECODE_ERROR);
+ }
+ }
+
+ // Used to skip unrecognized markers.
+ void jpeg_decoder::skip_variable_marker()
+ {
+ uint num_left;
+
+ num_left = get_bits(16);
+
+ if (num_left < 2)
+ stop_decoding(JPGD_BAD_VARIABLE_MARKER);
+
+ num_left -= 2;
+
+ while (num_left)
+ {
+ get_bits(8);
+ num_left--;
+ }
+ }
+
+ // Read a define restart interval (DRI) marker.
+ void jpeg_decoder::read_dri_marker()
+ {
+ if (get_bits(16) != 4)
+ stop_decoding(JPGD_BAD_DRI_LENGTH);
+
+ m_restart_interval = get_bits(16);
+ }
+
+ // Read a start of scan (SOS) marker.
+ void jpeg_decoder::read_sos_marker()
+ {
+ uint num_left;
+ int i, ci, n, c, cc;
+
+ num_left = get_bits(16);
+
+ n = get_bits(8);
+
+ m_comps_in_scan = n;
+
+ num_left -= 3;
+
+ if ((num_left != (uint)(n * 2 + 3)) || (n < 1) || (n > JPGD_MAX_COMPS_IN_SCAN))
+ stop_decoding(JPGD_BAD_SOS_LENGTH);
+
+ for (i = 0; i < n; i++)
+ {
+ cc = get_bits(8);
+ c = get_bits(8);
+ num_left -= 2;
+
+ for (ci = 0; ci < m_comps_in_frame; ci++)
+ if (cc == m_comp_ident[ci])
+ break;
+
+ if (ci >= m_comps_in_frame)
+ stop_decoding(JPGD_BAD_SOS_COMP_ID);
+
+ if (ci >= JPGD_MAX_COMPONENTS)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ m_comp_list[i] = ci;
+
+ m_comp_dc_tab[ci] = (c >> 4) & 15;
+ m_comp_ac_tab[ci] = (c & 15) + (JPGD_MAX_HUFF_TABLES >> 1);
+
+ if (m_comp_dc_tab[ci] >= JPGD_MAX_HUFF_TABLES)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ if (m_comp_ac_tab[ci] >= JPGD_MAX_HUFF_TABLES)
+ stop_decoding(JPGD_DECODE_ERROR);
+ }
+
+ m_spectral_start = get_bits(8);
+ m_spectral_end = get_bits(8);
+ m_successive_high = get_bits(4);
+ m_successive_low = get_bits(4);
+
+ if (!m_progressive_flag)
+ {
+ m_spectral_start = 0;
+ m_spectral_end = 63;
+ }
+
+ num_left -= 3;
+
+ /* read past whatever is num_left */
+ while (num_left)
+ {
+ get_bits(8);
+ num_left--;
+ }
+ }
+
+ // Finds the next marker.
+ int jpeg_decoder::next_marker()
+ {
+ uint c, bytes;
+
+ bytes = 0;
+
+ do
+ {
+ do
+ {
+ bytes++;
+ c = get_bits(8);
+ } while (c != 0xFF);
+
+ do
+ {
+ c = get_bits(8);
+ } while (c == 0xFF);
+
+ } while (c == 0);
+
+ // If bytes > 0 here, there where extra bytes before the marker (not good).
+
+ return c;
+ }
+
+ // Process markers. Returns when an SOFx, SOI, EOI, or SOS marker is
+ // encountered.
+ int jpeg_decoder::process_markers()
+ {
+ int c;
+
+ for (; ; )
+ {
+ c = next_marker();
+
+ switch (c)
+ {
+ case M_SOF0:
+ case M_SOF1:
+ case M_SOF2:
+ case M_SOF3:
+ case M_SOF5:
+ case M_SOF6:
+ case M_SOF7:
+ // case M_JPG:
+ case M_SOF9:
+ case M_SOF10:
+ case M_SOF11:
+ case M_SOF13:
+ case M_SOF14:
+ case M_SOF15:
+ case M_SOI:
+ case M_EOI:
+ case M_SOS:
+ {
+ return c;
+ }
+ case M_DHT:
+ {
+ read_dht_marker();
+ break;
+ }
+ // No arithmitic support - dumb patents!
+ case M_DAC:
+ {
+ stop_decoding(JPGD_NO_ARITHMITIC_SUPPORT);
+ break;
+ }
+ case M_DQT:
+ {
+ read_dqt_marker();
+ break;
+ }
+ case M_DRI:
+ {
+ read_dri_marker();
+ break;
+ }
+ //case M_APP0: /* no need to read the JFIF marker */
+ case M_JPG:
+ case M_RST0: /* no parameters */
+ case M_RST1:
+ case M_RST2:
+ case M_RST3:
+ case M_RST4:
+ case M_RST5:
+ case M_RST6:
+ case M_RST7:
+ case M_TEM:
+ {
+ stop_decoding(JPGD_UNEXPECTED_MARKER);
+ break;
+ }
+ default: /* must be DNL, DHP, EXP, APPn, JPGn, COM, or RESn or APP0 */
+ {
+ skip_variable_marker();
+ break;
+ }
+ }
+ }
+ }
+
+ // Finds the start of image (SOI) marker.
+ void jpeg_decoder::locate_soi_marker()
+ {
+ uint lastchar, thischar;
+ uint bytesleft;
+
+ lastchar = get_bits(8);
+
+ thischar = get_bits(8);
+
+ /* ok if it's a normal JPEG file without a special header */
+
+ if ((lastchar == 0xFF) && (thischar == M_SOI))
+ return;
+
+ bytesleft = 4096;
+
+ for (; ; )
+ {
+ if (--bytesleft == 0)
+ stop_decoding(JPGD_NOT_JPEG);
+
+ lastchar = thischar;
+
+ thischar = get_bits(8);
+
+ if (lastchar == 0xFF)
+ {
+ if (thischar == M_SOI)
+ break;
+ else if (thischar == M_EOI) // get_bits will keep returning M_EOI if we read past the end
+ stop_decoding(JPGD_NOT_JPEG);
+ }
+ }
+
+ // Check the next character after marker: if it's not 0xFF, it can't be the start of the next marker, so the file is bad.
+ thischar = (m_bit_buf >> 24) & 0xFF;
+
+ if (thischar != 0xFF)
+ stop_decoding(JPGD_NOT_JPEG);
+ }
+
+ // Find a start of frame (SOF) marker.
+ void jpeg_decoder::locate_sof_marker()
+ {
+ locate_soi_marker();
+
+ int c = process_markers();
+
+ switch (c)
+ {
+ case M_SOF2:
+ {
+ m_progressive_flag = JPGD_TRUE;
+ read_sof_marker();
+ break;
+ }
+ case M_SOF0: /* baseline DCT */
+ case M_SOF1: /* extended sequential DCT */
+ {
+ read_sof_marker();
+ break;
+ }
+ case M_SOF9: /* Arithmitic coding */
+ {
+ stop_decoding(JPGD_NO_ARITHMITIC_SUPPORT);
+ break;
+ }
+ default:
+ {
+ stop_decoding(JPGD_UNSUPPORTED_MARKER);
+ break;
+ }
+ }
+ }
+
+ // Find a start of scan (SOS) marker.
+ int jpeg_decoder::locate_sos_marker()
+ {
+ int c;
+
+ c = process_markers();
+
+ if (c == M_EOI)
+ return JPGD_FALSE;
+ else if (c != M_SOS)
+ stop_decoding(JPGD_UNEXPECTED_MARKER);
+
+ read_sos_marker();
+
+ return JPGD_TRUE;
+ }
+
+ // Reset everything to default/uninitialized state.
+ void jpeg_decoder::init(jpeg_decoder_stream* pStream, uint32_t flags)
+ {
+ m_flags = flags;
+ m_pMem_blocks = nullptr;
+ m_error_code = JPGD_SUCCESS;
+ m_ready_flag = false;
+ m_image_x_size = m_image_y_size = 0;
+ m_pStream = pStream;
+ m_progressive_flag = JPGD_FALSE;
+
+ memset(m_huff_ac, 0, sizeof(m_huff_ac));
+ memset(m_huff_num, 0, sizeof(m_huff_num));
+ memset(m_huff_val, 0, sizeof(m_huff_val));
+ memset(m_quant, 0, sizeof(m_quant));
+
+ m_scan_type = 0;
+ m_comps_in_frame = 0;
+
+ memset(m_comp_h_samp, 0, sizeof(m_comp_h_samp));
+ memset(m_comp_v_samp, 0, sizeof(m_comp_v_samp));
+ memset(m_comp_quant, 0, sizeof(m_comp_quant));
+ memset(m_comp_ident, 0, sizeof(m_comp_ident));
+ memset(m_comp_h_blocks, 0, sizeof(m_comp_h_blocks));
+ memset(m_comp_v_blocks, 0, sizeof(m_comp_v_blocks));
+
+ m_comps_in_scan = 0;
+ memset(m_comp_list, 0, sizeof(m_comp_list));
+ memset(m_comp_dc_tab, 0, sizeof(m_comp_dc_tab));
+ memset(m_comp_ac_tab, 0, sizeof(m_comp_ac_tab));
+
+ m_spectral_start = 0;
+ m_spectral_end = 0;
+ m_successive_low = 0;
+ m_successive_high = 0;
+ m_max_mcu_x_size = 0;
+ m_max_mcu_y_size = 0;
+ m_blocks_per_mcu = 0;
+ m_max_blocks_per_row = 0;
+ m_mcus_per_row = 0;
+ m_mcus_per_col = 0;
+
+ memset(m_mcu_org, 0, sizeof(m_mcu_org));
+
+ m_total_lines_left = 0;
+ m_mcu_lines_left = 0;
+ m_num_buffered_scanlines = 0;
+ m_real_dest_bytes_per_scan_line = 0;
+ m_dest_bytes_per_scan_line = 0;
+ m_dest_bytes_per_pixel = 0;
+
+ memset(m_pHuff_tabs, 0, sizeof(m_pHuff_tabs));
+
+ memset(m_dc_coeffs, 0, sizeof(m_dc_coeffs));
+ memset(m_ac_coeffs, 0, sizeof(m_ac_coeffs));
+ memset(m_block_y_mcu, 0, sizeof(m_block_y_mcu));
+
+ m_eob_run = 0;
+
+ m_pIn_buf_ofs = m_in_buf;
+ m_in_buf_left = 0;
+ m_eof_flag = false;
+ m_tem_flag = 0;
+
+ memset(m_in_buf_pad_start, 0, sizeof(m_in_buf_pad_start));
+ memset(m_in_buf, 0, sizeof(m_in_buf));
+ memset(m_in_buf_pad_end, 0, sizeof(m_in_buf_pad_end));
+
+ m_restart_interval = 0;
+ m_restarts_left = 0;
+ m_next_restart_num = 0;
+
+ m_max_mcus_per_row = 0;
+ m_max_blocks_per_mcu = 0;
+ m_max_mcus_per_col = 0;
+
+ memset(m_last_dc_val, 0, sizeof(m_last_dc_val));
+ m_pMCU_coefficients = nullptr;
+ m_pSample_buf = nullptr;
+ m_pSample_buf_prev = nullptr;
+ m_sample_buf_prev_valid = false;
+
+ m_total_bytes_read = 0;
+
+ m_pScan_line_0 = nullptr;
+ m_pScan_line_1 = nullptr;
+
+ // Ready the input buffer.
+ prep_in_buffer();
+
+ // Prime the bit buffer.
+ m_bits_left = 16;
+ m_bit_buf = 0;
+
+ get_bits(16);
+ get_bits(16);
+
+ for (int i = 0; i < JPGD_MAX_BLOCKS_PER_MCU; i++)
+ m_mcu_block_max_zag[i] = 64;
+ }
+
+#define SCALEBITS 16
+#define ONE_HALF ((int) 1 << (SCALEBITS-1))
+#define FIX(x) ((int) ((x) * (1L<<SCALEBITS) + 0.5f))
+
+ // Create a few tables that allow us to quickly convert YCbCr to RGB.
+ void jpeg_decoder::create_look_ups()
+ {
+ for (int i = 0; i <= 255; i++)
+ {
+ int k = i - 128;
+ m_crr[i] = (FIX(1.40200f) * k + ONE_HALF) >> SCALEBITS;
+ m_cbb[i] = (FIX(1.77200f) * k + ONE_HALF) >> SCALEBITS;
+ m_crg[i] = (-FIX(0.71414f)) * k;
+ m_cbg[i] = (-FIX(0.34414f)) * k + ONE_HALF;
+ }
+ }
+
+ // This method throws back into the stream any bytes that where read
+ // into the bit buffer during initial marker scanning.
+ void jpeg_decoder::fix_in_buffer()
+ {
+ // In case any 0xFF's where pulled into the buffer during marker scanning.
+ assert((m_bits_left & 7) == 0);
+
+ if (m_bits_left == 16)
+ stuff_char((uint8)(m_bit_buf & 0xFF));
+
+ if (m_bits_left >= 8)
+ stuff_char((uint8)((m_bit_buf >> 8) & 0xFF));
+
+ stuff_char((uint8)((m_bit_buf >> 16) & 0xFF));
+ stuff_char((uint8)((m_bit_buf >> 24) & 0xFF));
+
+ m_bits_left = 16;
+ get_bits_no_markers(16);
+ get_bits_no_markers(16);
+ }
+
+ void jpeg_decoder::transform_mcu(int mcu_row)
+ {
+ jpgd_block_t* pSrc_ptr = m_pMCU_coefficients;
+ if (mcu_row * m_blocks_per_mcu >= m_max_blocks_per_row)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ uint8* pDst_ptr = m_pSample_buf + mcu_row * m_blocks_per_mcu * 64;
+
+ for (int mcu_block = 0; mcu_block < m_blocks_per_mcu; mcu_block++)
+ {
+ idct(pSrc_ptr, pDst_ptr, m_mcu_block_max_zag[mcu_block]);
+ pSrc_ptr += 64;
+ pDst_ptr += 64;
+ }
+ }
+
+ // Loads and dequantizes the next row of (already decoded) coefficients.
+ // Progressive images only.
+ void jpeg_decoder::load_next_row()
+ {
+ int i;
+ jpgd_block_t* p;
+ jpgd_quant_t* q;
+ int mcu_row, mcu_block, row_block = 0;
+ int component_num, component_id;
+ int block_x_mcu[JPGD_MAX_COMPONENTS];
+
+ memset(block_x_mcu, 0, JPGD_MAX_COMPONENTS * sizeof(int));
+
+ for (mcu_row = 0; mcu_row < m_mcus_per_row; mcu_row++)
+ {
+ int block_x_mcu_ofs = 0, block_y_mcu_ofs = 0;
+
+ for (mcu_block = 0; mcu_block < m_blocks_per_mcu; mcu_block++)
+ {
+ component_id = m_mcu_org[mcu_block];
+ if (m_comp_quant[component_id] >= JPGD_MAX_QUANT_TABLES)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ q = m_quant[m_comp_quant[component_id]];
+
+ p = m_pMCU_coefficients + 64 * mcu_block;
+
+ jpgd_block_t* pAC = coeff_buf_getp(m_ac_coeffs[component_id], block_x_mcu[component_id] + block_x_mcu_ofs, m_block_y_mcu[component_id] + block_y_mcu_ofs);
+ jpgd_block_t* pDC = coeff_buf_getp(m_dc_coeffs[component_id], block_x_mcu[component_id] + block_x_mcu_ofs, m_block_y_mcu[component_id] + block_y_mcu_ofs);
+ p[0] = pDC[0];
+ memcpy(&p[1], &pAC[1], 63 * sizeof(jpgd_block_t));
+
+ for (i = 63; i > 0; i--)
+ if (p[g_ZAG[i]])
+ break;
+
+ m_mcu_block_max_zag[mcu_block] = i + 1;
+
+ for (; i >= 0; i--)
+ if (p[g_ZAG[i]])
+ p[g_ZAG[i]] = static_cast<jpgd_block_t>(p[g_ZAG[i]] * q[i]);
+
+ row_block++;
+
+ if (m_comps_in_scan == 1)
+ block_x_mcu[component_id]++;
+ else
+ {
+ if (++block_x_mcu_ofs == m_comp_h_samp[component_id])
+ {
+ block_x_mcu_ofs = 0;
+
+ if (++block_y_mcu_ofs == m_comp_v_samp[component_id])
+ {
+ block_y_mcu_ofs = 0;
+
+ block_x_mcu[component_id] += m_comp_h_samp[component_id];
+ }
+ }
+ }
+ }
+
+ transform_mcu(mcu_row);
+ }
+
+ if (m_comps_in_scan == 1)
+ m_block_y_mcu[m_comp_list[0]]++;
+ else
+ {
+ for (component_num = 0; component_num < m_comps_in_scan; component_num++)
+ {
+ component_id = m_comp_list[component_num];
+
+ m_block_y_mcu[component_id] += m_comp_v_samp[component_id];
+ }
+ }
+ }
+
+ // Restart interval processing.
+ void jpeg_decoder::process_restart()
+ {
+ int i;
+ int c = 0;
+
+ // Align to a byte boundry
+ // FIXME: Is this really necessary? get_bits_no_markers() never reads in markers!
+ //get_bits_no_markers(m_bits_left & 7);
+
+ // Let's scan a little bit to find the marker, but not _too_ far.
+ // 1536 is a "fudge factor" that determines how much to scan.
+ for (i = 1536; i > 0; i--)
+ if (get_char() == 0xFF)
+ break;
+
+ if (i == 0)
+ stop_decoding(JPGD_BAD_RESTART_MARKER);
+
+ for (; i > 0; i--)
+ if ((c = get_char()) != 0xFF)
+ break;
+
+ if (i == 0)
+ stop_decoding(JPGD_BAD_RESTART_MARKER);
+
+ // Is it the expected marker? If not, something bad happened.
+ if (c != (m_next_restart_num + M_RST0))
+ stop_decoding(JPGD_BAD_RESTART_MARKER);
+
+ // Reset each component's DC prediction values.
+ memset(&m_last_dc_val, 0, m_comps_in_frame * sizeof(uint));
+
+ m_eob_run = 0;
+
+ m_restarts_left = m_restart_interval;
+
+ m_next_restart_num = (m_next_restart_num + 1) & 7;
+
+ // Get the bit buffer going again...
+
+ m_bits_left = 16;
+ get_bits_no_markers(16);
+ get_bits_no_markers(16);
+ }
+
+ static inline int dequantize_ac(int c, int q) { c *= q; return c; }
+
+ // Decodes and dequantizes the next row of coefficients.
+ void jpeg_decoder::decode_next_row()
+ {
+ int row_block = 0;
+
+ for (int mcu_row = 0; mcu_row < m_mcus_per_row; mcu_row++)
+ {
+ if ((m_restart_interval) && (m_restarts_left == 0))
+ process_restart();
+
+ jpgd_block_t* p = m_pMCU_coefficients;
+ for (int mcu_block = 0; mcu_block < m_blocks_per_mcu; mcu_block++, p += 64)
+ {
+ int component_id = m_mcu_org[mcu_block];
+ if (m_comp_quant[component_id] >= JPGD_MAX_QUANT_TABLES)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ jpgd_quant_t* q = m_quant[m_comp_quant[component_id]];
+
+ int r, s;
+ s = huff_decode(m_pHuff_tabs[m_comp_dc_tab[component_id]], r);
+ if (s >= 16)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ s = JPGD_HUFF_EXTEND(r, s);
+
+ m_last_dc_val[component_id] = (s += m_last_dc_val[component_id]);
+
+ p[0] = static_cast<jpgd_block_t>(s * q[0]);
+
+ int prev_num_set = m_mcu_block_max_zag[mcu_block];
+
+ huff_tables* pH = m_pHuff_tabs[m_comp_ac_tab[component_id]];
+
+ int k;
+ for (k = 1; k < 64; k++)
+ {
+ int extra_bits;
+ s = huff_decode(pH, extra_bits);
+
+ r = s >> 4;
+ s &= 15;
+
+ if (s)
+ {
+ if (r)
+ {
+ if ((k + r) > 63)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ if (k < prev_num_set)
+ {
+ int n = JPGD_MIN(r, prev_num_set - k);
+ int kt = k;
+ while (n--)
+ p[g_ZAG[kt++]] = 0;
+ }
+
+ k += r;
+ }
+
+ s = JPGD_HUFF_EXTEND(extra_bits, s);
+
+ if (k >= 64)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ p[g_ZAG[k]] = static_cast<jpgd_block_t>(dequantize_ac(s, q[k])); //s * q[k];
+ }
+ else
+ {
+ if (r == 15)
+ {
+ if ((k + 16) > 64)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ if (k < prev_num_set)
+ {
+ int n = JPGD_MIN(16, prev_num_set - k);
+ int kt = k;
+ while (n--)
+ {
+ if (kt > 63)
+ stop_decoding(JPGD_DECODE_ERROR);
+ p[g_ZAG[kt++]] = 0;
+ }
+ }
+
+ k += 16 - 1; // - 1 because the loop counter is k
+
+ if (p[g_ZAG[k & 63]] != 0)
+ stop_decoding(JPGD_DECODE_ERROR);
+ }
+ else
+ break;
+ }
+ }
+
+ if (k < prev_num_set)
+ {
+ int kt = k;
+ while (kt < prev_num_set)
+ p[g_ZAG[kt++]] = 0;
+ }
+
+ m_mcu_block_max_zag[mcu_block] = k;
+
+ row_block++;
+ }
+
+ transform_mcu(mcu_row);
+
+ m_restarts_left--;
+ }
+ }
+
+ // YCbCr H1V1 (1x1:1:1, 3 m_blocks per MCU) to RGB
+ void jpeg_decoder::H1V1Convert()
+ {
+ int row = m_max_mcu_y_size - m_mcu_lines_left;
+ uint8* d = m_pScan_line_0;
+ uint8* s = m_pSample_buf + row * 8;
+
+ for (int i = m_max_mcus_per_row; i > 0; i--)
+ {
+ for (int j = 0; j < 8; j++)
+ {
+ int y = s[j];
+ int cb = s[64 + j];
+ int cr = s[128 + j];
+
+ d[0] = clamp(y + m_crr[cr]);
+ d[1] = clamp(y + ((m_crg[cr] + m_cbg[cb]) >> 16));
+ d[2] = clamp(y + m_cbb[cb]);
+ d[3] = 255;
+
+ d += 4;
+ }
+
+ s += 64 * 3;
+ }
+ }
+
+ // YCbCr H2V1 (2x1:1:1, 4 m_blocks per MCU) to RGB
+ void jpeg_decoder::H2V1Convert()
+ {
+ int row = m_max_mcu_y_size - m_mcu_lines_left;
+ uint8* d0 = m_pScan_line_0;
+ uint8* y = m_pSample_buf + row * 8;
+ uint8* c = m_pSample_buf + 2 * 64 + row * 8;
+
+ for (int i = m_max_mcus_per_row; i > 0; i--)
+ {
+ for (int l = 0; l < 2; l++)
+ {
+ for (int j = 0; j < 4; j++)
+ {
+ int cb = c[0];
+ int cr = c[64];
+
+ int rc = m_crr[cr];
+ int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
+ int bc = m_cbb[cb];
+
+ int yy = y[j << 1];
+ d0[0] = clamp(yy + rc);
+ d0[1] = clamp(yy + gc);
+ d0[2] = clamp(yy + bc);
+ d0[3] = 255;
+
+ yy = y[(j << 1) + 1];
+ d0[4] = clamp(yy + rc);
+ d0[5] = clamp(yy + gc);
+ d0[6] = clamp(yy + bc);
+ d0[7] = 255;
+
+ d0 += 8;
+
+ c++;
+ }
+ y += 64;
+ }
+
+ y += 64 * 4 - 64 * 2;
+ c += 64 * 4 - 8;
+ }
+ }
+
+ // YCbCr H2V1 (2x1:1:1, 4 m_blocks per MCU) to RGB
+ void jpeg_decoder::H2V1ConvertFiltered()
+ {
+ const uint BLOCKS_PER_MCU = 4;
+ int row = m_max_mcu_y_size - m_mcu_lines_left;
+ uint8* d0 = m_pScan_line_0;
+
+ const int half_image_x_size = (m_image_x_size >> 1) - 1;
+ const int row_x8 = row * 8;
+
+ for (int x = 0; x < m_image_x_size; x++)
+ {
+ int y = m_pSample_buf[check_sample_buf_ofs((x >> 4) * BLOCKS_PER_MCU * 64 + ((x & 8) ? 64 : 0) + (x & 7) + row_x8)];
+
+ int c_x0 = (x - 1) >> 1;
+ int c_x1 = JPGD_MIN(c_x0 + 1, half_image_x_size);
+ c_x0 = JPGD_MAX(c_x0, 0);
+
+ int a = (c_x0 >> 3) * BLOCKS_PER_MCU * 64 + (c_x0 & 7) + row_x8 + 128;
+ int cb0 = m_pSample_buf[check_sample_buf_ofs(a)];
+ int cr0 = m_pSample_buf[check_sample_buf_ofs(a + 64)];
+
+ int b = (c_x1 >> 3) * BLOCKS_PER_MCU * 64 + (c_x1 & 7) + row_x8 + 128;
+ int cb1 = m_pSample_buf[check_sample_buf_ofs(b)];
+ int cr1 = m_pSample_buf[check_sample_buf_ofs(b + 64)];
+
+ int w0 = (x & 1) ? 3 : 1;
+ int w1 = (x & 1) ? 1 : 3;
+
+ int cb = (cb0 * w0 + cb1 * w1 + 2) >> 2;
+ int cr = (cr0 * w0 + cr1 * w1 + 2) >> 2;
+
+ int rc = m_crr[cr];
+ int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
+ int bc = m_cbb[cb];
+
+ d0[0] = clamp(y + rc);
+ d0[1] = clamp(y + gc);
+ d0[2] = clamp(y + bc);
+ d0[3] = 255;
+
+ d0 += 4;
+ }
+ }
+
+ // YCbCr H2V1 (1x2:1:1, 4 m_blocks per MCU) to RGB
+ void jpeg_decoder::H1V2Convert()
+ {
+ int row = m_max_mcu_y_size - m_mcu_lines_left;
+ uint8* d0 = m_pScan_line_0;
+ uint8* d1 = m_pScan_line_1;
+ uint8* y;
+ uint8* c;
+
+ if (row < 8)
+ y = m_pSample_buf + row * 8;
+ else
+ y = m_pSample_buf + 64 * 1 + (row & 7) * 8;
+
+ c = m_pSample_buf + 64 * 2 + (row >> 1) * 8;
+
+ for (int i = m_max_mcus_per_row; i > 0; i--)
+ {
+ for (int j = 0; j < 8; j++)
+ {
+ int cb = c[0 + j];
+ int cr = c[64 + j];
+
+ int rc = m_crr[cr];
+ int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
+ int bc = m_cbb[cb];
+
+ int yy = y[j];
+ d0[0] = clamp(yy + rc);
+ d0[1] = clamp(yy + gc);
+ d0[2] = clamp(yy + bc);
+ d0[3] = 255;
+
+ yy = y[8 + j];
+ d1[0] = clamp(yy + rc);
+ d1[1] = clamp(yy + gc);
+ d1[2] = clamp(yy + bc);
+ d1[3] = 255;
+
+ d0 += 4;
+ d1 += 4;
+ }
+
+ y += 64 * 4;
+ c += 64 * 4;
+ }
+ }
+
+ // YCbCr H2V1 (1x2:1:1, 4 m_blocks per MCU) to RGB
+ void jpeg_decoder::H1V2ConvertFiltered()
+ {
+ const uint BLOCKS_PER_MCU = 4;
+ int y = m_image_y_size - m_total_lines_left;
+ int row = y & 15;
+
+ const int half_image_y_size = (m_image_y_size >> 1) - 1;
+
+ uint8* d0 = m_pScan_line_0;
+
+ const int w0 = (row & 1) ? 3 : 1;
+ const int w1 = (row & 1) ? 1 : 3;
+
+ int c_y0 = (y - 1) >> 1;
+ int c_y1 = JPGD_MIN(c_y0 + 1, half_image_y_size);
+
+ const uint8_t* p_YSamples = m_pSample_buf;
+ const uint8_t* p_C0Samples = m_pSample_buf;
+ if ((c_y0 >= 0) && (((row & 15) == 0) || ((row & 15) == 15)) && (m_total_lines_left > 1))
+ {
+ assert(y > 0);
+ assert(m_sample_buf_prev_valid);
+
+ if ((row & 15) == 15)
+ p_YSamples = m_pSample_buf_prev;
+
+ p_C0Samples = m_pSample_buf_prev;
+ }
+
+ const int y_sample_base_ofs = ((row & 8) ? 64 : 0) + (row & 7) * 8;
+ const int y0_base = (c_y0 & 7) * 8 + 128;
+ const int y1_base = (c_y1 & 7) * 8 + 128;
+
+ for (int x = 0; x < m_image_x_size; x++)
+ {
+ const int base_ofs = (x >> 3) * BLOCKS_PER_MCU * 64 + (x & 7);
+
+ int y_sample = p_YSamples[check_sample_buf_ofs(base_ofs + y_sample_base_ofs)];
+
+ int a = base_ofs + y0_base;
+ int cb0_sample = p_C0Samples[check_sample_buf_ofs(a)];
+ int cr0_sample = p_C0Samples[check_sample_buf_ofs(a + 64)];
+
+ int b = base_ofs + y1_base;
+ int cb1_sample = m_pSample_buf[check_sample_buf_ofs(b)];
+ int cr1_sample = m_pSample_buf[check_sample_buf_ofs(b + 64)];
+
+ int cb = (cb0_sample * w0 + cb1_sample * w1 + 2) >> 2;
+ int cr = (cr0_sample * w0 + cr1_sample * w1 + 2) >> 2;
+
+ int rc = m_crr[cr];
+ int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
+ int bc = m_cbb[cb];
+
+ d0[0] = clamp(y_sample + rc);
+ d0[1] = clamp(y_sample + gc);
+ d0[2] = clamp(y_sample + bc);
+ d0[3] = 255;
+
+ d0 += 4;
+ }
+ }
+
+ // YCbCr H2V2 (2x2:1:1, 6 m_blocks per MCU) to RGB
+ void jpeg_decoder::H2V2Convert()
+ {
+ int row = m_max_mcu_y_size - m_mcu_lines_left;
+ uint8* d0 = m_pScan_line_0;
+ uint8* d1 = m_pScan_line_1;
+ uint8* y;
+ uint8* c;
+
+ if (row < 8)
+ y = m_pSample_buf + row * 8;
+ else
+ y = m_pSample_buf + 64 * 2 + (row & 7) * 8;
+
+ c = m_pSample_buf + 64 * 4 + (row >> 1) * 8;
+
+ for (int i = m_max_mcus_per_row; i > 0; i--)
+ {
+ for (int l = 0; l < 2; l++)
+ {
+ for (int j = 0; j < 8; j += 2)
+ {
+ int cb = c[0];
+ int cr = c[64];
+
+ int rc = m_crr[cr];
+ int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
+ int bc = m_cbb[cb];
+
+ int yy = y[j];
+ d0[0] = clamp(yy + rc);
+ d0[1] = clamp(yy + gc);
+ d0[2] = clamp(yy + bc);
+ d0[3] = 255;
+
+ yy = y[j + 1];
+ d0[4] = clamp(yy + rc);
+ d0[5] = clamp(yy + gc);
+ d0[6] = clamp(yy + bc);
+ d0[7] = 255;
+
+ yy = y[j + 8];
+ d1[0] = clamp(yy + rc);
+ d1[1] = clamp(yy + gc);
+ d1[2] = clamp(yy + bc);
+ d1[3] = 255;
+
+ yy = y[j + 8 + 1];
+ d1[4] = clamp(yy + rc);
+ d1[5] = clamp(yy + gc);
+ d1[6] = clamp(yy + bc);
+ d1[7] = 255;
+
+ d0 += 8;
+ d1 += 8;
+
+ c++;
+ }
+ y += 64;
+ }
+
+ y += 64 * 6 - 64 * 2;
+ c += 64 * 6 - 8;
+ }
+ }
+
+ uint32_t jpeg_decoder::H2V2ConvertFiltered()
+ {
+ const uint BLOCKS_PER_MCU = 6;
+ int y = m_image_y_size - m_total_lines_left;
+ int row = y & 15;
+
+ const int half_image_y_size = (m_image_y_size >> 1) - 1;
+
+ uint8* d0 = m_pScan_line_0;
+
+ int c_y0 = (y - 1) >> 1;
+ int c_y1 = JPGD_MIN(c_y0 + 1, half_image_y_size);
+
+ const uint8_t* p_YSamples = m_pSample_buf;
+ const uint8_t* p_C0Samples = m_pSample_buf;
+ if ((c_y0 >= 0) && (((row & 15) == 0) || ((row & 15) == 15)) && (m_total_lines_left > 1))
+ {
+ assert(y > 0);
+ assert(m_sample_buf_prev_valid);
+
+ if ((row & 15) == 15)
+ p_YSamples = m_pSample_buf_prev;
+
+ p_C0Samples = m_pSample_buf_prev;
+ }
+
+ const int y_sample_base_ofs = ((row & 8) ? 128 : 0) + (row & 7) * 8;
+ const int y0_base = (c_y0 & 7) * 8 + 256;
+ const int y1_base = (c_y1 & 7) * 8 + 256;
+
+ const int half_image_x_size = (m_image_x_size >> 1) - 1;
+
+ static const uint8_t s_muls[2][2][4] =
+ {
+ { { 1, 3, 3, 9 }, { 3, 9, 1, 3 }, },
+ { { 3, 1, 9, 3 }, { 9, 3, 3, 1 } }
+ };
+
+ if (((row & 15) >= 1) && ((row & 15) <= 14))
+ {
+ assert((row & 1) == 1);
+ assert(((y + 1 - 1) >> 1) == c_y0);
+
+ assert(p_YSamples == m_pSample_buf);
+ assert(p_C0Samples == m_pSample_buf);
+
+ uint8* d1 = m_pScan_line_1;
+ const int y_sample_base_ofs1 = (((row + 1) & 8) ? 128 : 0) + ((row + 1) & 7) * 8;
+
+ for (int x = 0; x < m_image_x_size; x++)
+ {
+ int k = (x >> 4) * BLOCKS_PER_MCU * 64 + ((x & 8) ? 64 : 0) + (x & 7);
+ int y_sample0 = p_YSamples[check_sample_buf_ofs(k + y_sample_base_ofs)];
+ int y_sample1 = p_YSamples[check_sample_buf_ofs(k + y_sample_base_ofs1)];
+
+ int c_x0 = (x - 1) >> 1;
+ int c_x1 = JPGD_MIN(c_x0 + 1, half_image_x_size);
+ c_x0 = JPGD_MAX(c_x0, 0);
+
+ int a = (c_x0 >> 3) * BLOCKS_PER_MCU * 64 + (c_x0 & 7);
+ int cb00_sample = p_C0Samples[check_sample_buf_ofs(a + y0_base)];
+ int cr00_sample = p_C0Samples[check_sample_buf_ofs(a + y0_base + 64)];
+
+ int cb01_sample = m_pSample_buf[check_sample_buf_ofs(a + y1_base)];
+ int cr01_sample = m_pSample_buf[check_sample_buf_ofs(a + y1_base + 64)];
+
+ int b = (c_x1 >> 3) * BLOCKS_PER_MCU * 64 + (c_x1 & 7);
+ int cb10_sample = p_C0Samples[check_sample_buf_ofs(b + y0_base)];
+ int cr10_sample = p_C0Samples[check_sample_buf_ofs(b + y0_base + 64)];
+
+ int cb11_sample = m_pSample_buf[check_sample_buf_ofs(b + y1_base)];
+ int cr11_sample = m_pSample_buf[check_sample_buf_ofs(b + y1_base + 64)];
+
+ {
+ const uint8_t* pMuls = &s_muls[row & 1][x & 1][0];
+ int cb = (cb00_sample * pMuls[0] + cb01_sample * pMuls[1] + cb10_sample * pMuls[2] + cb11_sample * pMuls[3] + 8) >> 4;
+ int cr = (cr00_sample * pMuls[0] + cr01_sample * pMuls[1] + cr10_sample * pMuls[2] + cr11_sample * pMuls[3] + 8) >> 4;
+
+ int rc = m_crr[cr];
+ int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
+ int bc = m_cbb[cb];
+
+ d0[0] = clamp(y_sample0 + rc);
+ d0[1] = clamp(y_sample0 + gc);
+ d0[2] = clamp(y_sample0 + bc);
+ d0[3] = 255;
+
+ d0 += 4;
+ }
+
+ {
+ const uint8_t* pMuls = &s_muls[(row + 1) & 1][x & 1][0];
+ int cb = (cb00_sample * pMuls[0] + cb01_sample * pMuls[1] + cb10_sample * pMuls[2] + cb11_sample * pMuls[3] + 8) >> 4;
+ int cr = (cr00_sample * pMuls[0] + cr01_sample * pMuls[1] + cr10_sample * pMuls[2] + cr11_sample * pMuls[3] + 8) >> 4;
+
+ int rc = m_crr[cr];
+ int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
+ int bc = m_cbb[cb];
+
+ d1[0] = clamp(y_sample1 + rc);
+ d1[1] = clamp(y_sample1 + gc);
+ d1[2] = clamp(y_sample1 + bc);
+ d1[3] = 255;
+
+ d1 += 4;
+ }
+
+ if (((x & 1) == 1) && (x < m_image_x_size - 1))
+ {
+ const int nx = x + 1;
+ assert(c_x0 == (nx - 1) >> 1);
+
+ k = (nx >> 4) * BLOCKS_PER_MCU * 64 + ((nx & 8) ? 64 : 0) + (nx & 7);
+ y_sample0 = p_YSamples[check_sample_buf_ofs(k + y_sample_base_ofs)];
+ y_sample1 = p_YSamples[check_sample_buf_ofs(k + y_sample_base_ofs1)];
+
+ {
+ const uint8_t* pMuls = &s_muls[row & 1][nx & 1][0];
+ int cb = (cb00_sample * pMuls[0] + cb01_sample * pMuls[1] + cb10_sample * pMuls[2] + cb11_sample * pMuls[3] + 8) >> 4;
+ int cr = (cr00_sample * pMuls[0] + cr01_sample * pMuls[1] + cr10_sample * pMuls[2] + cr11_sample * pMuls[3] + 8) >> 4;
+
+ int rc = m_crr[cr];
+ int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
+ int bc = m_cbb[cb];
+
+ d0[0] = clamp(y_sample0 + rc);
+ d0[1] = clamp(y_sample0 + gc);
+ d0[2] = clamp(y_sample0 + bc);
+ d0[3] = 255;
+
+ d0 += 4;
+ }
+
+ {
+ const uint8_t* pMuls = &s_muls[(row + 1) & 1][nx & 1][0];
+ int cb = (cb00_sample * pMuls[0] + cb01_sample * pMuls[1] + cb10_sample * pMuls[2] + cb11_sample * pMuls[3] + 8) >> 4;
+ int cr = (cr00_sample * pMuls[0] + cr01_sample * pMuls[1] + cr10_sample * pMuls[2] + cr11_sample * pMuls[3] + 8) >> 4;
+
+ int rc = m_crr[cr];
+ int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
+ int bc = m_cbb[cb];
+
+ d1[0] = clamp(y_sample1 + rc);
+ d1[1] = clamp(y_sample1 + gc);
+ d1[2] = clamp(y_sample1 + bc);
+ d1[3] = 255;
+
+ d1 += 4;
+ }
+
+ ++x;
+ }
+ }
+
+ return 2;
+ }
+ else
+ {
+ for (int x = 0; x < m_image_x_size; x++)
+ {
+ int y_sample = p_YSamples[check_sample_buf_ofs((x >> 4) * BLOCKS_PER_MCU * 64 + ((x & 8) ? 64 : 0) + (x & 7) + y_sample_base_ofs)];
+
+ int c_x0 = (x - 1) >> 1;
+ int c_x1 = JPGD_MIN(c_x0 + 1, half_image_x_size);
+ c_x0 = JPGD_MAX(c_x0, 0);
+
+ int a = (c_x0 >> 3) * BLOCKS_PER_MCU * 64 + (c_x0 & 7);
+ int cb00_sample = p_C0Samples[check_sample_buf_ofs(a + y0_base)];
+ int cr00_sample = p_C0Samples[check_sample_buf_ofs(a + y0_base + 64)];
+
+ int cb01_sample = m_pSample_buf[check_sample_buf_ofs(a + y1_base)];
+ int cr01_sample = m_pSample_buf[check_sample_buf_ofs(a + y1_base + 64)];
+
+ int b = (c_x1 >> 3) * BLOCKS_PER_MCU * 64 + (c_x1 & 7);
+ int cb10_sample = p_C0Samples[check_sample_buf_ofs(b + y0_base)];
+ int cr10_sample = p_C0Samples[check_sample_buf_ofs(b + y0_base + 64)];
+
+ int cb11_sample = m_pSample_buf[check_sample_buf_ofs(b + y1_base)];
+ int cr11_sample = m_pSample_buf[check_sample_buf_ofs(b + y1_base + 64)];
+
+ const uint8_t* pMuls = &s_muls[row & 1][x & 1][0];
+ int cb = (cb00_sample * pMuls[0] + cb01_sample * pMuls[1] + cb10_sample * pMuls[2] + cb11_sample * pMuls[3] + 8) >> 4;
+ int cr = (cr00_sample * pMuls[0] + cr01_sample * pMuls[1] + cr10_sample * pMuls[2] + cr11_sample * pMuls[3] + 8) >> 4;
+
+ int rc = m_crr[cr];
+ int gc = ((m_crg[cr] + m_cbg[cb]) >> 16);
+ int bc = m_cbb[cb];
+
+ d0[0] = clamp(y_sample + rc);
+ d0[1] = clamp(y_sample + gc);
+ d0[2] = clamp(y_sample + bc);
+ d0[3] = 255;
+
+ d0 += 4;
+ }
+
+ return 1;
+ }
+ }
+
+ // Y (1 block per MCU) to 8-bit grayscale
+ void jpeg_decoder::gray_convert()
+ {
+ int row = m_max_mcu_y_size - m_mcu_lines_left;
+ uint8* d = m_pScan_line_0;
+ uint8* s = m_pSample_buf + row * 8;
+
+ for (int i = m_max_mcus_per_row; i > 0; i--)
+ {
+ *(uint*)d = *(uint*)s;
+ *(uint*)(&d[4]) = *(uint*)(&s[4]);
+
+ s += 64;
+ d += 8;
+ }
+ }
+
+ // Find end of image (EOI) marker, so we can return to the user the exact size of the input stream.
+ void jpeg_decoder::find_eoi()
+ {
+ if (!m_progressive_flag)
+ {
+ // Attempt to read the EOI marker.
+ //get_bits_no_markers(m_bits_left & 7);
+
+ // Prime the bit buffer
+ m_bits_left = 16;
+ get_bits(16);
+ get_bits(16);
+
+ // The next marker _should_ be EOI
+ process_markers();
+ }
+
+ m_total_bytes_read -= m_in_buf_left;
+ }
+
+ int jpeg_decoder::decode_next_mcu_row()
+ {
+ if (setjmp(m_jmp_state))
+ return JPGD_FAILED;
+
+ const bool chroma_y_filtering = (m_flags & cFlagLinearChromaFiltering) && ((m_scan_type == JPGD_YH2V2) || (m_scan_type == JPGD_YH1V2));
+ if (chroma_y_filtering)
+ {
+ std::swap(m_pSample_buf, m_pSample_buf_prev);
+
+ m_sample_buf_prev_valid = true;
+ }
+
+ if (m_progressive_flag)
+ load_next_row();
+ else
+ decode_next_row();
+
+ // Find the EOI marker if that was the last row.
+ if (m_total_lines_left <= m_max_mcu_y_size)
+ find_eoi();
+
+ m_mcu_lines_left = m_max_mcu_y_size;
+ return 0;
+ }
+
+ int jpeg_decoder::decode(const void** pScan_line, uint* pScan_line_len)
+ {
+ if ((m_error_code) || (!m_ready_flag))
+ return JPGD_FAILED;
+
+ if (m_total_lines_left == 0)
+ return JPGD_DONE;
+
+ const bool chroma_y_filtering = (m_flags & cFlagLinearChromaFiltering) && ((m_scan_type == JPGD_YH2V2) || (m_scan_type == JPGD_YH1V2));
+
+ bool get_another_mcu_row = false;
+ bool got_mcu_early = false;
+ if (chroma_y_filtering)
+ {
+ if (m_total_lines_left == m_image_y_size)
+ get_another_mcu_row = true;
+ else if ((m_mcu_lines_left == 1) && (m_total_lines_left > 1))
+ {
+ get_another_mcu_row = true;
+ got_mcu_early = true;
+ }
+ }
+ else
+ {
+ get_another_mcu_row = (m_mcu_lines_left == 0);
+ }
+
+ if (get_another_mcu_row)
+ {
+ int status = decode_next_mcu_row();
+ if (status != 0)
+ return status;
+ }
+
+ switch (m_scan_type)
+ {
+ case JPGD_YH2V2:
+ {
+ if (m_flags & cFlagLinearChromaFiltering)
+ {
+ if (m_num_buffered_scanlines == 1)
+ {
+ *pScan_line = m_pScan_line_1;
+ }
+ else if (m_num_buffered_scanlines == 0)
+ {
+ m_num_buffered_scanlines = H2V2ConvertFiltered();
+ *pScan_line = m_pScan_line_0;
+ }
+
+ m_num_buffered_scanlines--;
+ }
+ else
+ {
+ if ((m_mcu_lines_left & 1) == 0)
+ {
+ H2V2Convert();
+ *pScan_line = m_pScan_line_0;
+ }
+ else
+ *pScan_line = m_pScan_line_1;
+ }
+
+ break;
+ }
+ case JPGD_YH2V1:
+ {
+ if (m_flags & cFlagLinearChromaFiltering)
+ H2V1ConvertFiltered();
+ else
+ H2V1Convert();
+ *pScan_line = m_pScan_line_0;
+ break;
+ }
+ case JPGD_YH1V2:
+ {
+ if (chroma_y_filtering)
+ {
+ H1V2ConvertFiltered();
+ *pScan_line = m_pScan_line_0;
+ }
+ else
+ {
+ if ((m_mcu_lines_left & 1) == 0)
+ {
+ H1V2Convert();
+ *pScan_line = m_pScan_line_0;
+ }
+ else
+ *pScan_line = m_pScan_line_1;
+ }
+
+ break;
+ }
+ case JPGD_YH1V1:
+ {
+ H1V1Convert();
+ *pScan_line = m_pScan_line_0;
+ break;
+ }
+ case JPGD_GRAYSCALE:
+ {
+ gray_convert();
+ *pScan_line = m_pScan_line_0;
+
+ break;
+ }
+ }
+
+ *pScan_line_len = m_real_dest_bytes_per_scan_line;
+
+ if (!got_mcu_early)
+ {
+ m_mcu_lines_left--;
+ }
+
+ m_total_lines_left--;
+
+ return JPGD_SUCCESS;
+ }
+
+ // Creates the tables needed for efficient Huffman decoding.
+ void jpeg_decoder::make_huff_table(int index, huff_tables* pH)
+ {
+ int p, i, l, si;
+ uint8 huffsize[258];
+ uint huffcode[258];
+ uint code;
+ uint subtree;
+ int code_size;
+ int lastp;
+ int nextfreeentry;
+ int currententry;
+
+ pH->ac_table = m_huff_ac[index] != 0;
+
+ p = 0;
+
+ for (l = 1; l <= 16; l++)
+ {
+ for (i = 1; i <= m_huff_num[index][l]; i++)
+ {
+ if (p >= 257)
+ stop_decoding(JPGD_DECODE_ERROR);
+ huffsize[p++] = static_cast<uint8>(l);
+ }
+ }
+
+ assert(p < 258);
+ huffsize[p] = 0;
+
+ lastp = p;
+
+ code = 0;
+ si = huffsize[0];
+ p = 0;
+
+ while (huffsize[p])
+ {
+ while (huffsize[p] == si)
+ {
+ if (p >= 257)
+ stop_decoding(JPGD_DECODE_ERROR);
+ huffcode[p++] = code;
+ code++;
+ }
+
+ code <<= 1;
+ si++;
+ }
+
+ memset(pH->look_up, 0, sizeof(pH->look_up));
+ memset(pH->look_up2, 0, sizeof(pH->look_up2));
+ memset(pH->tree, 0, sizeof(pH->tree));
+ memset(pH->code_size, 0, sizeof(pH->code_size));
+
+ nextfreeentry = -1;
+
+ p = 0;
+
+ while (p < lastp)
+ {
+ i = m_huff_val[index][p];
+
+ code = huffcode[p];
+ code_size = huffsize[p];
+
+ assert(i < JPGD_HUFF_CODE_SIZE_MAX_LENGTH);
+ pH->code_size[i] = static_cast<uint8>(code_size);
+
+ if (code_size <= 8)
+ {
+ code <<= (8 - code_size);
+
+ for (l = 1 << (8 - code_size); l > 0; l--)
+ {
+ if (code >= 256)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ pH->look_up[code] = i;
+
+ bool has_extrabits = false;
+ int extra_bits = 0;
+ int num_extra_bits = i & 15;
+
+ int bits_to_fetch = code_size;
+ if (num_extra_bits)
+ {
+ int total_codesize = code_size + num_extra_bits;
+ if (total_codesize <= 8)
+ {
+ has_extrabits = true;
+ extra_bits = ((1 << num_extra_bits) - 1) & (code >> (8 - total_codesize));
+
+ if (extra_bits > 0x7FFF)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ bits_to_fetch += num_extra_bits;
+ }
+ }
+
+ if (!has_extrabits)
+ pH->look_up2[code] = i | (bits_to_fetch << 8);
+ else
+ pH->look_up2[code] = i | 0x8000 | (extra_bits << 16) | (bits_to_fetch << 8);
+
+ code++;
+ }
+ }
+ else
+ {
+ subtree = (code >> (code_size - 8)) & 0xFF;
+
+ currententry = pH->look_up[subtree];
+
+ if (currententry == 0)
+ {
+ pH->look_up[subtree] = currententry = nextfreeentry;
+ pH->look_up2[subtree] = currententry = nextfreeentry;
+
+ nextfreeentry -= 2;
+ }
+
+ code <<= (16 - (code_size - 8));
+
+ for (l = code_size; l > 9; l--)
+ {
+ if ((code & 0x8000) == 0)
+ currententry--;
+
+ unsigned int idx = -currententry - 1;
+
+ if (idx >= JPGD_HUFF_TREE_MAX_LENGTH)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ if (pH->tree[idx] == 0)
+ {
+ pH->tree[idx] = nextfreeentry;
+
+ currententry = nextfreeentry;
+
+ nextfreeentry -= 2;
+ }
+ else
+ {
+ currententry = pH->tree[idx];
+ }
+
+ code <<= 1;
+ }
+
+ if ((code & 0x8000) == 0)
+ currententry--;
+
+ if ((-currententry - 1) >= JPGD_HUFF_TREE_MAX_LENGTH)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ pH->tree[-currententry - 1] = i;
+ }
+
+ p++;
+ }
+ }
+
+ // Verifies the quantization tables needed for this scan are available.
+ void jpeg_decoder::check_quant_tables()
+ {
+ for (int i = 0; i < m_comps_in_scan; i++)
+ if (m_quant[m_comp_quant[m_comp_list[i]]] == nullptr)
+ stop_decoding(JPGD_UNDEFINED_QUANT_TABLE);
+ }
+
+ // Verifies that all the Huffman tables needed for this scan are available.
+ void jpeg_decoder::check_huff_tables()
+ {
+ for (int i = 0; i < m_comps_in_scan; i++)
+ {
+ if ((m_spectral_start == 0) && (m_huff_num[m_comp_dc_tab[m_comp_list[i]]] == nullptr))
+ stop_decoding(JPGD_UNDEFINED_HUFF_TABLE);
+
+ if ((m_spectral_end > 0) && (m_huff_num[m_comp_ac_tab[m_comp_list[i]]] == nullptr))
+ stop_decoding(JPGD_UNDEFINED_HUFF_TABLE);
+ }
+
+ for (int i = 0; i < JPGD_MAX_HUFF_TABLES; i++)
+ if (m_huff_num[i])
+ {
+ if (!m_pHuff_tabs[i])
+ m_pHuff_tabs[i] = (huff_tables*)alloc(sizeof(huff_tables));
+
+ make_huff_table(i, m_pHuff_tabs[i]);
+ }
+ }
+
+ // Determines the component order inside each MCU.
+ // Also calcs how many MCU's are on each row, etc.
+ bool jpeg_decoder::calc_mcu_block_order()
+ {
+ int component_num, component_id;
+ int max_h_samp = 0, max_v_samp = 0;
+
+ for (component_id = 0; component_id < m_comps_in_frame; component_id++)
+ {
+ if (m_comp_h_samp[component_id] > max_h_samp)
+ max_h_samp = m_comp_h_samp[component_id];
+
+ if (m_comp_v_samp[component_id] > max_v_samp)
+ max_v_samp = m_comp_v_samp[component_id];
+ }
+
+ for (component_id = 0; component_id < m_comps_in_frame; component_id++)
+ {
+ m_comp_h_blocks[component_id] = ((((m_image_x_size * m_comp_h_samp[component_id]) + (max_h_samp - 1)) / max_h_samp) + 7) / 8;
+ m_comp_v_blocks[component_id] = ((((m_image_y_size * m_comp_v_samp[component_id]) + (max_v_samp - 1)) / max_v_samp) + 7) / 8;
+ }
+
+ if (m_comps_in_scan == 1)
+ {
+ m_mcus_per_row = m_comp_h_blocks[m_comp_list[0]];
+ m_mcus_per_col = m_comp_v_blocks[m_comp_list[0]];
+ }
+ else
+ {
+ m_mcus_per_row = (((m_image_x_size + 7) / 8) + (max_h_samp - 1)) / max_h_samp;
+ m_mcus_per_col = (((m_image_y_size + 7) / 8) + (max_v_samp - 1)) / max_v_samp;
+ }
+
+ if (m_comps_in_scan == 1)
+ {
+ m_mcu_org[0] = m_comp_list[0];
+
+ m_blocks_per_mcu = 1;
+ }
+ else
+ {
+ m_blocks_per_mcu = 0;
+
+ for (component_num = 0; component_num < m_comps_in_scan; component_num++)
+ {
+ int num_blocks;
+
+ component_id = m_comp_list[component_num];
+
+ num_blocks = m_comp_h_samp[component_id] * m_comp_v_samp[component_id];
+
+ while (num_blocks--)
+ m_mcu_org[m_blocks_per_mcu++] = component_id;
+ }
+ }
+
+ if (m_blocks_per_mcu > m_max_blocks_per_mcu)
+ return false;
+
+ for (int mcu_block = 0; mcu_block < m_blocks_per_mcu; mcu_block++)
+ {
+ int comp_id = m_mcu_org[mcu_block];
+ if (comp_id >= JPGD_MAX_QUANT_TABLES)
+ return false;
+ }
+
+ return true;
+ }
+
+ // Starts a new scan.
+ int jpeg_decoder::init_scan()
+ {
+ if (!locate_sos_marker())
+ return JPGD_FALSE;
+
+ if (!calc_mcu_block_order())
+ return JPGD_FALSE;
+
+ check_huff_tables();
+
+ check_quant_tables();
+
+ memset(m_last_dc_val, 0, m_comps_in_frame * sizeof(uint));
+
+ m_eob_run = 0;
+
+ if (m_restart_interval)
+ {
+ m_restarts_left = m_restart_interval;
+ m_next_restart_num = 0;
+ }
+
+ fix_in_buffer();
+
+ return JPGD_TRUE;
+ }
+
+ // Starts a frame. Determines if the number of components or sampling factors
+ // are supported.
+ void jpeg_decoder::init_frame()
+ {
+ int i;
+
+ if (m_comps_in_frame == 1)
+ {
+ if ((m_comp_h_samp[0] != 1) || (m_comp_v_samp[0] != 1))
+ stop_decoding(JPGD_UNSUPPORTED_SAMP_FACTORS);
+
+ m_scan_type = JPGD_GRAYSCALE;
+ m_max_blocks_per_mcu = 1;
+ m_max_mcu_x_size = 8;
+ m_max_mcu_y_size = 8;
+ }
+ else if (m_comps_in_frame == 3)
+ {
+ if (((m_comp_h_samp[1] != 1) || (m_comp_v_samp[1] != 1)) ||
+ ((m_comp_h_samp[2] != 1) || (m_comp_v_samp[2] != 1)))
+ stop_decoding(JPGD_UNSUPPORTED_SAMP_FACTORS);
+
+ if ((m_comp_h_samp[0] == 1) && (m_comp_v_samp[0] == 1))
+ {
+ m_scan_type = JPGD_YH1V1;
+
+ m_max_blocks_per_mcu = 3;
+ m_max_mcu_x_size = 8;
+ m_max_mcu_y_size = 8;
+ }
+ else if ((m_comp_h_samp[0] == 2) && (m_comp_v_samp[0] == 1))
+ {
+ m_scan_type = JPGD_YH2V1;
+ m_max_blocks_per_mcu = 4;
+ m_max_mcu_x_size = 16;
+ m_max_mcu_y_size = 8;
+ }
+ else if ((m_comp_h_samp[0] == 1) && (m_comp_v_samp[0] == 2))
+ {
+ m_scan_type = JPGD_YH1V2;
+ m_max_blocks_per_mcu = 4;
+ m_max_mcu_x_size = 8;
+ m_max_mcu_y_size = 16;
+ }
+ else if ((m_comp_h_samp[0] == 2) && (m_comp_v_samp[0] == 2))
+ {
+ m_scan_type = JPGD_YH2V2;
+ m_max_blocks_per_mcu = 6;
+ m_max_mcu_x_size = 16;
+ m_max_mcu_y_size = 16;
+ }
+ else
+ stop_decoding(JPGD_UNSUPPORTED_SAMP_FACTORS);
+ }
+ else
+ stop_decoding(JPGD_UNSUPPORTED_COLORSPACE);
+
+ m_max_mcus_per_row = (m_image_x_size + (m_max_mcu_x_size - 1)) / m_max_mcu_x_size;
+ m_max_mcus_per_col = (m_image_y_size + (m_max_mcu_y_size - 1)) / m_max_mcu_y_size;
+
+ // These values are for the *destination* pixels: after conversion.
+ if (m_scan_type == JPGD_GRAYSCALE)
+ m_dest_bytes_per_pixel = 1;
+ else
+ m_dest_bytes_per_pixel = 4;
+
+ m_dest_bytes_per_scan_line = ((m_image_x_size + 15) & 0xFFF0) * m_dest_bytes_per_pixel;
+
+ m_real_dest_bytes_per_scan_line = (m_image_x_size * m_dest_bytes_per_pixel);
+
+ // Initialize two scan line buffers.
+ m_pScan_line_0 = (uint8*)alloc(m_dest_bytes_per_scan_line, true);
+ if ((m_scan_type == JPGD_YH1V2) || (m_scan_type == JPGD_YH2V2))
+ m_pScan_line_1 = (uint8*)alloc(m_dest_bytes_per_scan_line, true);
+
+ m_max_blocks_per_row = m_max_mcus_per_row * m_max_blocks_per_mcu;
+
+ // Should never happen
+ if (m_max_blocks_per_row > JPGD_MAX_BLOCKS_PER_ROW)
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ // Allocate the coefficient buffer, enough for one MCU
+ m_pMCU_coefficients = (jpgd_block_t*)alloc(m_max_blocks_per_mcu * 64 * sizeof(jpgd_block_t));
+
+ for (i = 0; i < m_max_blocks_per_mcu; i++)
+ m_mcu_block_max_zag[i] = 64;
+
+ m_pSample_buf = (uint8*)alloc(m_max_blocks_per_row * 64);
+ m_pSample_buf_prev = (uint8*)alloc(m_max_blocks_per_row * 64);
+
+ m_total_lines_left = m_image_y_size;
+
+ m_mcu_lines_left = 0;
+
+ create_look_ups();
+ }
+
+ // The coeff_buf series of methods originally stored the coefficients
+ // into a "virtual" file which was located in EMS, XMS, or a disk file. A cache
+ // was used to make this process more efficient. Now, we can store the entire
+ // thing in RAM.
+ jpeg_decoder::coeff_buf* jpeg_decoder::coeff_buf_open(int block_num_x, int block_num_y, int block_len_x, int block_len_y)
+ {
+ coeff_buf* cb = (coeff_buf*)alloc(sizeof(coeff_buf));
+
+ cb->block_num_x = block_num_x;
+ cb->block_num_y = block_num_y;
+ cb->block_len_x = block_len_x;
+ cb->block_len_y = block_len_y;
+ cb->block_size = (block_len_x * block_len_y) * sizeof(jpgd_block_t);
+ cb->pData = (uint8*)alloc(cb->block_size * block_num_x * block_num_y, true);
+ return cb;
+ }
+
+ inline jpgd_block_t* jpeg_decoder::coeff_buf_getp(coeff_buf* cb, int block_x, int block_y)
+ {
+ if ((block_x >= cb->block_num_x) || (block_y >= cb->block_num_y))
+ stop_decoding(JPGD_DECODE_ERROR);
+
+ return (jpgd_block_t*)(cb->pData + block_x * cb->block_size + block_y * (cb->block_size * cb->block_num_x));
+ }
+
+ // The following methods decode the various types of m_blocks encountered
+ // in progressively encoded images.
+ void jpeg_decoder::decode_block_dc_first(jpeg_decoder* pD, int component_id, int block_x, int block_y)
+ {
+ int s, r;
+ jpgd_block_t* p = pD->coeff_buf_getp(pD->m_dc_coeffs[component_id], block_x, block_y);
+
+ if ((s = pD->huff_decode(pD->m_pHuff_tabs[pD->m_comp_dc_tab[component_id]])) != 0)
+ {
+ if (s >= 16)
+ pD->stop_decoding(JPGD_DECODE_ERROR);
+
+ r = pD->get_bits_no_markers(s);
+ s = JPGD_HUFF_EXTEND(r, s);
+ }
+
+ pD->m_last_dc_val[component_id] = (s += pD->m_last_dc_val[component_id]);
+
+ p[0] = static_cast<jpgd_block_t>(s << pD->m_successive_low);
+ }
+
+ void jpeg_decoder::decode_block_dc_refine(jpeg_decoder* pD, int component_id, int block_x, int block_y)
+ {
+ if (pD->get_bits_no_markers(1))
+ {
+ jpgd_block_t* p = pD->coeff_buf_getp(pD->m_dc_coeffs[component_id], block_x, block_y);
+
+ p[0] |= (1 << pD->m_successive_low);
+ }
+ }
+
+ void jpeg_decoder::decode_block_ac_first(jpeg_decoder* pD, int component_id, int block_x, int block_y)
+ {
+ int k, s, r;
+
+ if (pD->m_eob_run)
+ {
+ pD->m_eob_run--;
+ return;
+ }
+
+ jpgd_block_t* p = pD->coeff_buf_getp(pD->m_ac_coeffs[component_id], block_x, block_y);
+
+ for (k = pD->m_spectral_start; k <= pD->m_spectral_end; k++)
+ {
+ unsigned int idx = pD->m_comp_ac_tab[component_id];
+ if (idx >= JPGD_MAX_HUFF_TABLES)
+ pD->stop_decoding(JPGD_DECODE_ERROR);
+
+ s = pD->huff_decode(pD->m_pHuff_tabs[idx]);
+
+ r = s >> 4;
+ s &= 15;
+
+ if (s)
+ {
+ if ((k += r) > 63)
+ pD->stop_decoding(JPGD_DECODE_ERROR);
+
+ r = pD->get_bits_no_markers(s);
+ s = JPGD_HUFF_EXTEND(r, s);
+
+ p[g_ZAG[k]] = static_cast<jpgd_block_t>(s << pD->m_successive_low);
+ }
+ else
+ {
+ if (r == 15)
+ {
+ if ((k += 15) > 63)
+ pD->stop_decoding(JPGD_DECODE_ERROR);
+ }
+ else
+ {
+ pD->m_eob_run = 1 << r;
+
+ if (r)
+ pD->m_eob_run += pD->get_bits_no_markers(r);
+
+ pD->m_eob_run--;
+
+ break;
+ }
+ }
+ }
+ }
+
+ void jpeg_decoder::decode_block_ac_refine(jpeg_decoder* pD, int component_id, int block_x, int block_y)
+ {
+ int s, k, r;
+
+ int p1 = 1 << pD->m_successive_low;
+
+ //int m1 = (-1) << pD->m_successive_low;
+ int m1 = static_cast<int>((UINT32_MAX << pD->m_successive_low));
+
+ jpgd_block_t* p = pD->coeff_buf_getp(pD->m_ac_coeffs[component_id], block_x, block_y);
+ if (pD->m_spectral_end > 63)
+ pD->stop_decoding(JPGD_DECODE_ERROR);
+
+ k = pD->m_spectral_start;
+
+ if (pD->m_eob_run == 0)
+ {
+ for (; k <= pD->m_spectral_end; k++)
+ {
+ unsigned int idx = pD->m_comp_ac_tab[component_id];
+ if (idx >= JPGD_MAX_HUFF_TABLES)
+ pD->stop_decoding(JPGD_DECODE_ERROR);
+
+ s = pD->huff_decode(pD->m_pHuff_tabs[idx]);
+
+ r = s >> 4;
+ s &= 15;
+
+ if (s)
+ {
+ if (s != 1)
+ pD->stop_decoding(JPGD_DECODE_ERROR);
+
+ if (pD->get_bits_no_markers(1))
+ s = p1;
+ else
+ s = m1;
+ }
+ else
+ {
+ if (r != 15)
+ {
+ pD->m_eob_run = 1 << r;
+
+ if (r)
+ pD->m_eob_run += pD->get_bits_no_markers(r);
+
+ break;
+ }
+ }
+
+ do
+ {
+ jpgd_block_t* this_coef = p + g_ZAG[k & 63];
+
+ if (*this_coef != 0)
+ {
+ if (pD->get_bits_no_markers(1))
+ {
+ if ((*this_coef & p1) == 0)
+ {
+ if (*this_coef >= 0)
+ *this_coef = static_cast<jpgd_block_t>(*this_coef + p1);
+ else
+ *this_coef = static_cast<jpgd_block_t>(*this_coef + m1);
+ }
+ }
+ }
+ else
+ {
+ if (--r < 0)
+ break;
+ }
+
+ k++;
+
+ } while (k <= pD->m_spectral_end);
+
+ if ((s) && (k < 64))
+ {
+ p[g_ZAG[k]] = static_cast<jpgd_block_t>(s);
+ }
+ }
+ }
+
+ if (pD->m_eob_run > 0)
+ {
+ for (; k <= pD->m_spectral_end; k++)
+ {
+ jpgd_block_t* this_coef = p + g_ZAG[k & 63]; // logical AND to shut up static code analysis
+
+ if (*this_coef != 0)
+ {
+ if (pD->get_bits_no_markers(1))
+ {
+ if ((*this_coef & p1) == 0)
+ {
+ if (*this_coef >= 0)
+ *this_coef = static_cast<jpgd_block_t>(*this_coef + p1);
+ else
+ *this_coef = static_cast<jpgd_block_t>(*this_coef + m1);
+ }
+ }
+ }
+ }
+
+ pD->m_eob_run--;
+ }
+ }
+
+ // Decode a scan in a progressively encoded image.
+ void jpeg_decoder::decode_scan(pDecode_block_func decode_block_func)
+ {
+ int mcu_row, mcu_col, mcu_block;
+ int block_x_mcu[JPGD_MAX_COMPONENTS], block_y_mcu[JPGD_MAX_COMPONENTS];
+
+ memset(block_y_mcu, 0, sizeof(block_y_mcu));
+
+ for (mcu_col = 0; mcu_col < m_mcus_per_col; mcu_col++)
+ {
+ int component_num, component_id;
+
+ memset(block_x_mcu, 0, sizeof(block_x_mcu));
+
+ for (mcu_row = 0; mcu_row < m_mcus_per_row; mcu_row++)
+ {
+ int block_x_mcu_ofs = 0, block_y_mcu_ofs = 0;
+
+ if ((m_restart_interval) && (m_restarts_left == 0))
+ process_restart();
+
+ for (mcu_block = 0; mcu_block < m_blocks_per_mcu; mcu_block++)
+ {
+ component_id = m_mcu_org[mcu_block];
+
+ decode_block_func(this, component_id, block_x_mcu[component_id] + block_x_mcu_ofs, block_y_mcu[component_id] + block_y_mcu_ofs);
+
+ if (m_comps_in_scan == 1)
+ block_x_mcu[component_id]++;
+ else
+ {
+ if (++block_x_mcu_ofs == m_comp_h_samp[component_id])
+ {
+ block_x_mcu_ofs = 0;
+
+ if (++block_y_mcu_ofs == m_comp_v_samp[component_id])
+ {
+ block_y_mcu_ofs = 0;
+ block_x_mcu[component_id] += m_comp_h_samp[component_id];
+ }
+ }
+ }
+ }
+
+ m_restarts_left--;
+ }
+
+ if (m_comps_in_scan == 1)
+ block_y_mcu[m_comp_list[0]]++;
+ else
+ {
+ for (component_num = 0; component_num < m_comps_in_scan; component_num++)
+ {
+ component_id = m_comp_list[component_num];
+ block_y_mcu[component_id] += m_comp_v_samp[component_id];
+ }
+ }
+ }
+ }
+
+ // Decode a progressively encoded image.
+ void jpeg_decoder::init_progressive()
+ {
+ int i;
+
+ if (m_comps_in_frame == 4)
+ stop_decoding(JPGD_UNSUPPORTED_COLORSPACE);
+
+ // Allocate the coefficient buffers.
+ for (i = 0; i < m_comps_in_frame; i++)
+ {
+ m_dc_coeffs[i] = coeff_buf_open(m_max_mcus_per_row * m_comp_h_samp[i], m_max_mcus_per_col * m_comp_v_samp[i], 1, 1);
+ m_ac_coeffs[i] = coeff_buf_open(m_max_mcus_per_row * m_comp_h_samp[i], m_max_mcus_per_col * m_comp_v_samp[i], 8, 8);
+ }
+
+ for (; ; )
+ {
+ int dc_only_scan, refinement_scan;
+ pDecode_block_func decode_block_func;
+
+ if (!init_scan())
+ break;
+
+ dc_only_scan = (m_spectral_start == 0);
+ refinement_scan = (m_successive_high != 0);
+
+ if ((m_spectral_start > m_spectral_end) || (m_spectral_end > 63))
+ stop_decoding(JPGD_BAD_SOS_SPECTRAL);
+
+ if (dc_only_scan)
+ {
+ if (m_spectral_end)
+ stop_decoding(JPGD_BAD_SOS_SPECTRAL);
+ }
+ else if (m_comps_in_scan != 1) /* AC scans can only contain one component */
+ stop_decoding(JPGD_BAD_SOS_SPECTRAL);
+
+ if ((refinement_scan) && (m_successive_low != m_successive_high - 1))
+ stop_decoding(JPGD_BAD_SOS_SUCCESSIVE);
+
+ if (dc_only_scan)
+ {
+ if (refinement_scan)
+ decode_block_func = decode_block_dc_refine;
+ else
+ decode_block_func = decode_block_dc_first;
+ }
+ else
+ {
+ if (refinement_scan)
+ decode_block_func = decode_block_ac_refine;
+ else
+ decode_block_func = decode_block_ac_first;
+ }
+
+ decode_scan(decode_block_func);
+
+ m_bits_left = 16;
+ get_bits(16);
+ get_bits(16);
+ }
+
+ m_comps_in_scan = m_comps_in_frame;
+
+ for (i = 0; i < m_comps_in_frame; i++)
+ m_comp_list[i] = i;
+
+ if (!calc_mcu_block_order())
+ stop_decoding(JPGD_DECODE_ERROR);
+ }
+
+ void jpeg_decoder::init_sequential()
+ {
+ if (!init_scan())
+ stop_decoding(JPGD_UNEXPECTED_MARKER);
+ }
+
+ void jpeg_decoder::decode_start()
+ {
+ init_frame();
+
+ if (m_progressive_flag)
+ init_progressive();
+ else
+ init_sequential();
+ }
+
+ void jpeg_decoder::decode_init(jpeg_decoder_stream* pStream, uint32_t flags)
+ {
+ init(pStream, flags);
+ locate_sof_marker();
+ }
+
+ jpeg_decoder::jpeg_decoder(jpeg_decoder_stream* pStream, uint32_t flags)
+ {
+ if (setjmp(m_jmp_state))
+ return;
+ decode_init(pStream, flags);
+ }
+
+ int jpeg_decoder::begin_decoding()
+ {
+ if (m_ready_flag)
+ return JPGD_SUCCESS;
+
+ if (m_error_code)
+ return JPGD_FAILED;
+
+ if (setjmp(m_jmp_state))
+ return JPGD_FAILED;
+
+ decode_start();
+
+ m_ready_flag = true;
+
+ return JPGD_SUCCESS;
+ }
+
+ jpeg_decoder::~jpeg_decoder()
+ {
+ free_all_blocks();
+ }
+
+ jpeg_decoder_file_stream::jpeg_decoder_file_stream()
+ {
+ m_pFile = nullptr;
+ m_eof_flag = false;
+ m_error_flag = false;
+ }
+
+ void jpeg_decoder_file_stream::close()
+ {
+ if (m_pFile)
+ {
+ fclose(m_pFile);
+ m_pFile = nullptr;
+ }
+
+ m_eof_flag = false;
+ m_error_flag = false;
+ }
+
+ jpeg_decoder_file_stream::~jpeg_decoder_file_stream()
+ {
+ close();
+ }
+
+ bool jpeg_decoder_file_stream::open(const char* Pfilename)
+ {
+ close();
+
+ m_eof_flag = false;
+ m_error_flag = false;
+
+#if defined(_MSC_VER)
+ m_pFile = nullptr;
+ fopen_s(&m_pFile, Pfilename, "rb");
+#else
+ m_pFile = fopen(Pfilename, "rb");
+#endif
+ return m_pFile != nullptr;
+ }
+
+ int jpeg_decoder_file_stream::read(uint8* pBuf, int max_bytes_to_read, bool* pEOF_flag)
+ {
+ if (!m_pFile)
+ return -1;
+
+ if (m_eof_flag)
+ {
+ *pEOF_flag = true;
+ return 0;
+ }
+
+ if (m_error_flag)
+ return -1;
+
+ int bytes_read = static_cast<int>(fread(pBuf, 1, max_bytes_to_read, m_pFile));
+ if (bytes_read < max_bytes_to_read)
+ {
+ if (ferror(m_pFile))
+ {
+ m_error_flag = true;
+ return -1;
+ }
+
+ m_eof_flag = true;
+ *pEOF_flag = true;
+ }
+
+ return bytes_read;
+ }
+
+ bool jpeg_decoder_mem_stream::open(const uint8* pSrc_data, uint size)
+ {
+ close();
+ m_pSrc_data = pSrc_data;
+ m_ofs = 0;
+ m_size = size;
+ return true;
+ }
+
+ int jpeg_decoder_mem_stream::read(uint8* pBuf, int max_bytes_to_read, bool* pEOF_flag)
+ {
+ *pEOF_flag = false;
+
+ if (!m_pSrc_data)
+ return -1;
+
+ uint bytes_remaining = m_size - m_ofs;
+ if ((uint)max_bytes_to_read > bytes_remaining)
+ {
+ max_bytes_to_read = bytes_remaining;
+ *pEOF_flag = true;
+ }
+
+ memcpy(pBuf, m_pSrc_data + m_ofs, max_bytes_to_read);
+ m_ofs += max_bytes_to_read;
+
+ return max_bytes_to_read;
+ }
+
+ unsigned char* decompress_jpeg_image_from_stream(jpeg_decoder_stream* pStream, int* width, int* height, int* actual_comps, int req_comps, uint32_t flags)
+ {
+ if (!actual_comps)
+ return nullptr;
+ *actual_comps = 0;
+
+ if ((!pStream) || (!width) || (!height) || (!req_comps))
+ return nullptr;
+
+ if ((req_comps != 1) && (req_comps != 3) && (req_comps != 4))
+ return nullptr;
+
+ jpeg_decoder decoder(pStream, flags);
+ if (decoder.get_error_code() != JPGD_SUCCESS)
+ return nullptr;
+
+ const int image_width = decoder.get_width(), image_height = decoder.get_height();
+ *width = image_width;
+ *height = image_height;
+ *actual_comps = decoder.get_num_components();
+
+ if (decoder.begin_decoding() != JPGD_SUCCESS)
+ return nullptr;
+
+ const int dst_bpl = image_width * req_comps;
+
+ uint8* pImage_data = (uint8*)jpgd_malloc(dst_bpl * image_height);
+ if (!pImage_data)
+ return nullptr;
+
+ for (int y = 0; y < image_height; y++)
+ {
+ const uint8* pScan_line;
+ uint scan_line_len;
+ if (decoder.decode((const void**)&pScan_line, &scan_line_len) != JPGD_SUCCESS)
+ {
+ jpgd_free(pImage_data);
+ return nullptr;
+ }
+
+ uint8* pDst = pImage_data + y * dst_bpl;
+
+ if (((req_comps == 1) && (decoder.get_num_components() == 1)) || ((req_comps == 4) && (decoder.get_num_components() == 3)))
+ memcpy(pDst, pScan_line, dst_bpl);
+ else if (decoder.get_num_components() == 1)
+ {
+ if (req_comps == 3)
+ {
+ for (int x = 0; x < image_width; x++)
+ {
+ uint8 luma = pScan_line[x];
+ pDst[0] = luma;
+ pDst[1] = luma;
+ pDst[2] = luma;
+ pDst += 3;
+ }
+ }
+ else
+ {
+ for (int x = 0; x < image_width; x++)
+ {
+ uint8 luma = pScan_line[x];
+ pDst[0] = luma;
+ pDst[1] = luma;
+ pDst[2] = luma;
+ pDst[3] = 255;
+ pDst += 4;
+ }
+ }
+ }
+ else if (decoder.get_num_components() == 3)
+ {
+ if (req_comps == 1)
+ {
+ const int YR = 19595, YG = 38470, YB = 7471;
+ for (int x = 0; x < image_width; x++)
+ {
+ int r = pScan_line[x * 4 + 0];
+ int g = pScan_line[x * 4 + 1];
+ int b = pScan_line[x * 4 + 2];
+ *pDst++ = static_cast<uint8>((r * YR + g * YG + b * YB + 32768) >> 16);
+ }
+ }
+ else
+ {
+ for (int x = 0; x < image_width; x++)
+ {
+ pDst[0] = pScan_line[x * 4 + 0];
+ pDst[1] = pScan_line[x * 4 + 1];
+ pDst[2] = pScan_line[x * 4 + 2];
+ pDst += 3;
+ }
+ }
+ }
+ }
+
+ return pImage_data;
+ }
+
+ unsigned char* decompress_jpeg_image_from_memory(const unsigned char* pSrc_data, int src_data_size, int* width, int* height, int* actual_comps, int req_comps, uint32_t flags)
+ {
+ jpgd::jpeg_decoder_mem_stream mem_stream(pSrc_data, src_data_size);
+ return decompress_jpeg_image_from_stream(&mem_stream, width, height, actual_comps, req_comps, flags);
+ }
+
+ unsigned char* decompress_jpeg_image_from_file(const char* pSrc_filename, int* width, int* height, int* actual_comps, int req_comps, uint32_t flags)
+ {
+ jpgd::jpeg_decoder_file_stream file_stream;
+ if (!file_stream.open(pSrc_filename))
+ return nullptr;
+ return decompress_jpeg_image_from_stream(&file_stream, width, height, actual_comps, req_comps, flags);
+ }
+
+} // namespace jpgd
diff --git a/jpgd.h b/jpgd.h
new file mode 100644
index 0000000..e0003f1
--- /dev/null
+++ b/jpgd.h
@@ -0,0 +1,347 @@
+// jpgd.h - C++ class for JPEG decompression.
+// Public domain, Rich Geldreich <richgel99@gmail.com>
+#ifndef JPEG_DECODER_H
+#define JPEG_DECODER_H
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <setjmp.h>
+#include <assert.h>
+#include <stdint.h>
+
+#ifdef _MSC_VER
+#define JPGD_NORETURN __declspec(noreturn)
+#elif defined(__GNUC__)
+#define JPGD_NORETURN __attribute__ ((noreturn))
+#else
+#define JPGD_NORETURN
+#endif
+
+#define JPGD_HUFF_TREE_MAX_LENGTH 512
+#define JPGD_HUFF_CODE_SIZE_MAX_LENGTH 256
+
+namespace jpgd
+{
+ typedef unsigned char uint8;
+ typedef signed short int16;
+ typedef unsigned short uint16;
+ typedef unsigned int uint;
+ typedef signed int int32;
+
+ // Loads a JPEG image from a memory buffer or a file.
+ // req_comps can be 1 (grayscale), 3 (RGB), or 4 (RGBA).
+ // On return, width/height will be set to the image's dimensions, and actual_comps will be set to the either 1 (grayscale) or 3 (RGB).
+ // Notes: For more control over where and how the source data is read, see the decompress_jpeg_image_from_stream() function below, or call the jpeg_decoder class directly.
+ // Requesting a 8 or 32bpp image is currently a little faster than 24bpp because the jpeg_decoder class itself currently always unpacks to either 8 or 32bpp.
+ unsigned char* decompress_jpeg_image_from_memory(const unsigned char* pSrc_data, int src_data_size, int* width, int* height, int* actual_comps, int req_comps, uint32_t flags = 0);
+ unsigned char* decompress_jpeg_image_from_file(const char* pSrc_filename, int* width, int* height, int* actual_comps, int req_comps, uint32_t flags = 0);
+
+ // Success/failure error codes.
+ enum jpgd_status
+ {
+ JPGD_SUCCESS = 0, JPGD_FAILED = -1, JPGD_DONE = 1,
+ JPGD_BAD_DHT_COUNTS = -256, JPGD_BAD_DHT_INDEX, JPGD_BAD_DHT_MARKER, JPGD_BAD_DQT_MARKER, JPGD_BAD_DQT_TABLE,
+ JPGD_BAD_PRECISION, JPGD_BAD_HEIGHT, JPGD_BAD_WIDTH, JPGD_TOO_MANY_COMPONENTS,
+ JPGD_BAD_SOF_LENGTH, JPGD_BAD_VARIABLE_MARKER, JPGD_BAD_DRI_LENGTH, JPGD_BAD_SOS_LENGTH,
+ JPGD_BAD_SOS_COMP_ID, JPGD_W_EXTRA_BYTES_BEFORE_MARKER, JPGD_NO_ARITHMITIC_SUPPORT, JPGD_UNEXPECTED_MARKER,
+ JPGD_NOT_JPEG, JPGD_UNSUPPORTED_MARKER, JPGD_BAD_DQT_LENGTH, JPGD_TOO_MANY_BLOCKS,
+ JPGD_UNDEFINED_QUANT_TABLE, JPGD_UNDEFINED_HUFF_TABLE, JPGD_NOT_SINGLE_SCAN, JPGD_UNSUPPORTED_COLORSPACE,
+ JPGD_UNSUPPORTED_SAMP_FACTORS, JPGD_DECODE_ERROR, JPGD_BAD_RESTART_MARKER,
+ JPGD_BAD_SOS_SPECTRAL, JPGD_BAD_SOS_SUCCESSIVE, JPGD_STREAM_READ, JPGD_NOTENOUGHMEM
+ };
+
+ // Input stream interface.
+ // Derive from this class to read input data from sources other than files or memory. Set m_eof_flag to true when no more data is available.
+ // The decoder is rather greedy: it will keep on calling this method until its internal input buffer is full, or until the EOF flag is set.
+ // It the input stream contains data after the JPEG stream's EOI (end of image) marker it will probably be pulled into the internal buffer.
+ // Call the get_total_bytes_read() method to determine the actual size of the JPEG stream after successful decoding.
+ class jpeg_decoder_stream
+ {
+ public:
+ jpeg_decoder_stream() { }
+ virtual ~jpeg_decoder_stream() { }
+
+ // The read() method is called when the internal input buffer is empty.
+ // Parameters:
+ // pBuf - input buffer
+ // max_bytes_to_read - maximum bytes that can be written to pBuf
+ // pEOF_flag - set this to true if at end of stream (no more bytes remaining)
+ // Returns -1 on error, otherwise return the number of bytes actually written to the buffer (which may be 0).
+ // Notes: This method will be called in a loop until you set *pEOF_flag to true or the internal buffer is full.
+ virtual int read(uint8* pBuf, int max_bytes_to_read, bool* pEOF_flag) = 0;
+ };
+
+ // stdio FILE stream class.
+ class jpeg_decoder_file_stream : public jpeg_decoder_stream
+ {
+ jpeg_decoder_file_stream(const jpeg_decoder_file_stream&);
+ jpeg_decoder_file_stream& operator =(const jpeg_decoder_file_stream&);
+
+ FILE* m_pFile;
+ bool m_eof_flag, m_error_flag;
+
+ public:
+ jpeg_decoder_file_stream();
+ virtual ~jpeg_decoder_file_stream();
+
+ bool open(const char* Pfilename);
+ void close();
+
+ virtual int read(uint8* pBuf, int max_bytes_to_read, bool* pEOF_flag);
+ };
+
+ // Memory stream class.
+ class jpeg_decoder_mem_stream : public jpeg_decoder_stream
+ {
+ const uint8* m_pSrc_data;
+ uint m_ofs, m_size;
+
+ public:
+ jpeg_decoder_mem_stream() : m_pSrc_data(NULL), m_ofs(0), m_size(0) { }
+ jpeg_decoder_mem_stream(const uint8* pSrc_data, uint size) : m_pSrc_data(pSrc_data), m_ofs(0), m_size(size) { }
+
+ virtual ~jpeg_decoder_mem_stream() { }
+
+ bool open(const uint8* pSrc_data, uint size);
+ void close() { m_pSrc_data = NULL; m_ofs = 0; m_size = 0; }
+
+ virtual int read(uint8* pBuf, int max_bytes_to_read, bool* pEOF_flag);
+ };
+
+ // Loads JPEG file from a jpeg_decoder_stream.
+ unsigned char* decompress_jpeg_image_from_stream(jpeg_decoder_stream* pStream, int* width, int* height, int* actual_comps, int req_comps, uint32_t flags = 0);
+
+ enum
+ {
+ JPGD_IN_BUF_SIZE = 8192, JPGD_MAX_BLOCKS_PER_MCU = 10, JPGD_MAX_HUFF_TABLES = 8, JPGD_MAX_QUANT_TABLES = 4,
+ JPGD_MAX_COMPONENTS = 4, JPGD_MAX_COMPS_IN_SCAN = 4, JPGD_MAX_BLOCKS_PER_ROW = 16384, JPGD_MAX_HEIGHT = 32768, JPGD_MAX_WIDTH = 32768
+ };
+
+ typedef int16 jpgd_quant_t;
+ typedef int16 jpgd_block_t;
+
+ class jpeg_decoder
+ {
+ public:
+ enum
+ {
+ cFlagLinearChromaFiltering = 1
+ };
+
+ // Call get_error_code() after constructing to determine if the stream is valid or not. You may call the get_width(), get_height(), etc.
+ // methods after the constructor is called. You may then either destruct the object, or begin decoding the image by calling begin_decoding(), then decode() on each scanline.
+ jpeg_decoder(jpeg_decoder_stream* pStream, uint32_t flags = cFlagLinearChromaFiltering);
+
+ ~jpeg_decoder();
+
+ // Call this method after constructing the object to begin decompression.
+ // If JPGD_SUCCESS is returned you may then call decode() on each scanline.
+
+ int begin_decoding();
+
+ // Returns the next scan line.
+ // For grayscale images, pScan_line will point to a buffer containing 8-bit pixels (get_bytes_per_pixel() will return 1).
+ // Otherwise, it will always point to a buffer containing 32-bit RGBA pixels (A will always be 255, and get_bytes_per_pixel() will return 4).
+ // Returns JPGD_SUCCESS if a scan line has been returned.
+ // Returns JPGD_DONE if all scan lines have been returned.
+ // Returns JPGD_FAILED if an error occurred. Call get_error_code() for a more info.
+ int decode(const void** pScan_line, uint* pScan_line_len);
+
+ inline jpgd_status get_error_code() const { return m_error_code; }
+
+ inline int get_width() const { return m_image_x_size; }
+ inline int get_height() const { return m_image_y_size; }
+
+ inline int get_num_components() const { return m_comps_in_frame; }
+
+ inline int get_bytes_per_pixel() const { return m_dest_bytes_per_pixel; }
+ inline int get_bytes_per_scan_line() const { return m_image_x_size * get_bytes_per_pixel(); }
+
+ // Returns the total number of bytes actually consumed by the decoder (which should equal the actual size of the JPEG file).
+ inline int get_total_bytes_read() const { return m_total_bytes_read; }
+
+ private:
+ jpeg_decoder(const jpeg_decoder&);
+ jpeg_decoder& operator =(const jpeg_decoder&);
+
+ typedef void (*pDecode_block_func)(jpeg_decoder*, int, int, int);
+
+ struct huff_tables
+ {
+ bool ac_table;
+ uint look_up[256];
+ uint look_up2[256];
+ uint8 code_size[JPGD_HUFF_CODE_SIZE_MAX_LENGTH];
+ uint tree[JPGD_HUFF_TREE_MAX_LENGTH];
+ };
+
+ struct coeff_buf
+ {
+ uint8* pData;
+ int block_num_x, block_num_y;
+ int block_len_x, block_len_y;
+ int block_size;
+ };
+
+ struct mem_block
+ {
+ mem_block* m_pNext;
+ size_t m_used_count;
+ size_t m_size;
+ char m_data[1];
+ };
+
+ jmp_buf m_jmp_state;
+ uint32_t m_flags;
+ mem_block* m_pMem_blocks;
+ int m_image_x_size;
+ int m_image_y_size;
+ jpeg_decoder_stream* m_pStream;
+
+ int m_progressive_flag;
+
+ uint8 m_huff_ac[JPGD_MAX_HUFF_TABLES];
+ uint8* m_huff_num[JPGD_MAX_HUFF_TABLES]; // pointer to number of Huffman codes per bit size
+ uint8* m_huff_val[JPGD_MAX_HUFF_TABLES]; // pointer to Huffman codes per bit size
+ jpgd_quant_t* m_quant[JPGD_MAX_QUANT_TABLES]; // pointer to quantization tables
+ int m_scan_type; // Gray, Yh1v1, Yh1v2, Yh2v1, Yh2v2 (CMYK111, CMYK4114 no longer supported)
+ int m_comps_in_frame; // # of components in frame
+ int m_comp_h_samp[JPGD_MAX_COMPONENTS]; // component's horizontal sampling factor
+ int m_comp_v_samp[JPGD_MAX_COMPONENTS]; // component's vertical sampling factor
+ int m_comp_quant[JPGD_MAX_COMPONENTS]; // component's quantization table selector
+ int m_comp_ident[JPGD_MAX_COMPONENTS]; // component's ID
+ int m_comp_h_blocks[JPGD_MAX_COMPONENTS];
+ int m_comp_v_blocks[JPGD_MAX_COMPONENTS];
+ int m_comps_in_scan; // # of components in scan
+ int m_comp_list[JPGD_MAX_COMPS_IN_SCAN]; // components in this scan
+ int m_comp_dc_tab[JPGD_MAX_COMPONENTS]; // component's DC Huffman coding table selector
+ int m_comp_ac_tab[JPGD_MAX_COMPONENTS]; // component's AC Huffman coding table selector
+ int m_spectral_start; // spectral selection start
+ int m_spectral_end; // spectral selection end
+ int m_successive_low; // successive approximation low
+ int m_successive_high; // successive approximation high
+ int m_max_mcu_x_size; // MCU's max. X size in pixels
+ int m_max_mcu_y_size; // MCU's max. Y size in pixels
+ int m_blocks_per_mcu;
+ int m_max_blocks_per_row;
+ int m_mcus_per_row, m_mcus_per_col;
+ int m_mcu_org[JPGD_MAX_BLOCKS_PER_MCU];
+ int m_total_lines_left; // total # lines left in image
+ int m_mcu_lines_left; // total # lines left in this MCU
+ int m_num_buffered_scanlines;
+ int m_real_dest_bytes_per_scan_line;
+ int m_dest_bytes_per_scan_line; // rounded up
+ int m_dest_bytes_per_pixel; // 4 (RGB) or 1 (Y)
+ huff_tables* m_pHuff_tabs[JPGD_MAX_HUFF_TABLES];
+ coeff_buf* m_dc_coeffs[JPGD_MAX_COMPONENTS];
+ coeff_buf* m_ac_coeffs[JPGD_MAX_COMPONENTS];
+ int m_eob_run;
+ int m_block_y_mcu[JPGD_MAX_COMPONENTS];
+ uint8* m_pIn_buf_ofs;
+ int m_in_buf_left;
+ int m_tem_flag;
+
+ uint8 m_in_buf_pad_start[64];
+ uint8 m_in_buf[JPGD_IN_BUF_SIZE + 128];
+ uint8 m_in_buf_pad_end[64];
+
+ int m_bits_left;
+ uint m_bit_buf;
+ int m_restart_interval;
+ int m_restarts_left;
+ int m_next_restart_num;
+ int m_max_mcus_per_row;
+ int m_max_blocks_per_mcu;
+
+ int m_max_mcus_per_col;
+ uint m_last_dc_val[JPGD_MAX_COMPONENTS];
+ jpgd_block_t* m_pMCU_coefficients;
+ int m_mcu_block_max_zag[JPGD_MAX_BLOCKS_PER_MCU];
+ uint8* m_pSample_buf;
+ uint8* m_pSample_buf_prev;
+ int m_crr[256];
+ int m_cbb[256];
+ int m_crg[256];
+ int m_cbg[256];
+ uint8* m_pScan_line_0;
+ uint8* m_pScan_line_1;
+ jpgd_status m_error_code;
+ int m_total_bytes_read;
+
+ bool m_ready_flag;
+ bool m_eof_flag;
+ bool m_sample_buf_prev_valid;
+
+ inline int check_sample_buf_ofs(int ofs) const { assert(ofs >= 0); assert(ofs < m_max_blocks_per_row * 64); return ofs; }
+ void free_all_blocks();
+ JPGD_NORETURN void stop_decoding(jpgd_status status);
+ void* alloc(size_t n, bool zero = false);
+ void word_clear(void* p, uint16 c, uint n);
+ void prep_in_buffer();
+ void read_dht_marker();
+ void read_dqt_marker();
+ void read_sof_marker();
+ void skip_variable_marker();
+ void read_dri_marker();
+ void read_sos_marker();
+ int next_marker();
+ int process_markers();
+ void locate_soi_marker();
+ void locate_sof_marker();
+ int locate_sos_marker();
+ void init(jpeg_decoder_stream* pStream, uint32_t flags);
+ void create_look_ups();
+ void fix_in_buffer();
+ void transform_mcu(int mcu_row);
+ coeff_buf* coeff_buf_open(int block_num_x, int block_num_y, int block_len_x, int block_len_y);
+ inline jpgd_block_t* coeff_buf_getp(coeff_buf* cb, int block_x, int block_y);
+ void load_next_row();
+ void decode_next_row();
+ void make_huff_table(int index, huff_tables* pH);
+ void check_quant_tables();
+ void check_huff_tables();
+ bool calc_mcu_block_order();
+ int init_scan();
+ void init_frame();
+ void process_restart();
+ void decode_scan(pDecode_block_func decode_block_func);
+ void init_progressive();
+ void init_sequential();
+ void decode_start();
+ void decode_init(jpeg_decoder_stream* pStream, uint32_t flags);
+ void H2V2Convert();
+ uint32_t H2V2ConvertFiltered();
+ void H2V1Convert();
+ void H2V1ConvertFiltered();
+ void H1V2Convert();
+ void H1V2ConvertFiltered();
+ void H1V1Convert();
+ void gray_convert();
+ void find_eoi();
+ inline uint get_char();
+ inline uint get_char(bool* pPadding_flag);
+ inline void stuff_char(uint8 q);
+ inline uint8 get_octet();
+ inline uint get_bits(int num_bits);
+ inline uint get_bits_no_markers(int numbits);
+ inline int huff_decode(huff_tables* pH);
+ inline int huff_decode(huff_tables* pH, int& extrabits);
+
+ // Clamps a value between 0-255.
+ static inline uint8 clamp(int i)
+ {
+ if (static_cast<uint>(i) > 255)
+ i = (((~i) >> 31) & 0xFF);
+ return static_cast<uint8>(i);
+ }
+ int decode_next_mcu_row();
+
+ static void decode_block_dc_first(jpeg_decoder* pD, int component_id, int block_x, int block_y);
+ static void decode_block_dc_refine(jpeg_decoder* pD, int component_id, int block_x, int block_y);
+ static void decode_block_ac_first(jpeg_decoder* pD, int component_id, int block_x, int block_y);
+ static void decode_block_ac_refine(jpeg_decoder* pD, int component_id, int block_x, int block_y);
+ };
+
+} // namespace jpgd
+
+#endif // JPEG_DECODER_H
