blob: 4ebb9d7ae27af6794505174bc6c0b4c12c939321 [file] [log] [blame]
/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "include/utils/SkBase64.h"
#include <cstdint>
#define DecodePad -2
#define EncodePad 64
static const char default_encode[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/=";
static const signed char decodeData[] = {
62, -1, -1, -1, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, DecodePad, -1, -1,
-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
};
#if defined _WIN32 // disable 'two', etc. may be used without having been initialized
#pragma warning ( push )
#pragma warning ( disable : 4701 )
#endif
SkBase64::Error SkBase64::Decode(const void* srcv, size_t srcLength, void* dstv, size_t* dstLength){
const unsigned char* src = static_cast<const unsigned char*>(srcv);
unsigned char* dst = static_cast<unsigned char*>(dstv);
int i = 0;
bool padTwo = false;
bool padThree = false;
char unsigned const * const end = src + srcLength;
while (src < end) {
unsigned char bytes[4];
int byte = 0;
do {
unsigned char srcByte = *src++;
if (srcByte == 0)
goto goHome;
if (srcByte <= ' ')
continue; // treat as white space
if (srcByte < '+' || srcByte > 'z')
return kBadCharError;
signed char decoded = decodeData[srcByte - '+'];
bytes[byte] = decoded;
if (decoded < 0) {
if (decoded == DecodePad)
goto handlePad;
return kBadCharError;
} else
byte++;
if (*src)
continue;
if (byte == 0)
goto goHome;
if (byte == 4)
break;
handlePad:
if (byte < 2)
return kPadError;
padThree = true;
if (byte == 2)
padTwo = true;
break;
} while (byte < 4);
int two = 0;
int three = 0;
if (dst) {
int one = (uint8_t) (bytes[0] << 2);
two = bytes[1];
one |= two >> 4;
two = (uint8_t) ((two << 4) & 0xFF);
three = bytes[2];
two |= three >> 2;
three = (uint8_t) ((three << 6) & 0xFF);
three |= bytes[3];
SkASSERT(one < 256 && two < 256 && three < 256);
dst[i] = (unsigned char) one;
}
i++;
if (padTwo)
break;
if (dst)
dst[i] = (unsigned char) two;
i++;
if (padThree)
break;
if (dst)
dst[i] = (unsigned char) three;
i++;
}
goHome:
*dstLength = i;
return kNoError;
}
#if defined _WIN32
#pragma warning ( pop )
#endif
size_t SkBase64::Encode(const void* srcv, size_t length, void* dstv, const char* encodeMap) {
const unsigned char* src = static_cast<const unsigned char*>(srcv);
unsigned char* dst = static_cast<unsigned char*>(dstv);
const char* encode;
if (nullptr == encodeMap) {
encode = default_encode;
} else {
encode = encodeMap;
}
if (dst) {
size_t remainder = length % 3;
char unsigned const * const end = &src[length - remainder];
while (src < end) {
unsigned a = *src++;
unsigned b = *src++;
unsigned c = *src++;
int d = c & 0x3F;
c = (c >> 6 | b << 2) & 0x3F;
b = (b >> 4 | a << 4) & 0x3F;
a = a >> 2;
*dst++ = encode[a];
*dst++ = encode[b];
*dst++ = encode[c];
*dst++ = encode[d];
}
if (remainder > 0) {
int k1 = 0;
int k2 = EncodePad;
int a = (uint8_t) *src++;
if (remainder == 2)
{
int b = *src++;
k1 = b >> 4;
k2 = (b << 2) & 0x3F;
}
*dst++ = encode[a >> 2];
*dst++ = encode[(k1 | a << 4) & 0x3F];
*dst++ = encode[k2];
*dst++ = encode[EncodePad];
}
}
return (length + 2) / 3 * 4;
}