| /* Copyright 2015 Google Inc. All Rights Reserved. |
| |
| Distributed under MIT license. |
| See file LICENSE for detail or copy at https://opensource.org/licenses/MIT |
| */ |
| |
| package org.brotli.dec; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.nio.ByteBuffer; |
| |
| /** |
| * API for Brotli decompression. |
| */ |
| final class Decode { |
| |
| static final int MIN_LARGE_WINDOW_BITS = 10; |
| /* Maximum was chosen to be 30 to allow efficient decoder implementation. |
| * Format allows bigger window, but Java does not support 2G+ arrays. */ |
| static final int MAX_LARGE_WINDOW_BITS = 30; |
| |
| //---------------------------------------------------------------------------- |
| // RunningState |
| //---------------------------------------------------------------------------- |
| private static final int UNINITIALIZED = 0; |
| private static final int INITIALIZED = 1; |
| private static final int BLOCK_START = 2; |
| private static final int COMPRESSED_BLOCK_START = 3; |
| private static final int MAIN_LOOP = 4; |
| private static final int READ_METADATA = 5; |
| private static final int COPY_UNCOMPRESSED = 6; |
| private static final int INSERT_LOOP = 7; |
| private static final int COPY_LOOP = 8; |
| private static final int USE_DICTIONARY = 9; |
| private static final int FINISHED = 10; |
| private static final int CLOSED = 11; |
| private static final int INIT_WRITE = 12; |
| private static final int WRITE = 13; |
| private static final int COPY_FROM_COMPOUND_DICTIONARY = 14; |
| |
| private static final int DEFAULT_CODE_LENGTH = 8; |
| private static final int CODE_LENGTH_REPEAT_CODE = 16; |
| private static final int NUM_LITERAL_CODES = 256; |
| private static final int NUM_COMMAND_CODES = 704; |
| private static final int NUM_BLOCK_LENGTH_CODES = 26; |
| private static final int LITERAL_CONTEXT_BITS = 6; |
| private static final int DISTANCE_CONTEXT_BITS = 2; |
| |
| private static final int CD_BLOCK_MAP_BITS = 8; |
| private static final int HUFFMAN_TABLE_BITS = 8; |
| private static final int HUFFMAN_TABLE_MASK = 0xFF; |
| |
| /** |
| * Maximum possible Huffman table size for an alphabet size of (index * 32), |
| * max code length 15 and root table bits 8. |
| * The biggest alphabet is "command" - 704 symbols. Though "distance" alphabet could theoretically |
| * outreach that limit (for 62 extra bit distances), practically it is limited by |
| * MAX_ALLOWED_DISTANCE and never gets bigger than 544 symbols. |
| */ |
| static final int[] MAX_HUFFMAN_TABLE_SIZE = { |
| 256, 402, 436, 468, 500, 534, 566, 598, 630, 662, 694, 726, 758, 790, 822, |
| 854, 886, 920, 952, 984, 1016, 1048, 1080 |
| }; |
| |
| private static final int HUFFMAN_TABLE_SIZE_26 = 396; |
| private static final int HUFFMAN_TABLE_SIZE_258 = 632; |
| |
| private static final int CODE_LENGTH_CODES = 18; |
| private static final int[] CODE_LENGTH_CODE_ORDER = { |
| 1, 2, 3, 4, 0, 5, 17, 6, 16, 7, 8, 9, 10, 11, 12, 13, 14, 15, |
| }; |
| |
| private static final int NUM_DISTANCE_SHORT_CODES = 16; |
| private static final int[] DISTANCE_SHORT_CODE_INDEX_OFFSET = { |
| 0, 3, 2, 1, 0, 0, 0, 0, 0, 0, 3, 3, 3, 3, 3, 3 |
| }; |
| |
| private static final int[] DISTANCE_SHORT_CODE_VALUE_OFFSET = { |
| 0, 0, 0, 0, -1, 1, -2, 2, -3, 3, -1, 1, -2, 2, -3, 3 |
| }; |
| |
| /** |
| * Static Huffman code for the code length code lengths. |
| */ |
| private static final int[] FIXED_TABLE = { |
| 0x020000, 0x020004, 0x020003, 0x030002, 0x020000, 0x020004, 0x020003, 0x040001, |
| 0x020000, 0x020004, 0x020003, 0x030002, 0x020000, 0x020004, 0x020003, 0x040005 |
| }; |
| |
| // TODO(eustas): generalize. |
| static final int MAX_TRANSFORMED_WORD_LENGTH = 5 + 24 + 8; |
| |
| private static final int MAX_DISTANCE_BITS = 24; |
| private static final int MAX_LARGE_WINDOW_DISTANCE_BITS = 62; |
| |
| /** |
| * Safe distance limit. |
| * |
| * Limit ((1 << 31) - 4) allows safe distance calculation without overflows, |
| * given the distance alphabet size is limited to corresponding size. |
| */ |
| private static final int MAX_ALLOWED_DISTANCE = 0x7FFFFFFC; |
| |
| //---------------------------------------------------------------------------- |
| // Prefix code LUT. |
| //---------------------------------------------------------------------------- |
| static final int[] BLOCK_LENGTH_OFFSET = { |
| 1, 5, 9, 13, 17, 25, 33, 41, 49, 65, 81, 97, 113, 145, 177, 209, 241, 305, 369, 497, |
| 753, 1265, 2289, 4337, 8433, 16625 |
| }; |
| |
| static final int[] BLOCK_LENGTH_N_BITS = { |
| 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7, 8, 9, 10, 11, 12, 13, 24 |
| }; |
| |
| static final short[] INSERT_LENGTH_N_BITS = { |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x02, 0x02, 0x03, 0x03, |
| 0x04, 0x04, 0x05, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0C, 0x0E, 0x18 |
| }; |
| |
| static final short[] COPY_LENGTH_N_BITS = { |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x02, 0x02, |
| 0x03, 0x03, 0x04, 0x04, 0x05, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x18 |
| }; |
| |
| // Each command is represented with 4x16-bit values: |
| // * [insertLenExtraBits, copyLenExtraBits] |
| // * insertLenOffset |
| // * copyLenOffset |
| // * distanceContext |
| static final short[] CMD_LOOKUP = new short[NUM_COMMAND_CODES * 4]; |
| |
| static { |
| unpackCommandLookupTable(CMD_LOOKUP); |
| } |
| |
| private static int log2floor(int i) { |
| int result = -1; |
| int step = 16; |
| while (step > 0) { |
| if ((i >>> step) != 0) { |
| result += step; |
| i = i >>> step; |
| } |
| step = step >> 1; |
| } |
| return result + i; |
| } |
| |
| private static int calculateDistanceAlphabetSize(int npostfix, int ndirect, int maxndistbits) { |
| return NUM_DISTANCE_SHORT_CODES + ndirect + 2 * (maxndistbits << npostfix); |
| } |
| |
| // TODO(eustas): add a correctness test for this function when |
| // large-window and dictionary are implemented. |
| private static int calculateDistanceAlphabetLimit(int maxDistance, int npostfix, int ndirect) { |
| if (maxDistance < ndirect + (2 << npostfix)) { |
| throw new IllegalArgumentException("maxDistance is too small"); |
| } |
| int offset = ((maxDistance - ndirect) >> npostfix) + 4; |
| int ndistbits = log2floor(offset) - 1; |
| int group = ((ndistbits - 1) << 1) | ((offset >> ndistbits) & 1); |
| return ((group - 1) << npostfix) + (1 << npostfix) + ndirect + NUM_DISTANCE_SHORT_CODES; |
| } |
| |
| private static void unpackCommandLookupTable(short[] cmdLookup) { |
| short[] insertLengthOffsets = new short[24]; |
| short[] copyLengthOffsets = new short[24]; |
| copyLengthOffsets[0] = 2; |
| for (int i = 0; i < 23; ++i) { |
| insertLengthOffsets[i + 1] = |
| (short) (insertLengthOffsets[i] + (1 << INSERT_LENGTH_N_BITS[i])); |
| copyLengthOffsets[i + 1] = |
| (short) (copyLengthOffsets[i] + (1 << COPY_LENGTH_N_BITS[i])); |
| } |
| |
| for (int cmdCode = 0; cmdCode < NUM_COMMAND_CODES; ++cmdCode) { |
| int rangeIdx = cmdCode >>> 6; |
| /* -4 turns any regular distance code to negative. */ |
| int distanceContextOffset = -4; |
| if (rangeIdx >= 2) { |
| rangeIdx -= 2; |
| distanceContextOffset = 0; |
| } |
| int insertCode = (((0x29850 >>> (rangeIdx * 2)) & 0x3) << 3) | ((cmdCode >>> 3) & 7); |
| int copyCode = (((0x26244 >>> (rangeIdx * 2)) & 0x3) << 3) | (cmdCode & 7); |
| short copyLengthOffset = copyLengthOffsets[copyCode]; |
| int distanceContext = |
| distanceContextOffset + (copyLengthOffset > 4 ? 3 : copyLengthOffset - 2); |
| int index = cmdCode * 4; |
| cmdLookup[index + 0] = |
| (short) (INSERT_LENGTH_N_BITS[insertCode] | (COPY_LENGTH_N_BITS[copyCode] << 8)); |
| cmdLookup[index + 1] = insertLengthOffsets[insertCode]; |
| cmdLookup[index + 2] = copyLengthOffsets[copyCode]; |
| cmdLookup[index + 3] = (short) distanceContext; |
| } |
| } |
| |
| /** |
| * Reads brotli stream header and parses "window bits". |
| * |
| * @param s initialized state, before any read is performed. |
| * @return -1 if header is invalid |
| */ |
| private static int decodeWindowBits(State s) { |
| /* Change the meaning of flag. Before that step it means "decoder must be capable of reading |
| * "large-window" brotli stream. After this step it means that "large-window" feature |
| * is actually detected. Despite the window size could be same as before (lgwin = 10..24), |
| * encoded distances are allowed to be much greater, thus bigger dictinary could be used. */ |
| int largeWindowEnabled = s.isLargeWindow; |
| s.isLargeWindow = 0; |
| |
| BitReader.fillBitWindow(s); |
| if (BitReader.readFewBits(s, 1) == 0) { |
| return 16; |
| } |
| int n = BitReader.readFewBits(s, 3); |
| if (n != 0) { |
| return 17 + n; |
| } |
| n = BitReader.readFewBits(s, 3); |
| if (n != 0) { |
| if (n == 1) { |
| if (largeWindowEnabled == 0) { |
| /* Reserved value in regular brotli stream. */ |
| return -1; |
| } |
| s.isLargeWindow = 1; |
| /* Check "reserved" bit for future (post-large-window) extensions. */ |
| if (BitReader.readFewBits(s, 1) == 1) { |
| return -1; |
| } |
| n = BitReader.readFewBits(s, 6); |
| if (n < MIN_LARGE_WINDOW_BITS || n > MAX_LARGE_WINDOW_BITS) { |
| /* Encoded window bits value is too small or too big. */ |
| return -1; |
| } |
| return n; |
| } else { |
| return 8 + n; |
| } |
| } |
| return 17; |
| } |
| |
| /** |
| * Switch decoder to "eager" mode. |
| * |
| * In "eager" mode decoder returns as soon as there is enough data to fill output buffer. |
| * |
| * @param s initialized state, before any read is performed. |
| */ |
| static void enableEagerOutput(State s) { |
| if (s.runningState != INITIALIZED) { |
| throw new IllegalStateException("State MUST be freshly initialized"); |
| } |
| s.isEager = 1; |
| } |
| |
| static void enableLargeWindow(State s) { |
| if (s.runningState != INITIALIZED) { |
| throw new IllegalStateException("State MUST be freshly initialized"); |
| } |
| s.isLargeWindow = 1; |
| } |
| |
| // TODO(eustas): do we need byte views? |
| static void attachDictionaryChunk(State s, byte[] data) { |
| if (s.runningState != INITIALIZED) { |
| throw new IllegalStateException("State MUST be freshly initialized"); |
| } |
| if (s.cdNumChunks == 0) { |
| s.cdChunks = new byte[16][]; |
| s.cdChunkOffsets = new int[16]; |
| s.cdBlockBits = -1; |
| } |
| if (s.cdNumChunks == 15) { |
| throw new IllegalStateException("Too many dictionary chunks"); |
| } |
| s.cdChunks[s.cdNumChunks] = data; |
| s.cdNumChunks++; |
| s.cdTotalSize += data.length; |
| s.cdChunkOffsets[s.cdNumChunks] = s.cdTotalSize; |
| } |
| |
| /** |
| * Associate input with decoder state. |
| * |
| * @param s uninitialized state without associated input |
| * @param input compressed data source |
| */ |
| static void initState(State s, InputStream input) { |
| if (s.runningState != UNINITIALIZED) { |
| throw new IllegalStateException("State MUST be uninitialized"); |
| } |
| /* 6 trees + 1 extra "offset" slot to simplify table decoding logic. */ |
| s.blockTrees = new int[7 + 3 * (HUFFMAN_TABLE_SIZE_258 + HUFFMAN_TABLE_SIZE_26)]; |
| s.blockTrees[0] = 7; |
| s.distRbIdx = 3; |
| int maxDistanceAlphabetLimit = calculateDistanceAlphabetLimit(MAX_ALLOWED_DISTANCE, 3, 15 << 3); |
| s.distExtraBits = new byte[maxDistanceAlphabetLimit]; |
| s.distOffset = new int[maxDistanceAlphabetLimit]; |
| s.input = input; |
| BitReader.initBitReader(s); |
| s.runningState = INITIALIZED; |
| } |
| |
| static void close(State s) throws IOException { |
| if (s.runningState == UNINITIALIZED) { |
| throw new IllegalStateException("State MUST be initialized"); |
| } |
| if (s.runningState == CLOSED) { |
| return; |
| } |
| s.runningState = CLOSED; |
| if (s.input != null) { |
| Utils.closeInput(s.input); |
| s.input = null; |
| } |
| } |
| |
| /** |
| * Decodes a number in the range [0..255], by reading 1 - 11 bits. |
| */ |
| private static int decodeVarLenUnsignedByte(State s) { |
| BitReader.fillBitWindow(s); |
| if (BitReader.readFewBits(s, 1) != 0) { |
| int n = BitReader.readFewBits(s, 3); |
| if (n == 0) { |
| return 1; |
| } else { |
| return BitReader.readFewBits(s, n) + (1 << n); |
| } |
| } |
| return 0; |
| } |
| |
| private static void decodeMetaBlockLength(State s) { |
| BitReader.fillBitWindow(s); |
| s.inputEnd = BitReader.readFewBits(s, 1); |
| s.metaBlockLength = 0; |
| s.isUncompressed = 0; |
| s.isMetadata = 0; |
| if ((s.inputEnd != 0) && BitReader.readFewBits(s, 1) != 0) { |
| return; |
| } |
| int sizeNibbles = BitReader.readFewBits(s, 2) + 4; |
| if (sizeNibbles == 7) { |
| s.isMetadata = 1; |
| if (BitReader.readFewBits(s, 1) != 0) { |
| throw new BrotliRuntimeException("Corrupted reserved bit"); |
| } |
| int sizeBytes = BitReader.readFewBits(s, 2); |
| if (sizeBytes == 0) { |
| return; |
| } |
| for (int i = 0; i < sizeBytes; i++) { |
| BitReader.fillBitWindow(s); |
| int bits = BitReader.readFewBits(s, 8); |
| if (bits == 0 && i + 1 == sizeBytes && sizeBytes > 1) { |
| throw new BrotliRuntimeException("Exuberant nibble"); |
| } |
| s.metaBlockLength |= bits << (i * 8); |
| } |
| } else { |
| for (int i = 0; i < sizeNibbles; i++) { |
| BitReader.fillBitWindow(s); |
| int bits = BitReader.readFewBits(s, 4); |
| if (bits == 0 && i + 1 == sizeNibbles && sizeNibbles > 4) { |
| throw new BrotliRuntimeException("Exuberant nibble"); |
| } |
| s.metaBlockLength |= bits << (i * 4); |
| } |
| } |
| s.metaBlockLength++; |
| if (s.inputEnd == 0) { |
| s.isUncompressed = BitReader.readFewBits(s, 1); |
| } |
| } |
| |
| /** |
| * Decodes the next Huffman code from bit-stream. |
| */ |
| private static int readSymbol(int[] tableGroup, int tableIdx, State s) { |
| int offset = tableGroup[tableIdx]; |
| int val = BitReader.peekBits(s); |
| offset += val & HUFFMAN_TABLE_MASK; |
| int bits = tableGroup[offset] >> 16; |
| int sym = tableGroup[offset] & 0xFFFF; |
| if (bits <= HUFFMAN_TABLE_BITS) { |
| s.bitOffset += bits; |
| return sym; |
| } |
| offset += sym; |
| int mask = (1 << bits) - 1; |
| offset += (val & mask) >>> HUFFMAN_TABLE_BITS; |
| s.bitOffset += ((tableGroup[offset] >> 16) + HUFFMAN_TABLE_BITS); |
| return tableGroup[offset] & 0xFFFF; |
| } |
| |
| private static int readBlockLength(int[] tableGroup, int tableIdx, State s) { |
| BitReader.fillBitWindow(s); |
| int code = readSymbol(tableGroup, tableIdx, s); |
| int n = BLOCK_LENGTH_N_BITS[code]; |
| BitReader.fillBitWindow(s); |
| return BLOCK_LENGTH_OFFSET[code] + BitReader.readBits(s, n); |
| } |
| |
| private static void moveToFront(int[] v, int index) { |
| int value = v[index]; |
| for (; index > 0; index--) { |
| v[index] = v[index - 1]; |
| } |
| v[0] = value; |
| } |
| |
| private static void inverseMoveToFrontTransform(byte[] v, int vLen) { |
| int[] mtf = new int[256]; |
| for (int i = 0; i < 256; i++) { |
| mtf[i] = i; |
| } |
| for (int i = 0; i < vLen; i++) { |
| int index = v[i] & 0xFF; |
| v[i] = (byte) mtf[index]; |
| if (index != 0) { |
| moveToFront(mtf, index); |
| } |
| } |
| } |
| |
| private static void readHuffmanCodeLengths( |
| int[] codeLengthCodeLengths, int numSymbols, int[] codeLengths, State s) { |
| int symbol = 0; |
| int prevCodeLen = DEFAULT_CODE_LENGTH; |
| int repeat = 0; |
| int repeatCodeLen = 0; |
| int space = 32768; |
| int[] table = new int[32 + 1]; /* Speculative single entry table group. */ |
| int tableIdx = table.length - 1; |
| Huffman.buildHuffmanTable(table, tableIdx, 5, codeLengthCodeLengths, CODE_LENGTH_CODES); |
| |
| while (symbol < numSymbols && space > 0) { |
| BitReader.readMoreInput(s); |
| BitReader.fillBitWindow(s); |
| int p = BitReader.peekBits(s) & 31; |
| s.bitOffset += table[p] >> 16; |
| int codeLen = table[p] & 0xFFFF; |
| if (codeLen < CODE_LENGTH_REPEAT_CODE) { |
| repeat = 0; |
| codeLengths[symbol++] = codeLen; |
| if (codeLen != 0) { |
| prevCodeLen = codeLen; |
| space -= 32768 >> codeLen; |
| } |
| } else { |
| int extraBits = codeLen - 14; |
| int newLen = 0; |
| if (codeLen == CODE_LENGTH_REPEAT_CODE) { |
| newLen = prevCodeLen; |
| } |
| if (repeatCodeLen != newLen) { |
| repeat = 0; |
| repeatCodeLen = newLen; |
| } |
| int oldRepeat = repeat; |
| if (repeat > 0) { |
| repeat -= 2; |
| repeat <<= extraBits; |
| } |
| BitReader.fillBitWindow(s); |
| repeat += BitReader.readFewBits(s, extraBits) + 3; |
| int repeatDelta = repeat - oldRepeat; |
| if (symbol + repeatDelta > numSymbols) { |
| throw new BrotliRuntimeException("symbol + repeatDelta > numSymbols"); // COV_NF_LINE |
| } |
| for (int i = 0; i < repeatDelta; i++) { |
| codeLengths[symbol++] = repeatCodeLen; |
| } |
| if (repeatCodeLen != 0) { |
| space -= repeatDelta << (15 - repeatCodeLen); |
| } |
| } |
| } |
| if (space != 0) { |
| throw new BrotliRuntimeException("Unused space"); // COV_NF_LINE |
| } |
| // TODO(eustas): Pass max_symbol to Huffman table builder instead? |
| Utils.fillIntsWithZeroes(codeLengths, symbol, numSymbols); |
| } |
| |
| private static void checkDupes(int[] symbols, int length) { |
| for (int i = 0; i < length - 1; ++i) { |
| for (int j = i + 1; j < length; ++j) { |
| if (symbols[i] == symbols[j]) { |
| throw new BrotliRuntimeException("Duplicate simple Huffman code symbol"); // COV_NF_LINE |
| } |
| } |
| } |
| } |
| |
| /** |
| * Reads up to 4 symbols directly and applies predefined histograms. |
| */ |
| private static int readSimpleHuffmanCode(int alphabetSizeMax, int alphabetSizeLimit, |
| int[] tableGroup, int tableIdx, State s) { |
| // TODO(eustas): Avoid allocation? |
| int[] codeLengths = new int[alphabetSizeLimit]; |
| int[] symbols = new int[4]; |
| |
| int maxBits = 1 + log2floor(alphabetSizeMax - 1); |
| |
| int numSymbols = BitReader.readFewBits(s, 2) + 1; |
| for (int i = 0; i < numSymbols; i++) { |
| BitReader.fillBitWindow(s); |
| int symbol = BitReader.readFewBits(s, maxBits); |
| if (symbol >= alphabetSizeLimit) { |
| throw new BrotliRuntimeException("Can't readHuffmanCode"); // COV_NF_LINE |
| } |
| symbols[i] = symbol; |
| } |
| checkDupes(symbols, numSymbols); |
| |
| int histogramId = numSymbols; |
| if (numSymbols == 4) { |
| histogramId += BitReader.readFewBits(s, 1); |
| } |
| |
| switch (histogramId) { |
| case 1: |
| codeLengths[symbols[0]] = 1; |
| break; |
| |
| case 2: |
| codeLengths[symbols[0]] = 1; |
| codeLengths[symbols[1]] = 1; |
| break; |
| |
| case 3: |
| codeLengths[symbols[0]] = 1; |
| codeLengths[symbols[1]] = 2; |
| codeLengths[symbols[2]] = 2; |
| break; |
| |
| case 4: // uniform 4-symbol histogram |
| codeLengths[symbols[0]] = 2; |
| codeLengths[symbols[1]] = 2; |
| codeLengths[symbols[2]] = 2; |
| codeLengths[symbols[3]] = 2; |
| break; |
| |
| case 5: // prioritized 4-symbol histogram |
| codeLengths[symbols[0]] = 1; |
| codeLengths[symbols[1]] = 2; |
| codeLengths[symbols[2]] = 3; |
| codeLengths[symbols[3]] = 3; |
| break; |
| |
| default: |
| break; |
| } |
| |
| // TODO(eustas): Use specialized version? |
| return Huffman.buildHuffmanTable( |
| tableGroup, tableIdx, HUFFMAN_TABLE_BITS, codeLengths, alphabetSizeLimit); |
| } |
| |
| // Decode Huffman-coded code lengths. |
| private static int readComplexHuffmanCode(int alphabetSizeLimit, int skip, |
| int[] tableGroup, int tableIdx, State s) { |
| // TODO(eustas): Avoid allocation? |
| int[] codeLengths = new int[alphabetSizeLimit]; |
| int[] codeLengthCodeLengths = new int[CODE_LENGTH_CODES]; |
| int space = 32; |
| int numCodes = 0; |
| for (int i = skip; i < CODE_LENGTH_CODES && space > 0; i++) { |
| int codeLenIdx = CODE_LENGTH_CODE_ORDER[i]; |
| BitReader.fillBitWindow(s); |
| int p = BitReader.peekBits(s) & 15; |
| // TODO(eustas): Demultiplex FIXED_TABLE. |
| s.bitOffset += FIXED_TABLE[p] >> 16; |
| int v = FIXED_TABLE[p] & 0xFFFF; |
| codeLengthCodeLengths[codeLenIdx] = v; |
| if (v != 0) { |
| space -= (32 >> v); |
| numCodes++; |
| } |
| } |
| if (space != 0 && numCodes != 1) { |
| throw new BrotliRuntimeException("Corrupted Huffman code histogram"); // COV_NF_LINE |
| } |
| |
| readHuffmanCodeLengths(codeLengthCodeLengths, alphabetSizeLimit, codeLengths, s); |
| |
| return Huffman.buildHuffmanTable( |
| tableGroup, tableIdx, HUFFMAN_TABLE_BITS, codeLengths, alphabetSizeLimit); |
| } |
| |
| /** |
| * Decodes Huffman table from bit-stream. |
| * |
| * @return number of slots used by resulting Huffman table |
| */ |
| private static int readHuffmanCode(int alphabetSizeMax, int alphabetSizeLimit, |
| int[] tableGroup, int tableIdx, State s) { |
| BitReader.readMoreInput(s); |
| BitReader.fillBitWindow(s); |
| int simpleCodeOrSkip = BitReader.readFewBits(s, 2); |
| if (simpleCodeOrSkip == 1) { |
| return readSimpleHuffmanCode(alphabetSizeMax, alphabetSizeLimit, tableGroup, tableIdx, s); |
| } else { |
| return readComplexHuffmanCode(alphabetSizeLimit, simpleCodeOrSkip, tableGroup, tableIdx, s); |
| } |
| } |
| |
| private static int decodeContextMap(int contextMapSize, byte[] contextMap, State s) { |
| BitReader.readMoreInput(s); |
| int numTrees = decodeVarLenUnsignedByte(s) + 1; |
| |
| if (numTrees == 1) { |
| Utils.fillBytesWithZeroes(contextMap, 0, contextMapSize); |
| return numTrees; |
| } |
| |
| BitReader.fillBitWindow(s); |
| int useRleForZeros = BitReader.readFewBits(s, 1); |
| int maxRunLengthPrefix = 0; |
| if (useRleForZeros != 0) { |
| maxRunLengthPrefix = BitReader.readFewBits(s, 4) + 1; |
| } |
| int alphabetSize = numTrees + maxRunLengthPrefix; |
| int tableSize = MAX_HUFFMAN_TABLE_SIZE[(alphabetSize + 31) >> 5]; |
| /* Speculative single entry table group. */ |
| int[] table = new int[tableSize + 1]; |
| int tableIdx = table.length - 1; |
| readHuffmanCode(alphabetSize, alphabetSize, table, tableIdx, s); |
| for (int i = 0; i < contextMapSize; ) { |
| BitReader.readMoreInput(s); |
| BitReader.fillBitWindow(s); |
| int code = readSymbol(table, tableIdx, s); |
| if (code == 0) { |
| contextMap[i] = 0; |
| i++; |
| } else if (code <= maxRunLengthPrefix) { |
| BitReader.fillBitWindow(s); |
| int reps = (1 << code) + BitReader.readFewBits(s, code); |
| while (reps != 0) { |
| if (i >= contextMapSize) { |
| throw new BrotliRuntimeException("Corrupted context map"); // COV_NF_LINE |
| } |
| contextMap[i] = 0; |
| i++; |
| reps--; |
| } |
| } else { |
| contextMap[i] = (byte) (code - maxRunLengthPrefix); |
| i++; |
| } |
| } |
| BitReader.fillBitWindow(s); |
| if (BitReader.readFewBits(s, 1) == 1) { |
| inverseMoveToFrontTransform(contextMap, contextMapSize); |
| } |
| return numTrees; |
| } |
| |
| private static int decodeBlockTypeAndLength(State s, int treeType, int numBlockTypes) { |
| final int[] ringBuffers = s.rings; |
| final int offset = 4 + treeType * 2; |
| BitReader.fillBitWindow(s); |
| int blockType = readSymbol(s.blockTrees, 2 * treeType, s); |
| int result = readBlockLength(s.blockTrees, 2 * treeType + 1, s); |
| |
| if (blockType == 1) { |
| blockType = ringBuffers[offset + 1] + 1; |
| } else if (blockType == 0) { |
| blockType = ringBuffers[offset]; |
| } else { |
| blockType -= 2; |
| } |
| if (blockType >= numBlockTypes) { |
| blockType -= numBlockTypes; |
| } |
| ringBuffers[offset] = ringBuffers[offset + 1]; |
| ringBuffers[offset + 1] = blockType; |
| return result; |
| } |
| |
| private static void decodeLiteralBlockSwitch(State s) { |
| s.literalBlockLength = decodeBlockTypeAndLength(s, 0, s.numLiteralBlockTypes); |
| int literalBlockType = s.rings[5]; |
| s.contextMapSlice = literalBlockType << LITERAL_CONTEXT_BITS; |
| s.literalTreeIdx = s.contextMap[s.contextMapSlice] & 0xFF; |
| int contextMode = s.contextModes[literalBlockType]; |
| s.contextLookupOffset1 = contextMode << 9; |
| s.contextLookupOffset2 = s.contextLookupOffset1 + 256; |
| } |
| |
| private static void decodeCommandBlockSwitch(State s) { |
| s.commandBlockLength = decodeBlockTypeAndLength(s, 1, s.numCommandBlockTypes); |
| s.commandTreeIdx = s.rings[7]; |
| } |
| |
| private static void decodeDistanceBlockSwitch(State s) { |
| s.distanceBlockLength = decodeBlockTypeAndLength(s, 2, s.numDistanceBlockTypes); |
| s.distContextMapSlice = s.rings[9] << DISTANCE_CONTEXT_BITS; |
| } |
| |
| private static void maybeReallocateRingBuffer(State s) { |
| int newSize = s.maxRingBufferSize; |
| if (newSize > s.expectedTotalSize) { |
| /* TODO(eustas): Handle 2GB+ cases more gracefully. */ |
| int minimalNewSize = s.expectedTotalSize; |
| while ((newSize >> 1) > minimalNewSize) { |
| newSize >>= 1; |
| } |
| if ((s.inputEnd == 0) && newSize < 16384 && s.maxRingBufferSize >= 16384) { |
| newSize = 16384; |
| } |
| } |
| if (newSize <= s.ringBufferSize) { |
| return; |
| } |
| int ringBufferSizeWithSlack = newSize + MAX_TRANSFORMED_WORD_LENGTH; |
| byte[] newBuffer = new byte[ringBufferSizeWithSlack]; |
| if (s.ringBuffer.length != 0) { |
| System.arraycopy(s.ringBuffer, 0, newBuffer, 0, s.ringBufferSize); |
| } |
| s.ringBuffer = newBuffer; |
| s.ringBufferSize = newSize; |
| } |
| |
| private static void readNextMetablockHeader(State s) { |
| if (s.inputEnd != 0) { |
| s.nextRunningState = FINISHED; |
| s.runningState = INIT_WRITE; |
| return; |
| } |
| // TODO(eustas): Reset? Do we need this? |
| s.literalTreeGroup = new int[0]; |
| s.commandTreeGroup = new int[0]; |
| s.distanceTreeGroup = new int[0]; |
| |
| BitReader.readMoreInput(s); |
| decodeMetaBlockLength(s); |
| if ((s.metaBlockLength == 0) && (s.isMetadata == 0)) { |
| return; |
| } |
| if ((s.isUncompressed != 0) || (s.isMetadata != 0)) { |
| BitReader.jumpToByteBoundary(s); |
| s.runningState = (s.isMetadata != 0) ? READ_METADATA : COPY_UNCOMPRESSED; |
| } else { |
| s.runningState = COMPRESSED_BLOCK_START; |
| } |
| |
| if (s.isMetadata != 0) { |
| return; |
| } |
| s.expectedTotalSize += s.metaBlockLength; |
| if (s.expectedTotalSize > 1 << 30) { |
| s.expectedTotalSize = 1 << 30; |
| } |
| if (s.ringBufferSize < s.maxRingBufferSize) { |
| maybeReallocateRingBuffer(s); |
| } |
| } |
| |
| private static int readMetablockPartition(State s, int treeType, int numBlockTypes) { |
| int offset = s.blockTrees[2 * treeType]; |
| if (numBlockTypes <= 1) { |
| s.blockTrees[2 * treeType + 1] = offset; |
| s.blockTrees[2 * treeType + 2] = offset; |
| return 1 << 28; |
| } |
| |
| int blockTypeAlphabetSize = numBlockTypes + 2; |
| offset += readHuffmanCode( |
| blockTypeAlphabetSize, blockTypeAlphabetSize, s.blockTrees, 2 * treeType, s); |
| s.blockTrees[2 * treeType + 1] = offset; |
| |
| int blockLengthAlphabetSize = NUM_BLOCK_LENGTH_CODES; |
| offset += readHuffmanCode( |
| blockLengthAlphabetSize, blockLengthAlphabetSize, s.blockTrees, 2 * treeType + 1, s); |
| s.blockTrees[2 * treeType + 2] = offset; |
| |
| return readBlockLength(s.blockTrees, 2 * treeType + 1, s); |
| } |
| |
| private static void calculateDistanceLut(State s, int alphabetSizeLimit) { |
| byte[] distExtraBits = s.distExtraBits; |
| int[] distOffset = s.distOffset; |
| int npostfix = s.distancePostfixBits; |
| int ndirect = s.numDirectDistanceCodes; |
| int postfix = 1 << npostfix; |
| int bits = 1; |
| int half = 0; |
| |
| /* Skip short codes. */ |
| int i = NUM_DISTANCE_SHORT_CODES; |
| |
| /* Fill direct codes. */ |
| for (int j = 0; j < ndirect; ++j) { |
| distExtraBits[i] = 0; |
| distOffset[i] = j + 1; |
| ++i; |
| } |
| |
| /* Fill regular distance codes. */ |
| while (i < alphabetSizeLimit) { |
| int base = ndirect + ((((2 + half) << bits) - 4) << npostfix) + 1; |
| /* Always fill the complete group. */ |
| for (int j = 0; j < postfix; ++j) { |
| distExtraBits[i] = (byte) bits; |
| distOffset[i] = base + j; |
| ++i; |
| } |
| bits = bits + half; |
| half = half ^ 1; |
| } |
| } |
| |
| private static void readMetablockHuffmanCodesAndContextMaps(State s) { |
| s.numLiteralBlockTypes = decodeVarLenUnsignedByte(s) + 1; |
| s.literalBlockLength = readMetablockPartition(s, 0, s.numLiteralBlockTypes); |
| s.numCommandBlockTypes = decodeVarLenUnsignedByte(s) + 1; |
| s.commandBlockLength = readMetablockPartition(s, 1, s.numCommandBlockTypes); |
| s.numDistanceBlockTypes = decodeVarLenUnsignedByte(s) + 1; |
| s.distanceBlockLength = readMetablockPartition(s, 2, s.numDistanceBlockTypes); |
| |
| BitReader.readMoreInput(s); |
| BitReader.fillBitWindow(s); |
| s.distancePostfixBits = BitReader.readFewBits(s, 2); |
| s.numDirectDistanceCodes = BitReader.readFewBits(s, 4) << s.distancePostfixBits; |
| // TODO(eustas): Reuse? |
| s.contextModes = new byte[s.numLiteralBlockTypes]; |
| for (int i = 0; i < s.numLiteralBlockTypes;) { |
| /* Ensure that less than 256 bits read between readMoreInput. */ |
| int limit = Math.min(i + 96, s.numLiteralBlockTypes); |
| for (; i < limit; ++i) { |
| BitReader.fillBitWindow(s); |
| s.contextModes[i] = (byte) BitReader.readFewBits(s, 2); |
| } |
| BitReader.readMoreInput(s); |
| } |
| |
| // TODO(eustas): Reuse? |
| s.contextMap = new byte[s.numLiteralBlockTypes << LITERAL_CONTEXT_BITS]; |
| int numLiteralTrees = decodeContextMap(s.numLiteralBlockTypes << LITERAL_CONTEXT_BITS, |
| s.contextMap, s); |
| s.trivialLiteralContext = 1; |
| for (int j = 0; j < s.numLiteralBlockTypes << LITERAL_CONTEXT_BITS; j++) { |
| if (s.contextMap[j] != j >> LITERAL_CONTEXT_BITS) { |
| s.trivialLiteralContext = 0; |
| break; |
| } |
| } |
| |
| // TODO(eustas): Reuse? |
| s.distContextMap = new byte[s.numDistanceBlockTypes << DISTANCE_CONTEXT_BITS]; |
| int numDistTrees = decodeContextMap(s.numDistanceBlockTypes << DISTANCE_CONTEXT_BITS, |
| s.distContextMap, s); |
| |
| s.literalTreeGroup = decodeHuffmanTreeGroup(NUM_LITERAL_CODES, NUM_LITERAL_CODES, |
| numLiteralTrees, s); |
| s.commandTreeGroup = decodeHuffmanTreeGroup(NUM_COMMAND_CODES, NUM_COMMAND_CODES, |
| s.numCommandBlockTypes, s); |
| int distanceAlphabetSizeMax = calculateDistanceAlphabetSize( |
| s.distancePostfixBits, s.numDirectDistanceCodes, MAX_DISTANCE_BITS); |
| int distanceAlphabetSizeLimit = distanceAlphabetSizeMax; |
| if (s.isLargeWindow == 1) { |
| distanceAlphabetSizeMax = calculateDistanceAlphabetSize( |
| s.distancePostfixBits, s.numDirectDistanceCodes, MAX_LARGE_WINDOW_DISTANCE_BITS); |
| distanceAlphabetSizeLimit = calculateDistanceAlphabetLimit( |
| MAX_ALLOWED_DISTANCE, s.distancePostfixBits, s.numDirectDistanceCodes); |
| } |
| s.distanceTreeGroup = decodeHuffmanTreeGroup(distanceAlphabetSizeMax, distanceAlphabetSizeLimit, |
| numDistTrees, s); |
| calculateDistanceLut(s, distanceAlphabetSizeLimit); |
| |
| s.contextMapSlice = 0; |
| s.distContextMapSlice = 0; |
| s.contextLookupOffset1 = s.contextModes[0] * 512; |
| s.contextLookupOffset2 = s.contextLookupOffset1 + 256; |
| s.literalTreeIdx = 0; |
| s.commandTreeIdx = 0; |
| |
| s.rings[4] = 1; |
| s.rings[5] = 0; |
| s.rings[6] = 1; |
| s.rings[7] = 0; |
| s.rings[8] = 1; |
| s.rings[9] = 0; |
| } |
| |
| private static void copyUncompressedData(State s) { |
| final byte[] ringBuffer = s.ringBuffer; |
| |
| // Could happen if block ends at ring buffer end. |
| if (s.metaBlockLength <= 0) { |
| BitReader.reload(s); |
| s.runningState = BLOCK_START; |
| return; |
| } |
| |
| int chunkLength = Math.min(s.ringBufferSize - s.pos, s.metaBlockLength); |
| BitReader.copyRawBytes(s, ringBuffer, s.pos, chunkLength); |
| s.metaBlockLength -= chunkLength; |
| s.pos += chunkLength; |
| if (s.pos == s.ringBufferSize) { |
| s.nextRunningState = COPY_UNCOMPRESSED; |
| s.runningState = INIT_WRITE; |
| return; |
| } |
| |
| BitReader.reload(s); |
| s.runningState = BLOCK_START; |
| } |
| |
| private static int writeRingBuffer(State s) { |
| int toWrite = Math.min(s.outputLength - s.outputUsed, |
| s.ringBufferBytesReady - s.ringBufferBytesWritten); |
| if (toWrite != 0) { |
| System.arraycopy(s.ringBuffer, s.ringBufferBytesWritten, s.output, |
| s.outputOffset + s.outputUsed, toWrite); |
| s.outputUsed += toWrite; |
| s.ringBufferBytesWritten += toWrite; |
| } |
| |
| if (s.outputUsed < s.outputLength) { |
| return 1; |
| } else { |
| return 0; |
| } |
| } |
| |
| private static int[] decodeHuffmanTreeGroup(int alphabetSizeMax, int alphabetSizeLimit, |
| int n, State s) { |
| int maxTableSize = MAX_HUFFMAN_TABLE_SIZE[(alphabetSizeLimit + 31) >> 5]; |
| int[] group = new int[n + n * maxTableSize]; |
| int next = n; |
| for (int i = 0; i < n; ++i) { |
| group[i] = next; |
| next += readHuffmanCode(alphabetSizeMax, alphabetSizeLimit, group, i, s); |
| } |
| return group; |
| } |
| |
| // Returns offset in ringBuffer that should trigger WRITE when filled. |
| private static int calculateFence(State s) { |
| int result = s.ringBufferSize; |
| if (s.isEager != 0) { |
| result = Math.min(result, s.ringBufferBytesWritten + s.outputLength - s.outputUsed); |
| } |
| return result; |
| } |
| |
| private static void doUseDictionary(State s, int fence) { |
| if (s.distance > MAX_ALLOWED_DISTANCE) { |
| throw new BrotliRuntimeException("Invalid backward reference"); |
| } |
| int address = s.distance - s.maxDistance - 1 - s.cdTotalSize; |
| if (address < 0) { |
| initializeCompoundDictionaryCopy(s, -address - 1, s.copyLength); |
| s.runningState = COPY_FROM_COMPOUND_DICTIONARY; |
| } else { |
| // Force lazy dictionary initialization. |
| ByteBuffer dictionaryData = Dictionary.getData(); |
| int wordLength = s.copyLength; |
| if (wordLength > Dictionary.MAX_DICTIONARY_WORD_LENGTH) { |
| throw new BrotliRuntimeException("Invalid backward reference"); // COV_NF_LINE |
| } |
| int shift = Dictionary.sizeBits[wordLength]; |
| if (shift == 0) { |
| throw new BrotliRuntimeException("Invalid backward reference"); // COV_NF_LINE |
| } |
| int offset = Dictionary.offsets[wordLength]; |
| int mask = (1 << shift) - 1; |
| int wordIdx = address & mask; |
| int transformIdx = address >>> shift; |
| offset += wordIdx * wordLength; |
| Transform.Transforms transforms = Transform.RFC_TRANSFORMS; |
| if (transformIdx >= transforms.numTransforms) { |
| throw new BrotliRuntimeException("Invalid backward reference"); // COV_NF_LINE |
| } |
| int len = Transform.transformDictionaryWord(s.ringBuffer, s.pos, dictionaryData, |
| offset, wordLength, transforms, transformIdx); |
| s.pos += len; |
| s.metaBlockLength -= len; |
| if (s.pos >= fence) { |
| s.nextRunningState = MAIN_LOOP; |
| s.runningState = INIT_WRITE; |
| return; |
| } |
| s.runningState = MAIN_LOOP; |
| } |
| } |
| |
| private static void initializeCompoundDictionary(State s) { |
| s.cdBlockMap = new byte[1 << CD_BLOCK_MAP_BITS]; |
| int blockBits = CD_BLOCK_MAP_BITS; |
| // If this function is executed, then s.cdTotalSize > 0. |
| while (((s.cdTotalSize - 1) >>> blockBits) != 0) { |
| blockBits++; |
| } |
| blockBits -= CD_BLOCK_MAP_BITS; |
| s.cdBlockBits = blockBits; |
| int cursor = 0; |
| int index = 0; |
| while (cursor < s.cdTotalSize) { |
| while (s.cdChunkOffsets[index + 1] < cursor) { |
| index++; |
| } |
| s.cdBlockMap[cursor >>> blockBits] = (byte) index; |
| cursor += 1 << blockBits; |
| } |
| } |
| |
| private static void initializeCompoundDictionaryCopy(State s, int address, int length) { |
| if (s.cdBlockBits == -1) { |
| initializeCompoundDictionary(s); |
| } |
| int index = s.cdBlockMap[address >>> s.cdBlockBits]; |
| while (address >= s.cdChunkOffsets[index + 1]) { |
| index++; |
| } |
| if (s.cdTotalSize > address + length) { |
| throw new BrotliRuntimeException("Invalid backward reference"); |
| } |
| /* Update the recent distances cache */ |
| s.distRbIdx = (s.distRbIdx + 1) & 0x3; |
| s.rings[s.distRbIdx] = s.distance; |
| s.metaBlockLength -= length; |
| s.cdBrIndex = index; |
| s.cdBrOffset = address - s.cdChunkOffsets[index]; |
| s.cdBrLength = length; |
| s.cdBrCopied = 0; |
| } |
| |
| private static int copyFromCompoundDictionary(State s, int fence) { |
| int pos = s.pos; |
| int origPos = pos; |
| while (s.cdBrLength != s.cdBrCopied) { |
| int space = fence - pos; |
| int chunkLength = s.cdChunkOffsets[s.cdBrIndex + 1] - s.cdChunkOffsets[s.cdBrIndex]; |
| int remChunkLength = chunkLength - s.cdBrOffset; |
| int length = s.cdBrLength - s.cdBrCopied; |
| if (length > remChunkLength) { |
| length = remChunkLength; |
| } |
| if (length > space) { |
| length = space; |
| } |
| Utils.copyBytes( |
| s.ringBuffer, pos, s.cdChunks[s.cdBrIndex], s.cdBrOffset, s.cdBrOffset + length); |
| pos += length; |
| s.cdBrOffset += length; |
| s.cdBrCopied += length; |
| if (length == remChunkLength) { |
| s.cdBrIndex++; |
| s.cdBrOffset = 0; |
| } |
| if (pos >= fence) { |
| break; |
| } |
| } |
| return pos - origPos; |
| } |
| |
| /** |
| * Actual decompress implementation. |
| */ |
| static void decompress(State s) { |
| if (s.runningState == UNINITIALIZED) { |
| throw new IllegalStateException("Can't decompress until initialized"); |
| } |
| if (s.runningState == CLOSED) { |
| throw new IllegalStateException("Can't decompress after close"); |
| } |
| if (s.runningState == INITIALIZED) { |
| int windowBits = decodeWindowBits(s); |
| if (windowBits == -1) { /* Reserved case for future expansion. */ |
| throw new BrotliRuntimeException("Invalid 'windowBits' code"); |
| } |
| s.maxRingBufferSize = 1 << windowBits; |
| s.maxBackwardDistance = s.maxRingBufferSize - 16; |
| s.runningState = BLOCK_START; |
| } |
| |
| int fence = calculateFence(s); |
| int ringBufferMask = s.ringBufferSize - 1; |
| byte[] ringBuffer = s.ringBuffer; |
| |
| while (s.runningState != FINISHED) { |
| // TODO(eustas): extract cases to methods for the better readability. |
| switch (s.runningState) { |
| case BLOCK_START: |
| if (s.metaBlockLength < 0) { |
| throw new BrotliRuntimeException("Invalid metablock length"); |
| } |
| readNextMetablockHeader(s); |
| /* Ring-buffer would be reallocated here. */ |
| fence = calculateFence(s); |
| ringBufferMask = s.ringBufferSize - 1; |
| ringBuffer = s.ringBuffer; |
| continue; |
| |
| case COMPRESSED_BLOCK_START: |
| readMetablockHuffmanCodesAndContextMaps(s); |
| s.runningState = MAIN_LOOP; |
| // Fall through |
| |
| case MAIN_LOOP: |
| if (s.metaBlockLength <= 0) { |
| s.runningState = BLOCK_START; |
| continue; |
| } |
| BitReader.readMoreInput(s); |
| if (s.commandBlockLength == 0) { |
| decodeCommandBlockSwitch(s); |
| } |
| s.commandBlockLength--; |
| BitReader.fillBitWindow(s); |
| int cmdCode = readSymbol(s.commandTreeGroup, s.commandTreeIdx, s) << 2; |
| short insertAndCopyExtraBits = CMD_LOOKUP[cmdCode]; |
| int insertLengthOffset = CMD_LOOKUP[cmdCode + 1]; |
| int copyLengthOffset = CMD_LOOKUP[cmdCode + 2]; |
| s.distanceCode = CMD_LOOKUP[cmdCode + 3]; |
| BitReader.fillBitWindow(s); |
| { |
| int insertLengthExtraBits = insertAndCopyExtraBits & 0xFF; |
| s.insertLength = insertLengthOffset + BitReader.readBits(s, insertLengthExtraBits); |
| } |
| BitReader.fillBitWindow(s); |
| { |
| int copyLengthExtraBits = insertAndCopyExtraBits >> 8; |
| s.copyLength = copyLengthOffset + BitReader.readBits(s, copyLengthExtraBits); |
| } |
| |
| s.j = 0; |
| s.runningState = INSERT_LOOP; |
| |
| // Fall through |
| case INSERT_LOOP: |
| if (s.trivialLiteralContext != 0) { |
| while (s.j < s.insertLength) { |
| BitReader.readMoreInput(s); |
| if (s.literalBlockLength == 0) { |
| decodeLiteralBlockSwitch(s); |
| } |
| s.literalBlockLength--; |
| BitReader.fillBitWindow(s); |
| ringBuffer[s.pos] = (byte) readSymbol(s.literalTreeGroup, s.literalTreeIdx, s); |
| s.pos++; |
| s.j++; |
| if (s.pos >= fence) { |
| s.nextRunningState = INSERT_LOOP; |
| s.runningState = INIT_WRITE; |
| break; |
| } |
| } |
| } else { |
| int prevByte1 = ringBuffer[(s.pos - 1) & ringBufferMask] & 0xFF; |
| int prevByte2 = ringBuffer[(s.pos - 2) & ringBufferMask] & 0xFF; |
| while (s.j < s.insertLength) { |
| BitReader.readMoreInput(s); |
| if (s.literalBlockLength == 0) { |
| decodeLiteralBlockSwitch(s); |
| } |
| int literalContext = Context.LOOKUP[s.contextLookupOffset1 + prevByte1] |
| | Context.LOOKUP[s.contextLookupOffset2 + prevByte2]; |
| int literalTreeIdx = s.contextMap[s.contextMapSlice + literalContext] & 0xFF; |
| s.literalBlockLength--; |
| prevByte2 = prevByte1; |
| BitReader.fillBitWindow(s); |
| prevByte1 = readSymbol(s.literalTreeGroup, literalTreeIdx, s); |
| ringBuffer[s.pos] = (byte) prevByte1; |
| s.pos++; |
| s.j++; |
| if (s.pos >= fence) { |
| s.nextRunningState = INSERT_LOOP; |
| s.runningState = INIT_WRITE; |
| break; |
| } |
| } |
| } |
| if (s.runningState != INSERT_LOOP) { |
| continue; |
| } |
| s.metaBlockLength -= s.insertLength; |
| if (s.metaBlockLength <= 0) { |
| s.runningState = MAIN_LOOP; |
| continue; |
| } |
| int distanceCode = s.distanceCode; |
| if (distanceCode < 0) { |
| // distanceCode in untouched; assigning it 0 won't affect distance ring buffer rolling. |
| s.distance = s.rings[s.distRbIdx]; |
| } else { |
| BitReader.readMoreInput(s); |
| if (s.distanceBlockLength == 0) { |
| decodeDistanceBlockSwitch(s); |
| } |
| s.distanceBlockLength--; |
| BitReader.fillBitWindow(s); |
| int distTreeIdx = s.distContextMap[s.distContextMapSlice + distanceCode] & 0xFF; |
| distanceCode = readSymbol(s.distanceTreeGroup, distTreeIdx, s); |
| if (distanceCode < NUM_DISTANCE_SHORT_CODES) { |
| int index = (s.distRbIdx + DISTANCE_SHORT_CODE_INDEX_OFFSET[distanceCode]) & 0x3; |
| s.distance = s.rings[index] + DISTANCE_SHORT_CODE_VALUE_OFFSET[distanceCode]; |
| if (s.distance < 0) { |
| throw new BrotliRuntimeException("Negative distance"); // COV_NF_LINE |
| } |
| } else { |
| int extraBits = s.distExtraBits[distanceCode]; |
| int bits; |
| if (s.bitOffset + extraBits <= BitReader.BITNESS) { |
| bits = BitReader.readFewBits(s, extraBits); |
| } else { |
| BitReader.fillBitWindow(s); |
| bits = BitReader.readBits(s, extraBits); |
| } |
| s.distance = s.distOffset[distanceCode] + (bits << s.distancePostfixBits); |
| } |
| } |
| |
| if (s.maxDistance != s.maxBackwardDistance |
| && s.pos < s.maxBackwardDistance) { |
| s.maxDistance = s.pos; |
| } else { |
| s.maxDistance = s.maxBackwardDistance; |
| } |
| |
| if (s.distance > s.maxDistance) { |
| s.runningState = USE_DICTIONARY; |
| continue; |
| } |
| |
| if (distanceCode > 0) { |
| s.distRbIdx = (s.distRbIdx + 1) & 0x3; |
| s.rings[s.distRbIdx] = s.distance; |
| } |
| |
| if (s.copyLength > s.metaBlockLength) { |
| throw new BrotliRuntimeException("Invalid backward reference"); // COV_NF_LINE |
| } |
| s.j = 0; |
| s.runningState = COPY_LOOP; |
| // fall through |
| case COPY_LOOP: |
| int src = (s.pos - s.distance) & ringBufferMask; |
| int dst = s.pos; |
| int copyLength = s.copyLength - s.j; |
| int srcEnd = src + copyLength; |
| int dstEnd = dst + copyLength; |
| if ((srcEnd < ringBufferMask) && (dstEnd < ringBufferMask)) { |
| if (copyLength < 12 || (srcEnd > dst && dstEnd > src)) { |
| for (int k = 0; k < copyLength; k += 4) { |
| ringBuffer[dst++] = ringBuffer[src++]; |
| ringBuffer[dst++] = ringBuffer[src++]; |
| ringBuffer[dst++] = ringBuffer[src++]; |
| ringBuffer[dst++] = ringBuffer[src++]; |
| } |
| } else { |
| Utils.copyBytesWithin(ringBuffer, dst, src, srcEnd); |
| } |
| s.j += copyLength; |
| s.metaBlockLength -= copyLength; |
| s.pos += copyLength; |
| } else { |
| for (; s.j < s.copyLength;) { |
| ringBuffer[s.pos] = |
| ringBuffer[(s.pos - s.distance) & ringBufferMask]; |
| s.metaBlockLength--; |
| s.pos++; |
| s.j++; |
| if (s.pos >= fence) { |
| s.nextRunningState = COPY_LOOP; |
| s.runningState = INIT_WRITE; |
| break; |
| } |
| } |
| } |
| if (s.runningState == COPY_LOOP) { |
| s.runningState = MAIN_LOOP; |
| } |
| continue; |
| |
| case USE_DICTIONARY: |
| doUseDictionary(s, fence); |
| continue; |
| |
| case COPY_FROM_COMPOUND_DICTIONARY: |
| s.pos += copyFromCompoundDictionary(s, fence); |
| if (s.pos >= fence) { |
| s.nextRunningState = COPY_FROM_COMPOUND_DICTIONARY; |
| s.runningState = INIT_WRITE; |
| return; |
| } |
| s.runningState = MAIN_LOOP; |
| continue; |
| |
| case READ_METADATA: |
| while (s.metaBlockLength > 0) { |
| BitReader.readMoreInput(s); |
| // Optimize |
| BitReader.fillBitWindow(s); |
| BitReader.readFewBits(s, 8); |
| s.metaBlockLength--; |
| } |
| s.runningState = BLOCK_START; |
| continue; |
| |
| case COPY_UNCOMPRESSED: |
| copyUncompressedData(s); |
| continue; |
| |
| case INIT_WRITE: |
| s.ringBufferBytesReady = Math.min(s.pos, s.ringBufferSize); |
| s.runningState = WRITE; |
| // fall through |
| case WRITE: |
| if (writeRingBuffer(s) == 0) { |
| // Output buffer is full. |
| return; |
| } |
| if (s.pos >= s.maxBackwardDistance) { |
| s.maxDistance = s.maxBackwardDistance; |
| } |
| // Wrap the ringBuffer. |
| if (s.pos >= s.ringBufferSize) { |
| if (s.pos > s.ringBufferSize) { |
| Utils.copyBytesWithin(ringBuffer, 0, s.ringBufferSize, s.pos); |
| } |
| s.pos &= ringBufferMask; |
| s.ringBufferBytesWritten = 0; |
| } |
| s.runningState = s.nextRunningState; |
| continue; |
| |
| default: |
| throw new BrotliRuntimeException("Unexpected state " + s.runningState); |
| } |
| } |
| if (s.runningState == FINISHED) { |
| if (s.metaBlockLength < 0) { |
| throw new BrotliRuntimeException("Invalid metablock length"); |
| } |
| BitReader.jumpToByteBoundary(s); |
| BitReader.checkHealth(s, 1); |
| } |
| } |
| } |
