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Diffstat (limited to 'zopfli/deflate.c')
| -rw-r--r-- | zopfli/deflate.c | 866 |
1 files changed, 866 insertions, 0 deletions
diff --git a/zopfli/deflate.c b/zopfli/deflate.c new file mode 100644 index 0000000..4b0724b --- /dev/null +++ b/zopfli/deflate.c @@ -0,0 +1,866 @@ +/* +Copyright 2011 Google Inc. All Rights Reserved. + +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. + +Author: lode.vandevenne@gmail.com (Lode Vandevenne) +Author: jyrki.alakuijala@gmail.com (Jyrki Alakuijala) +*/ + +#include "deflate.h" + +#include <assert.h> +#include <stdio.h> +#include <stdlib.h> + +#include "blocksplitter.h" +#include "lz77.h" +#include "squeeze.h" +#include "tree.h" + +/* +bp = bitpointer, always in range [0, 7]. +The outsize is number of necessary bytes to encode the bits. +Given the value of bp and the amount of bytes, the amount of bits represented +is not simply bytesize * 8 + bp because even representing one bit requires a +whole byte. It is: (bp == 0) ? (bytesize * 8) : ((bytesize - 1) * 8 + bp) +*/ +static void AddBit(int bit, + unsigned char* bp, unsigned char** out, size_t* outsize) { + if (*bp == 0) ZOPFLI_APPEND_DATA(0, out, outsize); + (*out)[*outsize - 1] |= bit << *bp; + *bp = (*bp + 1) & 7; +} + +static void AddBits(unsigned symbol, unsigned length, + unsigned char* bp, unsigned char** out, size_t* outsize) { + /* TODO(lode): make more efficient (add more bits at once). */ + unsigned i; + for (i = 0; i < length; i++) { + unsigned bit = (symbol >> i) & 1; + if (*bp == 0) ZOPFLI_APPEND_DATA(0, out, outsize); + (*out)[*outsize - 1] |= bit << *bp; + *bp = (*bp + 1) & 7; + } +} + +/* +Adds bits, like AddBits, but the order is inverted. The deflate specification +uses both orders in one standard. +*/ +static void AddHuffmanBits(unsigned symbol, unsigned length, + unsigned char* bp, unsigned char** out, + size_t* outsize) { + /* TODO(lode): make more efficient (add more bits at once). */ + unsigned i; + for (i = 0; i < length; i++) { + unsigned bit = (symbol >> (length - i - 1)) & 1; + if (*bp == 0) ZOPFLI_APPEND_DATA(0, out, outsize); + (*out)[*outsize - 1] |= bit << *bp; + *bp = (*bp + 1) & 7; + } +} + +/* +Ensures there are at least 2 distance codes to support buggy decoders. +Zlib 1.2.1 and below have a bug where it fails if there isn't at least 1 +distance code (with length > 0), even though it's valid according to the +deflate spec to have 0 distance codes. On top of that, some mobile phones +require at least two distance codes. To support these decoders too (but +potentially at the cost of a few bytes), add dummy code lengths of 1. +References to this bug can be found in the changelog of +Zlib 1.2.2 and here: http://www.jonof.id.au/forum/index.php?topic=515.0. + +d_lengths: the 32 lengths of the distance codes. +*/ +static void PatchDistanceCodesForBuggyDecoders(unsigned* d_lengths) { + int num_dist_codes = 0; /* Amount of non-zero distance codes */ + int i; + for (i = 0; i < 30 /* Ignore the two unused codes from the spec */; i++) { + if (d_lengths[i]) num_dist_codes++; + if (num_dist_codes >= 2) return; /* Two or more codes is fine. */ + } + + if (num_dist_codes == 0) { + d_lengths[0] = d_lengths[1] = 1; + } else if (num_dist_codes == 1) { + d_lengths[d_lengths[0] ? 1 : 0] = 1; + } +} + +/* +Encodes the Huffman tree and returns how many bits its encoding takes. If out +is a null pointer, only returns the size and runs faster. +*/ +static size_t EncodeTree(const unsigned* ll_lengths, + const unsigned* d_lengths, + int use_16, int use_17, int use_18, + unsigned char* bp, + unsigned char** out, size_t* outsize) { + unsigned lld_total; /* Total amount of literal, length, distance codes. */ + /* Runlength encoded version of lengths of litlen and dist trees. */ + unsigned* rle = 0; + unsigned* rle_bits = 0; /* Extra bits for rle values 16, 17 and 18. */ + size_t rle_size = 0; /* Size of rle array. */ + size_t rle_bits_size = 0; /* Should have same value as rle_size. */ + unsigned hlit = 29; /* 286 - 257 */ + unsigned hdist = 29; /* 32 - 1, but gzip does not like hdist > 29.*/ + unsigned hclen; + unsigned hlit2; + size_t i, j; + size_t clcounts[19]; + unsigned clcl[19]; /* Code length code lengths. */ + unsigned clsymbols[19]; + /* The order in which code length code lengths are encoded as per deflate. */ + static const unsigned order[19] = { + 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 + }; + int size_only = !out; + size_t result_size = 0; + + for(i = 0; i < 19; i++) clcounts[i] = 0; + + /* Trim zeros. */ + while (hlit > 0 && ll_lengths[257 + hlit - 1] == 0) hlit--; + while (hdist > 0 && d_lengths[1 + hdist - 1] == 0) hdist--; + hlit2 = hlit + 257; + + lld_total = hlit2 + hdist + 1; + + for (i = 0; i < lld_total; i++) { + /* This is an encoding of a huffman tree, so now the length is a symbol */ + unsigned char symbol = i < hlit2 ? ll_lengths[i] : d_lengths[i - hlit2]; + unsigned count = 1; + if(use_16 || (symbol == 0 && (use_17 || use_18))) { + for (j = i + 1; j < lld_total && symbol == + (j < hlit2 ? ll_lengths[j] : d_lengths[j - hlit2]); j++) { + count++; + } + } + i += count - 1; + + /* Repetitions of zeroes */ + if (symbol == 0 && count >= 3) { + if (use_18) { + while (count >= 11) { + unsigned count2 = count > 138 ? 138 : count; + if (!size_only) { + ZOPFLI_APPEND_DATA(18, &rle, &rle_size); + ZOPFLI_APPEND_DATA(count2 - 11, &rle_bits, &rle_bits_size); + } + clcounts[18]++; + count -= count2; + } + } + if (use_17) { + while (count >= 3) { + unsigned count2 = count > 10 ? 10 : count; + if (!size_only) { + ZOPFLI_APPEND_DATA(17, &rle, &rle_size); + ZOPFLI_APPEND_DATA(count2 - 3, &rle_bits, &rle_bits_size); + } + clcounts[17]++; + count -= count2; + } + } + } + + /* Repetitions of any symbol */ + if (use_16 && count >= 4) { + count--; /* Since the first one is hardcoded. */ + clcounts[symbol]++; + if (!size_only) { + ZOPFLI_APPEND_DATA(symbol, &rle, &rle_size); + ZOPFLI_APPEND_DATA(0, &rle_bits, &rle_bits_size); + } + while (count >= 3) { + unsigned count2 = count > 6 ? 6 : count; + if (!size_only) { + ZOPFLI_APPEND_DATA(16, &rle, &rle_size); + ZOPFLI_APPEND_DATA(count2 - 3, &rle_bits, &rle_bits_size); + } + clcounts[16]++; + count -= count2; + } + } + + /* No or insufficient repetition */ + clcounts[symbol] += count; + while (count > 0) { + if (!size_only) { + ZOPFLI_APPEND_DATA(symbol, &rle, &rle_size); + ZOPFLI_APPEND_DATA(0, &rle_bits, &rle_bits_size); + } + count--; + } + } + + ZopfliCalculateBitLengths(clcounts, 19, 7, clcl); + if (!size_only) ZopfliLengthsToSymbols(clcl, 19, 7, clsymbols); + + hclen = 15; + /* Trim zeros. */ + while (hclen > 0 && clcounts[order[hclen + 4 - 1]] == 0) hclen--; + + if (!size_only) { + AddBits(hlit, 5, bp, out, outsize); + AddBits(hdist, 5, bp, out, outsize); + AddBits(hclen, 4, bp, out, outsize); + + for (i = 0; i < hclen + 4; i++) { + AddBits(clcl[order[i]], 3, bp, out, outsize); + } + + for (i = 0; i < rle_size; i++) { + unsigned symbol = clsymbols[rle[i]]; + AddHuffmanBits(symbol, clcl[rle[i]], bp, out, outsize); + /* Extra bits. */ + if (rle[i] == 16) AddBits(rle_bits[i], 2, bp, out, outsize); + else if (rle[i] == 17) AddBits(rle_bits[i], 3, bp, out, outsize); + else if (rle[i] == 18) AddBits(rle_bits[i], 7, bp, out, outsize); + } + } + + result_size += 14; /* hlit, hdist, hclen bits */ + result_size += (hclen + 4) * 3; /* clcl bits */ + for(i = 0; i < 19; i++) { + result_size += clcl[i] * clcounts[i]; + } + /* Extra bits. */ + result_size += clcounts[16] * 2; + result_size += clcounts[17] * 3; + result_size += clcounts[18] * 7; + + /* Note: in case of "size_only" these are null pointers so no effect. */ + free(rle); + free(rle_bits); + + return result_size; +} + +static void AddDynamicTree(const unsigned* ll_lengths, + const unsigned* d_lengths, + unsigned char* bp, + unsigned char** out, size_t* outsize) { + int i; + int best = 0; + size_t bestsize = 0; + + for(i = 0; i < 8; i++) { + size_t size = EncodeTree(ll_lengths, d_lengths, + i & 1, i & 2, i & 4, + 0, 0, 0); + if (bestsize == 0 || size < bestsize) { + bestsize = size; + best = i; + } + } + + EncodeTree(ll_lengths, d_lengths, + best & 1, best & 2, best & 4, + bp, out, outsize); +} + +/* +Gives the exact size of the tree, in bits, as it will be encoded in DEFLATE. +*/ +static size_t CalculateTreeSize(const unsigned* ll_lengths, + const unsigned* d_lengths) { + size_t result = 0; + int i; + + for(i = 0; i < 8; i++) { + size_t size = EncodeTree(ll_lengths, d_lengths, + i & 1, i & 2, i & 4, + 0, 0, 0); + if (result == 0 || size < result) result = size; + } + + return result; +} + +/* +Adds all lit/len and dist codes from the lists as huffman symbols. Does not add +end code 256. expected_data_size is the uncompressed block size, used for +assert, but you can set it to 0 to not do the assertion. +*/ +static void AddLZ77Data(const unsigned short* litlens, + const unsigned short* dists, + size_t lstart, size_t lend, + size_t expected_data_size, + const unsigned* ll_symbols, const unsigned* ll_lengths, + const unsigned* d_symbols, const unsigned* d_lengths, + unsigned char* bp, + unsigned char** out, size_t* outsize) { + size_t testlength = 0; + size_t i; + + for (i = lstart; i < lend; i++) { + unsigned dist = dists[i]; + unsigned litlen = litlens[i]; + if (dist == 0) { + assert(litlen < 256); + assert(ll_lengths[litlen] > 0); + AddHuffmanBits(ll_symbols[litlen], ll_lengths[litlen], bp, out, outsize); + testlength++; + } else { + unsigned lls = ZopfliGetLengthSymbol(litlen); + unsigned ds = ZopfliGetDistSymbol(dist); + assert(litlen >= 3 && litlen <= 288); + assert(ll_lengths[lls] > 0); + assert(d_lengths[ds] > 0); + AddHuffmanBits(ll_symbols[lls], ll_lengths[lls], bp, out, outsize); + AddBits(ZopfliGetLengthExtraBitsValue(litlen), + ZopfliGetLengthExtraBits(litlen), + bp, out, outsize); + AddHuffmanBits(d_symbols[ds], d_lengths[ds], bp, out, outsize); + AddBits(ZopfliGetDistExtraBitsValue(dist), + ZopfliGetDistExtraBits(dist), + bp, out, outsize); + testlength += litlen; + } + } + assert(expected_data_size == 0 || testlength == expected_data_size); +} + +static void GetFixedTree(unsigned* ll_lengths, unsigned* d_lengths) { + size_t i; + for (i = 0; i < 144; i++) ll_lengths[i] = 8; + for (i = 144; i < 256; i++) ll_lengths[i] = 9; + for (i = 256; i < 280; i++) ll_lengths[i] = 7; + for (i = 280; i < 288; i++) ll_lengths[i] = 8; + for (i = 0; i < 32; i++) d_lengths[i] = 5; +} + +/* +Calculates size of the part after the header and tree of an LZ77 block, in bits. +*/ +static size_t CalculateBlockSymbolSize(const unsigned* ll_lengths, + const unsigned* d_lengths, + const unsigned short* litlens, + const unsigned short* dists, + size_t lstart, size_t lend) { + size_t result = 0; + size_t i; + for (i = lstart; i < lend; i++) { + if (dists[i] == 0) { + result += ll_lengths[litlens[i]]; + } else { + result += ll_lengths[ZopfliGetLengthSymbol(litlens[i])]; + result += d_lengths[ZopfliGetDistSymbol(dists[i])]; + result += ZopfliGetLengthExtraBits(litlens[i]); + result += ZopfliGetDistExtraBits(dists[i]); + } + } + result += ll_lengths[256]; /*end symbol*/ + return result; +} + +static size_t AbsDiff(size_t x, size_t y) { + if (x > y) + return x - y; + else + return y - x; +} + +/* +Change the population counts in a way that the consequent Hufmann tree +compression, especially its rle-part will be more likely to compress this data +more efficiently. length containts the size of the histogram. +*/ +void OptimizeHuffmanForRle(int length, size_t* counts) { + int i, k, stride; + size_t symbol, sum, limit; + int* good_for_rle; + + /* 1) We don't want to touch the trailing zeros. We may break the + rules of the format by adding more data in the distance codes. */ + for (; length >= 0; --length) { + if (length == 0) { + return; + } + if (counts[length - 1] != 0) { + /* Now counts[0..length - 1] does not have trailing zeros. */ + break; + } + } + /* 2) Let's mark all population counts that already can be encoded + with an rle code.*/ + good_for_rle = (int*)malloc(length * sizeof(int)); + for (i = 0; i < length; ++i) good_for_rle[i] = 0; + + /* Let's not spoil any of the existing good rle codes. + Mark any seq of 0's that is longer than 5 as a good_for_rle. + Mark any seq of non-0's that is longer than 7 as a good_for_rle.*/ + symbol = counts[0]; + stride = 0; + for (i = 0; i < length + 1; ++i) { + if (i == length || counts[i] != symbol) { + if ((symbol == 0 && stride >= 5) || (symbol != 0 && stride >= 7)) { + for (k = 0; k < stride; ++k) { + good_for_rle[i - k - 1] = 1; + } + } + stride = 1; + if (i != length) { + symbol = counts[i]; + } + } else { + ++stride; + } + } + + /* 3) Let's replace those population counts that lead to more rle codes. */ + stride = 0; + limit = counts[0]; + sum = 0; + for (i = 0; i < length + 1; ++i) { + if (i == length || good_for_rle[i] + /* Heuristic for selecting the stride ranges to collapse. */ + || AbsDiff(counts[i], limit) >= 4) { + if (stride >= 4 || (stride >= 3 && sum == 0)) { + /* The stride must end, collapse what we have, if we have enough (4). */ + int count = (sum + stride / 2) / stride; + if (count < 1) count = 1; + if (sum == 0) { + /* Don't make an all zeros stride to be upgraded to ones. */ + count = 0; + } + for (k = 0; k < stride; ++k) { + /* We don't want to change value at counts[i], + that is already belonging to the next stride. Thus - 1. */ + counts[i - k - 1] = count; + } + } + stride = 0; + sum = 0; + if (i < length - 3) { + /* All interesting strides have a count of at least 4, + at least when non-zeros. */ + limit = (counts[i] + counts[i + 1] + + counts[i + 2] + counts[i + 3] + 2) / 4; + } else if (i < length) { + limit = counts[i]; + } else { + limit = 0; + } + } + ++stride; + if (i != length) { + sum += counts[i]; + } + } + + free(good_for_rle); +} + +/* +Calculates the bit lengths for the symbols for dynamic blocks. Chooses bit +lengths that give the smallest size of tree encoding + encoding of all the +symbols to have smallest output size. This are not necessarily the ideal Huffman +bit lengths. +*/ +static void GetDynamicLengths(const unsigned short* litlens, + const unsigned short* dists, + size_t lstart, size_t lend, + unsigned* ll_lengths, unsigned* d_lengths) { + size_t ll_counts[288]; + size_t d_counts[32]; + + ZopfliLZ77Counts(litlens, dists, lstart, lend, ll_counts, d_counts); + OptimizeHuffmanForRle(288, ll_counts); + OptimizeHuffmanForRle(32, d_counts); + ZopfliCalculateBitLengths(ll_counts, 288, 15, ll_lengths); + ZopfliCalculateBitLengths(d_counts, 32, 15, d_lengths); + PatchDistanceCodesForBuggyDecoders(d_lengths); +} + +double ZopfliCalculateBlockSize(const unsigned short* litlens, + const unsigned short* dists, + size_t lstart, size_t lend, int btype) { + unsigned ll_lengths[288]; + unsigned d_lengths[32]; + + double result = 3; /* bfinal and btype bits */ + + assert(btype == 1 || btype == 2); /* This is not for uncompressed blocks. */ + + if(btype == 1) { + GetFixedTree(ll_lengths, d_lengths); + } else { + GetDynamicLengths(litlens, dists, lstart, lend, ll_lengths, d_lengths); + result += CalculateTreeSize(ll_lengths, d_lengths); + } + + result += CalculateBlockSymbolSize( + ll_lengths, d_lengths, litlens, dists, lstart, lend); + + return result; +} + +/* +Adds a deflate block with the given LZ77 data to the output. +options: global program options +btype: the block type, must be 1 or 2 +final: whether to set the "final" bit on this block, must be the last block +litlens: literal/length array of the LZ77 data, in the same format as in + ZopfliLZ77Store. +dists: distance array of the LZ77 data, in the same format as in + ZopfliLZ77Store. +lstart: where to start in the LZ77 data +lend: where to end in the LZ77 data (not inclusive) +expected_data_size: the uncompressed block size, used for assert, but you can + set it to 0 to not do the assertion. +bp: output bit pointer +out: dynamic output array to append to +outsize: dynamic output array size +*/ +static void AddLZ77Block(const ZopfliOptions* options, int btype, int final, + const unsigned short* litlens, + const unsigned short* dists, + size_t lstart, size_t lend, + size_t expected_data_size, + unsigned char* bp, + unsigned char** out, size_t* outsize) { + unsigned ll_lengths[288]; + unsigned d_lengths[32]; + unsigned ll_symbols[288]; + unsigned d_symbols[32]; + size_t detect_block_size = *outsize; + size_t compressed_size; + size_t uncompressed_size = 0; + size_t i; + + AddBit(final, bp, out, outsize); + AddBit(btype & 1, bp, out, outsize); + AddBit((btype & 2) >> 1, bp, out, outsize); + + if (btype == 1) { + /* Fixed block. */ + GetFixedTree(ll_lengths, d_lengths); + } else { + /* Dynamic block. */ + unsigned detect_tree_size; + assert(btype == 2); + + GetDynamicLengths(litlens, dists, lstart, lend, ll_lengths, d_lengths); + + detect_tree_size = *outsize; + AddDynamicTree(ll_lengths, d_lengths, bp, out, outsize); + if (options->verbose) { + fprintf(stderr, "treesize: %d\n", (int)(*outsize - detect_tree_size)); + } + } + + ZopfliLengthsToSymbols(ll_lengths, 288, 15, ll_symbols); + ZopfliLengthsToSymbols(d_lengths, 32, 15, d_symbols); + + detect_block_size = *outsize; + AddLZ77Data(litlens, dists, lstart, lend, expected_data_size, + ll_symbols, ll_lengths, d_symbols, d_lengths, + bp, out, outsize); + /* End symbol. */ + AddHuffmanBits(ll_symbols[256], ll_lengths[256], bp, out, outsize); + + for (i = lstart; i < lend; i++) { + uncompressed_size += dists[i] == 0 ? 1 : litlens[i]; + } + compressed_size = *outsize - detect_block_size; + if (options->verbose) { + fprintf(stderr, "compressed block size: %d (%dk) (unc: %d)\n", + (int)compressed_size, (int)(compressed_size / 1024), + (int)(uncompressed_size)); + } +} + +static void DeflateDynamicBlock(const ZopfliOptions* options, int final, + const unsigned char* in, + size_t instart, size_t inend, + unsigned char* bp, + unsigned char** out, size_t* outsize) { + ZopfliBlockState s; + size_t blocksize = inend - instart; + ZopfliLZ77Store store; + int btype = 2; + + ZopfliInitLZ77Store(&store); + + s.options = options; + s.blockstart = instart; + s.blockend = inend; +#ifdef ZOPFLI_LONGEST_MATCH_CACHE + s.lmc = (ZopfliLongestMatchCache*)malloc(sizeof(ZopfliLongestMatchCache)); + ZopfliInitCache(blocksize, s.lmc); +#endif + + ZopfliLZ77Optimal(&s, in, instart, inend, &store); + + /* For small block, encoding with fixed tree can be smaller. For large block, + don't bother doing this expensive test, dynamic tree will be better.*/ + if (store.size < 1000) { + double dyncost, fixedcost; + ZopfliLZ77Store fixedstore; + ZopfliInitLZ77Store(&fixedstore); + ZopfliLZ77OptimalFixed(&s, in, instart, inend, &fixedstore); + dyncost = ZopfliCalculateBlockSize(store.litlens, store.dists, + 0, store.size, 2); + fixedcost = ZopfliCalculateBlockSize(fixedstore.litlens, fixedstore.dists, + 0, fixedstore.size, 1); + if (fixedcost < dyncost) { + btype = 1; + ZopfliCleanLZ77Store(&store); + store = fixedstore; + } else { + ZopfliCleanLZ77Store(&fixedstore); + } + } + + AddLZ77Block(s.options, btype, final, + store.litlens, store.dists, 0, store.size, + blocksize, bp, out, outsize); + +#ifdef ZOPFLI_LONGEST_MATCH_CACHE + ZopfliCleanCache(s.lmc); + free(s.lmc); +#endif + ZopfliCleanLZ77Store(&store); +} + +static void DeflateFixedBlock(const ZopfliOptions* options, int final, + const unsigned char* in, + size_t instart, size_t inend, + unsigned char* bp, + unsigned char** out, size_t* outsize) { + ZopfliBlockState s; + size_t blocksize = inend - instart; + ZopfliLZ77Store store; + + ZopfliInitLZ77Store(&store); + + s.options = options; + s.blockstart = instart; + s.blockend = inend; +#ifdef ZOPFLI_LONGEST_MATCH_CACHE + s.lmc = (ZopfliLongestMatchCache*)malloc(sizeof(ZopfliLongestMatchCache)); + ZopfliInitCache(blocksize, s.lmc); +#endif + + ZopfliLZ77OptimalFixed(&s, in, instart, inend, &store); + + AddLZ77Block(s.options, 1, final, store.litlens, store.dists, 0, store.size, + blocksize, bp, out, outsize); + +#ifdef ZOPFLI_LONGEST_MATCH_CACHE + ZopfliCleanCache(s.lmc); + free(s.lmc); +#endif + ZopfliCleanLZ77Store(&store); +} + +static void DeflateNonCompressedBlock(const ZopfliOptions* options, int final, + const unsigned char* in, size_t instart, + size_t inend, + unsigned char* bp, + unsigned char** out, size_t* outsize) { + size_t i; + size_t blocksize = inend - instart; + unsigned short nlen = ~blocksize; + + (void)options; + assert(blocksize < 65536); /* Non compressed blocks are max this size. */ + + AddBit(final, bp, out, outsize); + /* BTYPE 00 */ + AddBit(0, bp, out, outsize); + AddBit(0, bp, out, outsize); + + /* Any bits of input up to the next byte boundary are ignored. */ + *bp = 0; + + ZOPFLI_APPEND_DATA(blocksize % 256, out, outsize); + ZOPFLI_APPEND_DATA((blocksize / 256) % 256, out, outsize); + ZOPFLI_APPEND_DATA(nlen % 256, out, outsize); + ZOPFLI_APPEND_DATA((nlen / 256) % 256, out, outsize); + + for (i = instart; i < inend; i++) { + ZOPFLI_APPEND_DATA(in[i], out, outsize); + } +} + +static void DeflateBlock(const ZopfliOptions* options, + int btype, int final, + const unsigned char* in, size_t instart, size_t inend, + unsigned char* bp, + unsigned char** out, size_t* outsize) { + if (btype == 0) { + DeflateNonCompressedBlock( + options, final, in, instart, inend, bp, out, outsize); + } else if (btype == 1) { + DeflateFixedBlock(options, final, in, instart, inend, bp, out, outsize); + } else { + assert (btype == 2); + DeflateDynamicBlock(options, final, in, instart, inend, bp, out, outsize); + } +} + +/* +Does squeeze strategy where first block splitting is done, then each block is +squeezed. +Parameters: see description of the ZopfliDeflate function. +*/ +static void DeflateSplittingFirst(const ZopfliOptions* options, + int btype, int final, + const unsigned char* in, + size_t instart, size_t inend, + unsigned char* bp, + unsigned char** out, size_t* outsize) { + size_t i; + size_t* splitpoints = 0; + size_t npoints = 0; + if (btype == 0) { + ZopfliBlockSplitSimple(in, instart, inend, 65535, &splitpoints, &npoints); + } else if (btype == 1) { + /* If all blocks are fixed tree, splitting into separate blocks only + increases the total size. Leave npoints at 0, this represents 1 block. */ + } else { + ZopfliBlockSplit(options, in, instart, inend, + options->blocksplittingmax, &splitpoints, &npoints); + } + + for (i = 0; i <= npoints; i++) { + size_t start = i == 0 ? instart : splitpoints[i - 1]; + size_t end = i == npoints ? inend : splitpoints[i]; + DeflateBlock(options, btype, i == npoints && final, in, start, end, + bp, out, outsize); + } + + free(splitpoints); +} + +/* +Does squeeze strategy where first the best possible lz77 is done, and then based +on that data, block splitting is done. +Parameters: see description of the ZopfliDeflate function. +*/ +static void DeflateSplittingLast(const ZopfliOptions* options, + int btype, int final, + const unsigned char* in, + size_t instart, size_t inend, + unsigned char* bp, + unsigned char** out, size_t* outsize) { + size_t i; + ZopfliBlockState s; + ZopfliLZ77Store store; + size_t* splitpoints = 0; + size_t npoints = 0; + + if (btype == 0) { + /* This function only supports LZ77 compression. DeflateSplittingFirst + supports the special case of noncompressed data. Punt it to that one. */ + DeflateSplittingFirst(options, btype, final, + in, instart, inend, + bp, out, outsize); + } + assert(btype == 1 || btype == 2); + + ZopfliInitLZ77Store(&store); + + s.options = options; + s.blockstart = instart; + s.blockend = inend; +#ifdef ZOPFLI_LONGEST_MATCH_CACHE + s.lmc = (ZopfliLongestMatchCache*)malloc(sizeof(ZopfliLongestMatchCache)); + ZopfliInitCache(inend - instart, s.lmc); +#endif + + if (btype == 2) { + ZopfliLZ77Optimal(&s, in, instart, inend, &store); + } else { + assert (btype == 1); + ZopfliLZ77OptimalFixed(&s, in, instart, inend, &store); + } + + if (btype == 1) { + /* If all blocks are fixed tree, splitting into separate blocks only + increases the total size. Leave npoints at 0, this represents 1 block. */ + } else { + ZopfliBlockSplitLZ77(options, store.litlens, store.dists, store.size, + options->blocksplittingmax, &splitpoints, &npoints); + } + + for (i = 0; i <= npoints; i++) { + size_t start = i == 0 ? 0 : splitpoints[i - 1]; + size_t end = i == npoints ? store.size : splitpoints[i]; + AddLZ77Block(options, btype, i == npoints && final, + store.litlens, store.dists, start, end, 0, + bp, out, outsize); + } + +#ifdef ZOPFLI_LONGEST_MATCH_CACHE + ZopfliCleanCache(s.lmc); + free(s.lmc); +#endif + + ZopfliCleanLZ77Store(&store); + free(splitpoints); +} + +/* +Deflate a part, to allow ZopfliDeflate() to use multiple master blocks if +needed. +It is possible to call this function multiple times in a row, shifting +instart and inend to next bytes of the data. If instart is larger than 0, then +previous bytes are used as the initial dictionary for LZ77. +This function will usually output multiple deflate blocks. If final is 1, then +the final bit will be set on the last block. +*/ +void ZopfliDeflatePart(const ZopfliOptions* options, int btype, int final, + const unsigned char* in, size_t instart, size_t inend, + unsigned char* bp, unsigned char** out, + size_t* outsize) { + if (options->blocksplitting) { + if (options->blocksplittinglast) { + DeflateSplittingLast(options, btype, final, in, instart, inend, + bp, out, outsize); + } else { + DeflateSplittingFirst(options, btype, final, in, instart, inend, + bp, out, outsize); + } + } else { + DeflateBlock(options, btype, final, in, instart, inend, bp, out, outsize); + } +} + +void ZopfliDeflate(const ZopfliOptions* options, int btype, int final, + const unsigned char* in, size_t insize, + unsigned char* bp, unsigned char** out, size_t* outsize) { +#if ZOPFLI_MASTER_BLOCK_SIZE == 0 + ZopfliDeflatePart(options, btype, final, in, 0, insize, bp, out, outsize); +#else + size_t i = 0; + while (i < insize) { + int masterfinal = (i + ZOPFLI_MASTER_BLOCK_SIZE >= insize); + int final2 = final && masterfinal; + size_t size = masterfinal ? insize - i : ZOPFLI_MASTER_BLOCK_SIZE; + ZopfliDeflatePart(options, btype, final2, + in, i, i + size, bp, out, outsize); + i += size; + } +#endif + if (options->verbose) { + fprintf(stderr, + "Original Size: %d, Deflate: %d, Compression: %f%% Removed\n", + (int)insize, (int)*outsize, + 100.0 * (double)(insize - *outsize) / (double)insize); + } +} |