X-Git-Url: https://wimlib.net/git/?a=blobdiff_plain;f=src%2Flzx-compress.c;h=cf5ea48ef834e4511d29dcf9b91c7cc637bd3de8;hb=acb16926b00fabdba062ff4300da5d3aef32ceeb;hp=7e811e4ea53a3504ce016617140acfbab2e40180;hpb=60f0432ff69a60ed5b846c60f639723913e50bd9;p=wimlib diff --git a/src/lzx-compress.c b/src/lzx-compress.c index 7e811e4e..cf5ea48e 100644 --- a/src/lzx-compress.c +++ b/src/lzx-compress.c @@ -196,8 +196,10 @@ #include "wimlib/compressor_ops.h" #include "wimlib/compress_common.h" +#include "wimlib/endianness.h" #include "wimlib/error.h" #include "wimlib/lz_mf.h" +#include "wimlib/lz_repsearch.h" #include "wimlib/lzx.h" #include "wimlib/util.h" #include @@ -327,14 +329,24 @@ struct lzx_compressor { /* Allocated size of @cur_window. */ u32 max_window_size; + /* log2 order of the LZX window size for LZ match offset encoding + * purposes. Will be >= LZX_MIN_WINDOW_ORDER and <= + * LZX_MAX_WINDOW_ORDER. + * + * Note: 1 << @window_order is normally equal to @max_window_size, but + * it will be greater than @max_window_size in the event that the + * compressor was created with a non-power-of-2 block size. (See + * lzx_get_window_order().) */ + unsigned window_order; + /* Compression parameters. */ struct lzx_compressor_params params; unsigned (*get_matches_func)(struct lzx_compressor *, const struct lz_match **); void (*skip_bytes_func)(struct lzx_compressor *, unsigned n); - /* Number of symbols in the main alphabet (depends on the - * @max_window_size since it determines the maximum allowed offset). */ + /* Number of symbols in the main alphabet (depends on the @window_order + * since it determines the maximum allowed offset). */ unsigned num_main_syms; /* The current match offset LRU queue. */ @@ -455,6 +467,129 @@ struct lzx_mc_pos_data { struct lzx_lru_queue queue; }; + +/* + * Structure to keep track of the current state of sending bits to the + * compressed output buffer. + * + * The LZX bitstream is encoded as a sequence of 16-bit coding units. + */ +struct lzx_output_bitstream { + + /* Bits that haven't yet been written to the output buffer. */ + u32 bitbuf; + + /* Number of bits currently held in @bitbuf. */ + u32 bitcount; + + /* Pointer to the start of the output buffer. */ + le16 *start; + + /* Pointer to the position in the output buffer at which the next coding + * unit should be written. */ + le16 *next; + + /* Pointer past the end of the output buffer. */ + le16 *end; +}; + +/* + * Initialize the output bitstream. + * + * @os + * The output bitstream structure to initialize. + * @buffer + * The buffer being written to. + * @size + * Size of @buffer, in bytes. + */ +static void +lzx_init_output(struct lzx_output_bitstream *os, void *buffer, u32 size) +{ + os->bitbuf = 0; + os->bitcount = 0; + os->start = buffer; + os->next = os->start; + os->end = os->start + size / sizeof(le16); +} + +/* + * Write some bits to the output bitstream. + * + * The bits are given by the low-order @num_bits bits of @bits. Higher-order + * bits in @bits cannot be set. At most 17 bits can be written at once. + * + * @max_bits is a compile-time constant that specifies the maximum number of + * bits that can ever be written at the call site. Currently, it is used to + * optimize away the conditional code for writing a second 16-bit coding unit + * when writing fewer than 17 bits. + * + * If the output buffer space is exhausted, then the bits will be ignored, and + * lzx_flush_output() will return 0 when it gets called. + */ +static _always_inline_attribute void +lzx_write_varbits(struct lzx_output_bitstream *os, + const u32 bits, const unsigned int num_bits, + const unsigned int max_num_bits) +{ + /* This code is optimized for LZX, which never needs to write more than + * 17 bits at once. */ + LZX_ASSERT(num_bits <= 17); + LZX_ASSERT(num_bits <= max_num_bits); + LZX_ASSERT(os->bitcount <= 15); + + /* Add the bits to the bit buffer variable. @bitcount will be at most + * 15, so there will be just enough space for the maximum possible + * @num_bits of 17. */ + os->bitcount += num_bits; + os->bitbuf = (os->bitbuf << num_bits) | bits; + + /* Check whether any coding units need to be written. */ + if (os->bitcount >= 16) { + + os->bitcount -= 16; + + /* Write a coding unit, unless it would overflow the buffer. */ + if (os->next != os->end) + *os->next++ = cpu_to_le16(os->bitbuf >> os->bitcount); + + /* If writing 17 bits, a second coding unit might need to be + * written. But because 'max_num_bits' is a compile-time + * constant, the compiler will optimize away this code at most + * call sites. */ + if (max_num_bits == 17 && os->bitcount == 16) { + if (os->next != os->end) + *os->next++ = cpu_to_le16(os->bitbuf); + os->bitcount = 0; + } + } +} + +/* Use when @num_bits is a compile-time constant. Otherwise use + * lzx_write_varbits(). */ +static _always_inline_attribute void +lzx_write_bits(struct lzx_output_bitstream *os, + const u32 bits, const unsigned int num_bits) +{ + lzx_write_varbits(os, bits, num_bits, num_bits); +} + +/* + * Flush the last coding unit to the output buffer if needed. Return the total + * number of bytes written to the output buffer, or 0 if an overflow occurred. + */ +static u32 +lzx_flush_output(struct lzx_output_bitstream *os) +{ + if (os->next == os->end) + return 0; + + if (os->bitcount != 0) + *os->next++ = cpu_to_le16(os->bitbuf << (16 - os->bitcount)); + + return (const u8 *)os->next - (const u8 *)os->start; +} + /* Returns the LZX position slot that corresponds to a given match offset, * taking into account the recent offset queue and updating it if the offset is * found in it. */ @@ -522,7 +657,7 @@ lzx_make_huffman_codes(const struct lzx_freqs *freqs, /* * Output a precomputed LZX match. * - * @out: + * @os: * The bitstream to which to write the match. * @block_type: * The type of the LZX block (LZX_BLOCKTYPE_ALIGNED or @@ -534,30 +669,23 @@ lzx_make_huffman_codes(const struct lzx_freqs *freqs, * and aligned offset Huffman codes for the current LZX compressed block. */ static void -lzx_write_match(struct output_bitstream *out, int block_type, +lzx_write_match(struct lzx_output_bitstream *os, int block_type, struct lzx_item match, const struct lzx_codes *codes) { - /* low 8 bits are the match length minus 2 */ unsigned match_len_minus_2 = match.data & 0xff; - /* Next 17 bits are the position footer */ - unsigned position_footer = (match.data >> 8) & 0x1ffff; /* 17 bits */ - /* Next 6 bits are the position slot. */ - unsigned position_slot = (match.data >> 25) & 0x3f; /* 6 bits */ + u32 position_footer = (match.data >> 8) & 0x1ffff; + unsigned position_slot = (match.data >> 25) & 0x3f; unsigned len_header; unsigned len_footer; unsigned main_symbol; unsigned num_extra_bits; - unsigned verbatim_bits; - unsigned aligned_bits; /* If the match length is less than MIN_MATCH_LEN (= 2) + - * NUM_PRIMARY_LENS (= 7), the length header contains - * the match length minus MIN_MATCH_LEN, and there is no - * length footer. + * NUM_PRIMARY_LENS (= 7), the length header contains the match length + * minus MIN_MATCH_LEN, and there is no length footer. * - * Otherwise, the length header contains - * NUM_PRIMARY_LENS, and the length footer contains - * the match length minus NUM_PRIMARY_LENS minus + * Otherwise, the length header contains NUM_PRIMARY_LENS, and the + * length footer contains the match length minus NUM_PRIMARY_LENS minus * MIN_MATCH_LEN. */ if (match_len_minus_2 < LZX_NUM_PRIMARY_LENS) { len_header = match_len_minus_2; @@ -575,46 +703,49 @@ lzx_write_match(struct output_bitstream *out, int block_type, main_symbol = ((position_slot << 3) | len_header) + LZX_NUM_CHARS; /* Output main symbol. */ - bitstream_put_bits(out, codes->codewords.main[main_symbol], - codes->lens.main[main_symbol]); + lzx_write_varbits(os, codes->codewords.main[main_symbol], + codes->lens.main[main_symbol], + LZX_MAX_MAIN_CODEWORD_LEN); /* If there is a length footer, output it using the * length Huffman code. */ - if (len_header == LZX_NUM_PRIMARY_LENS) - bitstream_put_bits(out, codes->codewords.len[len_footer], - codes->lens.len[len_footer]); + if (len_header == LZX_NUM_PRIMARY_LENS) { + lzx_write_varbits(os, codes->codewords.len[len_footer], + codes->lens.len[len_footer], + LZX_MAX_LEN_CODEWORD_LEN); + } + + /* Output the position footer. */ num_extra_bits = lzx_get_num_extra_bits(position_slot); - /* For aligned offset blocks with at least 3 extra bits, output the - * verbatim bits literally, then the aligned bits encoded using the - * aligned offset code. Otherwise, only the verbatim bits need to be - * output. */ if ((block_type == LZX_BLOCKTYPE_ALIGNED) && (num_extra_bits >= 3)) { - verbatim_bits = position_footer >> 3; - bitstream_put_bits(out, verbatim_bits, - num_extra_bits - 3); + /* Aligned offset blocks: The low 3 bits of the position footer + * are Huffman-encoded using the aligned offset code. The + * remaining bits are output literally. */ - aligned_bits = (position_footer & 7); - bitstream_put_bits(out, - codes->codewords.aligned[aligned_bits], - codes->lens.aligned[aligned_bits]); + lzx_write_varbits(os, + position_footer >> 3, num_extra_bits - 3, 14); + + lzx_write_varbits(os, + codes->codewords.aligned[position_footer & 7], + codes->lens.aligned[position_footer & 7], + LZX_MAX_ALIGNED_CODEWORD_LEN); } else { - /* verbatim bits is the same as the position - * footer, in this case. */ - bitstream_put_bits(out, position_footer, num_extra_bits); + /* Verbatim blocks, or fewer than 3 extra bits: All position + * footer bits are output literally. */ + lzx_write_varbits(os, position_footer, num_extra_bits, 17); } } /* Output an LZX literal (encoded with the main Huffman code). */ static void -lzx_write_literal(struct output_bitstream *out, u8 literal, +lzx_write_literal(struct lzx_output_bitstream *os, unsigned literal, const struct lzx_codes *codes) { - bitstream_put_bits(out, - codes->codewords.main[literal], - codes->lens.main[literal]); + lzx_write_varbits(os, codes->codewords.main[literal], + codes->lens.main[literal], LZX_MAX_MAIN_CODEWORD_LEN); } static unsigned @@ -774,7 +905,7 @@ lzx_build_precode(const u8 lens[restrict], * as deltas from the codeword lengths of the corresponding code in the previous * block. * - * @out: + * @os: * Bitstream to which to write the compressed Huffman code. * @lens: * The codeword lengths, indexed by symbol, in the Huffman code. @@ -785,7 +916,7 @@ lzx_build_precode(const u8 lens[restrict], * The number of symbols in the Huffman code. */ static void -lzx_write_compressed_code(struct output_bitstream *out, +lzx_write_compressed_code(struct lzx_output_bitstream *os, const u8 lens[restrict], const u8 prev_lens[restrict], unsigned num_syms) @@ -810,28 +941,28 @@ lzx_write_compressed_code(struct output_bitstream *out, /* Write the lengths of the precode codes to the output. */ for (i = 0; i < LZX_PRECODE_NUM_SYMBOLS; i++) - bitstream_put_bits(out, precode_lens[i], - LZX_PRECODE_ELEMENT_SIZE); + lzx_write_bits(os, precode_lens[i], LZX_PRECODE_ELEMENT_SIZE); /* Write the length symbols, encoded with the precode, to the output. */ for (i = 0; i < num_output_syms; ) { precode_sym = output_syms[i++]; - bitstream_put_bits(out, precode_codewords[precode_sym], - precode_lens[precode_sym]); + lzx_write_varbits(os, precode_codewords[precode_sym], + precode_lens[precode_sym], + LZX_MAX_PRE_CODEWORD_LEN); switch (precode_sym) { case 17: - bitstream_put_bits(out, output_syms[i++], 4); + lzx_write_bits(os, output_syms[i++], 4); break; case 18: - bitstream_put_bits(out, output_syms[i++], 5); + lzx_write_bits(os, output_syms[i++], 5); break; case 19: - bitstream_put_bits(out, output_syms[i++], 1); - bitstream_put_bits(out, - precode_codewords[output_syms[i]], - precode_lens[output_syms[i]]); + lzx_write_bits(os, output_syms[i++], 1); + lzx_write_varbits(os, precode_codewords[output_syms[i]], + precode_lens[output_syms[i]], + LZX_MAX_PRE_CODEWORD_LEN); i++; break; default: @@ -845,7 +976,7 @@ lzx_write_compressed_code(struct output_bitstream *out, * compressed block to the output bitstream in the final compressed * representation. * - * @ostream + * @os * The output bitstream. * @block_type * The chosen type of the LZX compressed block (LZX_BLOCKTYPE_ALIGNED or @@ -859,7 +990,7 @@ lzx_write_compressed_code(struct output_bitstream *out, * LZX compressed block. */ static void -lzx_write_items(struct output_bitstream *ostream, int block_type, +lzx_write_items(struct lzx_output_bitstream *os, int block_type, const struct lzx_item items[], u32 num_items, const struct lzx_codes *codes) { @@ -868,32 +999,30 @@ lzx_write_items(struct output_bitstream *ostream, int block_type, * indicates whether the item is an actual LZ-style match (1) or * a literal byte (0). */ if (items[i].data & 0x80000000) - lzx_write_match(ostream, block_type, items[i], codes); + lzx_write_match(os, block_type, items[i], codes); else - lzx_write_literal(ostream, items[i].data, codes); + lzx_write_literal(os, items[i].data, codes); } } /* Write an LZX aligned offset or verbatim block to the output. */ static void lzx_write_compressed_block(int block_type, - unsigned block_size, - unsigned max_window_size, + u32 block_size, + unsigned window_order, unsigned num_main_syms, struct lzx_item * chosen_items, - unsigned num_chosen_items, + u32 num_chosen_items, const struct lzx_codes * codes, const struct lzx_codes * prev_codes, - struct output_bitstream * ostream) + struct lzx_output_bitstream * os) { - unsigned i; - LZX_ASSERT(block_type == LZX_BLOCKTYPE_ALIGNED || block_type == LZX_BLOCKTYPE_VERBATIM); /* The first three bits indicate the type of block and are one of the * LZX_BLOCKTYPE_* constants. */ - bitstream_put_bits(ostream, block_type, 3); + lzx_write_bits(os, block_type, 3); /* Output the block size. * @@ -911,73 +1040,59 @@ lzx_write_compressed_block(int block_type, * because WIMs created with chunk size greater than 32768 can seemingly * only be opened by wimlib anyway. */ if (block_size == LZX_DEFAULT_BLOCK_SIZE) { - bitstream_put_bits(ostream, 1, 1); + lzx_write_bits(os, 1, 1); } else { - bitstream_put_bits(ostream, 0, 1); + lzx_write_bits(os, 0, 1); - if (max_window_size >= 65536) - bitstream_put_bits(ostream, block_size >> 16, 8); + if (window_order >= 16) + lzx_write_bits(os, block_size >> 16, 8); - bitstream_put_bits(ostream, block_size, 16); + lzx_write_bits(os, block_size & 0xFFFF, 16); } - /* Write out lengths of the main code. Note that the LZX specification - * incorrectly states that the aligned offset code comes after the - * length code, but in fact it is the very first code to be written - * (before the main code). */ - if (block_type == LZX_BLOCKTYPE_ALIGNED) - for (i = 0; i < LZX_ALIGNEDCODE_NUM_SYMBOLS; i++) - bitstream_put_bits(ostream, codes->lens.aligned[i], - LZX_ALIGNEDCODE_ELEMENT_SIZE); - - /* Write the precode and lengths for the first LZX_NUM_CHARS symbols in - * the main code, which are the codewords for literal bytes. */ - lzx_write_compressed_code(ostream, - codes->lens.main, + /* Output the aligned offset code. */ + if (block_type == LZX_BLOCKTYPE_ALIGNED) { + for (int i = 0; i < LZX_ALIGNEDCODE_NUM_SYMBOLS; i++) { + lzx_write_bits(os, codes->lens.aligned[i], + LZX_ALIGNEDCODE_ELEMENT_SIZE); + } + } + + /* Output the main code (two parts). */ + lzx_write_compressed_code(os, codes->lens.main, prev_codes->lens.main, LZX_NUM_CHARS); - - /* Write the precode and lengths for the rest of the main code, which - * are the codewords for match headers. */ - lzx_write_compressed_code(ostream, - codes->lens.main + LZX_NUM_CHARS, + lzx_write_compressed_code(os, codes->lens.main + LZX_NUM_CHARS, prev_codes->lens.main + LZX_NUM_CHARS, num_main_syms - LZX_NUM_CHARS); - /* Write the precode and lengths for the length code. */ - lzx_write_compressed_code(ostream, - codes->lens.len, + /* Output the length code. */ + lzx_write_compressed_code(os, codes->lens.len, prev_codes->lens.len, LZX_LENCODE_NUM_SYMBOLS); - /* Write the actual matches and literals. */ - lzx_write_items(ostream, block_type, - chosen_items, num_chosen_items, codes); + /* Output the compressed matches and literals. */ + lzx_write_items(os, block_type, chosen_items, num_chosen_items, codes); } /* Write out the LZX blocks that were computed. */ static void -lzx_write_all_blocks(struct lzx_compressor *c, struct output_bitstream *ostream) +lzx_write_all_blocks(struct lzx_compressor *c, struct lzx_output_bitstream *os) { const struct lzx_codes *prev_codes = &c->zero_codes; for (unsigned i = 0; i < c->num_blocks; i++) { const struct lzx_block_spec *spec = &c->block_specs[i]; - LZX_DEBUG("Writing block %u/%u (type=%d, size=%u, num_chosen_items=%u)...", - i + 1, c->num_blocks, - spec->block_type, spec->block_size, - spec->num_chosen_items); - lzx_write_compressed_block(spec->block_type, spec->block_size, - c->max_window_size, + c->window_order, c->num_main_syms, spec->chosen_items, spec->num_chosen_items, &spec->codes, prev_codes, - ostream); + os); prev_codes = &spec->codes; } @@ -1001,7 +1116,7 @@ lzx_tally_match(unsigned match_len, u32 match_offset, struct lzx_freqs *freqs, struct lzx_lru_queue *queue) { unsigned position_slot; - unsigned position_footer; + u32 position_footer; u32 len_header; unsigned main_symbol; unsigned len_footer; @@ -1013,7 +1128,7 @@ lzx_tally_match(unsigned match_len, u32 match_offset, * as part of the main symbol) and a position footer. */ position_slot = lzx_get_position_slot(match_offset, queue); position_footer = (match_offset + LZX_OFFSET_OFFSET) & - ((1U << lzx_get_num_extra_bits(position_slot)) - 1); + (((u32)1 << lzx_get_num_extra_bits(position_slot)) - 1); /* The match length shall be encoded as a length header (itself encoded * as part of the main symbol) and an optional length footer. */ @@ -1374,6 +1489,23 @@ lzx_match_chooser_reverse_list(struct lzx_compressor *c, unsigned cur_pos) }; } +/* + * Find the longest repeat offset match. + * + * If no match of at least LZX_MIN_MATCH_LEN bytes is found, then return 0. + * + * If a match of at least LZX_MIN_MATCH_LEN bytes is found, then return its + * length and set *slot_ret to the index of its offset in @queue. + */ +static inline u32 +lzx_repsearch(const u8 * const strptr, const u32 bytes_remaining, + const struct lzx_lru_queue *queue, unsigned *slot_ret) +{ + BUILD_BUG_ON(LZX_MIN_MATCH_LEN != 2); + return lz_repsearch(strptr, bytes_remaining, LZX_MAX_MATCH_LEN, + queue->R, LZX_NUM_RECENT_OFFSETS, slot_ret); +} + /* * lzx_choose_near_optimal_match() - * @@ -1466,22 +1598,13 @@ lzx_choose_near_optimal_item(struct lzx_compressor *c) /* Search for matches at repeat offsets. As a heuristic, we only keep * the one with the longest match length. */ - longest_rep_len = LZX_MIN_MATCH_LEN - 1; - if (c->match_window_pos >= 1) { - unsigned limit = min(LZX_MAX_MATCH_LEN, - c->match_window_end - c->match_window_pos); - for (int i = 0; i < LZX_NUM_RECENT_OFFSETS; i++) { - u32 offset = c->queue.R[i]; - const u8 *strptr = &c->cur_window[c->match_window_pos]; - const u8 *matchptr = strptr - offset; - unsigned len = 0; - while (len < limit && strptr[len] == matchptr[len]) - len++; - if (len > longest_rep_len) { - longest_rep_len = len; - longest_rep_slot = i; - } - } + if (likely(c->match_window_pos >= 1)) { + longest_rep_len = lzx_repsearch(&c->cur_window[c->match_window_pos], + c->match_window_end - c->match_window_pos, + &c->queue, + &longest_rep_slot); + } else { + longest_rep_len = 0; } /* If there's a long match with a repeat offset, choose it immediately. */ @@ -1565,7 +1688,10 @@ lzx_choose_near_optimal_item(struct lzx_compressor *c) } end_pos = longest_len; - if (longest_rep_len >= LZX_MIN_MATCH_LEN) { + if (longest_rep_len) { + + LZX_ASSERT(longest_rep_len >= LZX_MIN_MATCH_LEN); + u32 cost; while (end_pos < longest_rep_len) @@ -1637,21 +1763,10 @@ lzx_choose_near_optimal_item(struct lzx_compressor *c) /* Search for matches at repeat offsets. Again, as a heuristic * we only keep the longest one. */ - longest_rep_len = LZX_MIN_MATCH_LEN - 1; - unsigned limit = min(LZX_MAX_MATCH_LEN, - c->match_window_end - c->match_window_pos); - for (int i = 0; i < LZX_NUM_RECENT_OFFSETS; i++) { - u32 offset = optimum[cur_pos].queue.R[i]; - const u8 *strptr = &c->cur_window[c->match_window_pos]; - const u8 *matchptr = strptr - offset; - unsigned len = 0; - while (len < limit && strptr[len] == matchptr[len]) - len++; - if (len > longest_rep_len) { - longest_rep_len = len; - longest_rep_slot = i; - } - } + longest_rep_len = lzx_repsearch(&c->cur_window[c->match_window_pos], + c->match_window_end - c->match_window_pos, + &optimum[cur_pos].queue, + &longest_rep_slot); /* If we found a long match at a repeat offset, choose it * immediately. */ @@ -1813,7 +1928,9 @@ lzx_choose_near_optimal_item(struct lzx_compressor *c) * of the longest repeat offset match. Still didn't seem quite * worth it, though. */ - if (longest_rep_len >= LZX_MIN_MATCH_LEN) { + if (longest_rep_len) { + + LZX_ASSERT(longest_rep_len >= LZX_MIN_MATCH_LEN); while (end_pos < cur_pos + longest_rep_len) optimum[++end_pos].cost = MC_INFINITE_COST; @@ -1964,7 +2081,7 @@ lzx_choose_items_for_block(struct lzx_compressor *c, struct lzx_block_spec *spec struct lz_match lz_match; struct lzx_item lzx_item; - LZX_ASSERT(num_passes >= 1); + LZX_ASSERT(num_passes_remaining >= 1); LZX_ASSERT(lz_mf_get_position(c->mf) == spec->window_pos); c->match_window_end = spec->window_pos + spec->block_size; @@ -2150,13 +2267,17 @@ static void lzx_free_compressor(void *_c); static u64 -lzx_get_needed_memory(size_t max_window_size, unsigned int compression_level) +lzx_get_needed_memory(size_t max_block_size, unsigned int compression_level) { struct lzx_compressor_params params; u64 size = 0; + unsigned window_order; + u32 max_window_size; - if (!lzx_window_size_valid(max_window_size)) + window_order = lzx_get_window_order(max_block_size); + if (window_order == 0) return 0; + max_window_size = max_block_size; lzx_build_params(compression_level, max_window_size, ¶ms); @@ -2182,15 +2303,19 @@ lzx_get_needed_memory(size_t max_window_size, unsigned int compression_level) } static int -lzx_create_compressor(size_t max_window_size, unsigned int compression_level, +lzx_create_compressor(size_t max_block_size, unsigned int compression_level, void **c_ret) { struct lzx_compressor *c; struct lzx_compressor_params params; struct lz_mf_params mf_params; + unsigned window_order; + u32 max_window_size; - if (!lzx_window_size_valid(max_window_size)) + window_order = lzx_get_window_order(max_block_size); + if (window_order == 0) return WIMLIB_ERR_INVALID_PARAM; + max_window_size = max_block_size; lzx_build_params(compression_level, max_window_size, ¶ms); lzx_build_mf_params(¶ms, max_window_size, &mf_params); @@ -2202,8 +2327,9 @@ lzx_create_compressor(size_t max_window_size, unsigned int compression_level, goto oom; c->params = params; - c->num_main_syms = lzx_get_num_main_syms(max_window_size); + c->num_main_syms = lzx_get_num_main_syms(window_order); c->max_window_size = max_window_size; + c->window_order = window_order; c->cur_window = ALIGNED_MALLOC(max_window_size, 16); if (!c->cur_window) @@ -2258,44 +2384,28 @@ lzx_compress(const void *uncompressed_data, size_t uncompressed_size, void *compressed_data, size_t compressed_size_avail, void *_c) { struct lzx_compressor *c = _c; - struct output_bitstream ostream; - size_t compressed_size; + struct lzx_output_bitstream os; - if (uncompressed_size < 100) { - LZX_DEBUG("Too small to bother compressing."); + /* Don't bother compressing very small inputs. */ + if (uncompressed_size < 100) return 0; - } - - LZX_DEBUG("Attempting to compress %zu bytes...", - uncompressed_size); /* The input data must be preprocessed. To avoid changing the original * input, copy it to a temporary buffer. */ memcpy(c->cur_window, uncompressed_data, uncompressed_size); c->cur_window_size = uncompressed_size; - /* Before doing any actual compression, do the call instruction (0xe8 - * byte) translation on the uncompressed data. */ + /* Preprocess the data. */ lzx_do_e8_preprocessing(c->cur_window, c->cur_window_size); /* Prepare the compressed data. */ lzx_prepare_blocks(c); - /* Generate the compressed data. */ - init_output_bitstream(&ostream, compressed_data, compressed_size_avail); - lzx_write_all_blocks(c, &ostream); - - compressed_size = flush_output_bitstream(&ostream); - if (compressed_size == (u32)~0UL) { - LZX_DEBUG("Data did not compress to %zu bytes or less!", - compressed_size_avail); - return 0; - } - - LZX_DEBUG("Done: compressed %zu => %zu bytes.", - uncompressed_size, compressed_size); - - return compressed_size; + /* Generate the compressed data and return its size, or 0 if an overflow + * occurred. */ + lzx_init_output(&os, compressed_data, compressed_size_avail); + lzx_write_all_blocks(c, &os); + return lzx_flush_output(&os); } static void