diff options
Diffstat (limited to 'src/Common/zlib/deflate.c')
| -rw-r--r-- | src/Common/zlib/deflate.c | 108 |
1 files changed, 78 insertions, 30 deletions
diff --git a/src/Common/zlib/deflate.c b/src/Common/zlib/deflate.c index 1ec76144..799fb93c 100644 --- a/src/Common/zlib/deflate.c +++ b/src/Common/zlib/deflate.c @@ -1,5 +1,5 @@ /* deflate.c -- compress data using the deflation algorithm - * Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler + * Copyright (C) 1995-2022 Jean-loup Gailly and Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h */ @@ -52,7 +52,7 @@ #include "deflate.h" const char deflate_copyright[] = - " deflate 1.2.11 Copyright 1995-2017 Jean-loup Gailly and Mark Adler "; + " deflate 1.2.12 Copyright 1995-2022 Jean-loup Gailly and Mark Adler "; /* If you use the zlib library in a product, an acknowledgment is welcome in the documentation of your product. If for some reason you cannot @@ -190,8 +190,11 @@ local const config configuration_table[10] = { * prev[] will be initialized on the fly. */ #define CLEAR_HASH(s) \ - s->head[s->hash_size-1] = NIL; \ - zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head)); + do { \ + s->head[s->hash_size-1] = NIL; \ + zmemzero((Bytef *)s->head, \ + (unsigned)(s->hash_size-1)*sizeof(*s->head)); \ + } while (0) /* =========================================================================== * Slide the hash table when sliding the window down (could be avoided with 32 @@ -252,11 +255,6 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, int wrap = 1; static const char my_version[] = ZLIB_VERSION; - ushf *overlay; - /* We overlay pending_buf and d_buf+l_buf. This works since the average - * output size for (length,distance) codes is <= 24 bits. - */ - if (version == Z_NULL || version[0] != my_version[0] || stream_size != sizeof(z_stream)) { return Z_VERSION_ERROR; @@ -326,9 +324,47 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ - overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); - s->pending_buf = (uchf *) overlay; - s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); + /* We overlay pending_buf and sym_buf. This works since the average size + * for length/distance pairs over any compressed block is assured to be 31 + * bits or less. + * + * Analysis: The longest fixed codes are a length code of 8 bits plus 5 + * extra bits, for lengths 131 to 257. The longest fixed distance codes are + * 5 bits plus 13 extra bits, for distances 16385 to 32768. The longest + * possible fixed-codes length/distance pair is then 31 bits total. + * + * sym_buf starts one-fourth of the way into pending_buf. So there are + * three bytes in sym_buf for every four bytes in pending_buf. Each symbol + * in sym_buf is three bytes -- two for the distance and one for the + * literal/length. As each symbol is consumed, the pointer to the next + * sym_buf value to read moves forward three bytes. From that symbol, up to + * 31 bits are written to pending_buf. The closest the written pending_buf + * bits gets to the next sym_buf symbol to read is just before the last + * code is written. At that time, 31*(n-2) bits have been written, just + * after 24*(n-2) bits have been consumed from sym_buf. sym_buf starts at + * 8*n bits into pending_buf. (Note that the symbol buffer fills when n-1 + * symbols are written.) The closest the writing gets to what is unread is + * then n+14 bits. Here n is lit_bufsize, which is 16384 by default, and + * can range from 128 to 32768. + * + * Therefore, at a minimum, there are 142 bits of space between what is + * written and what is read in the overlain buffers, so the symbols cannot + * be overwritten by the compressed data. That space is actually 139 bits, + * due to the three-bit fixed-code block header. + * + * That covers the case where either Z_FIXED is specified, forcing fixed + * codes, or when the use of fixed codes is chosen, because that choice + * results in a smaller compressed block than dynamic codes. That latter + * condition then assures that the above analysis also covers all dynamic + * blocks. A dynamic-code block will only be chosen to be emitted if it has + * fewer bits than a fixed-code block would for the same set of symbols. + * Therefore its average symbol length is assured to be less than 31. So + * the compressed data for a dynamic block also cannot overwrite the + * symbols from which it is being constructed. + */ + + s->pending_buf = (uchf *) ZALLOC(strm, s->lit_bufsize, 4); + s->pending_buf_size = (ulg)s->lit_bufsize * 4; if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || s->pending_buf == Z_NULL) { @@ -337,8 +373,12 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, deflateEnd (strm); return Z_MEM_ERROR; } - s->d_buf = overlay + s->lit_bufsize/sizeof(ush); - s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; + s->sym_buf = s->pending_buf + s->lit_bufsize; + s->sym_end = (s->lit_bufsize - 1) * 3; + /* We avoid equality with lit_bufsize*3 because of wraparound at 64K + * on 16 bit machines and because stored blocks are restricted to + * 64K-1 bytes. + */ s->level = level; s->strategy = strategy; @@ -488,13 +528,13 @@ int ZEXPORT deflateResetKeep (strm) #ifdef GZIP s->wrap == 2 ? GZIP_STATE : #endif - s->wrap ? INIT_STATE : BUSY_STATE; + INIT_STATE; strm->adler = #ifdef GZIP s->wrap == 2 ? crc32(0L, Z_NULL, 0) : #endif adler32(0L, Z_NULL, 0); - s->last_flush = Z_NO_FLUSH; + s->last_flush = -2; _tr_init(s); @@ -549,7 +589,8 @@ int ZEXPORT deflatePrime (strm, bits, value) if (deflateStateCheck(strm)) return Z_STREAM_ERROR; s = strm->state; - if ((Bytef *)(s->d_buf) < s->pending_out + ((Buf_size + 7) >> 3)) + if (bits < 0 || bits > 16 || + s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3)) return Z_BUF_ERROR; do { put = Buf_size - s->bi_valid; @@ -587,12 +628,12 @@ int ZEXPORT deflateParams(strm, level, strategy) func = configuration_table[s->level].func; if ((strategy != s->strategy || func != configuration_table[level].func) && - s->high_water) { + s->last_flush != -2) { /* Flush the last buffer: */ int err = deflate(strm, Z_BLOCK); if (err == Z_STREAM_ERROR) return err; - if (strm->avail_out == 0) + if (strm->avail_in || (s->strstart - s->block_start) + s->lookahead) return Z_BUF_ERROR; } if (s->level != level) { @@ -811,6 +852,8 @@ int ZEXPORT deflate (strm, flush) } /* Write the header */ + if (s->status == INIT_STATE && s->wrap == 0) + s->status = BUSY_STATE; if (s->status == INIT_STATE) { /* zlib header */ uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; @@ -1108,7 +1151,6 @@ int ZEXPORT deflateCopy (dest, source) #else deflate_state *ds; deflate_state *ss; - ushf *overlay; if (deflateStateCheck(source) || dest == Z_NULL) { @@ -1128,8 +1170,7 @@ int ZEXPORT deflateCopy (dest, source) ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); - overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); - ds->pending_buf = (uchf *) overlay; + ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, 4); if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || ds->pending_buf == Z_NULL) { @@ -1143,8 +1184,7 @@ int ZEXPORT deflateCopy (dest, source) zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); - ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); - ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; + ds->sym_buf = ds->pending_buf + ds->lit_bufsize; ds->l_desc.dyn_tree = ds->dyn_ltree; ds->d_desc.dyn_tree = ds->dyn_dtree; @@ -1513,6 +1553,8 @@ local void fill_window(s) s->match_start -= wsize; s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ s->block_start -= (long) wsize; + if (s->insert > s->strstart) + s->insert = s->strstart; slide_hash(s); more += wsize; } @@ -1742,6 +1784,7 @@ local block_state deflate_stored(s, flush) s->matches = 2; /* clear hash */ zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size); s->strstart = s->w_size; + s->insert = s->strstart; } else { if (s->window_size - s->strstart <= used) { @@ -1750,12 +1793,14 @@ local block_state deflate_stored(s, flush) zmemcpy(s->window, s->window + s->w_size, s->strstart); if (s->matches < 2) s->matches++; /* add a pending slide_hash() */ + if (s->insert > s->strstart) + s->insert = s->strstart; } zmemcpy(s->window + s->strstart, s->strm->next_in - used, used); s->strstart += used; + s->insert += MIN(used, s->w_size - s->insert); } s->block_start = s->strstart; - s->insert += MIN(used, s->w_size - s->insert); } if (s->high_water < s->strstart) s->high_water = s->strstart; @@ -1770,7 +1815,7 @@ local block_state deflate_stored(s, flush) return block_done; /* Fill the window with any remaining input. */ - have = s->window_size - s->strstart - 1; + have = s->window_size - s->strstart; if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) { /* Slide the window down. */ s->block_start -= s->w_size; @@ -1779,12 +1824,15 @@ local block_state deflate_stored(s, flush) if (s->matches < 2) s->matches++; /* add a pending slide_hash() */ have += s->w_size; /* more space now */ + if (s->insert > s->strstart) + s->insert = s->strstart; } if (have > s->strm->avail_in) have = s->strm->avail_in; if (have) { read_buf(s->strm, s->window + s->strstart, have); s->strstart += have; + s->insert += MIN(have, s->w_size - s->insert); } if (s->high_water < s->strstart) s->high_water = s->strstart; @@ -1912,7 +1960,7 @@ local block_state deflate_fast(s, flush) FLUSH_BLOCK(s, 1); return finish_done; } - if (s->last_lit) + if (s->sym_next) FLUSH_BLOCK(s, 0); return block_done; } @@ -2043,7 +2091,7 @@ local block_state deflate_slow(s, flush) FLUSH_BLOCK(s, 1); return finish_done; } - if (s->last_lit) + if (s->sym_next) FLUSH_BLOCK(s, 0); return block_done; } @@ -2118,7 +2166,7 @@ local block_state deflate_rle(s, flush) FLUSH_BLOCK(s, 1); return finish_done; } - if (s->last_lit) + if (s->sym_next) FLUSH_BLOCK(s, 0); return block_done; } @@ -2157,7 +2205,7 @@ local block_state deflate_huff(s, flush) FLUSH_BLOCK(s, 1); return finish_done; } - if (s->last_lit) + if (s->sym_next) FLUSH_BLOCK(s, 0); return block_done; } |