diff --git a/FAQ b/FAQ index b6b11bd0..57dd4f59 100644 --- a/FAQ +++ b/FAQ @@ -156,6 +156,10 @@ The latest zlib FAQ is at http://zlib.net/zlib_faq.html library memory allocation routines by default. zlib's *Init* functions allow for the application to provide custom memory allocation routines. + If the non-default BUILDFIXED or DYNAMIC_CRC_TABLE defines are used on a + system without atomics (e.g. pre-C11), then inflate() and crc32() will not + be thread safe. + Of course, you should only operate on any given zlib or gzip stream from a single thread at a time. diff --git a/README b/README index 02259d47..17b70fcb 100644 --- a/README +++ b/README @@ -1,8 +1,8 @@ ZLIB DATA COMPRESSION LIBRARY zlib 1.3.1.2 is a general purpose data compression library. All the code is -thread safe. The data format used by the zlib library is described by RFCs -(Request for Comments) 1950 to 1952 at +thread safe (though see the FAQ for caveats). The data format used by the zlib +library is described by RFCs (Request for Comments) 1950 to 1952 at https://datatracker.ietf.org/doc/html/rfc1950 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). diff --git a/crc32.c b/crc32.c index 33d8c795..630049fc 100644 --- a/crc32.c +++ b/crc32.c @@ -204,83 +204,8 @@ local z_crc_t FAR crc_table[256]; local void write_table64(FILE *, const z_word_t FAR *, int); #endif /* MAKECRCH */ -/* - Define a once() function depending on the availability of atomics. If this is - compiled with DYNAMIC_CRC_TABLE defined, and if CRCs will be computed in - multiple threads, and if atomics are not available, then get_crc_table() must - be called to initialize the tables and must return before any threads are - allowed to compute or combine CRCs. - */ - -/* Definition of once functionality. */ -typedef struct once_s once_t; - -/* Check for the availability of atomics. */ -#if defined(__STDC__) && __STDC_VERSION__ >= 201112L && \ - !defined(__STDC_NO_ATOMICS__) - -#include - -/* Structure for once(), which must be initialized with ONCE_INIT. */ -struct once_s { - atomic_flag begun; - atomic_int done; -}; -#define ONCE_INIT {ATOMIC_FLAG_INIT, 0} - -/* - Run the provided init() function exactly once, even if multiple threads - invoke once() at the same time. The state must be a once_t initialized with - ONCE_INIT. - */ -local void once(once_t *state, void (*init)(void)) { - if (!atomic_load(&state->done)) { - if (atomic_flag_test_and_set(&state->begun)) - while (!atomic_load(&state->done)) - ; - else { - init(); - atomic_store(&state->done, 1); - } - } -} - -#else /* no atomics */ - -/* Structure for once(), which must be initialized with ONCE_INIT. */ -struct once_s { - volatile int begun; - volatile int done; -}; -#define ONCE_INIT {0, 0} - -/* Test and set. Alas, not atomic, but tries to minimize the period of - vulnerability. */ -local int test_and_set(int volatile *flag) { - int was; - - was = *flag; - *flag = 1; - return was; -} - -/* Run the provided init() function once. This is not thread-safe. */ -local void once(once_t *state, void (*init)(void)) { - if (!state->done) { - if (test_and_set(&state->begun)) - while (!state->done) - ; - else { - init(); - state->done = 1; - } - } -} - -#endif - /* State for once(). */ -local once_t made = ONCE_INIT; +local z_once_t made = Z_ONCE_INIT; /* Generate tables for a byte-wise 32-bit CRC calculation on the polynomial: @@ -548,7 +473,7 @@ local void braid(z_crc_t ltl[][256], z_word_t big[][256], int n, int w) { */ const z_crc_t FAR * ZEXPORT get_crc_table(void) { #ifdef DYNAMIC_CRC_TABLE - once(&made, make_crc_table); + z_once(&made, make_crc_table); #endif /* DYNAMIC_CRC_TABLE */ return (const z_crc_t FAR *)crc_table; } @@ -585,7 +510,7 @@ unsigned long ZEXPORT crc32_z(unsigned long crc, const unsigned char FAR *buf, if (buf == Z_NULL) return 0; #ifdef DYNAMIC_CRC_TABLE - once(&made, make_crc_table); + z_once(&made, make_crc_table); #endif /* DYNAMIC_CRC_TABLE */ /* Pre-condition the CRC */ @@ -697,7 +622,7 @@ unsigned long ZEXPORT crc32_z(unsigned long crc, const unsigned char FAR *buf, if (buf == Z_NULL) return 0; #ifdef DYNAMIC_CRC_TABLE - once(&made, make_crc_table); + z_once(&made, make_crc_table); #endif /* DYNAMIC_CRC_TABLE */ /* Pre-condition the CRC */ @@ -1022,7 +947,7 @@ uLong ZEXPORT crc32_combine64(uLong crc1, uLong crc2, z_off64_t len2) { if (len2 < 0) return 0; #ifdef DYNAMIC_CRC_TABLE - once(&made, make_crc_table); + z_once(&made, make_crc_table); #endif /* DYNAMIC_CRC_TABLE */ return multmodp(x2nmodp(len2, 3), crc1) ^ (crc2 & 0xffffffff); } @@ -1037,7 +962,7 @@ uLong ZEXPORT crc32_combine_gen64(z_off64_t len2) { if (len2 < 0) return 0; #ifdef DYNAMIC_CRC_TABLE - once(&made, make_crc_table); + z_once(&made, make_crc_table); #endif /* DYNAMIC_CRC_TABLE */ return x2nmodp(len2, 3); } diff --git a/infback.c b/infback.c index 5608530c..518bf3e7 100644 --- a/infback.c +++ b/infback.c @@ -63,57 +63,6 @@ int ZEXPORT inflateBackInit_(z_streamp strm, int windowBits, return Z_OK; } -/* - Return state with length and distance decoding tables and index sizes set to - fixed code decoding. Normally this returns fixed tables from inffixed.h. - If BUILDFIXED is defined, then instead this routine builds the tables the - first time it's called, and returns those tables the first time and - thereafter. This reduces the size of the code by about 2K bytes, in - exchange for a little execution time. However, BUILDFIXED should not be - used for threaded applications, since the rewriting of the tables and virgin - may not be thread-safe. - */ -local void fixedtables(struct inflate_state FAR *state) { -#ifdef BUILDFIXED - static int virgin = 1; - static code *lenfix, *distfix; - static code fixed[544]; - - /* build fixed huffman tables if first call (may not be thread safe) */ - if (virgin) { - unsigned sym, bits; - static code *next; - - /* literal/length table */ - sym = 0; - while (sym < 144) state->lens[sym++] = 8; - while (sym < 256) state->lens[sym++] = 9; - while (sym < 280) state->lens[sym++] = 7; - while (sym < 288) state->lens[sym++] = 8; - next = fixed; - lenfix = next; - bits = 9; - inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work); - - /* distance table */ - sym = 0; - while (sym < 32) state->lens[sym++] = 5; - distfix = next; - bits = 5; - inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work); - - /* do this just once */ - virgin = 0; - } -#else /* !BUILDFIXED */ -# include "inffixed.h" -#endif /* BUILDFIXED */ - state->lencode = lenfix; - state->lenbits = 9; - state->distcode = distfix; - state->distbits = 5; -} - /* Macros for inflateBack(): */ /* Load returned state from inflate_fast() */ @@ -293,7 +242,7 @@ int ZEXPORT inflateBack(z_streamp strm, in_func in, void FAR *in_desc, state->mode = STORED; break; case 1: /* fixed block */ - fixedtables(state); + inflate_fixed(state); Tracev((stderr, "inflate: fixed codes block%s\n", state->last ? " (last)" : "")); state->mode = LEN; /* decode codes */ diff --git a/inffixed.h b/inffixed.h index d6283277..05ce88e4 100644 --- a/inffixed.h +++ b/inffixed.h @@ -1,94 +1,94 @@ - /* inffixed.h -- table for decoding fixed codes - * Generated automatically by makefixed(). - */ +/* inffixed.h -- table for decoding fixed codes + * Generated automatically by makefixed(). + */ - /* WARNING: this file should *not* be used by applications. - It is part of the implementation of this library and is - subject to change. Applications should only use zlib.h. - */ +/* WARNING: this file should *not* be used by applications. + It is part of the implementation of this library and is + subject to change. Applications should only use zlib.h. + */ - static const code lenfix[512] = { - {96,7,0},{0,8,80},{0,8,16},{20,8,115},{18,7,31},{0,8,112},{0,8,48}, - {0,9,192},{16,7,10},{0,8,96},{0,8,32},{0,9,160},{0,8,0},{0,8,128}, - {0,8,64},{0,9,224},{16,7,6},{0,8,88},{0,8,24},{0,9,144},{19,7,59}, - {0,8,120},{0,8,56},{0,9,208},{17,7,17},{0,8,104},{0,8,40},{0,9,176}, - {0,8,8},{0,8,136},{0,8,72},{0,9,240},{16,7,4},{0,8,84},{0,8,20}, - {21,8,227},{19,7,43},{0,8,116},{0,8,52},{0,9,200},{17,7,13},{0,8,100}, - {0,8,36},{0,9,168},{0,8,4},{0,8,132},{0,8,68},{0,9,232},{16,7,8}, - {0,8,92},{0,8,28},{0,9,152},{20,7,83},{0,8,124},{0,8,60},{0,9,216}, - {18,7,23},{0,8,108},{0,8,44},{0,9,184},{0,8,12},{0,8,140},{0,8,76}, - {0,9,248},{16,7,3},{0,8,82},{0,8,18},{21,8,163},{19,7,35},{0,8,114}, - {0,8,50},{0,9,196},{17,7,11},{0,8,98},{0,8,34},{0,9,164},{0,8,2}, - {0,8,130},{0,8,66},{0,9,228},{16,7,7},{0,8,90},{0,8,26},{0,9,148}, - {20,7,67},{0,8,122},{0,8,58},{0,9,212},{18,7,19},{0,8,106},{0,8,42}, - {0,9,180},{0,8,10},{0,8,138},{0,8,74},{0,9,244},{16,7,5},{0,8,86}, - {0,8,22},{64,8,0},{19,7,51},{0,8,118},{0,8,54},{0,9,204},{17,7,15}, - {0,8,102},{0,8,38},{0,9,172},{0,8,6},{0,8,134},{0,8,70},{0,9,236}, - {16,7,9},{0,8,94},{0,8,30},{0,9,156},{20,7,99},{0,8,126},{0,8,62}, - {0,9,220},{18,7,27},{0,8,110},{0,8,46},{0,9,188},{0,8,14},{0,8,142}, - {0,8,78},{0,9,252},{96,7,0},{0,8,81},{0,8,17},{21,8,131},{18,7,31}, - {0,8,113},{0,8,49},{0,9,194},{16,7,10},{0,8,97},{0,8,33},{0,9,162}, - {0,8,1},{0,8,129},{0,8,65},{0,9,226},{16,7,6},{0,8,89},{0,8,25}, - {0,9,146},{19,7,59},{0,8,121},{0,8,57},{0,9,210},{17,7,17},{0,8,105}, - {0,8,41},{0,9,178},{0,8,9},{0,8,137},{0,8,73},{0,9,242},{16,7,4}, - {0,8,85},{0,8,21},{16,8,258},{19,7,43},{0,8,117},{0,8,53},{0,9,202}, - {17,7,13},{0,8,101},{0,8,37},{0,9,170},{0,8,5},{0,8,133},{0,8,69}, - {0,9,234},{16,7,8},{0,8,93},{0,8,29},{0,9,154},{20,7,83},{0,8,125}, - {0,8,61},{0,9,218},{18,7,23},{0,8,109},{0,8,45},{0,9,186},{0,8,13}, - {0,8,141},{0,8,77},{0,9,250},{16,7,3},{0,8,83},{0,8,19},{21,8,195}, - {19,7,35},{0,8,115},{0,8,51},{0,9,198},{17,7,11},{0,8,99},{0,8,35}, - {0,9,166},{0,8,3},{0,8,131},{0,8,67},{0,9,230},{16,7,7},{0,8,91}, - {0,8,27},{0,9,150},{20,7,67},{0,8,123},{0,8,59},{0,9,214},{18,7,19}, - {0,8,107},{0,8,43},{0,9,182},{0,8,11},{0,8,139},{0,8,75},{0,9,246}, - {16,7,5},{0,8,87},{0,8,23},{64,8,0},{19,7,51},{0,8,119},{0,8,55}, - {0,9,206},{17,7,15},{0,8,103},{0,8,39},{0,9,174},{0,8,7},{0,8,135}, - {0,8,71},{0,9,238},{16,7,9},{0,8,95},{0,8,31},{0,9,158},{20,7,99}, - {0,8,127},{0,8,63},{0,9,222},{18,7,27},{0,8,111},{0,8,47},{0,9,190}, - {0,8,15},{0,8,143},{0,8,79},{0,9,254},{96,7,0},{0,8,80},{0,8,16}, - {20,8,115},{18,7,31},{0,8,112},{0,8,48},{0,9,193},{16,7,10},{0,8,96}, - {0,8,32},{0,9,161},{0,8,0},{0,8,128},{0,8,64},{0,9,225},{16,7,6}, - {0,8,88},{0,8,24},{0,9,145},{19,7,59},{0,8,120},{0,8,56},{0,9,209}, - {17,7,17},{0,8,104},{0,8,40},{0,9,177},{0,8,8},{0,8,136},{0,8,72}, - {0,9,241},{16,7,4},{0,8,84},{0,8,20},{21,8,227},{19,7,43},{0,8,116}, - {0,8,52},{0,9,201},{17,7,13},{0,8,100},{0,8,36},{0,9,169},{0,8,4}, - {0,8,132},{0,8,68},{0,9,233},{16,7,8},{0,8,92},{0,8,28},{0,9,153}, - {20,7,83},{0,8,124},{0,8,60},{0,9,217},{18,7,23},{0,8,108},{0,8,44}, - {0,9,185},{0,8,12},{0,8,140},{0,8,76},{0,9,249},{16,7,3},{0,8,82}, - {0,8,18},{21,8,163},{19,7,35},{0,8,114},{0,8,50},{0,9,197},{17,7,11}, - {0,8,98},{0,8,34},{0,9,165},{0,8,2},{0,8,130},{0,8,66},{0,9,229}, - {16,7,7},{0,8,90},{0,8,26},{0,9,149},{20,7,67},{0,8,122},{0,8,58}, - {0,9,213},{18,7,19},{0,8,106},{0,8,42},{0,9,181},{0,8,10},{0,8,138}, - {0,8,74},{0,9,245},{16,7,5},{0,8,86},{0,8,22},{64,8,0},{19,7,51}, - {0,8,118},{0,8,54},{0,9,205},{17,7,15},{0,8,102},{0,8,38},{0,9,173}, - {0,8,6},{0,8,134},{0,8,70},{0,9,237},{16,7,9},{0,8,94},{0,8,30}, - {0,9,157},{20,7,99},{0,8,126},{0,8,62},{0,9,221},{18,7,27},{0,8,110}, - {0,8,46},{0,9,189},{0,8,14},{0,8,142},{0,8,78},{0,9,253},{96,7,0}, - {0,8,81},{0,8,17},{21,8,131},{18,7,31},{0,8,113},{0,8,49},{0,9,195}, - {16,7,10},{0,8,97},{0,8,33},{0,9,163},{0,8,1},{0,8,129},{0,8,65}, - {0,9,227},{16,7,6},{0,8,89},{0,8,25},{0,9,147},{19,7,59},{0,8,121}, - {0,8,57},{0,9,211},{17,7,17},{0,8,105},{0,8,41},{0,9,179},{0,8,9}, - {0,8,137},{0,8,73},{0,9,243},{16,7,4},{0,8,85},{0,8,21},{16,8,258}, - {19,7,43},{0,8,117},{0,8,53},{0,9,203},{17,7,13},{0,8,101},{0,8,37}, - {0,9,171},{0,8,5},{0,8,133},{0,8,69},{0,9,235},{16,7,8},{0,8,93}, - {0,8,29},{0,9,155},{20,7,83},{0,8,125},{0,8,61},{0,9,219},{18,7,23}, - {0,8,109},{0,8,45},{0,9,187},{0,8,13},{0,8,141},{0,8,77},{0,9,251}, - {16,7,3},{0,8,83},{0,8,19},{21,8,195},{19,7,35},{0,8,115},{0,8,51}, - {0,9,199},{17,7,11},{0,8,99},{0,8,35},{0,9,167},{0,8,3},{0,8,131}, - {0,8,67},{0,9,231},{16,7,7},{0,8,91},{0,8,27},{0,9,151},{20,7,67}, - {0,8,123},{0,8,59},{0,9,215},{18,7,19},{0,8,107},{0,8,43},{0,9,183}, - {0,8,11},{0,8,139},{0,8,75},{0,9,247},{16,7,5},{0,8,87},{0,8,23}, - {64,8,0},{19,7,51},{0,8,119},{0,8,55},{0,9,207},{17,7,15},{0,8,103}, - {0,8,39},{0,9,175},{0,8,7},{0,8,135},{0,8,71},{0,9,239},{16,7,9}, - {0,8,95},{0,8,31},{0,9,159},{20,7,99},{0,8,127},{0,8,63},{0,9,223}, - {18,7,27},{0,8,111},{0,8,47},{0,9,191},{0,8,15},{0,8,143},{0,8,79}, - {0,9,255} - }; +static const code lenfix[512] = { + {96,7,0},{0,8,80},{0,8,16},{20,8,115},{18,7,31},{0,8,112},{0,8,48}, + {0,9,192},{16,7,10},{0,8,96},{0,8,32},{0,9,160},{0,8,0},{0,8,128}, + {0,8,64},{0,9,224},{16,7,6},{0,8,88},{0,8,24},{0,9,144},{19,7,59}, + {0,8,120},{0,8,56},{0,9,208},{17,7,17},{0,8,104},{0,8,40},{0,9,176}, + {0,8,8},{0,8,136},{0,8,72},{0,9,240},{16,7,4},{0,8,84},{0,8,20}, + {21,8,227},{19,7,43},{0,8,116},{0,8,52},{0,9,200},{17,7,13},{0,8,100}, + {0,8,36},{0,9,168},{0,8,4},{0,8,132},{0,8,68},{0,9,232},{16,7,8}, + {0,8,92},{0,8,28},{0,9,152},{20,7,83},{0,8,124},{0,8,60},{0,9,216}, + {18,7,23},{0,8,108},{0,8,44},{0,9,184},{0,8,12},{0,8,140},{0,8,76}, + {0,9,248},{16,7,3},{0,8,82},{0,8,18},{21,8,163},{19,7,35},{0,8,114}, + {0,8,50},{0,9,196},{17,7,11},{0,8,98},{0,8,34},{0,9,164},{0,8,2}, + {0,8,130},{0,8,66},{0,9,228},{16,7,7},{0,8,90},{0,8,26},{0,9,148}, + {20,7,67},{0,8,122},{0,8,58},{0,9,212},{18,7,19},{0,8,106},{0,8,42}, + {0,9,180},{0,8,10},{0,8,138},{0,8,74},{0,9,244},{16,7,5},{0,8,86}, + {0,8,22},{64,8,0},{19,7,51},{0,8,118},{0,8,54},{0,9,204},{17,7,15}, + {0,8,102},{0,8,38},{0,9,172},{0,8,6},{0,8,134},{0,8,70},{0,9,236}, + {16,7,9},{0,8,94},{0,8,30},{0,9,156},{20,7,99},{0,8,126},{0,8,62}, + {0,9,220},{18,7,27},{0,8,110},{0,8,46},{0,9,188},{0,8,14},{0,8,142}, + {0,8,78},{0,9,252},{96,7,0},{0,8,81},{0,8,17},{21,8,131},{18,7,31}, + {0,8,113},{0,8,49},{0,9,194},{16,7,10},{0,8,97},{0,8,33},{0,9,162}, + {0,8,1},{0,8,129},{0,8,65},{0,9,226},{16,7,6},{0,8,89},{0,8,25}, + {0,9,146},{19,7,59},{0,8,121},{0,8,57},{0,9,210},{17,7,17},{0,8,105}, + {0,8,41},{0,9,178},{0,8,9},{0,8,137},{0,8,73},{0,9,242},{16,7,4}, + {0,8,85},{0,8,21},{16,8,258},{19,7,43},{0,8,117},{0,8,53},{0,9,202}, + {17,7,13},{0,8,101},{0,8,37},{0,9,170},{0,8,5},{0,8,133},{0,8,69}, + {0,9,234},{16,7,8},{0,8,93},{0,8,29},{0,9,154},{20,7,83},{0,8,125}, + {0,8,61},{0,9,218},{18,7,23},{0,8,109},{0,8,45},{0,9,186},{0,8,13}, + {0,8,141},{0,8,77},{0,9,250},{16,7,3},{0,8,83},{0,8,19},{21,8,195}, + {19,7,35},{0,8,115},{0,8,51},{0,9,198},{17,7,11},{0,8,99},{0,8,35}, + {0,9,166},{0,8,3},{0,8,131},{0,8,67},{0,9,230},{16,7,7},{0,8,91}, + {0,8,27},{0,9,150},{20,7,67},{0,8,123},{0,8,59},{0,9,214},{18,7,19}, + {0,8,107},{0,8,43},{0,9,182},{0,8,11},{0,8,139},{0,8,75},{0,9,246}, + {16,7,5},{0,8,87},{0,8,23},{64,8,0},{19,7,51},{0,8,119},{0,8,55}, + {0,9,206},{17,7,15},{0,8,103},{0,8,39},{0,9,174},{0,8,7},{0,8,135}, + {0,8,71},{0,9,238},{16,7,9},{0,8,95},{0,8,31},{0,9,158},{20,7,99}, + {0,8,127},{0,8,63},{0,9,222},{18,7,27},{0,8,111},{0,8,47},{0,9,190}, + {0,8,15},{0,8,143},{0,8,79},{0,9,254},{96,7,0},{0,8,80},{0,8,16}, + {20,8,115},{18,7,31},{0,8,112},{0,8,48},{0,9,193},{16,7,10},{0,8,96}, + {0,8,32},{0,9,161},{0,8,0},{0,8,128},{0,8,64},{0,9,225},{16,7,6}, + {0,8,88},{0,8,24},{0,9,145},{19,7,59},{0,8,120},{0,8,56},{0,9,209}, + {17,7,17},{0,8,104},{0,8,40},{0,9,177},{0,8,8},{0,8,136},{0,8,72}, + {0,9,241},{16,7,4},{0,8,84},{0,8,20},{21,8,227},{19,7,43},{0,8,116}, + {0,8,52},{0,9,201},{17,7,13},{0,8,100},{0,8,36},{0,9,169},{0,8,4}, + {0,8,132},{0,8,68},{0,9,233},{16,7,8},{0,8,92},{0,8,28},{0,9,153}, + {20,7,83},{0,8,124},{0,8,60},{0,9,217},{18,7,23},{0,8,108},{0,8,44}, + {0,9,185},{0,8,12},{0,8,140},{0,8,76},{0,9,249},{16,7,3},{0,8,82}, + {0,8,18},{21,8,163},{19,7,35},{0,8,114},{0,8,50},{0,9,197},{17,7,11}, + {0,8,98},{0,8,34},{0,9,165},{0,8,2},{0,8,130},{0,8,66},{0,9,229}, + {16,7,7},{0,8,90},{0,8,26},{0,9,149},{20,7,67},{0,8,122},{0,8,58}, + {0,9,213},{18,7,19},{0,8,106},{0,8,42},{0,9,181},{0,8,10},{0,8,138}, + {0,8,74},{0,9,245},{16,7,5},{0,8,86},{0,8,22},{64,8,0},{19,7,51}, + {0,8,118},{0,8,54},{0,9,205},{17,7,15},{0,8,102},{0,8,38},{0,9,173}, + {0,8,6},{0,8,134},{0,8,70},{0,9,237},{16,7,9},{0,8,94},{0,8,30}, + {0,9,157},{20,7,99},{0,8,126},{0,8,62},{0,9,221},{18,7,27},{0,8,110}, + {0,8,46},{0,9,189},{0,8,14},{0,8,142},{0,8,78},{0,9,253},{96,7,0}, + {0,8,81},{0,8,17},{21,8,131},{18,7,31},{0,8,113},{0,8,49},{0,9,195}, + {16,7,10},{0,8,97},{0,8,33},{0,9,163},{0,8,1},{0,8,129},{0,8,65}, + {0,9,227},{16,7,6},{0,8,89},{0,8,25},{0,9,147},{19,7,59},{0,8,121}, + {0,8,57},{0,9,211},{17,7,17},{0,8,105},{0,8,41},{0,9,179},{0,8,9}, + {0,8,137},{0,8,73},{0,9,243},{16,7,4},{0,8,85},{0,8,21},{16,8,258}, + {19,7,43},{0,8,117},{0,8,53},{0,9,203},{17,7,13},{0,8,101},{0,8,37}, + {0,9,171},{0,8,5},{0,8,133},{0,8,69},{0,9,235},{16,7,8},{0,8,93}, + {0,8,29},{0,9,155},{20,7,83},{0,8,125},{0,8,61},{0,9,219},{18,7,23}, + {0,8,109},{0,8,45},{0,9,187},{0,8,13},{0,8,141},{0,8,77},{0,9,251}, + {16,7,3},{0,8,83},{0,8,19},{21,8,195},{19,7,35},{0,8,115},{0,8,51}, + {0,9,199},{17,7,11},{0,8,99},{0,8,35},{0,9,167},{0,8,3},{0,8,131}, + {0,8,67},{0,9,231},{16,7,7},{0,8,91},{0,8,27},{0,9,151},{20,7,67}, + {0,8,123},{0,8,59},{0,9,215},{18,7,19},{0,8,107},{0,8,43},{0,9,183}, + {0,8,11},{0,8,139},{0,8,75},{0,9,247},{16,7,5},{0,8,87},{0,8,23}, + {64,8,0},{19,7,51},{0,8,119},{0,8,55},{0,9,207},{17,7,15},{0,8,103}, + {0,8,39},{0,9,175},{0,8,7},{0,8,135},{0,8,71},{0,9,239},{16,7,9}, + {0,8,95},{0,8,31},{0,9,159},{20,7,99},{0,8,127},{0,8,63},{0,9,223}, + {18,7,27},{0,8,111},{0,8,47},{0,9,191},{0,8,15},{0,8,143},{0,8,79}, + {0,9,255} +}; - static const code distfix[32] = { - {16,5,1},{23,5,257},{19,5,17},{27,5,4097},{17,5,5},{25,5,1025}, - {21,5,65},{29,5,16385},{16,5,3},{24,5,513},{20,5,33},{28,5,8193}, - {18,5,9},{26,5,2049},{22,5,129},{64,5,0},{16,5,2},{23,5,385}, - {19,5,25},{27,5,6145},{17,5,7},{25,5,1537},{21,5,97},{29,5,24577}, - {16,5,4},{24,5,769},{20,5,49},{28,5,12289},{18,5,13},{26,5,3073}, - {22,5,193},{64,5,0} - }; +static const code distfix[32] = { + {16,5,1},{23,5,257},{19,5,17},{27,5,4097},{17,5,5},{25,5,1025}, + {21,5,65},{29,5,16385},{16,5,3},{24,5,513},{20,5,33},{28,5,8193}, + {18,5,9},{26,5,2049},{22,5,129},{64,5,0},{16,5,2},{23,5,385}, + {19,5,25},{27,5,6145},{17,5,7},{25,5,1537},{21,5,97},{29,5,24577}, + {16,5,4},{24,5,769},{20,5,49},{28,5,12289},{18,5,13},{26,5,3073}, + {22,5,193},{64,5,0} +}; diff --git a/inflate.c b/inflate.c index 301b5e71..623c95b7 100644 --- a/inflate.c +++ b/inflate.c @@ -85,12 +85,6 @@ #include "inflate.h" #include "inffast.h" -#ifdef MAKEFIXED -# ifndef BUILDFIXED -# define BUILDFIXED -# endif -#endif - local int inflateStateCheck(z_streamp strm) { struct inflate_state FAR *state; if (strm == Z_NULL || @@ -240,118 +234,6 @@ int ZEXPORT inflatePrime(z_streamp strm, int bits, int value) { return Z_OK; } -/* - Return state with length and distance decoding tables and index sizes set to - fixed code decoding. Normally this returns fixed tables from inffixed.h. - If BUILDFIXED is defined, then instead this routine builds the tables the - first time it's called, and returns those tables the first time and - thereafter. This reduces the size of the code by about 2K bytes, in - exchange for a little execution time. However, BUILDFIXED should not be - used for threaded applications, since the rewriting of the tables and virgin - may not be thread-safe. - */ -local void fixedtables(struct inflate_state FAR *state) { -#ifdef BUILDFIXED - static int virgin = 1; - static code *lenfix, *distfix; - static code fixed[544]; - - /* build fixed huffman tables if first call (may not be thread safe) */ - if (virgin) { - unsigned sym, bits; - static code *next; - - /* literal/length table */ - sym = 0; - while (sym < 144) state->lens[sym++] = 8; - while (sym < 256) state->lens[sym++] = 9; - while (sym < 280) state->lens[sym++] = 7; - while (sym < 288) state->lens[sym++] = 8; - next = fixed; - lenfix = next; - bits = 9; - inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work); - - /* distance table */ - sym = 0; - while (sym < 32) state->lens[sym++] = 5; - distfix = next; - bits = 5; - inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work); - - /* do this just once */ - virgin = 0; - } -#else /* !BUILDFIXED */ -# include "inffixed.h" -#endif /* BUILDFIXED */ - state->lencode = lenfix; - state->lenbits = 9; - state->distcode = distfix; - state->distbits = 5; -} - -#ifdef MAKEFIXED -#include - -/* - Write out the inffixed.h that is #include'd above. Defining MAKEFIXED also - defines BUILDFIXED, so the tables are built on the fly. makefixed() writes - those tables to stdout, which would be piped to inffixed.h. A small program - can simply call makefixed to do this: - - void makefixed(void); - - int main(void) - { - makefixed(); - return 0; - } - - Then that can be linked with zlib built with MAKEFIXED defined and run: - - a.out > inffixed.h - */ -void makefixed(void) -{ - unsigned low, size; - struct inflate_state state; - - fixedtables(&state); - puts(" /* inffixed.h -- table for decoding fixed codes"); - puts(" * Generated automatically by makefixed()."); - puts(" */"); - puts(""); - puts(" /* WARNING: this file should *not* be used by applications."); - puts(" It is part of the implementation of this library and is"); - puts(" subject to change. Applications should only use zlib.h."); - puts(" */"); - puts(""); - size = 1U << 9; - printf(" static const code lenfix[%u] = {", size); - low = 0; - for (;;) { - if ((low % 7) == 0) printf("\n "); - printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op, - state.lencode[low].bits, state.lencode[low].val); - if (++low == size) break; - putchar(','); - } - puts("\n };"); - size = 1U << 5; - printf("\n static const code distfix[%u] = {", size); - low = 0; - for (;;) { - if ((low % 6) == 0) printf("\n "); - printf("{%u,%u,%d}", state.distcode[low].op, state.distcode[low].bits, - state.distcode[low].val); - if (++low == size) break; - putchar(','); - } - puts("\n };"); -} -#endif /* MAKEFIXED */ - /* Update the window with the last wsize (normally 32K) bytes written before returning. If window does not exist yet, create it. This is only called @@ -841,7 +723,7 @@ int ZEXPORT inflate(z_streamp strm, int flush) { state->mode = STORED; break; case 1: /* fixed block */ - fixedtables(state); + inflate_fixed(state); Tracev((stderr, "inflate: fixed codes block%s\n", state->last ? " (last)" : "")); state->mode = LEN_; /* decode codes */ diff --git a/inftrees.c b/inftrees.c index f7849a7f..c050f8bb 100644 --- a/inftrees.c +++ b/inftrees.c @@ -5,6 +5,7 @@ #include "zutil.h" #include "inftrees.h" +#include "inflate.h" #define MAXBITS 15 @@ -297,3 +298,116 @@ int ZLIB_INTERNAL inflate_table(codetype type, unsigned short FAR *lens, *bits = root; return 0; } + +#ifdef BUILDFIXED +/* + If this is compiled with BUILDFIXED defined, and if inflate will be used in + multiple threads, and if atomics are not available, then inflate() must be + called with a fixed block (e.g. 0x03 0x00) to initialize the tables and must + return before any other threads are allowed to call inflate. + */ + +static code *lenfix, *distfix; +static code fixed[544]; + +/* State for z_once(). */ +local z_once_t built = Z_ONCE_INIT; + +local void buildtables(void) { + unsigned sym, bits; + static code *next; + unsigned short lens[288], work[288]; + + /* literal/length table */ + sym = 0; + while (sym < 144) lens[sym++] = 8; + while (sym < 256) lens[sym++] = 9; + while (sym < 280) lens[sym++] = 7; + while (sym < 288) lens[sym++] = 8; + next = fixed; + lenfix = next; + bits = 9; + inflate_table(LENS, lens, 288, &(next), &(bits), work); + + /* distance table */ + sym = 0; + while (sym < 32) lens[sym++] = 5; + distfix = next; + bits = 5; + inflate_table(DISTS, lens, 32, &(next), &(bits), work); +} +#else /* !BUILDFIXED */ +# include "inffixed.h" +#endif /* BUILDFIXED */ + +/* + Return state with length and distance decoding tables and index sizes set to + fixed code decoding. Normally this returns fixed tables from inffixed.h. + If BUILDFIXED is defined, then instead this routine builds the tables the + first time it's called, and returns those tables the first time and + thereafter. This reduces the size of the code by about 2K bytes, in + exchange for a little execution time. However, BUILDFIXED should not be + used for threaded applications if atomics are not available, as it will + not be thread-safe. + */ +void inflate_fixed(struct inflate_state FAR *state) { +#ifdef BUILDFIXED + z_once(&built, buildtables); +#endif /* BUILDFIXED */ + state->lencode = lenfix; + state->lenbits = 9; + state->distcode = distfix; + state->distbits = 5; +} + +#ifdef MAKEFIXED +#include + +/* + Write out the inffixed.h that will be #include'd above. Defining MAKEFIXED + also defines BUILDFIXED, so the tables are built on the fly. main() writes + those tables to stdout, which would directed to inffixed.h. Compile this + along with zutil.c: + + cc -DMAKEFIXED -o fix inftrees.c zutil.c + ./fix > inffixed.h + */ +int main(void) { + unsigned low, size; + struct inflate_state state; + + inflate_fixed(&state); + puts("/* inffixed.h -- table for decoding fixed codes"); + puts(" * Generated automatically by makefixed()."); + puts(" */"); + puts(""); + puts("/* WARNING: this file should *not* be used by applications."); + puts(" It is part of the implementation of this library and is"); + puts(" subject to change. Applications should only use zlib.h."); + puts(" */"); + puts(""); + size = 1U << 9; + printf("static const code lenfix[%u] = {", size); + low = 0; + for (;;) { + if ((low % 7) == 0) printf("\n "); + printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op, + state.lencode[low].bits, state.lencode[low].val); + if (++low == size) break; + putchar(','); + } + puts("\n};"); + size = 1U << 5; + printf("\nstatic const code distfix[%u] = {", size); + low = 0; + for (;;) { + if ((low % 6) == 0) printf("\n "); + printf("{%u,%u,%d}", state.distcode[low].op, state.distcode[low].bits, + state.distcode[low].val); + if (++low == size) break; + putchar(','); + } + puts("\n};"); + return 0; +} +#endif /* MAKEFIXED */ diff --git a/inftrees.h b/inftrees.h index 396f74b5..00ec96ec 100644 --- a/inftrees.h +++ b/inftrees.h @@ -60,3 +60,5 @@ typedef enum { int ZLIB_INTERNAL inflate_table(codetype type, unsigned short FAR *lens, unsigned codes, code FAR * FAR *table, unsigned FAR *bits, unsigned short FAR *work); +struct inflate_state; +void ZLIB_INTERNAL inflate_fixed(struct inflate_state FAR *state); diff --git a/zconf.h b/zconf.h index 7d936c74..524192ad 100644 --- a/zconf.h +++ b/zconf.h @@ -131,6 +131,7 @@ # define inflate_copyright z_inflate_copyright # define inflate_fast z_inflate_fast # define inflate_table z_inflate_table +# define inflate_fixed z_inflate_fixed # ifndef Z_SOLO # define uncompress z_uncompress # define uncompress2 z_uncompress2 diff --git a/zconf.h.in b/zconf.h.in index 7d936c74..524192ad 100644 --- a/zconf.h.in +++ b/zconf.h.in @@ -131,6 +131,7 @@ # define inflate_copyright z_inflate_copyright # define inflate_fast z_inflate_fast # define inflate_table z_inflate_table +# define inflate_fixed z_inflate_fixed # ifndef Z_SOLO # define uncompress z_uncompress # define uncompress2 z_uncompress2 diff --git a/zlib.map b/zlib.map index e267d828..aba65ab6 100644 --- a/zlib.map +++ b/zlib.map @@ -11,9 +11,11 @@ ZLIB_1.2.0 { inflate_copyright; inflate_fast; inflate_table; + inflate_fixed; zcalloc; zcfree; z_errmsg; + z_once; gz_error; gz_intmax; _*; diff --git a/zutil.c b/zutil.c index 6e8a3697..3a94e917 100644 --- a/zutil.c +++ b/zutil.c @@ -305,3 +305,61 @@ void ZLIB_INTERNAL zcfree(voidpf opaque, voidpf ptr) { #endif /* MY_ZCALLOC */ #endif /* !Z_SOLO */ + +#if defined(BUILDFIXED) || defined(DYNAMIC_CRC_TABLE) +/* + Define a z_once() function depending on the availability of atomics. + */ + +/* Check for the availability of atomics. */ +#if defined(__STDC__) && __STDC_VERSION__ >= 201112L && \ + !defined(__STDC_NO_ATOMICS__) + +#include + +/* + Run the provided init() function exactly once, even if multiple threads + invoke once() at the same time. The state must be a once_t initialized with + Z_ONCE_INIT. + */ +void z_once(z_once_t *state, void (*init)(void)) { + if (!atomic_load(&state->done)) { + if (atomic_flag_test_and_set(&state->begun)) + while (!atomic_load(&state->done)) + ; + else { + init(); + atomic_store(&state->done, 1); + } + } +} + +#else /* no atomics */ + +#warning zlib not thread-safe + +/* Test and set. Alas, not atomic, but tries to limit the period of + vulnerability. */ +local int test_and_set(int volatile *flag) { + int was; + + was = *flag; + *flag = 1; + return was; +} + +/* Run the provided init() function once. This is not thread-safe. */ +void z_once(z_once_t *state, void (*init)(void)) { + if (!state->done) { + if (test_and_set(&state->begun)) + while (!state->done) + ; + else { + init(); + state->done = 1; + } + } +} + +#endif +#endif diff --git a/zutil.h b/zutil.h index 27ca6938..94fa1aff 100644 --- a/zutil.h +++ b/zutil.h @@ -254,4 +254,30 @@ extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */ #define ZSWAP32(q) ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + \ (((q) & 0xff00) << 8) + (((q) & 0xff) << 24)) +#ifdef MAKEFIXED +# ifndef BUILDFIXED +# define BUILDFIXED +# endif +#endif +#if defined(BUILDFIXED) || defined(DYNAMIC_CRC_TABLE) +/* Structure for z_once(), which must be initialized with Z_ONCE_INIT. */ +typedef struct z_once_s z_once_t; +void ZLIB_INTERNAL z_once(z_once_t *state, void (*init)(void)); +#if defined(__STDC__) && __STDC_VERSION__ >= 201112L && \ + !defined(__STDC_NO_ATOMICS__) +#include +struct z_once_s { + atomic_flag begun; + atomic_int done; +}; +#define Z_ONCE_INIT {ATOMIC_FLAG_INIT, 0} +#else /* no atomics! */ +struct z_once_s { + volatile int begun; + volatile int done; +}; +#define Z_ONCE_INIT {0, 0} +#endif +#endif + #endif /* ZUTIL_H */