# HG changeset patch # User Matti Hamalainen # Date 1425005185 -7200 # Node ID 70bcb294a4379386d6e6f40f1088fc8273ea20b2 # Parent 1832ac20edb22448582592fca85ee12f8bfec16a Remove the zlib implementation from stb_image. diff -r 1832ac20edb2 -r 70bcb294a437 src/stb_image.c --- a/src/stb_image.c Fri Feb 27 04:46:13 2015 +0200 +++ b/src/stb_image.c Fri Feb 27 04:46:25 2015 +0200 @@ -3284,461 +3284,6 @@ #endif -// public domain zlib decode v0.2 Sean Barrett 2006-11-18 -// simple implementation -// - all input must be provided in an upfront buffer -// - all output is written to a single output buffer (can malloc/realloc) -// performance -// - fast huffman - -#ifdef STBI_INTERNAL_ZLIB - -// fast-way is faster to check than jpeg huffman, but slow way is slower -#define STBI__ZFAST_BITS 9 // accelerate all cases in default tables -#define STBI__ZFAST_MASK ((1 << STBI__ZFAST_BITS) - 1) - -// zlib-style huffman encoding -// (jpegs packs from left, zlib from right, so can't share code) -typedef struct -{ - Uint16 fast[1 << STBI__ZFAST_BITS]; - Uint16 firstcode[16]; - int maxcode[17]; - Uint16 firstsymbol[16]; - Uint8 size[288]; - Uint16 value[288]; -} stbi__zhuffman; - -stbi_inline static int stbi__bitreverse16(int n) -{ - n = ((n & 0xAAAA) >> 1) | ((n & 0x5555) << 1); - n = ((n & 0xCCCC) >> 2) | ((n & 0x3333) << 2); - n = ((n & 0xF0F0) >> 4) | ((n & 0x0F0F) << 4); - n = ((n & 0xFF00) >> 8) | ((n & 0x00FF) << 8); - return n; -} - -stbi_inline static int stbi__bit_reverse(int v, int bits) -{ - STBI_ASSERT(bits <= 16); - // to bit reverse n bits, reverse 16 and shift - // e.g. 11 bits, bit reverse and shift away 5 - return stbi__bitreverse16(v) >> (16-bits); -} - -static int stbi__zbuild_huffman(stbi__zhuffman *z, Uint8 *sizelist, int num) -{ - int i,k=0; - int code, next_code[16], sizes[17]; - - // DEFLATE spec for generating codes - memset(sizes, 0, sizeof(sizes)); - memset(z->fast, 0, sizeof(z->fast)); - for (i=0; i < num; ++i) - ++sizes[sizelist[i]]; - sizes[0] = 0; - for (i=1; i < 16; ++i) - STBI_ASSERT(sizes[i] <= (1 << i)); - code = 0; - for (i=1; i < 16; ++i) { - next_code[i] = code; - z->firstcode[i] = (Uint16) code; - z->firstsymbol[i] = (Uint16) k; - code = (code + sizes[i]); - if (sizes[i]) - if (code-1 >= (1 << i)) return stbi__err("bad codelengths","Corrupt JPEG"); - z->maxcode[i] = code << (16-i); // preshift for inner loop - code <<= 1; - k += sizes[i]; - } - z->maxcode[16] = 0x10000; // sentinel - for (i=0; i < num; ++i) { - int s = sizelist[i]; - if (s) { - int c = next_code[s] - z->firstcode[s] + z->firstsymbol[s]; - Uint16 fastv = (Uint16) ((s << 9) | i); - z->size [c] = (Uint8) s; - z->value[c] = (Uint16) i; - if (s <= STBI__ZFAST_BITS) { - int k = stbi__bit_reverse(next_code[s],s); - while (k < (1 << STBI__ZFAST_BITS)) { - z->fast[k] = fastv; - k += (1 << s); - } - } - ++next_code[s]; - } - } - return 1; -} - -// zlib-from-memory implementation for PNG reading -// because PNG allows splitting the zlib stream arbitrarily, -// and it's annoying structurally to have PNG call ZLIB call PNG, -// we require PNG read all the IDATs and combine them into a single -// memory buffer - -typedef struct -{ - Uint8 *zbuffer, *zbuffer_end; - int num_bits; - Uint32 code_buffer; - - char *zout; - char *zout_start; - char *zout_end; - int z_expandable; - - stbi__zhuffman z_length, z_distance; -} stbi__zbuf; - -stbi_inline static Uint8 stbi__zget8(stbi__zbuf *z) -{ - if (z->zbuffer >= z->zbuffer_end) return 0; - return *z->zbuffer++; -} - -static void stbi__fill_bits(stbi__zbuf *z) -{ - do { - STBI_ASSERT(z->code_buffer < (1U << z->num_bits)); - z->code_buffer |= stbi__zget8(z) << z->num_bits; - z->num_bits += 8; - } while (z->num_bits <= 24); -} - -stbi_inline static unsigned int stbi__zreceive(stbi__zbuf *z, int n) -{ - unsigned int k; - if (z->num_bits < n) stbi__fill_bits(z); - k = z->code_buffer & ((1 << n) - 1); - z->code_buffer >>= n; - z->num_bits -= n; - return k; -} - -static int stbi__zhuffman_decode_slowpath(stbi__zbuf *a, stbi__zhuffman *z) -{ - int b,s,k; - // not resolved by fast table, so compute it the slow way - // use jpeg approach, which requires MSbits at top - k = stbi__bit_reverse(a->code_buffer, 16); - for (s=STBI__ZFAST_BITS+1; ; ++s) - if (k < z->maxcode[s]) - break; - if (s == 16) return -1; // invalid code! - // code size is s, so: - b = (k >> (16-s)) - z->firstcode[s] + z->firstsymbol[s]; - STBI_ASSERT(z->size[b] == s); - a->code_buffer >>= s; - a->num_bits -= s; - return z->value[b]; -} - -stbi_inline static int stbi__zhuffman_decode(stbi__zbuf *a, stbi__zhuffman *z) -{ - int b,s; - if (a->num_bits < 16) stbi__fill_bits(a); - b = z->fast[a->code_buffer & STBI__ZFAST_MASK]; - if (b) { - s = b >> 9; - a->code_buffer >>= s; - a->num_bits -= s; - return b & 511; - } - return stbi__zhuffman_decode_slowpath(a, z); -} - -static int stbi__zexpand(stbi__zbuf *z, char *zout, int n) // need to make room for n bytes -{ - char *q; - int cur, limit; - z->zout = zout; - if (!z->z_expandable) return stbi__err("output buffer limit","Corrupt PNG"); - cur = (int) (z->zout - z->zout_start); - limit = (int) (z->zout_end - z->zout_start); - while (cur + n > limit) - limit *= 2; - q = (char *) STBI_REALLOC(z->zout_start, limit); - if (q == NULL) return stbi__err("outofmem", "Out of memory"); - z->zout_start = q; - z->zout = q + cur; - z->zout_end = q + limit; - return 1; -} - -static int stbi__zlength_base[31] = { - 3,4,5,6,7,8,9,10,11,13, - 15,17,19,23,27,31,35,43,51,59, - 67,83,99,115,131,163,195,227,258,0,0 }; - -static int stbi__zlength_extra[31]= -{ 0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0,0,0 }; - -static int stbi__zdist_base[32] = { 1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193, -257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577,0,0}; - -static int stbi__zdist_extra[32] = -{ 0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13}; - -static int stbi__parse_huffman_block(stbi__zbuf *a) -{ - char *zout = a->zout; - for(;;) { - int z = stbi__zhuffman_decode(a, &a->z_length); - if (z < 256) { - if (z < 0) return stbi__err("bad huffman code","Corrupt PNG"); // error in huffman codes - if (zout >= a->zout_end) { - if (!stbi__zexpand(a, zout, 1)) return 0; - zout = a->zout; - } - *zout++ = (char) z; - } else { - Uint8 *p; - int len,dist; - if (z == 256) { - a->zout = zout; - return 1; - } - z -= 257; - len = stbi__zlength_base[z]; - if (stbi__zlength_extra[z]) len += stbi__zreceive(a, stbi__zlength_extra[z]); - z = stbi__zhuffman_decode(a, &a->z_distance); - if (z < 0) return stbi__err("bad huffman code","Corrupt PNG"); - dist = stbi__zdist_base[z]; - if (stbi__zdist_extra[z]) dist += stbi__zreceive(a, stbi__zdist_extra[z]); - if (zout - a->zout_start < dist) return stbi__err("bad dist","Corrupt PNG"); - if (zout + len > a->zout_end) { - if (!stbi__zexpand(a, zout, len)) return 0; - zout = a->zout; - } - p = (Uint8 *) (zout - dist); - if (dist == 1) { // run of one byte; common in images. - Uint8 v = *p; - do *zout++ = v; while (--len); - } else { - do *zout++ = *p++; while (--len); - } - } - } -} - -static int stbi__compute_huffman_codes(stbi__zbuf *a) -{ - static Uint8 length_dezigzag[19] = { 16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15 }; - stbi__zhuffman z_codelength; - Uint8 lencodes[286+32+137];//padding for maximum single op - Uint8 codelength_sizes[19]; - int i,n; - - int hlit = stbi__zreceive(a,5) + 257; - int hdist = stbi__zreceive(a,5) + 1; - int hclen = stbi__zreceive(a,4) + 4; - - memset(codelength_sizes, 0, sizeof(codelength_sizes)); - for (i=0; i < hclen; ++i) { - int s = stbi__zreceive(a,3); - codelength_sizes[length_dezigzag[i]] = (Uint8) s; - } - if (!stbi__zbuild_huffman(&z_codelength, codelength_sizes, 19)) return 0; - - n = 0; - while (n < hlit + hdist) { - int c = stbi__zhuffman_decode(a, &z_codelength); - STBI_ASSERT(c >= 0 && c < 19); - if (c < 16) - lencodes[n++] = (Uint8) c; - else if (c == 16) { - c = stbi__zreceive(a,2)+3; - memset(lencodes+n, lencodes[n-1], c); - n += c; - } else if (c == 17) { - c = stbi__zreceive(a,3)+3; - memset(lencodes+n, 0, c); - n += c; - } else { - STBI_ASSERT(c == 18); - c = stbi__zreceive(a,7)+11; - memset(lencodes+n, 0, c); - n += c; - } - } - if (n != hlit+hdist) return stbi__err("bad codelengths","Corrupt PNG"); - if (!stbi__zbuild_huffman(&a->z_length, lencodes, hlit)) return 0; - if (!stbi__zbuild_huffman(&a->z_distance, lencodes+hlit, hdist)) return 0; - return 1; -} - -static int stbi__parse_uncomperssed_block(stbi__zbuf *a) -{ - Uint8 header[4]; - int len,nlen,k; - if (a->num_bits & 7) - stbi__zreceive(a, a->num_bits & 7); // discard - // drain the bit-packed data into header - k = 0; - while (a->num_bits > 0) { - header[k++] = (Uint8) (a->code_buffer & 255); // suppress MSVC run-time check - a->code_buffer >>= 8; - a->num_bits -= 8; - } - STBI_ASSERT(a->num_bits == 0); - // now fill header the normal way - while (k < 4) - header[k++] = stbi__zget8(a); - len = header[1] * 256 + header[0]; - nlen = header[3] * 256 + header[2]; - if (nlen != (len ^ 0xffff)) return stbi__err("zlib corrupt","Corrupt PNG"); - if (a->zbuffer + len > a->zbuffer_end) return stbi__err("read past buffer","Corrupt PNG"); - if (a->zout + len > a->zout_end) - if (!stbi__zexpand(a, a->zout, len)) return 0; - memcpy(a->zout, a->zbuffer, len); - a->zbuffer += len; - a->zout += len; - return 1; -} - -static int stbi__parse_zlib_header(stbi__zbuf *a) -{ - int cmf = stbi__zget8(a); - int cm = cmf & 15; - /* int cinfo = cmf >> 4; */ - int flg = stbi__zget8(a); - if ((cmf*256+flg) % 31 != 0) return stbi__err("bad zlib header","Corrupt PNG"); // zlib spec - if (flg & 32) return stbi__err("no preset dict","Corrupt PNG"); // preset dictionary not allowed in png - if (cm != 8) return stbi__err("bad compression","Corrupt PNG"); // DEFLATE required for png - // window = 1 << (8 + cinfo)... but who cares, we fully buffer output - return 1; -} - -// @TODO: should statically initialize these for optimal thread safety -static Uint8 stbi__zdefault_length[288], stbi__zdefault_distance[32]; -static void stbi__init_zdefaults(void) -{ - int i; // use <= to match clearly with spec - for (i=0; i <= 143; ++i) stbi__zdefault_length[i] = 8; - for ( ; i <= 255; ++i) stbi__zdefault_length[i] = 9; - for ( ; i <= 279; ++i) stbi__zdefault_length[i] = 7; - for ( ; i <= 287; ++i) stbi__zdefault_length[i] = 8; - - for (i=0; i <= 31; ++i) stbi__zdefault_distance[i] = 5; -} - -static int stbi__parse_zlib(stbi__zbuf *a, int parse_header) -{ - int final, type; - if (parse_header) - if (!stbi__parse_zlib_header(a)) return 0; - a->num_bits = 0; - a->code_buffer = 0; - do { - final = stbi__zreceive(a,1); - type = stbi__zreceive(a,2); - if (type == 0) { - if (!stbi__parse_uncomperssed_block(a)) return 0; - } else if (type == 3) { - return 0; - } else { - if (type == 1) { - // use fixed code lengths - if (!stbi__zdefault_distance[31]) stbi__init_zdefaults(); - if (!stbi__zbuild_huffman(&a->z_length , stbi__zdefault_length , 288)) return 0; - if (!stbi__zbuild_huffman(&a->z_distance, stbi__zdefault_distance, 32)) return 0; - } else { - if (!stbi__compute_huffman_codes(a)) return 0; - } - if (!stbi__parse_huffman_block(a)) return 0; - } - } while (!final); - return 1; -} - -static int stbi__do_zlib(stbi__zbuf *a, char *obuf, int olen, int exp, int parse_header) -{ - a->zout_start = obuf; - a->zout = obuf; - a->zout_end = obuf + olen; - a->z_expandable = exp; - - return stbi__parse_zlib(a, parse_header); -} - -STBIDEF char *stbi_zlib_decode_malloc_guesssize(const char *buffer, int len, int initial_size, int *outlen) -{ - stbi__zbuf a; - char *p = (char *) stbi__malloc(initial_size); - if (p == NULL) return NULL; - a.zbuffer = (Uint8 *) buffer; - a.zbuffer_end = (Uint8 *) buffer + len; - if (stbi__do_zlib(&a, p, initial_size, 1, 1)) { - if (outlen) *outlen = (int) (a.zout - a.zout_start); - return a.zout_start; - } else { - STBI_FREE(a.zout_start); - return NULL; - } -} - -STBIDEF char *stbi_zlib_decode_malloc(char const *buffer, int len, int *outlen) -{ - return stbi_zlib_decode_malloc_guesssize(buffer, len, 16384, outlen); -} - -STBIDEF char *stbi_zlib_decode_malloc_guesssize_headerflag(const char *buffer, int len, int initial_size, int *outlen, int parse_header) -{ - stbi__zbuf a; - char *p = (char *) stbi__malloc(initial_size); - if (p == NULL) return NULL; - a.zbuffer = (Uint8 *) buffer; - a.zbuffer_end = (Uint8 *) buffer + len; - if (stbi__do_zlib(&a, p, initial_size, 1, parse_header)) { - if (outlen) *outlen = (int) (a.zout - a.zout_start); - return a.zout_start; - } else { - STBI_FREE(a.zout_start); - return NULL; - } -} - -STBIDEF int stbi_zlib_decode_buffer(char *obuffer, int olen, char const *ibuffer, int ilen) -{ - stbi__zbuf a; - a.zbuffer = (Uint8 *) ibuffer; - a.zbuffer_end = (Uint8 *) ibuffer + ilen; - if (stbi__do_zlib(&a, obuffer, olen, 0, 1)) - return (int) (a.zout - a.zout_start); - else - return -1; -} - -STBIDEF char *stbi_zlib_decode_noheader_malloc(char const *buffer, int len, int *outlen) -{ - stbi__zbuf a; - char *p = (char *) stbi__malloc(16384); - if (p == NULL) return NULL; - a.zbuffer = (Uint8 *) buffer; - a.zbuffer_end = (Uint8 *) buffer+len; - if (stbi__do_zlib(&a, p, 16384, 1, 0)) { - if (outlen) *outlen = (int) (a.zout - a.zout_start); - return a.zout_start; - } else { - STBI_FREE(a.zout_start); - return NULL; - } -} - -STBIDEF int stbi_zlib_decode_noheader_buffer(char *obuffer, int olen, const char *ibuffer, int ilen) -{ - stbi__zbuf a; - a.zbuffer = (Uint8 *) ibuffer; - a.zbuffer_end = (Uint8 *) ibuffer + ilen; - if (stbi__do_zlib(&a, obuffer, olen, 0, 0)) - return (int) (a.zout - a.zout_start); - else - return -1; -} -#endif - // public domain "baseline" PNG decoder v0.10 Sean Barrett 2006-11-18 // simple implementation // - only 8-bit samples