ref: 4041be70bf23c172dda3d107e19d84c2fb58f644
dir: /common/id3lib/zlib/src/inflate.c/
/* inflate.c -- zlib interface to inflate modules * Copyright (C) 1995-1998 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h */ #include "zutil.h" #include "infblock.h" struct inflate_blocks_state {int dummy;}; /* for buggy compilers */ typedef enum { METHOD, /* waiting for method byte */ FLAG, /* waiting for flag byte */ DICT4, /* four dictionary check bytes to go */ DICT3, /* three dictionary check bytes to go */ DICT2, /* two dictionary check bytes to go */ DICT1, /* one dictionary check byte to go */ DICT0, /* waiting for inflateSetDictionary */ BLOCKS, /* decompressing blocks */ CHECK4, /* four check bytes to go */ CHECK3, /* three check bytes to go */ CHECK2, /* two check bytes to go */ CHECK1, /* one check byte to go */ DONE, /* finished check, done */ BAD} /* got an error--stay here */ inflate_mode; /* inflate private state */ struct internal_state { /* mode */ inflate_mode mode; /* current inflate mode */ /* mode dependent information */ union { uInt method; /* if FLAGS, method byte */ struct { uLong was; /* computed check value */ uLong need; /* stream check value */ } check; /* if CHECK, check values to compare */ uInt marker; /* if BAD, inflateSync's marker bytes count */ } sub; /* submode */ /* mode independent information */ int nowrap; /* flag for no wrapper */ uInt wbits; /* log2(window size) (8..15, defaults to 15) */ inflate_blocks_statef *blocks; /* current inflate_blocks state */ }; int ZEXPORT inflateReset(z) z_streamp z; { if (z == Z_NULL || z->state == Z_NULL) return Z_STREAM_ERROR; z->total_in = z->total_out = 0; z->msg = Z_NULL; z->state->mode = z->state->nowrap ? BLOCKS : METHOD; inflate_blocks_reset(z->state->blocks, z, Z_NULL); Tracev((stderr, "inflate: reset\n")); return Z_OK; } int ZEXPORT inflateEnd(z) z_streamp z; { if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL) return Z_STREAM_ERROR; if (z->state->blocks != Z_NULL) inflate_blocks_free(z->state->blocks, z); ZFREE(z, z->state); z->state = Z_NULL; Tracev((stderr, "inflate: end\n")); return Z_OK; } int ZEXPORT inflateInit2_(z, w, version, stream_size) z_streamp z; int w; const char *version; int stream_size; { if (version == Z_NULL || version[0] != ZLIB_VERSION[0] || stream_size != sizeof(z_stream)) return Z_VERSION_ERROR; /* initialize state */ if (z == Z_NULL) return Z_STREAM_ERROR; z->msg = Z_NULL; if (z->zalloc == Z_NULL) { z->zalloc = zcalloc; z->opaque = (voidpf)0; } if (z->zfree == Z_NULL) z->zfree = zcfree; if ((z->state = (struct internal_state FAR *) ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL) return Z_MEM_ERROR; z->state->blocks = Z_NULL; /* handle undocumented nowrap option (no zlib header or check) */ z->state->nowrap = 0; if (w < 0) { w = - w; z->state->nowrap = 1; } /* set window size */ if (w < 8 || w > 15) { inflateEnd(z); return Z_STREAM_ERROR; } z->state->wbits = (uInt)w; /* create inflate_blocks state */ if ((z->state->blocks = inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w)) == Z_NULL) { inflateEnd(z); return Z_MEM_ERROR; } Tracev((stderr, "inflate: allocated\n")); /* reset state */ inflateReset(z); return Z_OK; } int ZEXPORT inflateInit_(z, version, stream_size) z_streamp z; const char *version; int stream_size; { return inflateInit2_(z, DEF_WBITS, version, stream_size); } #define NEEDBYTE {if(z->avail_in==0)return r;r=f;} #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++) int ZEXPORT inflate(z, f) z_streamp z; int f; { int r; uInt b; if (z == Z_NULL || z->state == Z_NULL || z->next_in == Z_NULL) return Z_STREAM_ERROR; f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK; r = Z_BUF_ERROR; while (1) switch (z->state->mode) { case METHOD: NEEDBYTE if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED) { z->state->mode = BAD; z->msg = (char*)"unknown compression method"; z->state->sub.marker = 5; /* can't try inflateSync */ break; } if ((z->state->sub.method >> 4) + 8 > z->state->wbits) { z->state->mode = BAD; z->msg = (char*)"invalid window size"; z->state->sub.marker = 5; /* can't try inflateSync */ break; } z->state->mode = FLAG; case FLAG: NEEDBYTE b = NEXTBYTE; if (((z->state->sub.method << 8) + b) % 31) { z->state->mode = BAD; z->msg = (char*)"incorrect header check"; z->state->sub.marker = 5; /* can't try inflateSync */ break; } Tracev((stderr, "inflate: zlib header ok\n")); if (!(b & PRESET_DICT)) { z->state->mode = BLOCKS; break; } z->state->mode = DICT4; case DICT4: NEEDBYTE z->state->sub.check.need = (uLong)NEXTBYTE << 24; z->state->mode = DICT3; case DICT3: NEEDBYTE z->state->sub.check.need += (uLong)NEXTBYTE << 16; z->state->mode = DICT2; case DICT2: NEEDBYTE z->state->sub.check.need += (uLong)NEXTBYTE << 8; z->state->mode = DICT1; case DICT1: NEEDBYTE z->state->sub.check.need += (uLong)NEXTBYTE; z->adler = z->state->sub.check.need; z->state->mode = DICT0; return Z_NEED_DICT; case DICT0: z->state->mode = BAD; z->msg = (char*)"need dictionary"; z->state->sub.marker = 0; /* can try inflateSync */ return Z_STREAM_ERROR; case BLOCKS: r = inflate_blocks(z->state->blocks, z, r); if (r == Z_DATA_ERROR) { z->state->mode = BAD; z->state->sub.marker = 0; /* can try inflateSync */ break; } if (r == Z_OK) r = f; if (r != Z_STREAM_END) return r; r = f; inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was); if (z->state->nowrap) { z->state->mode = DONE; break; } z->state->mode = CHECK4; case CHECK4: NEEDBYTE z->state->sub.check.need = (uLong)NEXTBYTE << 24; z->state->mode = CHECK3; case CHECK3: NEEDBYTE z->state->sub.check.need += (uLong)NEXTBYTE << 16; z->state->mode = CHECK2; case CHECK2: NEEDBYTE z->state->sub.check.need += (uLong)NEXTBYTE << 8; z->state->mode = CHECK1; case CHECK1: NEEDBYTE z->state->sub.check.need += (uLong)NEXTBYTE; if (z->state->sub.check.was != z->state->sub.check.need) { z->state->mode = BAD; z->msg = (char*)"incorrect data check"; z->state->sub.marker = 5; /* can't try inflateSync */ break; } Tracev((stderr, "inflate: zlib check ok\n")); z->state->mode = DONE; case DONE: return Z_STREAM_END; case BAD: return Z_DATA_ERROR; default: return Z_STREAM_ERROR; } #ifdef NEED_DUMMY_RETURN return Z_STREAM_ERROR; /* Some dumb compilers complain without this */ #endif } int ZEXPORT inflateSetDictionary(z, dictionary, dictLength) z_streamp z; const Bytef *dictionary; uInt dictLength; { uInt length = dictLength; if (z == Z_NULL || z->state == Z_NULL || z->state->mode != DICT0) return Z_STREAM_ERROR; if (adler32(1L, dictionary, dictLength) != z->adler) return Z_DATA_ERROR; z->adler = 1L; if (length >= ((uInt)1<<z->state->wbits)) { length = (1<<z->state->wbits)-1; dictionary += dictLength - length; } inflate_set_dictionary(z->state->blocks, dictionary, length); z->state->mode = BLOCKS; return Z_OK; } int ZEXPORT inflateSync(z) z_streamp z; { uInt n; /* number of bytes to look at */ Bytef *p; /* pointer to bytes */ uInt m; /* number of marker bytes found in a row */ uLong r, w; /* temporaries to save total_in and total_out */ /* set up */ if (z == Z_NULL || z->state == Z_NULL) return Z_STREAM_ERROR; if (z->state->mode != BAD) { z->state->mode = BAD; z->state->sub.marker = 0; } if ((n = z->avail_in) == 0) return Z_BUF_ERROR; p = z->next_in; m = z->state->sub.marker; /* search */ while (n && m < 4) { static const Byte mark[4] = {0, 0, 0xff, 0xff}; if (*p == mark[m]) m++; else if (*p) m = 0; else m = 4 - m; p++, n--; } /* restore */ z->total_in += p - z->next_in; z->next_in = p; z->avail_in = n; z->state->sub.marker = m; /* return no joy or set up to restart on a new block */ if (m != 4) return Z_DATA_ERROR; r = z->total_in; w = z->total_out; inflateReset(z); z->total_in = r; z->total_out = w; z->state->mode = BLOCKS; return Z_OK; } /* Returns true if inflate is currently at the end of a block generated * by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP * implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH * but removes the length bytes of the resulting empty stored block. When * decompressing, PPP checks that at the end of input packet, inflate is * waiting for these length bytes. */ int ZEXPORT inflateSyncPoint(z) z_streamp z; { if (z == Z_NULL || z->state == Z_NULL || z->state->blocks == Z_NULL) return Z_STREAM_ERROR; return inflate_blocks_sync_point(z->state->blocks); }