| /* inflate.c -- zlib interface to inflate modules |
| * Copyright (C) 1995-2002 Mark Adler |
| * For conditions of distribution and use, see copyright notice in zlib.h |
| */ |
| |
| #include "zutil.h" |
| #include "infblock.h" |
| |
| #define DONE INFLATE_DONE |
| #define BAD INFLATE_BAD |
| |
| 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 */ |
| |
| }; |
| |
| |
| ZEXPORT(int) 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; |
| } |
| |
| |
| ZEXPORT(int) 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; |
| } |
| |
| |
| ZEXPORT(int) 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; |
| } |
| |
| |
| |
| #undef NEEDBYTE |
| #define NEEDBYTE {if(z->avail_in==0)return r;r=f;} |
| |
| #undef NEXTBYTE |
| #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++) |
| |
| |
| ZEXPORT(int) 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 |
| } |
| |