Mercurial > might-and-magic-trilogy
diff lib/zlib/inflate.c @ 0:8b8875f5b359
Initial commit
author | Nomad |
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date | Fri, 05 Oct 2012 16:07:14 +0200 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/lib/zlib/inflate.c Fri Oct 05 16:07:14 2012 +0200 @@ -0,0 +1,366 @@ +/* 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); +}