From bcf78a20978d76f64b7cd46d1a4d7a79a578c77b Mon Sep 17 00:00:00 2001 From: Mark Adler Date: Fri, 9 Sep 2011 22:36:31 -0700 Subject: zlib 0.71 --- inflate.c | 221 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 221 insertions(+) create mode 100644 inflate.c (limited to 'inflate.c') diff --git a/inflate.c b/inflate.c new file mode 100644 index 0000000..478f46d --- /dev/null +++ b/inflate.c @@ -0,0 +1,221 @@ +/* inflate.c -- zlib interface to inflate modules + * Copyright (C) 1995 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 */ + +/* inflate private state */ +struct internal_state { + + /* mode */ + enum { + METHOD, /* waiting for method byte */ + FLAG, /* waiting for flag byte */ + START, /* make new blocks state */ + 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 */ + ERROR} /* got an error--stay here */ + mode; /* current inflate mode */ + + int no_header; + uInt w_size; /* LZ77 window size (32K by default) */ + uInt w_bits; /* log2(w_size) (8..16) */ + + /* mode dependent information */ + union { + uInt method; /* if FLAGS, method byte */ + struct inflate_blocks_state + *blocks; /* if BLOCKS, current state */ + struct { + uLong was; /* computed check value */ + uLong need; /* stream check value */ + } check; /* if CHECK, check values to compare */ + } sub; /* submode */ +}; + + +int inflateInit (strm) +z_stream *strm; +{ + return inflateInit2(strm, WBITS); +} + +int inflateInit2(z, windowBits) +z_stream *z; +int windowBits; +{ + if (z == Z_NULL) + return Z_STREAM_ERROR; + if (z->zalloc == Z_NULL) z->zalloc = zcalloc; + if (z->zfree == Z_NULL) z->zfree = zcfree; + z->total_in = z->total_out = 0; + z->msg = Z_NULL; + if ((z->state = (struct internal_state *) + ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL) + return Z_MEM_ERROR; + z->state->mode = METHOD; + + z->state->no_header = 0; + if (windowBits < 0) { /* undocumented feature: no zlib header */ + windowBits = - windowBits; + z->state->no_header = 1; + z->state->sub.method = DEFLATED; + z->state->mode = START; + } + if (windowBits < 8 || windowBits > 15) { + inflateEnd(z); + return Z_STREAM_ERROR; + } + z->state->w_bits = windowBits; + z->state->w_size = 1<avail_in--,z->total_in++,*z->next_in++) + +int inflate(z, f) +z_stream *z; +int f; +{ + int r; + uInt b; + uLong c; + + if (z == Z_NULL || z->next_in == Z_NULL) + return Z_STREAM_ERROR; + r = Z_BUF_ERROR; + while (1) switch (z->state->mode) + { + case METHOD: + if (z->avail_in == 0) return r; r = Z_OK; + if (((z->state->sub.method = NEXTBYTE) & 0xf != DEFLATED)) + { + z->state->mode = ERROR; + z->msg = "unknown compression method"; + return Z_DATA_ERROR; + } + if ((z->state->sub.method >> 4) > z->state->w_bits) + { + z->state->mode = ERROR; + z->msg = "invalid window size"; + return Z_DATA_ERROR; + } + z->state->mode = FLAG; + case FLAG: + if (z->avail_in == 0) return r; r = Z_OK; + if ((b = NEXTBYTE) & 0x20) + { + z->state->mode = ERROR; + z->msg = "invalid reserved bit"; + return Z_DATA_ERROR; + } + if (((z->state->sub.method << 8) + b) % 31) + { + z->state->mode = ERROR; + z->msg = "incorrect header check"; + return Z_DATA_ERROR; + } + z->state->mode = START; + case START: + if ((z->state->sub.blocks = inflate_blocks_new(z,z->state->w_size)) + == Z_NULL) + return Z_MEM_ERROR; + z->state->mode = BLOCKS; + case BLOCKS: + if ((r = inflate_blocks(z->state->sub.blocks, z, r)) != Z_STREAM_END) + return r; + inflate_blocks_free(z->state->sub.blocks, z, &c, &r); + if (z->state->no_header) { + z->state->mode = DONE; + return Z_STREAM_END; + } + z->state->sub.check.was = c; + if (r != -1) + { + z->state->sub.check.need = (uLong)r << 24; + z->state->mode = CHECK3; + r = Z_OK; + break; + } + r = Z_OK; + z->state->mode = CHECK4; + case CHECK4: + if (z->avail_in == 0) return r; r = Z_OK; + z->state->sub.check.need = (uLong)NEXTBYTE << 24; + z->state->mode = CHECK3; + case CHECK3: + if (z->avail_in == 0) return r; r = Z_OK; + z->state->sub.check.need += (uLong)NEXTBYTE << 16; + z->state->mode = CHECK2; + case CHECK2: + if (z->avail_in == 0) return r; r = Z_OK; + z->state->sub.check.need += (uLong)NEXTBYTE << 8; + z->state->mode = CHECK1; + case CHECK1: + if (z->avail_in == 0) return r; r = Z_OK; + z->state->sub.check.need += (uLong)NEXTBYTE; + if (z->state->sub.check.was != z->state->sub.check.need) + { + z->state->mode = ERROR; + z->msg = "incorrect data check"; + return Z_DATA_ERROR; + } + z->state->mode = DONE; + case DONE: + return Z_STREAM_END; + case ERROR: + return Z_DATA_ERROR; + default: + return Z_STREAM_ERROR; + } +} + + +int inflateEnd(z) +z_stream *z; +{ + uLong c; + int e; + + if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL) + return Z_STREAM_ERROR; + if (z->state->mode == BLOCKS) + inflate_blocks_free(z->state->sub.blocks, z, &c, &e); + ZFREE(z, z->state); + z->state = Z_NULL; + return Z_OK; +} + + +/* inflateSync not implemented yet--this just consumes input */ +int inflateSync(z) +z_stream *z; +{ + if (z == Z_NULL) return Z_STREAM_ERROR; + if (z->avail_in == 0) return Z_BUF_ERROR; + do { + z->total_in++; + } while (--z->avail_in); + return Z_DATA_ERROR; +} + + +/* inflateReset not fully implemented yet--this frees and reallocates */ +int inflateReset(z) +z_stream *z; +{ + int r; + + if ((r = inflateEnd(z)) != Z_OK) + return r; + return inflateInit(z); +} -- cgit v1.2.3-55-g6feb