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