| /* 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 */ |
| |
| /* 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 */ |
| |
| /* mode independent information */ |
| int nowrap; /* flag for no wrapper */ |
| uInt wbits; /* log2(window size) (8..15, defaults to 15) */ |
| |
| }; |
| |
| |
| int inflateInit(z) |
| z_stream *z; |
| { |
| return inflateInit2(z, WBITS); |
| } |
| |
| |
| int inflateInit2(z, w) |
| z_stream *z; |
| int w; |
| { |
| /* initialize state */ |
| 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; |
| |
| /* handle undocumented nowrap option (no zlib header or check) */ |
| z->state->nowrap = 0; |
| if (w < 0) |
| { |
| w = - w; |
| z->state->nowrap = 1; |
| z->state->mode = START; |
| } |
| |
| /* set window size */ |
| if (w < 8 || w > 15) |
| { |
| inflateEnd(z); |
| return Z_STREAM_ERROR; |
| } |
| z->state->wbits = w; |
| return Z_OK; |
| } |
| |
| |
| #define NEXTBYTE (z->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) + 8 > z->state->wbits) |
| { |
| 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->nowrap ? Z_NULL : adler32, |
| 1<< z->state->wbits)) == 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->nowrap) |
| { |
| if (r != -1) |
| z->msg = "inflate bug--took one too many bytes"; |
| z->state->mode = r == -1 ? DONE : ERROR; |
| break; |
| } |
| 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); |
| } |