2 * Copyright 2007 David Gibson, IBM Corporation.
3 * Based on earlier work, Copyright (C) Paul Mackerras 1997.
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
15 #include "gunzip_util.h"
17 struct gunzip_state state;
25 void gunzip_start(struct gunzip_state *state, void *src, int srclen)
30 memset(state, 0, sizeof(*state));
32 /* Check for gzip magic number */
33 if ((hdr[0] == 0x1f) && (hdr[1] == 0x8b)) {
34 /* gzip data, initialize zlib parameters */
37 state->s.workspace = state->scratch;
38 if (zlib_inflate_workspacesize() > sizeof(state->scratch)) {
39 printf("insufficient scratch space for gunzip\n\r");
46 if (hdr[2] != Z_DEFLATED || (flags & RESERVED) != 0) {
47 printf("bad gzipped data\n\r");
50 if ((flags & EXTRA_FIELD) != 0)
51 hdrlen = 12 + hdr[10] + (hdr[11] << 8);
52 if ((flags & ORIG_NAME) != 0)
53 while (hdr[hdrlen++] != 0)
55 if ((flags & COMMENT) != 0)
56 while (hdr[hdrlen++] != 0)
58 if ((flags & HEAD_CRC) != 0)
60 if (hdrlen >= srclen) {
61 printf("gunzip_start: ran out of data in header\n\r");
65 r = zlib_inflateInit2(&state->s, -MAX_WBITS);
67 printf("inflateInit2 returned %d\n\r", r);
72 state->s.next_in = src + hdrlen;
73 state->s.avail_in = srclen - hdrlen;
76 int gunzip_partial(struct gunzip_state *state, void *dst, int dstlen)
80 if (state->s.workspace) {
84 state->s.next_out = dst;
85 state->s.avail_out = dstlen;
86 r = zlib_inflate(&state->s, Z_FULL_FLUSH);
87 if (r != Z_OK && r != Z_STREAM_END) {
88 printf("inflate returned %d msg: %s\n\r", r, state->s.msg);
91 len = state->s.next_out - (unsigned char *)dst;
93 /* uncompressed image */
94 len = min(state->s.avail_in, (unsigned)dstlen);
95 memcpy(dst, state->s.next_in, len);
96 state->s.next_in += len;
97 state->s.avail_in -= len;
102 void gunzip_exactly(struct gunzip_state *state, void *dst, int dstlen)
106 len = gunzip_partial(state, dst, dstlen);
108 printf("gunzip_block: ran out of data\n\r");
113 void gunzip_discard(struct gunzip_state *state, int len)
115 static char discard_buf[128];
117 while (len > sizeof(discard_buf)) {
118 gunzip_exactly(state, discard_buf, sizeof(discard_buf));
119 len -= sizeof(discard_buf);
123 gunzip_exactly(state, discard_buf, len);
126 int gunzip_finish(struct gunzip_state *state, void *dst, int dstlen)
130 if (state->s.workspace) {
131 len = gunzip_partial(state, dst, dstlen);
132 zlib_inflateEnd(&state->s);
134 /* uncompressed image */
135 len = min(state->s.avail_in, (unsigned)dstlen);
136 memcpy(dst, state->s.next_in, len);