2 * LZO1X Decompressor from MiniLZO
4 * Copyright (C) 1996-2005 Markus F.X.J. Oberhumer <markus@oberhumer.com>
6 * The full LZO package can be found at:
7 * http://www.oberhumer.com/opensource/lzo/
9 * Changed for kernel use by:
10 * Nitin Gupta <nitingupta910@gmail.com>
11 * Richard Purdie <rpurdie@openedhand.com>
15 #include <linux/lzo.h>
16 #include <asm/byteorder.h>
17 #include <asm/unaligned.h>
20 #define HAVE_IP(x, ip_end, ip) ((size_t)(ip_end - ip) < (x))
21 #define HAVE_OP(x, op_end, op) ((size_t)(op_end - op) < (x))
22 #define HAVE_LB(m_pos, out, op) (m_pos < out || m_pos >= op)
24 #define COPY4(dst, src) \
25 put_unaligned(get_unaligned((const u32 *)(src)), (u32 *)(dst))
27 static const unsigned char lzop_magic[] = {
28 0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a
31 #define HEADER_HAS_FILTER 0x00000800L
33 static inline const unsigned char *parse_header(const unsigned char *src)
38 /* read magic: 9 first bytes */
39 for (i = 0; i < ARRAY_SIZE(lzop_magic); i++) {
40 if (*src++ != lzop_magic[i])
43 /* get version (2bytes), skip library version (2),
44 * 'need to be extracted' version (2) and
46 version = get_unaligned_be16(src);
48 if (version >= 0x0940)
50 if (get_unaligned_be32(src) & HEADER_HAS_FILTER)
51 src += 4; /* filter info */
53 /* skip flags, mode and mtime_low */
55 if (version >= 0x0940)
56 src += 4; /* skip mtime_high */
59 /* don't care about the file name, and skip checksum */
65 int lzop_decompress(const unsigned char *src, size_t src_len,
66 unsigned char *dst, size_t *dst_len)
68 unsigned char *start = dst;
69 const unsigned char *send = src + src_len;
71 size_t tmp, remaining;
74 src = parse_header(src);
80 /* read uncompressed block size */
81 dlen = get_unaligned_be32(src);
84 /* exit if last block */
86 *dst_len = dst - start;
90 /* read compressed block size, and skip block checksum info */
91 slen = get_unaligned_be32(src);
94 if (slen <= 0 || slen > dlen)
97 /* abort if buffer ran out of room */
99 return LZO_E_OUTPUT_OVERRUN;
103 r = lzo1x_decompress_safe((u8 *) src, slen, dst, &tmp);
116 return LZO_E_INPUT_OVERRUN;
119 int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
120 unsigned char *out, size_t *out_len)
122 const unsigned char * const ip_end = in + in_len;
123 unsigned char * const op_end = out + *out_len;
124 const unsigned char *ip = in, *m_pos;
125 unsigned char *op = out;
134 if (HAVE_OP(t, op_end, op))
136 if (HAVE_IP(t + 1, ip_end, ip))
141 goto first_literal_run;
144 while ((ip < ip_end)) {
149 if (HAVE_IP(1, ip_end, ip))
154 if (HAVE_IP(1, ip_end, ip))
159 if (HAVE_OP(t + 3, op_end, op))
161 if (HAVE_IP(t + 4, ip_end, ip))
191 m_pos = op - (1 + M2_MAX_OFFSET);
195 if (HAVE_LB(m_pos, out, op))
196 goto lookbehind_overrun;
198 if (HAVE_OP(3, op_end, op))
210 m_pos -= (t >> 2) & 7;
213 if (HAVE_LB(m_pos, out, op))
214 goto lookbehind_overrun;
215 if (HAVE_OP(t + 3 - 1, op_end, op))
218 } else if (t >= 32) {
221 if (HAVE_IP(1, ip_end, ip))
226 if (HAVE_IP(1, ip_end, ip))
232 m_pos -= get_unaligned_le16(ip) >> 2;
234 } else if (t >= 16) {
236 m_pos -= (t & 8) << 11;
240 if (HAVE_IP(1, ip_end, ip))
245 if (HAVE_IP(1, ip_end, ip))
250 m_pos -= get_unaligned_le16(ip) >> 2;
260 if (HAVE_LB(m_pos, out, op))
261 goto lookbehind_overrun;
262 if (HAVE_OP(2, op_end, op))
270 if (HAVE_LB(m_pos, out, op))
271 goto lookbehind_overrun;
272 if (HAVE_OP(t + 3 - 1, op_end, op))
275 if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) {
303 if (HAVE_OP(t, op_end, op))
305 if (HAVE_IP(t + 1, ip_end, ip))
316 } while (ip < ip_end);
320 return LZO_E_EOF_NOT_FOUND;
324 return (ip == ip_end ? LZO_E_OK :
325 (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
328 return LZO_E_INPUT_OVERRUN;
332 return LZO_E_OUTPUT_OVERRUN;
336 return LZO_E_LOOKBEHIND_OVERRUN;