Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
[linux-2.6.git] / lib / lzo / lzo1x_decompress.c
1 /*
2  *  LZO1X Decompressor from MiniLZO
3  *
4  *  Copyright (C) 1996-2005 Markus F.X.J. Oberhumer <markus@oberhumer.com>
5  *
6  *  The full LZO package can be found at:
7  *  http://www.oberhumer.com/opensource/lzo/
8  *
9  *  Changed for kernel use by:
10  *  Nitin Gupta <nitingupta910@gmail.com>
11  *  Richard Purdie <rpurdie@openedhand.com>
12  */
13
14 #ifndef STATIC
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #endif
18
19 #include <asm/unaligned.h>
20 #include <linux/lzo.h>
21 #include "lzodefs.h"
22
23 #define HAVE_IP(x, ip_end, ip) ((size_t)(ip_end - ip) < (x))
24 #define HAVE_OP(x, op_end, op) ((size_t)(op_end - op) < (x))
25 #define HAVE_LB(m_pos, out, op) (m_pos < out || m_pos >= op)
26
27 #define COPY4(dst, src) \
28                 put_unaligned(get_unaligned((const u32 *)(src)), (u32 *)(dst))
29
30 int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
31                         unsigned char *out, size_t *out_len)
32 {
33         const unsigned char * const ip_end = in + in_len;
34         unsigned char * const op_end = out + *out_len;
35         const unsigned char *ip = in, *m_pos;
36         unsigned char *op = out;
37         size_t t;
38
39         *out_len = 0;
40
41         if (*ip > 17) {
42                 t = *ip++ - 17;
43                 if (t < 4)
44                         goto match_next;
45                 if (HAVE_OP(t, op_end, op))
46                         goto output_overrun;
47                 if (HAVE_IP(t + 1, ip_end, ip))
48                         goto input_overrun;
49                 do {
50                         *op++ = *ip++;
51                 } while (--t > 0);
52                 goto first_literal_run;
53         }
54
55         while ((ip < ip_end)) {
56                 t = *ip++;
57                 if (t >= 16)
58                         goto match;
59                 if (t == 0) {
60                         if (HAVE_IP(1, ip_end, ip))
61                                 goto input_overrun;
62                         while (*ip == 0) {
63                                 t += 255;
64                                 ip++;
65                                 if (HAVE_IP(1, ip_end, ip))
66                                         goto input_overrun;
67                         }
68                         t += 15 + *ip++;
69                 }
70                 if (HAVE_OP(t + 3, op_end, op))
71                         goto output_overrun;
72                 if (HAVE_IP(t + 4, ip_end, ip))
73                         goto input_overrun;
74
75                 COPY4(op, ip);
76                 op += 4;
77                 ip += 4;
78                 if (--t > 0) {
79                         if (t >= 4) {
80                                 do {
81                                         COPY4(op, ip);
82                                         op += 4;
83                                         ip += 4;
84                                         t -= 4;
85                                 } while (t >= 4);
86                                 if (t > 0) {
87                                         do {
88                                                 *op++ = *ip++;
89                                         } while (--t > 0);
90                                 }
91                         } else {
92                                 do {
93                                         *op++ = *ip++;
94                                 } while (--t > 0);
95                         }
96                 }
97
98 first_literal_run:
99                 t = *ip++;
100                 if (t >= 16)
101                         goto match;
102                 m_pos = op - (1 + M2_MAX_OFFSET);
103                 m_pos -= t >> 2;
104                 m_pos -= *ip++ << 2;
105
106                 if (HAVE_LB(m_pos, out, op))
107                         goto lookbehind_overrun;
108
109                 if (HAVE_OP(3, op_end, op))
110                         goto output_overrun;
111                 *op++ = *m_pos++;
112                 *op++ = *m_pos++;
113                 *op++ = *m_pos;
114
115                 goto match_done;
116
117                 do {
118 match:
119                         if (t >= 64) {
120                                 m_pos = op - 1;
121                                 m_pos -= (t >> 2) & 7;
122                                 m_pos -= *ip++ << 3;
123                                 t = (t >> 5) - 1;
124                                 if (HAVE_LB(m_pos, out, op))
125                                         goto lookbehind_overrun;
126                                 if (HAVE_OP(t + 3 - 1, op_end, op))
127                                         goto output_overrun;
128                                 goto copy_match;
129                         } else if (t >= 32) {
130                                 t &= 31;
131                                 if (t == 0) {
132                                         if (HAVE_IP(1, ip_end, ip))
133                                                 goto input_overrun;
134                                         while (*ip == 0) {
135                                                 t += 255;
136                                                 ip++;
137                                                 if (HAVE_IP(1, ip_end, ip))
138                                                         goto input_overrun;
139                                         }
140                                         t += 31 + *ip++;
141                                 }
142                                 m_pos = op - 1;
143                                 m_pos -= get_unaligned_le16(ip) >> 2;
144                                 ip += 2;
145                         } else if (t >= 16) {
146                                 m_pos = op;
147                                 m_pos -= (t & 8) << 11;
148
149                                 t &= 7;
150                                 if (t == 0) {
151                                         if (HAVE_IP(1, ip_end, ip))
152                                                 goto input_overrun;
153                                         while (*ip == 0) {
154                                                 t += 255;
155                                                 ip++;
156                                                 if (HAVE_IP(1, ip_end, ip))
157                                                         goto input_overrun;
158                                         }
159                                         t += 7 + *ip++;
160                                 }
161                                 m_pos -= get_unaligned_le16(ip) >> 2;
162                                 ip += 2;
163                                 if (m_pos == op)
164                                         goto eof_found;
165                                 m_pos -= 0x4000;
166                         } else {
167                                 m_pos = op - 1;
168                                 m_pos -= t >> 2;
169                                 m_pos -= *ip++ << 2;
170
171                                 if (HAVE_LB(m_pos, out, op))
172                                         goto lookbehind_overrun;
173                                 if (HAVE_OP(2, op_end, op))
174                                         goto output_overrun;
175
176                                 *op++ = *m_pos++;
177                                 *op++ = *m_pos;
178                                 goto match_done;
179                         }
180
181                         if (HAVE_LB(m_pos, out, op))
182                                 goto lookbehind_overrun;
183                         if (HAVE_OP(t + 3 - 1, op_end, op))
184                                 goto output_overrun;
185
186                         if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) {
187                                 COPY4(op, m_pos);
188                                 op += 4;
189                                 m_pos += 4;
190                                 t -= 4 - (3 - 1);
191                                 do {
192                                         COPY4(op, m_pos);
193                                         op += 4;
194                                         m_pos += 4;
195                                         t -= 4;
196                                 } while (t >= 4);
197                                 if (t > 0)
198                                         do {
199                                                 *op++ = *m_pos++;
200                                         } while (--t > 0);
201                         } else {
202 copy_match:
203                                 *op++ = *m_pos++;
204                                 *op++ = *m_pos++;
205                                 do {
206                                         *op++ = *m_pos++;
207                                 } while (--t > 0);
208                         }
209 match_done:
210                         t = ip[-2] & 3;
211                         if (t == 0)
212                                 break;
213 match_next:
214                         if (HAVE_OP(t, op_end, op))
215                                 goto output_overrun;
216                         if (HAVE_IP(t + 1, ip_end, ip))
217                                 goto input_overrun;
218
219                         *op++ = *ip++;
220                         if (t > 1) {
221                                 *op++ = *ip++;
222                                 if (t > 2)
223                                         *op++ = *ip++;
224                         }
225
226                         t = *ip++;
227                 } while (ip < ip_end);
228         }
229
230         *out_len = op - out;
231         return LZO_E_EOF_NOT_FOUND;
232
233 eof_found:
234         *out_len = op - out;
235         return (ip == ip_end ? LZO_E_OK :
236                 (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
237 input_overrun:
238         *out_len = op - out;
239         return LZO_E_INPUT_OVERRUN;
240
241 output_overrun:
242         *out_len = op - out;
243         return LZO_E_OUTPUT_OVERRUN;
244
245 lookbehind_overrun:
246         *out_len = op - out;
247         return LZO_E_LOOKBEHIND_OVERRUN;
248 }
249 #ifndef STATIC
250 EXPORT_SYMBOL_GPL(lzo1x_decompress_safe);
251
252 MODULE_LICENSE("GPL");
253 MODULE_DESCRIPTION("LZO1X Decompressor");
254
255 #endif