2 * LZO1X Compressor from LZO
4 * Copyright (C) 1996-2012 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 Linux kernel use by:
10 * Nitin Gupta <nitingupta910@gmail.com>
11 * Richard Purdie <rpurdie@openedhand.com>
14 #include <linux/module.h>
15 #include <linux/kernel.h>
16 #include <asm/unaligned.h>
17 #include <linux/lzo.h>
20 static noinline size_t
21 lzo1x_1_do_compress(const unsigned char *in, size_t in_len,
22 unsigned char *out, size_t *out_len,
23 size_t ti, void *wrkmem, signed char *state_offset,
24 const unsigned char bitstream_version)
26 const unsigned char *ip;
28 const unsigned char * const in_end = in + in_len;
29 const unsigned char * const ip_end = in + in_len - 20;
30 const unsigned char *ii;
31 lzo_dict_t * const dict = (lzo_dict_t *) wrkmem;
36 ip += ti < 4 ? 4 - ti : 0;
39 const unsigned char *m_pos = NULL;
40 size_t t, m_len, m_off;
44 ip += 1 + ((ip - ii) >> 5);
46 if (unlikely(ip >= ip_end))
48 dv = get_unaligned_le32(ip);
50 if (dv == 0 && bitstream_version) {
51 const unsigned char *ir = ip + 4;
52 const unsigned char *limit = ip_end
53 < (ip + MAX_ZERO_RUN_LENGTH + 1)
54 ? ip_end : ip + MAX_ZERO_RUN_LENGTH + 1;
55 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && \
56 defined(LZO_FAST_64BIT_MEMORY_ACCESS)
59 for (; (ir + 32) <= limit; ir += 32) {
60 dv64 = get_unaligned((u64 *)ir);
61 dv64 |= get_unaligned((u64 *)ir + 1);
62 dv64 |= get_unaligned((u64 *)ir + 2);
63 dv64 |= get_unaligned((u64 *)ir + 3);
67 for (; (ir + 8) <= limit; ir += 8) {
68 dv64 = get_unaligned((u64 *)ir);
70 # if defined(__LITTLE_ENDIAN)
71 ir += __builtin_ctzll(dv64) >> 3;
72 # elif defined(__BIG_ENDIAN)
73 ir += __builtin_clzll(dv64) >> 3;
75 # error "missing endian definition"
81 while ((ir < (const unsigned char *)
82 ALIGN((uintptr_t)ir, 4)) &&
83 (ir < limit) && (*ir == 0))
85 for (; (ir + 4) <= limit; ir += 4) {
88 # if defined(__LITTLE_ENDIAN)
89 ir += __builtin_ctz(dv) >> 3;
90 # elif defined(__BIG_ENDIAN)
91 ir += __builtin_clz(dv) >> 3;
93 # error "missing endian definition"
99 while (likely(ir < limit) && unlikely(*ir == 0))
101 run_length = ir - ip;
102 if (run_length > MAX_ZERO_RUN_LENGTH)
103 run_length = MAX_ZERO_RUN_LENGTH;
105 t = ((dv * 0x1824429d) >> (32 - D_BITS)) & D_MASK;
106 m_pos = in + dict[t];
107 dict[t] = (lzo_dict_t) (ip - in);
108 if (unlikely(dv != get_unaligned_le32(m_pos)))
117 op[*state_offset] |= t;
120 } else if (t <= 16) {
123 COPY8(op + 8, ii + 8);
131 while (unlikely(tt > 255)) {
139 COPY8(op + 8, ii + 8);
150 if (unlikely(run_length)) {
152 run_length -= MIN_ZERO_RUN_LENGTH;
153 put_unaligned_le32((run_length << 21) | 0xfffc18
154 | (run_length & 0x7), op);
158 goto finished_writing_instruction;
163 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ64)
165 v = get_unaligned((const u64 *) (ip + m_len)) ^
166 get_unaligned((const u64 *) (m_pos + m_len));
167 if (unlikely(v == 0)) {
170 v = get_unaligned((const u64 *) (ip + m_len)) ^
171 get_unaligned((const u64 *) (m_pos + m_len));
172 if (unlikely(ip + m_len >= ip_end))
176 # if defined(__LITTLE_ENDIAN)
177 m_len += (unsigned) __builtin_ctzll(v) / 8;
178 # elif defined(__BIG_ENDIAN)
179 m_len += (unsigned) __builtin_clzll(v) / 8;
181 # error "missing endian definition"
183 #elif defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ32)
185 v = get_unaligned((const u32 *) (ip + m_len)) ^
186 get_unaligned((const u32 *) (m_pos + m_len));
187 if (unlikely(v == 0)) {
190 v = get_unaligned((const u32 *) (ip + m_len)) ^
191 get_unaligned((const u32 *) (m_pos + m_len));
195 v = get_unaligned((const u32 *) (ip + m_len)) ^
196 get_unaligned((const u32 *) (m_pos + m_len));
197 if (unlikely(ip + m_len >= ip_end))
201 # if defined(__LITTLE_ENDIAN)
202 m_len += (unsigned) __builtin_ctz(v) / 8;
203 # elif defined(__BIG_ENDIAN)
204 m_len += (unsigned) __builtin_clz(v) / 8;
206 # error "missing endian definition"
209 if (unlikely(ip[m_len] == m_pos[m_len])) {
212 if (ip[m_len] != m_pos[m_len])
215 if (ip[m_len] != m_pos[m_len])
218 if (ip[m_len] != m_pos[m_len])
221 if (ip[m_len] != m_pos[m_len])
224 if (ip[m_len] != m_pos[m_len])
227 if (ip[m_len] != m_pos[m_len])
230 if (ip[m_len] != m_pos[m_len])
233 if (unlikely(ip + m_len >= ip_end))
235 } while (ip[m_len] == m_pos[m_len]);
243 if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) {
245 *op++ = (((m_len - 1) << 5) | ((m_off & 7) << 2));
246 *op++ = (m_off >> 3);
247 } else if (m_off <= M3_MAX_OFFSET) {
249 if (m_len <= M3_MAX_LEN)
250 *op++ = (M3_MARKER | (m_len - 2));
253 *op++ = M3_MARKER | 0;
254 while (unlikely(m_len > 255)) {
260 *op++ = (m_off << 2);
261 *op++ = (m_off >> 6);
264 if (m_len <= M4_MAX_LEN)
265 *op++ = (M4_MARKER | ((m_off >> 11) & 8)
269 *op++ = (M4_MARKER | ((m_off >> 11) & 8));
270 while (unlikely(m_len > 255)) {
276 *op++ = (m_off << 2);
277 *op++ = (m_off >> 6);
280 finished_writing_instruction:
285 return in_end - (ii - ti);
288 int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,
289 unsigned char *out, size_t *out_len,
290 void *wrkmem, const unsigned char bitstream_version)
292 const unsigned char *ip = in;
293 unsigned char *op = out;
296 signed char state_offset = -2;
297 unsigned int m4_max_offset;
299 // LZO v0 will never write 17 as first byte,
300 // so this is used to version the bitstream
301 if (bitstream_version > 0) {
303 *op++ = bitstream_version;
304 m4_max_offset = M4_MAX_OFFSET_V1;
306 m4_max_offset = M4_MAX_OFFSET_V0;
310 size_t ll = l <= (m4_max_offset + 1) ? l : (m4_max_offset + 1);
311 uintptr_t ll_end = (uintptr_t) ip + ll;
312 if ((ll_end + ((t + ll) >> 5)) <= ll_end)
314 BUILD_BUG_ON(D_SIZE * sizeof(lzo_dict_t) > LZO1X_1_MEM_COMPRESS);
315 memset(wrkmem, 0, D_SIZE * sizeof(lzo_dict_t));
316 t = lzo1x_1_do_compress(ip, ll, op, out_len, t, wrkmem,
317 &state_offset, bitstream_version);
325 const unsigned char *ii = in + in_len - t;
327 if (op == out && t <= 238) {
330 op[state_offset] |= t;
331 } else if (t <= 18) {
344 COPY8(op + 8, ii + 8);
354 *op++ = M4_MARKER | 1;
362 int lzo1x_1_compress(const unsigned char *in, size_t in_len,
363 unsigned char *out, size_t *out_len,
366 return lzogeneric1x_1_compress(in, in_len, out, out_len, wrkmem, 0);
369 int lzorle1x_1_compress(const unsigned char *in, size_t in_len,
370 unsigned char *out, size_t *out_len,
373 return lzogeneric1x_1_compress(in, in_len, out, out_len,
374 wrkmem, LZO_VERSION);
377 EXPORT_SYMBOL_GPL(lzo1x_1_compress);
378 EXPORT_SYMBOL_GPL(lzorle1x_1_compress);
380 MODULE_LICENSE("GPL");
381 MODULE_DESCRIPTION("LZO1X-1 Compressor");