1 /* 2 * LZO1X Compressor from LZO 3 * 4 * Copyright (C) 1996-2012 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 Linux kernel use by: 10 * Nitin Gupta <nitingupta910@gmail.com> 11 * Richard Purdie <rpurdie@openedhand.com> 12 */ 13 14 #include <linux/module.h> 15 #include <linux/kernel.h> 16 #include <asm/unaligned.h> 17 #include <linux/lzo.h> 18 #include "lzodefs.h" 19 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) 24 { 25 const unsigned char *ip; 26 unsigned char *op; 27 const unsigned char * const in_end = in + in_len; 28 const unsigned char * const ip_end = in + in_len - 20; 29 const unsigned char *ii; 30 lzo_dict_t * const dict = (lzo_dict_t *) wrkmem; 31 32 op = out; 33 ip = in; 34 ii = ip; 35 ip += ti < 4 ? 4 - ti : 0; 36 37 for (;;) { 38 const unsigned char *m_pos; 39 size_t t, m_len, m_off; 40 u32 dv; 41 literal: 42 ip += 1 + ((ip - ii) >> 5); 43 next: 44 if (unlikely(ip >= ip_end)) 45 break; 46 dv = get_unaligned_le32(ip); 47 t = ((dv * 0x1824429d) >> (32 - D_BITS)) & D_MASK; 48 m_pos = in + dict[t]; 49 dict[t] = (lzo_dict_t) (ip - in); 50 if (unlikely(dv != get_unaligned_le32(m_pos))) 51 goto literal; 52 53 ii -= ti; 54 ti = 0; 55 t = ip - ii; 56 if (t != 0) { 57 if (t <= 3) { 58 op[-2] |= t; 59 COPY4(op, ii); 60 op += t; 61 } else if (t <= 16) { 62 *op++ = (t - 3); 63 COPY8(op, ii); 64 COPY8(op + 8, ii + 8); 65 op += t; 66 } else { 67 if (t <= 18) { 68 *op++ = (t - 3); 69 } else { 70 size_t tt = t - 18; 71 *op++ = 0; 72 while (unlikely(tt > 255)) { 73 tt -= 255; 74 *op++ = 0; 75 } 76 *op++ = tt; 77 } 78 do { 79 COPY8(op, ii); 80 COPY8(op + 8, ii + 8); 81 op += 16; 82 ii += 16; 83 t -= 16; 84 } while (t >= 16); 85 if (t > 0) do { 86 *op++ = *ii++; 87 } while (--t > 0); 88 } 89 } 90 91 m_len = 4; 92 { 93 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ64) 94 u64 v; 95 v = get_unaligned((const u64 *) (ip + m_len)) ^ 96 get_unaligned((const u64 *) (m_pos + m_len)); 97 if (unlikely(v == 0)) { 98 do { 99 m_len += 8; 100 v = get_unaligned((const u64 *) (ip + m_len)) ^ 101 get_unaligned((const u64 *) (m_pos + m_len)); 102 if (unlikely(ip + m_len >= ip_end)) 103 goto m_len_done; 104 } while (v == 0); 105 } 106 # if defined(__LITTLE_ENDIAN) 107 m_len += (unsigned) __builtin_ctzll(v) / 8; 108 # elif defined(__BIG_ENDIAN) 109 m_len += (unsigned) __builtin_clzll(v) / 8; 110 # else 111 # error "missing endian definition" 112 # endif 113 #elif defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ32) 114 u32 v; 115 v = get_unaligned((const u32 *) (ip + m_len)) ^ 116 get_unaligned((const u32 *) (m_pos + m_len)); 117 if (unlikely(v == 0)) { 118 do { 119 m_len += 4; 120 v = get_unaligned((const u32 *) (ip + m_len)) ^ 121 get_unaligned((const u32 *) (m_pos + m_len)); 122 if (v != 0) 123 break; 124 m_len += 4; 125 v = get_unaligned((const u32 *) (ip + m_len)) ^ 126 get_unaligned((const u32 *) (m_pos + m_len)); 127 if (unlikely(ip + m_len >= ip_end)) 128 goto m_len_done; 129 } while (v == 0); 130 } 131 # if defined(__LITTLE_ENDIAN) 132 m_len += (unsigned) __builtin_ctz(v) / 8; 133 # elif defined(__BIG_ENDIAN) 134 m_len += (unsigned) __builtin_clz(v) / 8; 135 # else 136 # error "missing endian definition" 137 # endif 138 #else 139 if (unlikely(ip[m_len] == m_pos[m_len])) { 140 do { 141 m_len += 1; 142 if (ip[m_len] != m_pos[m_len]) 143 break; 144 m_len += 1; 145 if (ip[m_len] != m_pos[m_len]) 146 break; 147 m_len += 1; 148 if (ip[m_len] != m_pos[m_len]) 149 break; 150 m_len += 1; 151 if (ip[m_len] != m_pos[m_len]) 152 break; 153 m_len += 1; 154 if (ip[m_len] != m_pos[m_len]) 155 break; 156 m_len += 1; 157 if (ip[m_len] != m_pos[m_len]) 158 break; 159 m_len += 1; 160 if (ip[m_len] != m_pos[m_len]) 161 break; 162 m_len += 1; 163 if (unlikely(ip + m_len >= ip_end)) 164 goto m_len_done; 165 } while (ip[m_len] == m_pos[m_len]); 166 } 167 #endif 168 } 169 m_len_done: 170 171 m_off = ip - m_pos; 172 ip += m_len; 173 ii = ip; 174 if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) { 175 m_off -= 1; 176 *op++ = (((m_len - 1) << 5) | ((m_off & 7) << 2)); 177 *op++ = (m_off >> 3); 178 } else if (m_off <= M3_MAX_OFFSET) { 179 m_off -= 1; 180 if (m_len <= M3_MAX_LEN) 181 *op++ = (M3_MARKER | (m_len - 2)); 182 else { 183 m_len -= M3_MAX_LEN; 184 *op++ = M3_MARKER | 0; 185 while (unlikely(m_len > 255)) { 186 m_len -= 255; 187 *op++ = 0; 188 } 189 *op++ = (m_len); 190 } 191 *op++ = (m_off << 2); 192 *op++ = (m_off >> 6); 193 } else { 194 m_off -= 0x4000; 195 if (m_len <= M4_MAX_LEN) 196 *op++ = (M4_MARKER | ((m_off >> 11) & 8) 197 | (m_len - 2)); 198 else { 199 m_len -= M4_MAX_LEN; 200 *op++ = (M4_MARKER | ((m_off >> 11) & 8)); 201 while (unlikely(m_len > 255)) { 202 m_len -= 255; 203 *op++ = 0; 204 } 205 *op++ = (m_len); 206 } 207 *op++ = (m_off << 2); 208 *op++ = (m_off >> 6); 209 } 210 goto next; 211 } 212 *out_len = op - out; 213 return in_end - (ii - ti); 214 } 215 216 int lzo1x_1_compress(const unsigned char *in, size_t in_len, 217 unsigned char *out, size_t *out_len, 218 void *wrkmem) 219 { 220 const unsigned char *ip = in; 221 unsigned char *op = out; 222 size_t l = in_len; 223 size_t t = 0; 224 225 while (l > 20) { 226 size_t ll = l <= (M4_MAX_OFFSET + 1) ? l : (M4_MAX_OFFSET + 1); 227 uintptr_t ll_end = (uintptr_t) ip + ll; 228 if ((ll_end + ((t + ll) >> 5)) <= ll_end) 229 break; 230 BUILD_BUG_ON(D_SIZE * sizeof(lzo_dict_t) > LZO1X_1_MEM_COMPRESS); 231 memset(wrkmem, 0, D_SIZE * sizeof(lzo_dict_t)); 232 t = lzo1x_1_do_compress(ip, ll, op, out_len, t, wrkmem); 233 ip += ll; 234 op += *out_len; 235 l -= ll; 236 } 237 t += l; 238 239 if (t > 0) { 240 const unsigned char *ii = in + in_len - t; 241 242 if (op == out && t <= 238) { 243 *op++ = (17 + t); 244 } else if (t <= 3) { 245 op[-2] |= t; 246 } else if (t <= 18) { 247 *op++ = (t - 3); 248 } else { 249 size_t tt = t - 18; 250 *op++ = 0; 251 while (tt > 255) { 252 tt -= 255; 253 *op++ = 0; 254 } 255 *op++ = tt; 256 } 257 if (t >= 16) do { 258 COPY8(op, ii); 259 COPY8(op + 8, ii + 8); 260 op += 16; 261 ii += 16; 262 t -= 16; 263 } while (t >= 16); 264 if (t > 0) do { 265 *op++ = *ii++; 266 } while (--t > 0); 267 } 268 269 *op++ = M4_MARKER | 1; 270 *op++ = 0; 271 *op++ = 0; 272 273 *out_len = op - out; 274 return LZO_E_OK; 275 } 276 EXPORT_SYMBOL_GPL(lzo1x_1_compress); 277 278 MODULE_LICENSE("GPL"); 279 MODULE_DESCRIPTION("LZO1X-1 Compressor"); 280