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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * LZO1X Compressor from LZO4 *5 * Copyright (C) 1996-2012 Markus F.X.J. Oberhumer <markus@oberhumer.com>6 *7 * The full LZO package can be found at:8 * http://www.oberhumer.com/opensource/lzo/9 *10 * Changed for Linux kernel use by:11 * Nitin Gupta <nitingupta910@gmail.com>12 * Richard Purdie <rpurdie@openedhand.com>13 */14 15#include <linux/module.h>16#include <linux/kernel.h>17#include <linux/unaligned.h>18#include <linux/lzo.h>19#include "lzodefs.h"20 21static noinline size_t22lzo1x_1_do_compress(const unsigned char *in, size_t in_len,23 unsigned char *out, size_t *out_len,24 size_t ti, void *wrkmem, signed char *state_offset,25 const unsigned char bitstream_version)26{27 const unsigned char *ip;28 unsigned char *op;29 const unsigned char * const in_end = in + in_len;30 const unsigned char * const ip_end = in + in_len - 20;31 const unsigned char *ii;32 lzo_dict_t * const dict = (lzo_dict_t *) wrkmem;33 34 op = out;35 ip = in;36 ii = ip;37 ip += ti < 4 ? 4 - ti : 0;38 39 for (;;) {40 const unsigned char *m_pos = NULL;41 size_t t, m_len, m_off;42 u32 dv;43 u32 run_length = 0;44literal:45 ip += 1 + ((ip - ii) >> 5);46next:47 if (unlikely(ip >= ip_end))48 break;49 dv = get_unaligned_le32(ip);50 51 if (dv == 0 && bitstream_version) {52 const unsigned char *ir = ip + 4;53 const unsigned char *limit = min(ip_end, ip + MAX_ZERO_RUN_LENGTH + 1);54#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && \55 defined(LZO_FAST_64BIT_MEMORY_ACCESS)56 u64 dv64;57 58 for (; (ir + 32) <= limit; ir += 32) {59 dv64 = get_unaligned((u64 *)ir);60 dv64 |= get_unaligned((u64 *)ir + 1);61 dv64 |= get_unaligned((u64 *)ir + 2);62 dv64 |= get_unaligned((u64 *)ir + 3);63 if (dv64)64 break;65 }66 for (; (ir + 8) <= limit; ir += 8) {67 dv64 = get_unaligned((u64 *)ir);68 if (dv64) {69# if defined(__LITTLE_ENDIAN)70 ir += __builtin_ctzll(dv64) >> 3;71# elif defined(__BIG_ENDIAN)72 ir += __builtin_clzll(dv64) >> 3;73# else74# error "missing endian definition"75# endif76 break;77 }78 }79#else80 while ((ir < (const unsigned char *)81 ALIGN((uintptr_t)ir, 4)) &&82 (ir < limit) && (*ir == 0))83 ir++;84 if (IS_ALIGNED((uintptr_t)ir, 4)) {85 for (; (ir + 4) <= limit; ir += 4) {86 dv = *((u32 *)ir);87 if (dv) {88# if defined(__LITTLE_ENDIAN)89 ir += __builtin_ctz(dv) >> 3;90# elif defined(__BIG_ENDIAN)91 ir += __builtin_clz(dv) >> 3;92# else93# error "missing endian definition"94# endif95 break;96 }97 }98 }99#endif100 while (likely(ir < limit) && unlikely(*ir == 0))101 ir++;102 run_length = ir - ip;103 if (run_length > MAX_ZERO_RUN_LENGTH)104 run_length = MAX_ZERO_RUN_LENGTH;105 } else {106 t = ((dv * 0x1824429d) >> (32 - D_BITS)) & D_MASK;107 m_pos = in + dict[t];108 dict[t] = (lzo_dict_t) (ip - in);109 if (unlikely(dv != get_unaligned_le32(m_pos)))110 goto literal;111 }112 113 ii -= ti;114 ti = 0;115 t = ip - ii;116 if (t != 0) {117 if (t <= 3) {118 op[*state_offset] |= t;119 COPY4(op, ii);120 op += t;121 } else if (t <= 16) {122 *op++ = (t - 3);123 COPY8(op, ii);124 COPY8(op + 8, ii + 8);125 op += t;126 } else {127 if (t <= 18) {128 *op++ = (t - 3);129 } else {130 size_t tt = t - 18;131 *op++ = 0;132 while (unlikely(tt > 255)) {133 tt -= 255;134 *op++ = 0;135 }136 *op++ = tt;137 }138 do {139 COPY8(op, ii);140 COPY8(op + 8, ii + 8);141 op += 16;142 ii += 16;143 t -= 16;144 } while (t >= 16);145 if (t > 0) do {146 *op++ = *ii++;147 } while (--t > 0);148 }149 }150 151 if (unlikely(run_length)) {152 ip += run_length;153 run_length -= MIN_ZERO_RUN_LENGTH;154 put_unaligned_le32((run_length << 21) | 0xfffc18155 | (run_length & 0x7), op);156 op += 4;157 run_length = 0;158 *state_offset = -3;159 goto finished_writing_instruction;160 }161 162 m_len = 4;163 {164#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ64)165 u64 v;166 v = get_unaligned((const u64 *) (ip + m_len)) ^167 get_unaligned((const u64 *) (m_pos + m_len));168 if (unlikely(v == 0)) {169 do {170 m_len += 8;171 v = get_unaligned((const u64 *) (ip + m_len)) ^172 get_unaligned((const u64 *) (m_pos + m_len));173 if (unlikely(ip + m_len >= ip_end))174 goto m_len_done;175 } while (v == 0);176 }177# if defined(__LITTLE_ENDIAN)178 m_len += (unsigned) __builtin_ctzll(v) / 8;179# elif defined(__BIG_ENDIAN)180 m_len += (unsigned) __builtin_clzll(v) / 8;181# else182# error "missing endian definition"183# endif184#elif defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ32)185 u32 v;186 v = get_unaligned((const u32 *) (ip + m_len)) ^187 get_unaligned((const u32 *) (m_pos + m_len));188 if (unlikely(v == 0)) {189 do {190 m_len += 4;191 v = get_unaligned((const u32 *) (ip + m_len)) ^192 get_unaligned((const u32 *) (m_pos + m_len));193 if (v != 0)194 break;195 m_len += 4;196 v = get_unaligned((const u32 *) (ip + m_len)) ^197 get_unaligned((const u32 *) (m_pos + m_len));198 if (unlikely(ip + m_len >= ip_end))199 goto m_len_done;200 } while (v == 0);201 }202# if defined(__LITTLE_ENDIAN)203 m_len += (unsigned) __builtin_ctz(v) / 8;204# elif defined(__BIG_ENDIAN)205 m_len += (unsigned) __builtin_clz(v) / 8;206# else207# error "missing endian definition"208# endif209#else210 if (unlikely(ip[m_len] == m_pos[m_len])) {211 do {212 m_len += 1;213 if (ip[m_len] != m_pos[m_len])214 break;215 m_len += 1;216 if (ip[m_len] != m_pos[m_len])217 break;218 m_len += 1;219 if (ip[m_len] != m_pos[m_len])220 break;221 m_len += 1;222 if (ip[m_len] != m_pos[m_len])223 break;224 m_len += 1;225 if (ip[m_len] != m_pos[m_len])226 break;227 m_len += 1;228 if (ip[m_len] != m_pos[m_len])229 break;230 m_len += 1;231 if (ip[m_len] != m_pos[m_len])232 break;233 m_len += 1;234 if (unlikely(ip + m_len >= ip_end))235 goto m_len_done;236 } while (ip[m_len] == m_pos[m_len]);237 }238#endif239 }240m_len_done:241 242 m_off = ip - m_pos;243 ip += m_len;244 if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) {245 m_off -= 1;246 *op++ = (((m_len - 1) << 5) | ((m_off & 7) << 2));247 *op++ = (m_off >> 3);248 } else if (m_off <= M3_MAX_OFFSET) {249 m_off -= 1;250 if (m_len <= M3_MAX_LEN)251 *op++ = (M3_MARKER | (m_len - 2));252 else {253 m_len -= M3_MAX_LEN;254 *op++ = M3_MARKER | 0;255 while (unlikely(m_len > 255)) {256 m_len -= 255;257 *op++ = 0;258 }259 *op++ = (m_len);260 }261 *op++ = (m_off << 2);262 *op++ = (m_off >> 6);263 } else {264 m_off -= 0x4000;265 if (m_len <= M4_MAX_LEN)266 *op++ = (M4_MARKER | ((m_off >> 11) & 8)267 | (m_len - 2));268 else {269 if (unlikely(((m_off & 0x403f) == 0x403f)270 && (m_len >= 261)271 && (m_len <= 264))272 && likely(bitstream_version)) {273 // Under lzo-rle, block copies274 // for 261 <= length <= 264 and275 // (distance & 0x80f3) == 0x80f3276 // can result in ambiguous277 // output. Adjust length278 // to 260 to prevent ambiguity.279 ip -= m_len - 260;280 m_len = 260;281 }282 m_len -= M4_MAX_LEN;283 *op++ = (M4_MARKER | ((m_off >> 11) & 8));284 while (unlikely(m_len > 255)) {285 m_len -= 255;286 *op++ = 0;287 }288 *op++ = (m_len);289 }290 *op++ = (m_off << 2);291 *op++ = (m_off >> 6);292 }293 *state_offset = -2;294finished_writing_instruction:295 ii = ip;296 goto next;297 }298 *out_len = op - out;299 return in_end - (ii - ti);300}301 302static int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,303 unsigned char *out, size_t *out_len,304 void *wrkmem, const unsigned char bitstream_version)305{306 const unsigned char *ip = in;307 unsigned char *op = out;308 unsigned char *data_start;309 size_t l = in_len;310 size_t t = 0;311 signed char state_offset = -2;312 unsigned int m4_max_offset;313 314 // LZO v0 will never write 17 as first byte (except for zero-length315 // input), so this is used to version the bitstream316 if (bitstream_version > 0) {317 *op++ = 17;318 *op++ = bitstream_version;319 m4_max_offset = M4_MAX_OFFSET_V1;320 } else {321 m4_max_offset = M4_MAX_OFFSET_V0;322 }323 324 data_start = op;325 326 while (l > 20) {327 size_t ll = min_t(size_t, l, m4_max_offset + 1);328 uintptr_t ll_end = (uintptr_t) ip + ll;329 if ((ll_end + ((t + ll) >> 5)) <= ll_end)330 break;331 BUILD_BUG_ON(D_SIZE * sizeof(lzo_dict_t) > LZO1X_1_MEM_COMPRESS);332 memset(wrkmem, 0, D_SIZE * sizeof(lzo_dict_t));333 t = lzo1x_1_do_compress(ip, ll, op, out_len, t, wrkmem,334 &state_offset, bitstream_version);335 ip += ll;336 op += *out_len;337 l -= ll;338 }339 t += l;340 341 if (t > 0) {342 const unsigned char *ii = in + in_len - t;343 344 if (op == data_start && t <= 238) {345 *op++ = (17 + t);346 } else if (t <= 3) {347 op[state_offset] |= t;348 } else if (t <= 18) {349 *op++ = (t - 3);350 } else {351 size_t tt = t - 18;352 *op++ = 0;353 while (tt > 255) {354 tt -= 255;355 *op++ = 0;356 }357 *op++ = tt;358 }359 if (t >= 16) do {360 COPY8(op, ii);361 COPY8(op + 8, ii + 8);362 op += 16;363 ii += 16;364 t -= 16;365 } while (t >= 16);366 if (t > 0) do {367 *op++ = *ii++;368 } while (--t > 0);369 }370 371 *op++ = M4_MARKER | 1;372 *op++ = 0;373 *op++ = 0;374 375 *out_len = op - out;376 return LZO_E_OK;377}378 379int lzo1x_1_compress(const unsigned char *in, size_t in_len,380 unsigned char *out, size_t *out_len,381 void *wrkmem)382{383 return lzogeneric1x_1_compress(in, in_len, out, out_len, wrkmem, 0);384}385 386int lzorle1x_1_compress(const unsigned char *in, size_t in_len,387 unsigned char *out, size_t *out_len,388 void *wrkmem)389{390 return lzogeneric1x_1_compress(in, in_len, out, out_len,391 wrkmem, LZO_VERSION);392}393 394EXPORT_SYMBOL_GPL(lzo1x_1_compress);395EXPORT_SYMBOL_GPL(lzorle1x_1_compress);396 397MODULE_LICENSE("GPL");398MODULE_DESCRIPTION("LZO1X-1 Compressor");399