/* * LZO 1x decompression * Copyright (c) 2006 Reimar Doeffinger * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */#include "common.h"//! avoid e.g. MPlayers fast_memcpy, it slows things down here#undef memcpy#include <string.h>#include "lzo.h"//! define if we may write up to 12 bytes beyond the output buffer#define OUTBUF_PADDED 1//! define if we may read up to 4 bytes beyond the input buffer#define INBUF_PADDED 1typedef struct LZOContext {    const uint8_t *in, *in_end;    uint8_t *out_start, *out, *out_end;    int error;} LZOContext;/** * \brief read one byte from input buffer, avoiding overrun * \return byte read */static inline int get_byte(LZOContext *c) {    if (c->in < c->in_end)        return *c->in++;    c->error |= LZO_INPUT_DEPLETED;    return 1;}/** * \brief decode a length value in the coding used by lzo * \param x previous byte value * \param mask bits used from x * \return decoded length value */static inline int get_len(LZOContext *c, int x, int mask) {    int cnt = x & mask;    if (!cnt) {        while (!(x = get_byte(c))) cnt += 255;        cnt += mask + x;    }    return cnt;}/** * \brief copy bytes from input to output buffer with checking * \param cnt number of bytes to copy, must be > 0 */static inline void copy(LZOContext *c, int cnt) {    register const uint8_t *src = c->in;    register uint8_t *dst = c->out;    if (src + cnt > c->in_end) {        cnt = c->in_end - src;        c->error |= LZO_INPUT_DEPLETED;    }    if (dst + cnt > c->out_end) {        cnt = c->out_end - dst;        c->error |= LZO_OUTPUT_FULL;    }#if defined(INBUF_PADDED) && defined(OUTBUF_PADDED)    dst[0] = src[0];    dst[1] = src[1];    dst[2] = src[2];    dst[3] = src[3];    src += 4;    dst += 4;    cnt -= 4;    if (cnt > 0)#endif        memcpy(dst, src, cnt);    c->in = src + cnt;    c->out = dst + cnt;}/** * \brief copy previously decoded bytes to current position * \param back how many bytes back we start * \param cnt number of bytes to copy, must be > 0 * * cnt > back is valid, this will copy the bytes we just copied, * thus creating a repeating pattern with a period length of back. */static inline void copy_backptr(LZOContext *c, int back, int cnt) {    register uint8_t *src = &c->out[-back];    register uint8_t *dst = c->out;    if (src < c->out_start) {        c->error |= LZO_INVALID_BACKPTR;        return;    }    if (dst + cnt > c->out_end) {        cnt = c->out_end - dst;        c->error |= LZO_OUTPUT_FULL;    }    if (back == 1) {        memset(dst, *src, cnt);        dst += cnt;    } else {#ifdef OUTBUF_PADDED        dst[0] = src[0];        dst[1] = src[1];        dst[2] = src[2];        dst[3] = src[3];        src += 4;        dst += 4;        cnt -= 4;        if (cnt > 0) {            dst[0] = src[0];            dst[1] = src[1];            dst[2] = src[2];            dst[3] = src[3];            dst[4] = src[4];            dst[5] = src[5];            dst[6] = src[6];            dst[7] = src[7];            src += 8;            dst += 8;            cnt -= 8;        }#endif        if (cnt > 0) {            int blocklen = back;            while (cnt > blocklen) {                memcpy(dst, src, blocklen);                dst += blocklen;                cnt -= blocklen;                blocklen <<= 1;            }            memcpy(dst, src, cnt);        }        dst += cnt;    }    c->out = dst;}/** * \brief decode LZO 1x compressed data * \param out output buffer * \param outlen size of output buffer, number of bytes left are returned here * \param in input buffer * \param inlen size of input buffer, number of bytes left are returned here * \return 0 on success, otherwise error flags, see lzo.h * * make sure all buffers are appropriately padded, in must provide * LZO_INPUT_PADDING, out must provide LZO_OUTPUT_PADDING additional bytes */int lzo1x_decode(uint8_t *out, int *outlen, const uint8_t *in, int *inlen) {    enum {COPY, BACKPTR} state = COPY;    int x;    LZOContext c;    c.in = in;    c.in_end = in + *inlen;    c.out = c.out_start = out;    c.out_end = out + * outlen;    c.error = 0;    x = get_byte(&c);    if (x > 17) {        copy(&c, x - 17);        x = get_byte(&c);        if (x < 16) c.error |= LZO_ERROR;    }    while (!c.error) {        int cnt, back;        if (x >> 4) {            if (x >> 6) {                cnt = (x >> 5) - 1;                back = (get_byte(&c) << 3) + ((x >> 2) & 7) + 1;            } else if (x >> 5) {                cnt = get_len(&c, x, 31);                x = get_byte(&c);                back = (get_byte(&c) << 6) + (x >> 2) + 1;            } else {                cnt = get_len(&c, x, 7);                back = (1 << 14) + ((x & 8) << 11);                x = get_byte(&c);                back += (get_byte(&c) << 6) + (x >> 2);                if (back == (1 << 14)) {                    if (cnt != 1)                        c.error |= LZO_ERROR;                    break;                }            }        } else        switch (state) {            case COPY:                cnt = get_len(&c, x, 15);                copy(&c, cnt + 3);                x = get_byte(&c);                if (x >> 4)                    continue;                cnt = 1;                back = (1 << 11) + (get_byte(&c) << 2) + (x >> 2) + 1;                break;            case BACKPTR:                cnt = 0;                back = (get_byte(&c) << 2) + (x >> 2) + 1;                break;        }        copy_backptr(&c, back, cnt + 2);        cnt = x & 3;        state = cnt ? BACKPTR : COPY;        if (cnt)            copy(&c, cnt);        x = get_byte(&c);    }    *inlen = c.in_end - c.in;    *outlen = c.out_end - c.out;    return c.error;}