diff --git a/configure b/configure index 07fa501d6e..152e49bdf7 100755 --- a/configure +++ b/configure @@ -1928,6 +1928,7 @@ CONFIG_EXTRA=" rtpdec rtpenc_chain sinewin + snappy startcode tpeldsp videodsp diff --git a/libavcodec/Makefile b/libavcodec/Makefile index 7a964ecaa1..162966bd1f 100644 --- a/libavcodec/Makefile +++ b/libavcodec/Makefile @@ -103,6 +103,7 @@ RDFT-OBJS-$(CONFIG_HARDCODED_TABLES) += sin_tables.o OBJS-$(CONFIG_RDFT) += rdft.o $(RDFT-OBJS-yes) OBJS-$(CONFIG_SHARED) += log2_tab.o OBJS-$(CONFIG_SINEWIN) += sinewin.o +OBJS-$(CONFIG_SNAPPY) += snappy.o OBJS-$(CONFIG_STARTCODE) += startcode.o OBJS-$(CONFIG_TPELDSP) += tpeldsp.o OBJS-$(CONFIG_VIDEODSP) += videodsp.o diff --git a/libavcodec/snappy.c b/libavcodec/snappy.c new file mode 100644 index 0000000000..553d713281 --- /dev/null +++ b/libavcodec/snappy.c @@ -0,0 +1,173 @@ +/* + * Snappy decompression algorithm + * Copyright (c) 2015 Luca Barbato + * + * This file is part of FFmpeg. + * + * FFmpeg 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 2.1 of the License, or (at your option) any later version. + * + * FFmpeg 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 FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "libavutil/mem.h" + +#include "bytestream.h" +#include "snappy.h" + +enum { + SNAPPY_LITERAL, + SNAPPY_COPY_1, + SNAPPY_COPY_2, + SNAPPY_COPY_4, +}; + +static int64_t bytestream2_get_levarint(GetByteContext *gb) +{ + uint64_t val = 0; + int shift = 0; + int tmp; + + do { + tmp = bytestream2_get_byte(gb); + val |= (tmp & 127) << shift; + shift += 7; + } while (tmp & 128); + + return val; +} + +static int snappy_literal(GetByteContext *gb, uint8_t *p, int size, int val) +{ + unsigned int len = 1; + + switch (val) { + case 63: + len += bytestream2_get_le32(gb); + break; + case 62: + len += bytestream2_get_le24(gb); + break; + case 61: + len += bytestream2_get_le16(gb); + break; + case 60: + len += bytestream2_get_byte(gb); + break; + default: // val < 60 + len += val; + } + + if (size < len) + return AVERROR_INVALIDDATA; + + bytestream2_get_buffer(gb, p, len); + + return len; +} + +static int snappy_copy(uint8_t *start, uint8_t *p, int size, + unsigned int off, int len) +{ + uint8_t *q; + int i; + if (off > p - start || size < len) + return AVERROR_INVALIDDATA; + + q = p - off; + + for (i = 0; i < len; i++) + p[i] = q[i]; + + return len; +} + +static int snappy_copy1(GetByteContext *gb, uint8_t *start, uint8_t *p, + int size, int val) +{ + int len = 4 + (val & 0x7); + unsigned int off = bytestream2_get_byte(gb) | (val & 0x38) << 5; + + return snappy_copy(start, p, size, off, len); +} + +static int snappy_copy2(GetByteContext *gb, uint8_t *start, uint8_t *p, + int size, int val) +{ + int len = 1 + val; + unsigned int off = bytestream2_get_le16(gb); + + return snappy_copy(start, p, size, off, len); +} + +static int snappy_copy4(GetByteContext *gb, uint8_t *start, uint8_t *p, + int size, int val) +{ + int len = 1 + val; + unsigned int off = bytestream2_get_le32(gb); + + return snappy_copy(start, p, size, off, len); +} + +static int64_t decode_len(GetByteContext *gb) +{ + int64_t len = bytestream2_get_levarint(gb); + + if (len < 0 || len > UINT_MAX) + return AVERROR_INVALIDDATA; + + return len; +} + +int ff_snappy_uncompress(GetByteContext *gb, uint8_t **buf, int64_t *size) +{ + int64_t len = decode_len(gb); + int ret = 0; + uint8_t *p; + + if (len < 0) + return len; + + if ((ret = av_reallocp(buf, len)) < 0) + return AVERROR(ENOMEM); + + *size = len; + p = *buf; + + while (bytestream2_get_bytes_left(gb) > 0) { + uint8_t s = bytestream2_get_byte(gb); + int val = s >> 2; + + switch (s & 0x03) { + case SNAPPY_LITERAL: + ret = snappy_literal(gb, p, len, val); + break; + case SNAPPY_COPY_1: + ret = snappy_copy1(gb, *buf, p, len, val); + break; + case SNAPPY_COPY_2: + ret = snappy_copy2(gb, *buf, p, len, val); + break; + case SNAPPY_COPY_4: + ret = snappy_copy4(gb, *buf, p, len, val); + break; + } + + if (ret < 0) + return ret; + + p += ret; + len -= ret; + } + + return 0; +} diff --git a/libavcodec/snappy.h b/libavcodec/snappy.h new file mode 100644 index 0000000000..b283183cb6 --- /dev/null +++ b/libavcodec/snappy.h @@ -0,0 +1,51 @@ +/* + * Snappy module + * Copyright (c) Luca Barbato + * + * This file is part of FFmpeg. + * + * FFmpeg 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 2.1 of the License, or (at your option) any later version. + * + * FFmpeg 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 FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/** + * @file + * Snappy decompression + * + * Snappy is a compression/decompression algorithm that does not aim for + * maximum compression, but rather for very high speeds and reasonable + * compression. + * + * http://en.wikipedia.org/wiki/Snappy_%28software%29 + */ + +#ifndef AVCODEC_SNAPPY_H +#define AVCODEC_SNAPPY_H + +#include + +#include "bytestream.h" + +/** + * Decompress an input buffer using Snappy algorithm. Caller is + * responsible of freeing the memory allocated in buf. + * + * @param gb input GetByteContext. + * @param buf output buffer pointer. + * @param size output buffer size. + * @return 0 if success, AVERROR otherwise. + */ +int ff_snappy_uncompress(GetByteContext *gb, uint8_t **buf, int64_t *size); + +#endif /* AVCODEC_SNAPPY_H */