From 20dde48bcadd856c86a91d5463831a10be46db83 Mon Sep 17 00:00:00 2001 From: Peter Korsgaard Date: Thu, 19 Nov 2009 11:37:51 +0100 Subject: add lzop decompression support Add lzop decompression support to the existing lzo bitstream handling (think gzip versus zlib), and support it for uImage decompression if CONFIG_LZO is enabled. Lzop doesn't compress as good as gzip (~10% worse), but decompression is very fast (~0.7s faster here on a slow ppc). The lzop decompression code is based on Albin Tonnerre's recent ARM Linux lzo support patch. Cc: albin.tonnerre@free-electrons.com Signed-off-by: Peter Korsgaard --- lib_generic/lzo/lzo1x_decompress.c | 87 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) (limited to 'lib_generic') diff --git a/lib_generic/lzo/lzo1x_decompress.c b/lib_generic/lzo/lzo1x_decompress.c index 2780e118a..09bdc8f6c 100644 --- a/lib_generic/lzo/lzo1x_decompress.c +++ b/lib_generic/lzo/lzo1x_decompress.c @@ -24,6 +24,93 @@ #define COPY4(dst, src) \ put_unaligned(get_unaligned((const u32 *)(src)), (u32 *)(dst)) +static const unsigned char lzop_magic[] = { + 0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a +}; + +#define HEADER_HAS_FILTER 0x00000800L + +static inline const unsigned char *parse_header(const unsigned char *src) +{ + u8 level = 0; + u16 version; + int i; + + /* read magic: 9 first bytes */ + for (i = 0; i < ARRAY_SIZE(lzop_magic); i++) { + if (*src++ != lzop_magic[i]) + return NULL; + } + /* get version (2bytes), skip library version (2), + * 'need to be extracted' version (2) and + * method (1) */ + version = get_unaligned_be16(src); + src += 7; + if (version >= 0x0940) + level = *src++; + if (get_unaligned_be32(src) & HEADER_HAS_FILTER) + src += 4; /* filter info */ + + /* skip flags, mode and mtime_low */ + src += 12; + if (version >= 0x0940) + src += 4; /* skip mtime_high */ + + i = *src++; + /* don't care about the file name, and skip checksum */ + src += i + 4; + + return src; +} + +int lzop_decompress(const unsigned char *src, size_t src_len, + unsigned char *dst, size_t *dst_len) +{ + unsigned char *start = dst; + const unsigned char *send = src + src_len; + u32 slen, dlen; + size_t tmp; + int r; + + src = parse_header(src); + if (!src) + return LZO_E_ERROR; + + while (src < send) { + /* read uncompressed block size */ + dlen = get_unaligned_be32(src); + src += 4; + + /* exit if last block */ + if (dlen == 0) { + *dst_len = dst - start; + return LZO_E_OK; + } + + /* read compressed block size, and skip block checksum info */ + slen = get_unaligned_be32(src); + src += 8; + + if (slen <= 0 || slen > dlen) + return LZO_E_ERROR; + + /* decompress */ + tmp = dlen; + r = lzo1x_decompress_safe((u8 *) src, slen, dst, &tmp); + + if (r != LZO_E_OK) + return r; + + if (dlen != tmp) + return LZO_E_ERROR; + + src += slen; + dst += dlen; + } + + return LZO_E_INPUT_OVERRUN; +} + int lzo1x_decompress_safe(const unsigned char *in, size_t in_len, unsigned char *out, size_t *out_len) { -- cgit v1.2.3