From bc22c17e12c130dc929218a95aa347e0f3fd05dc Mon Sep 17 00:00:00 2001 From: Alain Knaff Date: Sun, 4 Jan 2009 22:46:16 +0100 Subject: bzip2/lzma: library support for gzip, bzip2 and lzma decompression Impact: Replaces inflate.c with a wrapper around zlib_inflate; new library code This is the first part of the bzip2/lzma patch The bzip patch is based on an idea by Christian Ludwig, includes support for compressing the kernel with bzip2 or lzma rather than gzip. Both compressors give smaller sizes than gzip. Lzma's decompresses faster than bzip2. It also supports ramdisks and initramfs' compressed using these two compressors. The functionality has been successfully used for a couple of years by the udpcast project This version applies to "tip" kernel 2.6.28 This part contains: - changed inflate.c to accomodate rest of patch - implementation of bzip2 compression (not used at this stage yet) - implementation of lzma compression (not used at this stage yet) - Makefile routines to support bzip2 and lzma kernel compression Signed-off-by: Alain Knaff Signed-off-by: H. Peter Anvin --- include/linux/decompress/generic.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 include/linux/decompress/generic.h (limited to 'include/linux/decompress/generic.h') diff --git a/include/linux/decompress/generic.h b/include/linux/decompress/generic.h new file mode 100644 index 0000000..f847f51 --- /dev/null +++ b/include/linux/decompress/generic.h @@ -0,0 +1,30 @@ +#ifndef DECOMPRESS_GENERIC_H +#define DECOMPRESS_GENERIC_H + +/* Minimal chunksize to be read. + *Bzip2 prefers at least 4096 + *Lzma prefers 0x10000 */ +#define COMPR_IOBUF_SIZE 4096 + +typedef int (*decompress_fn) (unsigned char *inbuf, int len, + int(*fill)(void*, unsigned int), + int(*writebb)(void*, unsigned int), + unsigned char *output, + int *posp, + void(*error)(char *x)); + +/* inbuf - input buffer + *len - len of pre-read data in inbuf + *fill - function to fill inbuf if empty + *writebb - function to write out outbug + *posp - if non-null, input position (number of bytes read) will be + * returned here + * + *If len != 0, the inbuf is initialized (with as much data), and fill + *should not be called + *If len = 0, the inbuf is allocated, but empty. Its size is IOBUF_SIZE + *fill should be called (repeatedly...) to read data, at most IOBUF_SIZE + */ + + +#endif -- cgit v1.1 From 889c92d21db40be0b7d22a59395060237895bb85 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Thu, 8 Jan 2009 15:14:17 -0800 Subject: bzip2/lzma: centralize format detection Centralize the compression format detection to a common routine in the lib directory, and use it for both initramfs and initrd. Signed-off-by: H. Peter Anvin --- include/linux/decompress/generic.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/decompress/generic.h') diff --git a/include/linux/decompress/generic.h b/include/linux/decompress/generic.h index f847f51..6dfb856 100644 --- a/include/linux/decompress/generic.h +++ b/include/linux/decompress/generic.h @@ -26,5 +26,8 @@ typedef int (*decompress_fn) (unsigned char *inbuf, int len, *fill should be called (repeatedly...) to read data, at most IOBUF_SIZE */ +/* Utility routine to detect the decompression method */ +decompress_fn decompress_method(const unsigned char *inbuf, int len, + const char **name); #endif -- cgit v1.1