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 <alain@knaff.lu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/include/linux/decompress/generic.h b/include/linux/decompress/generic.h
new file mode 100644
index 000000000000..f847f514f78e
--- /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