X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;ds=inline;f=lib%2Flizard.h;h=aa616515b21ad0d418a1d66de3015b5b104d346e;hb=e34560a76a7af3fb428604e4da3cd14cfd1bf454;hp=656aab8dac3ec864a9ab022073430b0eb7ab6c6f;hpb=d94fc019538bc9c96b694bf0cb1924fbd9251a6b;p=libucw.git

diff --git a/lib/lizard.h b/lib/lizard.h
index 656aab8d..aa616515 100644
--- a/lib/lizard.h
+++ b/lib/lizard.h
@@ -1,16 +1,49 @@
 /*
- *	LiZzaRd -- Fast compression method based on Lempel-Ziv 77
+ *	LiZaRd -- Fast compression method based on Lempel-Ziv 77
  *
  *	(c) 2004, Robert Spalek <robert@ucw.cz>
  *
- *	The file format is based on LZO1X and 
- *	the compression method is based on zlib.
+ *	This software may be freely distributed and used according to the terms
+ *	of the GNU Lesser General Public License.
  */
 
-#define	LIZZARD_MAX_PROLONG_FACTOR	129/128
-  /* Incompressible string of length 256 has a 2-byte header.
-   * Hence the scheme the file length get multiplied by 129/128 in the worst
-   * case + at most 4 bytes are added for header and EOF.  */
+#ifndef _UCW_LIZARD_H
+#define _UCW_LIZARD_H
 
-int lizzard_compress(byte *in, uns in_len, byte *out);
-int lizzard_decompress(byte *in, byte *out);
+#define	LIZARD_NEEDS_CHARS	8
+  /* The compression routine needs input buffer 8 characters longer, because it
+   * does not check the input bounds all the time.  */
+#define	LIZARD_MAX_MULTIPLY	23./22
+#define	LIZARD_MAX_ADD		4
+  /* In the worst case, the compressed file will not be longer than its
+   * original length * 23/22 + 4.
+   *
+   * The additive constant is for EOF and the header of the file.
+   *
+   * The multiplicative constant comes from 19-byte incompressible string
+   * followed by a 3-sequence that can be compressed into 2-byte link.  This
+   * breaks the copy-mode and it needs to be restarted with a new header.  The
+   * total length is 2(header) + 19(string) + 2(link) = 23.
+   */
+
+/* lizard.c */
+int lizard_compress(byte *in, uns in_len, byte *out);
+int lizard_decompress(byte *in, byte *out);
+
+/* lizard-safe.c */
+struct lizard_buffer;
+
+struct lizard_buffer *lizard_alloc(void);
+void lizard_free(struct lizard_buffer *buf);
+byte *lizard_decompress_safe(byte *in, struct lizard_buffer *buf, uns expected_length);
+
+/* adler32.c */
+uns update_adler32(uns adler, byte *ptr, uns len);
+
+static inline uns
+adler32(byte *buf, uns len)
+{
+  return update_adler32(1, buf, len);
+}
+
+#endif