X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;ds=sidebyside;f=lib%2Flizard.h;h=aa616515b21ad0d418a1d66de3015b5b104d346e;hb=bbcbba14a32658a09d7cd44cee40c8369065822f;hp=25ba4bcee29fc946a6b41e9c265b4b02770e0d46;hpb=2c6f7d0fdea90d70ed9d7d10b766e775c0e2f790;p=libucw.git

diff --git a/lib/lizard.h b/lib/lizard.h
index 25ba4bce..aa616515 100644
--- a/lib/lizard.h
+++ b/lib/lizard.h
@@ -1,27 +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_NEEDS_CHARS	8
+#ifndef _UCW_LIZARD_H
+#define _UCW_LIZARD_H
+
+#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	LIZZARD_MAX_MULTIPLY	65LL/64
-#define	LIZZARD_MAX_ADD		4
+#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 * 65/64 + 4.
+   * original length * 23/22 + 4.
    *
    * The additive constant is for EOF and the header of the file.
    *
-   * The multiplicative constant 129/128 comes from an incompressible string of
-   * length 256 that requires a 2-byte header.  However, if longer strings get
-   * interrupted by a sequence of length 3 compressed into 2 characters, the
-   * overlap is sligtly bigger.
-   * TODO: check */
-
-int lizzard_compress(byte *in, uns in_len, byte *out);
-int lizzard_decompress(byte *in, byte *out);
+   * 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