summaryrefslogtreecommitdiffstats
path: root/compat/zlib/inftrees.h
diff options
context:
space:
mode:
Diffstat (limited to 'compat/zlib/inftrees.h')
-rw-r--r--compat/zlib/inftrees.h62
1 files changed, 62 insertions, 0 deletions
diff --git a/compat/zlib/inftrees.h b/compat/zlib/inftrees.h
new file mode 100644
index 0000000..baa53a0
--- /dev/null
+++ b/compat/zlib/inftrees.h
@@ -0,0 +1,62 @@
+/* inftrees.h -- header to use inftrees.c
+ * Copyright (C) 1995-2005, 2010 Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+/* WARNING: this file should *not* be used by applications. It is
+ part of the implementation of the compression library and is
+ subject to change. Applications should only use zlib.h.
+ */
+
+/* Structure for decoding tables. Each entry provides either the
+ information needed to do the operation requested by the code that
+ indexed that table entry, or it provides a pointer to another
+ table that indexes more bits of the code. op indicates whether
+ the entry is a pointer to another table, a literal, a length or
+ distance, an end-of-block, or an invalid code. For a table
+ pointer, the low four bits of op is the number of index bits of
+ that table. For a length or distance, the low four bits of op
+ is the number of extra bits to get after the code. bits is
+ the number of bits in this code or part of the code to drop off
+ of the bit buffer. val is the actual byte to output in the case
+ of a literal, the base length or distance, or the offset from
+ the current table to the next table. Each entry is four bytes. */
+typedef struct {
+ unsigned char op; /* operation, extra bits, table bits */
+ unsigned char bits; /* bits in this part of the code */
+ unsigned short val; /* offset in table or code value */
+} code;
+
+/* op values as set by inflate_table():
+ 00000000 - literal
+ 0000tttt - table link, tttt != 0 is the number of table index bits
+ 0001eeee - length or distance, eeee is the number of extra bits
+ 01100000 - end of block
+ 01000000 - invalid code
+ */
+
+/* Maximum size of the dynamic table. The maximum number of code structures is
+ 1444, which is the sum of 852 for literal/length codes and 592 for distance
+ codes. These values were found by exhaustive searches using the program
+ examples/enough.c found in the zlib distribtution. The arguments to that
+ program are the number of symbols, the initial root table size, and the
+ maximum bit length of a code. "enough 286 9 15" for literal/length codes
+ returns returns 852, and "enough 30 6 15" for distance codes returns 592.
+ The initial root table size (9 or 6) is found in the fifth argument of the
+ inflate_table() calls in inflate.c and infback.c. If the root table size is
+ changed, then these maximum sizes would be need to be recalculated and
+ updated. */
+#define ENOUGH_LENS 852
+#define ENOUGH_DISTS 592
+#define ENOUGH (ENOUGH_LENS+ENOUGH_DISTS)
+
+/* Type of code to build for inflate_table() */
+typedef enum {
+ CODES,
+ LENS,
+ DISTS
+} codetype;
+
+int ZLIB_INTERNAL inflate_table OF((codetype type, unsigned short FAR *lens,
+ unsigned codes, code FAR * FAR *table,
+ unsigned FAR *bits, unsigned short FAR *work));