X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=inftrees.h;h=baa53a0b1a199ce6ea4c3f99d0306502ab4fab2c;hb=0530dbcef992b56b88a6bfd0fd2efa868669d04e;hp=27e7222f733555f3e86cd40c9d7f04e5f89a4400;hpb=bdde4e09d21edff02ea5093b7f6eccbf166b272f;p=zlib.git

diff --git a/inftrees.h b/inftrees.h
index 27e7222..baa53a0 100644
--- a/inftrees.h
+++ b/inftrees.h
@@ -1,6 +1,6 @@
 /* inftrees.h -- header to use inftrees.c
- * Copyright (C) 1995 Mark Adler
- * For conditions of distribution and use, see copyright notice in zlib.h 
+ * 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
@@ -8,61 +8,55 @@
    subject to change. Applications should only use zlib.h.
  */
 
-/* Huffman code lookup table entry--this entry is four bytes for machines
-   that have 16-bit pointers (e.g. PC's in the small or medium model).
-   Valid extra bits (exop) are 0..13.  exop == -64 is EOB (end of block),
-   exop == 16 means that v is a literal, exop < 0 means that v is a pointer
-   to the next table, which codes -exop bits, and lastly exop == -128
-   indicates an unused code.  If a code with exop == -128 is looked up,
-   this implies an error in the data. */
-
-#if defined(STDC) || defined(sgi)
-typedef signed char Char;
-#else
-typedef char Char; /* just hope that char is signed */
-#endif
-
-typedef struct inflate_huft_s inflate_huft;
-struct inflate_huft_s {
-  union {
-    struct {
-      Char Exop;        /* number of extra bits or operation */
-      Byte Bits;        /* number of bits in this code or subcode */
-    } what;
-    Byte *pad;          /* pad structure to a power of 2 (4 bytes for */
-  } word;               /*  16-bit, 8 bytes for 32-bit machines) */
-  union {
-    uInt Base;          /* literal, length base, or distance base */
-    inflate_huft *Next; /* pointer to next level of table */
-  } more;
-};
-
-#ifdef DEBUG
-  extern uInt inflate_hufts;
-#endif
-
-extern int inflate_trees_bits __P((
-    uInt *,                     /* 19 code lengths */
-    uInt *,                     /* bits tree desired/actual depth */
-    inflate_huft **,            /* bits tree result */
-    z_stream *));               /* for zalloc, zfree functions */
-
-extern int inflate_trees_dynamic __P((
-    uInt,                       /* number of literal/length codes */
-    uInt,                       /* number of distance codes */
-    uInt *,                     /* that many (total) code lengths */
-    uInt *,                     /* literal desired/actual bit depth */
-    uInt *,                     /* distance desired/actual bit depth */
-    inflate_huft **,            /* literal/length tree result */
-    inflate_huft **,            /* distance tree result */
-    z_stream *));               /* for zalloc, zfree functions */
-
-extern int inflate_trees_fixed __P((
-    uInt *,                     /* literal desired/actual bit depth */
-    uInt *,                     /* distance desired/actual bit depth */
-    inflate_huft **,            /* literal/length tree result */
-    inflate_huft **));          /* distance tree result */
+/* 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
+ */
 
-extern int inflate_trees_free __P((
-    inflate_huft *,             /* tables to free */
-    z_stream *));               /* for zfree function */
+/* 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));