bzip2-0.9.0cbzip2-0.9.0c

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+
+/*-------------------------------------------------------------*/
+/*--- Huffman coding low-level stuff                        ---*/
+/*---                                             huffman.c ---*/
+/*-------------------------------------------------------------*/
+
+/*--
+  This file is a part of bzip2 and/or libbzip2, a program and
+  library for lossless, block-sorting data compression.
+
+  Copyright (C) 1996-1998 Julian R Seward.  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions
+  are met:
+
+  1. Redistributions of source code must retain the above copyright
+     notice, this list of conditions and the following disclaimer.
+
+  2. The origin of this software must not be misrepresented; you must 
+     not claim that you wrote the original software.  If you use this 
+     software in a product, an acknowledgment in the product 
+     documentation would be appreciated but is not required.
+
+  3. Altered source versions must be plainly marked as such, and must
+     not be misrepresented as being the original software.
+
+  4. The name of the author may not be used to endorse or promote 
+     products derived from this software without specific prior written 
+     permission.
+
+  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
+  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+  GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+  Julian Seward, Guildford, Surrey, UK.
+  jseward@acm.org
+  bzip2/libbzip2 version 0.9.0c of 18 October 1998
+
+  This program is based on (at least) the work of:
+     Mike Burrows
+     David Wheeler
+     Peter Fenwick
+     Alistair Moffat
+     Radford Neal
+     Ian H. Witten
+     Robert Sedgewick
+     Jon L. Bentley
+
+  For more information on these sources, see the manual.
+--*/
+
+
+#include "bzlib_private.h"
+
+/*---------------------------------------------------*/
+#define WEIGHTOF(zz0)  ((zz0) & 0xffffff00)
+#define DEPTHOF(zz1)   ((zz1) & 0x000000ff)
+#define MYMAX(zz2,zz3) ((zz2) > (zz3) ? (zz2) : (zz3))
+
+#define ADDWEIGHTS(zw1,zw2)                           \
+   (WEIGHTOF(zw1)+WEIGHTOF(zw2)) |                    \
+   (1 + MYMAX(DEPTHOF(zw1),DEPTHOF(zw2)))
+
+#define UPHEAP(z)                                     \
+{                                                     \
+   Int32 zz, tmp;                                     \
+   zz = z; tmp = heap[zz];                            \
+   while (weight[tmp] < weight[heap[zz >> 1]]) {      \
+      heap[zz] = heap[zz >> 1];                       \
+      zz >>= 1;                                       \
+   }                                                  \
+   heap[zz] = tmp;                                    \
+}
+
+#define DOWNHEAP(z)                                   \
+{                                                     \
+   Int32 zz, yy, tmp;                                 \
+   zz = z; tmp = heap[zz];                            \
+   while (True) {                                     \
+      yy = zz << 1;                                   \
+      if (yy > nHeap) break;                          \
+      if (yy < nHeap &&                               \
+          weight[heap[yy+1]] < weight[heap[yy]])      \
+         yy++;                                        \
+      if (weight[tmp] < weight[heap[yy]]) break;      \
+      heap[zz] = heap[yy];                            \
+      zz = yy;                                        \
+   }                                                  \
+   heap[zz] = tmp;                                    \
+}
+
+
+/*---------------------------------------------------*/
+void hbMakeCodeLengths ( UChar *len, 
+                         Int32 *freq,
+                         Int32 alphaSize,
+                         Int32 maxLen )
+{
+   /*--
+      Nodes and heap entries run from 1.  Entry 0
+      for both the heap and nodes is a sentinel.
+   --*/
+   Int32 nNodes, nHeap, n1, n2, i, j, k;
+   Bool  tooLong;
+
+   Int32 heap   [ BZ_MAX_ALPHA_SIZE + 2 ];
+   Int32 weight [ BZ_MAX_ALPHA_SIZE * 2 ];
+   Int32 parent [ BZ_MAX_ALPHA_SIZE * 2 ]; 
+
+   for (i = 0; i < alphaSize; i++)
+      weight[i+1] = (freq[i] == 0 ? 1 : freq[i]) << 8;
+
+   while (True) {
+
+      nNodes = alphaSize;
+      nHeap = 0;
+
+      heap[0] = 0;
+      weight[0] = 0;
+      parent[0] = -2;
+
+      for (i = 1; i <= alphaSize; i++) {
+         parent[i] = -1;
+         nHeap++;
+         heap[nHeap] = i;
+         UPHEAP(nHeap);
+      }
+
+      AssertH( nHeap < (BZ_MAX_ALPHA_SIZE+2), 2001 );
+   
+      while (nHeap > 1) {
+         n1 = heap[1]; heap[1] = heap[nHeap]; nHeap--; DOWNHEAP(1);
+         n2 = heap[1]; heap[1] = heap[nHeap]; nHeap--; DOWNHEAP(1);
+         nNodes++;
+         parent[n1] = parent[n2] = nNodes;
+         weight[nNodes] = ADDWEIGHTS(weight[n1], weight[n2]);
+         parent[nNodes] = -1;
+         nHeap++;
+         heap[nHeap] = nNodes;
+         UPHEAP(nHeap);
+      }
+
+      AssertH( nNodes < (BZ_MAX_ALPHA_SIZE * 2), 2002 );
+
+      tooLong = False;
+      for (i = 1; i <= alphaSize; i++) {
+         j = 0;
+         k = i;
+         while (parent[k] >= 0) { k = parent[k]; j++; }
+         len[i-1] = j;
+         if (j > maxLen) tooLong = True;
+      }
+      
+      if (! tooLong) break;
+
+      for (i = 1; i < alphaSize; i++) {
+         j = weight[i] >> 8;
+         j = 1 + (j / 2);
+         weight[i] = j << 8;
+      }
+   }
+}
+
+
+/*---------------------------------------------------*/
+void hbAssignCodes ( Int32 *code,
+                     UChar *length,
+                     Int32 minLen,
+                     Int32 maxLen,
+                     Int32 alphaSize )
+{
+   Int32 n, vec, i;
+
+   vec = 0;
+   for (n = minLen; n <= maxLen; n++) {
+      for (i = 0; i < alphaSize; i++)
+         if (length[i] == n) { code[i] = vec; vec++; };
+      vec <<= 1;
+   }
+}
+
+
+/*---------------------------------------------------*/
+void hbCreateDecodeTables ( Int32 *limit,
+                            Int32 *base,
+                            Int32 *perm,
+                            UChar *length,
+                            Int32 minLen,
+                            Int32 maxLen,
+                            Int32 alphaSize )
+{
+   Int32 pp, i, j, vec;
+
+   pp = 0;
+   for (i = minLen; i <= maxLen; i++)
+      for (j = 0; j < alphaSize; j++)
+         if (length[j] == i) { perm[pp] = j; pp++; };
+
+   for (i = 0; i < BZ_MAX_CODE_LEN; i++) base[i] = 0;
+   for (i = 0; i < alphaSize; i++) base[length[i]+1]++;
+
+   for (i = 1; i < BZ_MAX_CODE_LEN; i++) base[i] += base[i-1];
+
+   for (i = 0; i < BZ_MAX_CODE_LEN; i++) limit[i] = 0;
+   vec = 0;
+
+   for (i = minLen; i <= maxLen; i++) {
+      vec += (base[i+1] - base[i]);
+      limit[i] = vec-1;
+      vec <<= 1;
+   }
+   for (i = minLen + 1; i <= maxLen; i++)
+      base[i] = ((limit[i-1] + 1) << 1) - base[i];
+}
+
+
+/*-------------------------------------------------------------*/
+/*--- end                                         huffman.c ---*/
+/*-------------------------------------------------------------*/