--- /dev/null
+#include <config.h>
+
+/*-------------------------------------------------------------*/
+/*--- 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) 1996-2002 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, Cambridge, UK.
+ jseward@acm.org
+ bzip2/libbzip2 version 1.0 of 21 March 2000
+
+ 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 BZ2_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 BZ2_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 BZ2_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 ---*/
+/*-------------------------------------------------------------*/
Code Review / kvmfornfv.git / blobdiff