| #include <config.h> | |
| #ifdef CONFIG_BZIP2 | |
| /*-------------------------------------------------------------*/ | |
| /*--- 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 ---*/ | |
| /*-------------------------------------------------------------*/ | |
| #endif /* CONFIG_BZIP2 */ |