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+//C- -*- C++ -*-
+//C- -------------------------------------------------------------------
+//C- DjVuLibre-3.5
+//C- Copyright (c) 2002 Leon Bottou and Yann Le Cun.
+//C- Copyright (c) 2001 AT&T
+//C-
+//C- This software is subject to, and may be distributed under, the
+//C- GNU General Public License, Version 2. The license should have
+//C- accompanied the software or you may obtain a copy of the license
+//C- from the Free Software Foundation at http://www.fsf.org .
+//C-
+//C- This program is distributed in the hope that it will be useful,
+//C- but WITHOUT ANY WARRANTY; without even the implied warranty of
+//C- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+//C- GNU General Public License for more details.
+//C-
+//C- DjVuLibre-3.5 is derived from the DjVu(r) Reference Library
+//C- distributed by Lizardtech Software. On July 19th 2002, Lizardtech
+//C- Software authorized us to replace the original DjVu(r) Reference
+//C- Library notice by the following text (see doc/lizard2002.djvu):
+//C-
+//C- ------------------------------------------------------------------
+//C- | DjVu (r) Reference Library (v. 3.5)
+//C- | Copyright (c) 1999-2001 LizardTech, Inc. All Rights Reserved.
+//C- | The DjVu Reference Library is protected by U.S. Pat. No.
+//C- | 6,058,214 and patents pending.
+//C- |
+//C- | This software is subject to, and may be distributed under, the
+//C- | GNU General Public License, Version 2. The license should have
+//C- | accompanied the software or you may obtain a copy of the license
+//C- | from the Free Software Foundation at http://www.fsf.org .
+//C- |
+//C- | The computer code originally released by LizardTech under this
+//C- | license and unmodified by other parties is deemed "the LIZARDTECH
+//C- | ORIGINAL CODE." Subject to any third party intellectual property
+//C- | claims, LizardTech grants recipient a worldwide, royalty-free,
+//C- | non-exclusive license to make, use, sell, or otherwise dispose of
+//C- | the LIZARDTECH ORIGINAL CODE or of programs derived from the
+//C- | LIZARDTECH ORIGINAL CODE in compliance with the terms of the GNU
+//C- | General Public License. This grant only confers the right to
+//C- | infringe patent claims underlying the LIZARDTECH ORIGINAL CODE to
+//C- | the extent such infringement is reasonably necessary to enable
+//C- | recipient to make, have made, practice, sell, or otherwise dispose
+//C- | of the LIZARDTECH ORIGINAL CODE (or portions thereof) and not to
+//C- | any greater extent that may be necessary to utilize further
+//C- | modifications or combinations.
+//C- |
+//C- | The LIZARDTECH ORIGINAL CODE is provided "AS IS" WITHOUT WARRANTY
+//C- | OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+//C- | TO ANY WARRANTY OF NON-INFRINGEMENT, OR ANY IMPLIED WARRANTY OF
+//C- | MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+//C- +------------------------------------------------------------------
+//
+// $Id: BSEncodeByteStream.cpp,v 1.8 2003/11/07 22:08:20 leonb Exp $
+// $Name: release_3_5_15 $
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+#if NEED_GNUG_PRAGMAS
+# pragma implementation
+#endif
+
+// - Author: Leon Bottou, 07/1998
+
+
+
+#include "BSByteStream.h"
+#include "GString.h"
+#undef BSORT_TIMER
+#ifdef BSORT_TIMER
+#include "GOS.h"
+#endif
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+
+#ifdef HAVE_NAMESPACES
+namespace DJVU {
+# ifdef NOT_DEFINED // Just to fool emacs c++ mode
+}
+#endif
+#endif
+
+
+// ========================================
+// --- Assertion
+
+#define ASSERT(expr) do{if(!(expr))G_THROW("assertion ("#expr") failed");}while(0)
+
+
+
+// ========================================
+// --- Global Definitions
+
+
+#ifdef OVERFLOW
+#undef OVERFLOW
+#endif
+// Overflow required when encoding
+static const int OVERFLOW=32;
+
+// Sorting tresholds
+static const int RANKSORT_THRESH=10;
+static const int QUICKSORT_STACK=512;
+static const int PRESORT_THRESH=10;
+static const int PRESORT_DEPTH=8;
+static const int RADIX_THRESH=32768;
+
+static const int FREQS0=100000;
+static const int FREQS1=1000000;
+
+// ========================================
+// -- Sorting Routines
+
+
+class _BSort // DJVU_CLASS
+{
+public:
+ ~_BSort();
+ _BSort(unsigned char *data, int size);
+ void run(int &markerpos);
+private:
+ // Members
+ int size;
+ unsigned char *data;
+ unsigned int *posn;
+ GPBuffer<unsigned int> gposn;
+ int *rank;
+ GPBuffer<int> grank;
+ // Helpers
+ inline int GT(int p1, int p2, int depth);
+ inline int GTD(int p1, int p2, int depth);
+ // -- final in-depth sort
+ void ranksort(int lo, int hi, int d);
+ // -- doubling sort
+ int pivot3r(int *rr, int lo, int hi);
+ void quicksort3r(int lo, int hi, int d);
+ // -- presort to depth PRESORT_DEPTH
+ unsigned char pivot3d(unsigned char *dd, int lo, int hi);
+ void quicksort3d(int lo, int hi, int d);
+ // -- radixsort
+ void radixsort16(void);
+ void radixsort8(void);
+};
+
+
+// blocksort -- the main entry point
+
+static void
+blocksort(unsigned char *data, int size, int &markerpos)
+{
+ _BSort bsort(data, size);
+ bsort.run(markerpos);
+}
+
+
+// _BSort construction
+
+_BSort::_BSort(unsigned char *xdata, int xsize)
+ : size(xsize), data(xdata), gposn(posn,xsize), grank(rank,xsize+1)
+{
+ ASSERT(size>0 && size<0x1000000);
+ rank[size] = -1;
+}
+
+_BSort::~_BSort()
+{
+}
+
+
+
+// GT -- compare suffixes using rank information
+
+inline int
+_BSort::GT(int p1, int p2, int depth)
+{
+ int r1, r2;
+ int twod = depth + depth;
+ while (1)
+ {
+ r1=rank[p1+depth]; r2=rank[p2+depth];
+ p1+=twod; p2+=twod;
+ if (r1!=r2)
+ return (r1>r2);
+ r1=rank[p1]; r2=rank[p2];
+ if (r1!=r2)
+ return (r1>r2);
+ r1=rank[p1+depth]; r2=rank[p2+depth];
+ p1+=twod; p2+=twod;
+ if (r1!=r2)
+ return (r1>r2);
+ r1=rank[p1]; r2=rank[p2];
+ if (r1!=r2)
+ return (r1>r2);
+ r1=rank[p1+depth]; r2=rank[p2+depth];
+ p1+=twod; p2+=twod;
+ if (r1!=r2)
+ return (r1>r2);
+ r1=rank[p1]; r2=rank[p2];
+ if (r1!=r2)
+ return (r1>r2);
+ r1=rank[p1+depth]; r2=rank[p2+depth];
+ p1+=twod; p2+=twod;
+ if (r1!=r2)
+ return (r1>r2);
+ r1=rank[p1]; r2=rank[p2];
+ if (r1!=r2)
+ return (r1>r2);
+ };
+}
+
+
+// _BSort::ranksort --
+// -- a simple insertion sort based on GT
+
+void
+_BSort::ranksort(int lo, int hi, int depth)
+{
+ int i,j;
+ for (i=lo+1; i<=hi; i++)
+ {
+ int tmp = posn[i];
+ for(j=i-1; j>=lo && GT(posn[j], tmp, depth); j--)
+ posn[j+1] = posn[j];
+ posn[j+1] = tmp;
+ }
+ for(i=lo;i<=hi;i++)
+ rank[posn[i]]=i;
+}
+
+// pivot -- return suitable pivot
+
+inline int
+_BSort::pivot3r(int *rr, int lo, int hi)
+{
+ int c1, c2, c3;
+ if (hi-lo > 256)
+ {
+ c1 = pivot3r(rr, lo, (6*lo+2*hi)/8);
+ c2 = pivot3r(rr, (5*lo+3*hi)/8, (3*lo+5*hi)/8);
+ c3 = pivot3r(rr, (2*lo+6*hi)/8, hi);
+ }
+ else
+ {
+ c1 = rr[posn[lo]];
+ c2 = rr[posn[(lo+hi)/2]];
+ c3 = rr[posn[hi]];
+ }
+ // Extract median
+ if (c1>c3)
+ { int tmp=c1; c1=c3; c3=tmp; }
+ if (c2<=c1)
+ return c1;
+ else if (c2>=c3)
+ return c3;
+ else
+ return c2;
+}
+
+
+// _BSort::quicksort3r -- Three way quicksort algorithm
+// Sort suffixes based on rank at pos+depth
+// The algorithm breaks into ranksort when size is
+// smaller than RANKSORT_THRESH
+
+static inline int
+mini(int a, int b)
+{
+ return (a<=b) ? a : b;
+}
+
+static inline void
+vswap(int i, int j, int n, unsigned int *x)
+{
+ while (n-- > 0)
+ { int tmp = x[i]; x[i++]=x[j]; x[j++]=tmp; }
+}
+
+void
+_BSort::quicksort3r(int lo, int hi, int depth)
+{
+ /* Initialize stack */
+ int slo[QUICKSORT_STACK];
+ int shi[QUICKSORT_STACK];
+ int sp = 1;
+ slo[0] = lo;
+ shi[0] = hi;
+ // Recursion elimination loop
+ while (--sp>=0)
+ {
+ lo = slo[sp];
+ hi = shi[sp];
+ // Test for insertion sort
+ if (hi-lo<RANKSORT_THRESH)
+ {
+ ranksort(lo, hi, depth);
+ }
+ else
+ {
+ int tmp;
+ int *rr=rank+depth;
+ int med = pivot3r(rr,lo,hi);
+ // -- positions are organized as follows:
+ // [lo..l1[ [l1..l[ ]h..h1] ]h1..hi]
+ // = < > =
+ int l1 = lo;
+ int h1 = hi;
+ while (rr[posn[l1]]==med && l1<h1) { l1++; }
+ while (rr[posn[h1]]==med && l1<h1) { h1--; }
+ int l = l1;
+ int h = h1;
+ // -- partition set
+ for (;;)
+ {
+ while (l<=h)
+ {
+ int c = rr[posn[l]] - med;
+ if (c > 0) break;
+ if (c == 0) { tmp=posn[l]; posn[l]=posn[l1]; posn[l1++]=tmp; }
+ l++;
+ }
+ while (l<=h)
+ {
+ int c = rr[posn[h]] - med;
+ if (c < 0) break;
+ if (c == 0) { tmp=posn[h]; posn[h]=posn[h1]; posn[h1--]=tmp; }
+ h--;
+ }
+ if (l>h) break;
+ tmp=posn[l]; posn[l]=posn[h]; posn[h]=tmp;
+ }
+ // -- reorganize as follows
+ // [lo..l1[ [l1..h1] ]h1..hi]
+ // < = >
+ tmp = mini(l1-lo, l-l1);
+ vswap(lo, l-tmp, tmp, posn);
+ l1 = lo + (l-l1);
+ tmp = mini(hi-h1, h1-h);
+ vswap(hi-tmp+1, h+1, tmp, posn);
+ h1 = hi - (h1-h);
+ // -- process segments
+ ASSERT(sp+2<QUICKSORT_STACK);
+ // ----- middle segment (=?) [l1, h1]
+ for(int i=l1;i<=h1;i++)
+ rank[posn[i]] = h1;
+ // ----- lower segment (<) [lo, l1[
+ if (l1 > lo)
+ {
+ for(int i=lo;i<l1;i++)
+ rank[posn[i]]=l1-1;
+ slo[sp]=lo;
+ shi[sp]=l1-1;
+ if (slo[sp] < shi[sp])
+ sp++;
+ }
+ // ----- upper segment (>) ]h1, hi]
+ if (h1 < hi)
+ {
+ slo[sp]=h1+1;
+ shi[sp]=hi;
+ if (slo[sp] < shi[sp])
+ sp++;
+ }
+ }
+ }
+}
+
+
+
+
+
+
+// GTD -- compare suffixes using data information
+// (up to depth PRESORT_DEPTH)
+
+inline int
+_BSort::GTD(int p1, int p2, int depth)
+{
+ unsigned char c1, c2;
+ p1+=depth; p2+=depth;
+ while (depth < PRESORT_DEPTH)
+ {
+ // Perform two
+ c1=data[p1]; c2=data[p2];
+ if (c1!=c2)
+ return (c1>c2);
+ c1=data[p1+1]; c2=data[p2+1];
+ p1+=2; p2+=2; depth+=2;
+ if (c1!=c2)
+ return (c1>c2);
+ }
+ if (p1<size && p2<size)
+ return 0;
+ return (p1<p2);
+}
+
+// pivot3d -- return suitable pivot
+
+inline unsigned char
+_BSort::pivot3d(unsigned char *rr, int lo, int hi)
+{
+ unsigned char c1, c2, c3;
+ if (hi-lo > 256)
+ {
+ c1 = pivot3d(rr, lo, (6*lo+2*hi)/8);
+ c2 = pivot3d(rr, (5*lo+3*hi)/8, (3*lo+5*hi)/8);
+ c3 = pivot3d(rr, (2*lo+6*hi)/8, hi);
+ }
+ else
+ {
+ c1 = rr[posn[lo]];
+ c2 = rr[posn[(lo+hi)/2]];
+ c3 = rr[posn[hi]];
+ }
+ // Extract median
+ if (c1>c3)
+ { int tmp=c1; c1=c3; c3=tmp; }
+ if (c2<=c1)
+ return c1;
+ else if (c2>=c3)
+ return c3;
+ else
+ return c2;
+}
+
+
+// _BSort::quicksort3d -- Three way quicksort algorithm
+// Sort suffixes based on strings until reaching
+// depth rank at pos+depth
+// The algorithm breaks into ranksort when size is
+// smaller than PRESORT_THRESH
+
+void
+_BSort::quicksort3d(int lo, int hi, int depth)
+{
+ /* Initialize stack */
+ int slo[QUICKSORT_STACK];
+ int shi[QUICKSORT_STACK];
+ int sd[QUICKSORT_STACK];
+ int sp = 1;
+ slo[0] = lo;
+ shi[0] = hi;
+ sd[0] = depth;
+ // Recursion elimination loop
+ while (--sp>=0)
+ {
+ lo = slo[sp];
+ hi = shi[sp];
+ depth = sd[sp];
+ // Test for insertion sort
+ if (depth >= PRESORT_DEPTH)
+ {
+ for (int i=lo; i<=hi; i++)
+ rank[posn[i]] = hi;
+ }
+ else if (hi-lo<PRESORT_THRESH)
+ {
+ int i,j;
+ for (i=lo+1; i<=hi; i++)
+ {
+ int tmp = posn[i];
+ for(j=i-1; j>=lo && GTD(posn[j], tmp, depth); j--)
+ posn[j+1] = posn[j];
+ posn[j+1] = tmp;
+ }
+ for(i=hi;i>=lo;i=j)
+ {
+ int tmp = posn[i];
+ rank[tmp] = i;
+ for (j=i-1; j>=lo && !GTD(tmp,posn[j],depth); j--)
+ rank[posn[j]] = i;
+ }
+ }
+ else
+ {
+ int tmp;
+ unsigned char *dd=data+depth;
+ unsigned char med = pivot3d(dd,lo,hi);
+ // -- positions are organized as follows:
+ // [lo..l1[ [l1..l[ ]h..h1] ]h1..hi]
+ // = < > =
+ int l1 = lo;
+ int h1 = hi;
+ while (dd[posn[l1]]==med && l1<h1) { l1++; }
+ while (dd[posn[h1]]==med && l1<h1) { h1--; }
+ int l = l1;
+ int h = h1;
+ // -- partition set
+ for (;;)
+ {
+ while (l<=h)
+ {
+ int c = (int)dd[posn[l]] - (int)med;
+ if (c > 0) break;
+ if (c == 0) { tmp=posn[l]; posn[l]=posn[l1]; posn[l1++]=tmp; }
+ l++;
+ }
+ while (l<=h)
+ {
+ int c = (int)dd[posn[h]] - (int)med;
+ if (c < 0) break;
+ if (c == 0) { tmp=posn[h]; posn[h]=posn[h1]; posn[h1--]=tmp; }
+ h--;
+ }
+ if (l>h) break;
+ tmp=posn[l]; posn[l]=posn[h]; posn[h]=tmp;
+ }
+ // -- reorganize as follows
+ // [lo..l1[ [l1..h1] ]h1..hi]
+ // < = >
+ tmp = mini(l1-lo, l-l1);
+ vswap(lo, l-tmp, tmp, posn);
+ l1 = lo + (l-l1);
+ tmp = mini(hi-h1, h1-h);
+ vswap(hi-tmp+1, h+1, tmp, posn);
+ h1 = hi - (h1-h);
+ // -- process segments
+ ASSERT(sp+3<QUICKSORT_STACK);
+ // ----- middle segment (=?) [l1, h1]
+ l = l1; h = h1;
+ if (med==0) // special case for marker [slow]
+ for (int i=l; i<=h; i++)
+ if ((int)posn[i]+depth == size-1)
+ {
+ tmp=posn[i]; posn[i]=posn[l]; posn[l]=tmp;
+ rank[tmp]=l++; break;
+ }
+ if (l<h)
+ { slo[sp] = l; shi[sp] = h; sd[sp++] = depth+1; }
+ else if (l==h)
+ { rank[posn[h]] = h; }
+ // ----- lower segment (<) [lo, l1[
+ l = lo;
+ h = l1-1;
+ if (l<h)
+ { slo[sp] = l; shi[sp] = h; sd[sp++] = depth; }
+ else if (l==h)
+ { rank[posn[h]] = h; }
+ // ----- upper segment (>) ]h1, hi]
+ l = h1+1;
+ h = hi;
+ if (l<h)
+ { slo[sp] = l; shi[sp] = h; sd[sp++] = depth; }
+ else if (l==h)
+ { rank[posn[h]] = h; }
+ }
+ }
+}
+
+
+
+
+// _BSort::radixsort8 -- 8 bit radix sort
+
+void
+_BSort::radixsort8(void)
+{
+ int i;
+ // Initialize frequency array
+ int lo[256], hi[256];
+ for (i=0; i<256; i++)
+ hi[i] = lo[i] = 0;
+ // Count occurences
+ for (i=0; i<size-1; i++)
+ hi[data[i]] ++;
+ // Compute positions (lo)
+ int last = 1;
+ for (i=0; i<256; i++)
+ {
+ lo[i] = last;
+ hi[i] = last + hi[i] - 1;
+ last = hi[i] + 1;
+ }
+ for (i=0; i<size-1; i++)
+ {
+ posn[ lo[data[i]]++ ] = i;
+ rank[ i ] = hi[data[i]];
+ }
+ // Process marker "$"
+ posn[0] = size-1;
+ rank[size-1] = 0;
+ // Extra element
+ rank[size] = -1;
+}
+
+
+// _BSort::radixsort16 -- 16 bit radix sort
+
+void
+_BSort::radixsort16(void)
+{
+ int i;
+ // Initialize frequency array
+ int *ftab;
+ GPBuffer<int> gftab(ftab,65536);
+ for (i=0; i<65536; i++)
+ ftab[i] = 0;
+ // Count occurences
+ unsigned char c1 = data[0];
+ for (i=0; i<size-1; i++)
+ {
+ unsigned char c2 = data[i+1];
+ ftab[(c1<<8)|c2] ++;
+ c1 = c2;
+ }
+ // Generate upper position
+ for (i=1;i<65536;i++)
+ ftab[i] += ftab[i-1];
+ // Fill rank array with upper bound
+ c1 = data[0];
+ for (i=0; i<size-2; i++)
+ {
+ unsigned char c2 = data[i+1];
+ rank[i] = ftab[(c1<<8)|c2];
+ c1 = c2;
+ }
+ // Fill posn array (backwards)
+ c1 = data[size-2];
+ for (i=size-3; i>=0; i--)
+ {
+ unsigned char c2 = data[i];
+ posn[ ftab[(c2<<8)|c1]-- ] = i;
+ c1 = c2;
+ }
+ // Fixup marker stuff
+ ASSERT(data[size-1]==0);
+ c1 = data[size-2];
+ posn[0] = size-1;
+ posn[ ftab[(c1<<8)] ] = size-2;
+ rank[size-1] = 0;
+ rank[size-2] = ftab[(c1<<8)];
+ // Extra element
+ rank[size] = -1;
+}
+
+
+
+// _BSort::run -- main sort loop
+
+void
+_BSort::run(int &markerpos)
+{
+ int lo, hi;
+ ASSERT(size>0);
+ ASSERT(data[size-1]==0);
+#ifdef BSORT_TIMER
+ long start = GOS::ticks();
+#endif
+ // Step 1: Radix sort
+ int depth = 0;
+ if (size > RADIX_THRESH)
+ {
+ radixsort16();
+ depth=2;
+ }
+ else
+ {
+ radixsort8();
+ depth=1;
+ }
+ // Step 2: Perform presort to depth PRESORT_DEPTH
+ for (lo=0; lo<size; lo++)
+ {
+ hi = rank[posn[lo]];
+ if (lo < hi)
+ quicksort3d(lo, hi, depth);
+ lo = hi;
+ }
+ depth = PRESORT_DEPTH;
+#ifdef BSORT_TIMER
+ long middle = GOS::ticks();
+#endif
+ // Step 3: Perform rank doubling
+ int again = 1;
+ while (again)
+ {
+ again = 0;
+ int sorted_lo = 0;
+ for (lo=0; lo<size; lo++)
+ {
+ hi = rank[posn[lo]&0xffffff];
+ if (lo == hi)
+ {
+ lo += (posn[lo]>>24) & 0xff;
+ }
+ else
+ {
+ if (hi-lo < RANKSORT_THRESH)
+ {
+ ranksort(lo, hi, depth);
+ }
+ else
+ {
+ again += 1;
+ while (sorted_lo < lo-1)
+ {
+ int step = mini(255, lo-1-sorted_lo);
+ posn[sorted_lo] = (posn[sorted_lo]&0xffffff) | (step<<24);
+ sorted_lo += step+1;
+ }
+ quicksort3r(lo, hi, depth);
+ sorted_lo = hi + 1;
+ }
+ lo = hi;
+ }
+ }
+ // Finish threading
+ while (sorted_lo < lo-1)
+ {
+ int step = mini(255, lo-1-sorted_lo);
+ posn[sorted_lo] = (posn[sorted_lo]&0xffffff) | (step<<24);
+ sorted_lo += step+1;
+ }
+ // Double depth
+ depth += depth;
+ }
+ // Step 4: Permute data
+ int i;
+ markerpos = -1;
+ for (i=0; i<size; i++)
+ rank[i] = data[i];
+ for (i=0; i<size; i++)
+ {
+ int j = posn[i] & 0xffffff;
+ if (j>0)
+ {
+ data[i] = rank[j-1];
+ }
+ else
+ {
+ data[i] = 0;
+ markerpos = i;
+ }
+ }
+ ASSERT(markerpos>=0 && markerpos<size);
+#ifdef BSORT_TIMER
+ long end = GOS::ticks();
+ DjVuPrintErrorUTF8("Sorting time: %d bytes in %ld + %ld = %ld ms\n",
+ size-1, middle-start, end-middle, end-start);
+#endif
+}
+
+
+// ========================================
+// -- Encoding
+
+static void
+encode_raw(ZPCodec &zp, int bits, int x)
+{
+ int n = 1;
+ int m = (1<<bits);
+ while (n < m)
+ {
+ x = (x & (m-1)) << 1;
+ int b = (x >> bits);
+ zp.encoder(b);
+ n = (n<<1) | b;
+ }
+}
+
+static inline void
+encode_binary(ZPCodec &zp, BitContext *ctx, int bits, int x)
+{
+ // Require 2^bits-1 contexts
+ int n = 1;
+ int m = (1<<bits);
+ ctx = ctx - 1;
+ while (n < m)
+ {
+ x = (x & (m-1)) << 1;
+ int b = (x >> bits);
+ zp.encoder(b, ctx[n]);
+ n = (n<<1) | b;
+ }
+}
+
+class BSByteStream::Encode : public BSByteStream
+{
+public:
+ /** Creates a Static object for allocating the memory area of
+ length #sz# starting at address #buffer#. */
+ Encode(GP<ByteStream> bs);
+ ~Encode();
+ void init(const int encoding);
+ // Virtual functions
+ virtual size_t write(const void *buffer, size_t sz);
+ virtual void flush(void);
+protected:
+ unsigned int encode(void);
+};
+
+unsigned int
+BSByteStream::Encode::encode()
+{
+ /////////////////////////////////
+ //////////// Block Sort Tranform
+
+ int markerpos = size-1;
+ blocksort(data,size,markerpos);
+
+ /////////////////////////////////
+ //////////// Encode Output Stream
+
+ // Header
+ ZPCodec &zp=*gzp;
+ encode_raw(zp, 24, size);
+ // Determine and Encode Estimation Speed
+ int fshift = 0;
+ if (size < FREQS0)
+ { fshift=0; zp.encoder(0); }
+ else if (size < FREQS1)
+ { fshift = 1; zp.encoder(1); zp.encoder(0); }
+ else
+ { fshift = 2; zp.encoder(1); zp.encoder(1); }
+ // MTF
+ unsigned char mtf[256];
+ unsigned char rmtf[256];
+ unsigned int freq[FREQMAX];
+ int m = 0;
+ for (m=0; m<256; m++)
+ mtf[m] = m;
+ for (m=0; m<256; m++)
+ rmtf[mtf[m]] = m;
+ int fadd = 4;
+ for (m=0; m<FREQMAX; m++)
+ freq[m] = 0;
+ // Encode
+ int i;
+ int mtfno = 3;
+ for (i=0; i<size; i++)
+ {
+ // Get MTF data
+ int c = data[i];
+ int ctxid = CTXIDS-1;
+ if (ctxid>mtfno) ctxid=mtfno;
+ mtfno = rmtf[c];
+ if (i==markerpos)
+ mtfno = 256;
+ // Encode using ZPCoder
+ int b;
+ BitContext *cx = ctx;
+ b = (mtfno==0);
+ zp.encoder(b, cx[ctxid]);
+ if (b) goto rotate; cx+=CTXIDS;
+ b = (mtfno==1);
+ zp.encoder(b, cx[ctxid]);
+ if (b) goto rotate; cx+=CTXIDS;
+ b = (mtfno<4);
+ zp.encoder(b, cx[0]);
+ if (b) { encode_binary(zp,cx+1,1,mtfno-2); goto rotate; }
+ cx+=1+1;
+ b = (mtfno<8);
+ zp.encoder(b, cx[0]);
+ if (b) { encode_binary(zp,cx+1,2,mtfno-4); goto rotate; }
+ cx+=1+3;
+ b = (mtfno<16);
+ zp.encoder(b, cx[0]);
+ if (b) { encode_binary(zp,cx+1,3,mtfno-8); goto rotate; }
+ cx+=1+7;
+ b = (mtfno<32);
+ zp.encoder(b, cx[0]);
+ if (b) { encode_binary(zp,cx+1,4,mtfno-16); goto rotate; }
+ cx+=1+15;
+ b = (mtfno<64);
+ zp.encoder(b, cx[0]);
+ if (b) { encode_binary(zp,cx+1,5,mtfno-32); goto rotate; }
+ cx+=1+31;
+ b = (mtfno<128);
+ zp.encoder(b, cx[0]);
+ if (b) { encode_binary(zp,cx+1,6,mtfno-64); goto rotate; }
+ cx+=1+63;
+ b = (mtfno<256);
+ zp.encoder(b, cx[0]);
+ if (b) { encode_binary(zp,cx+1,7,mtfno-128); goto rotate; }
+ continue;
+ // Rotate MTF according to empirical frequencies (new!)
+ rotate:
+ // Adjust frequencies for overflow
+ fadd = fadd + (fadd>>fshift);
+ if (fadd > 0x10000000)
+ {
+ fadd = fadd>>24;
+ freq[0] >>= 24;
+ freq[1] >>= 24;
+ freq[2] >>= 24;
+ freq[3] >>= 24;
+ for (int k=4; k<FREQMAX; k++)
+ freq[k] = freq[k]>>24;
+ }
+ // Relocate new char according to new freq
+ unsigned int fc = fadd;
+ if (mtfno < FREQMAX)
+ fc += freq[mtfno];
+ int k;
+ for (k=mtfno; k>=FREQMAX; k--)
+ {
+ mtf[k] = mtf[k-1];
+ rmtf[mtf[k]] = k;
+ }
+ for (; k>0 && fc>=freq[k-1]; k--)
+ {
+ mtf[k] = mtf[k-1];
+ freq[k] = freq[k-1];
+ rmtf[mtf[k]] = k;
+ }
+ mtf[k] = c;
+ freq[k] = fc;
+ rmtf[mtf[k]] = k;
+ }
+ // Terminate
+ return 0;
+}
+
+// ========================================
+// --- Construction
+
+BSByteStream::Encode::Encode(GP<ByteStream> xbs)
+: BSByteStream(xbs) {}
+
+void
+BSByteStream::Encode::init(const int xencoding)
+{
+ gzp=ZPCodec::create(gbs,true,true);
+ const int encoding=(xencoding<MINBLOCK)?MINBLOCK:xencoding;
+ if (encoding > MAXBLOCK)
+ G_THROW( ERR_MSG("ByteStream.blocksize") "\t" + GUTF8String(MAXBLOCK) );
+ // Record block size
+ blocksize = encoding * 1024;
+ // Initialize context array
+}
+
+BSByteStream::Encode::~Encode()
+{
+ // Flush
+ flush();
+ // Encode EOF marker
+ encode_raw(*gzp, 24, 0);
+ // Free allocated memory
+}
+
+GP<ByteStream>
+BSByteStream::create(GP<ByteStream> xbs,const int blocksize)
+{
+ BSByteStream::Encode *rbs=new BSByteStream::Encode(xbs);
+ GP<ByteStream> retval=rbs;
+ rbs->init(blocksize);
+ return retval;
+}
+
+// ========================================
+// -- ByteStream interface
+
+void
+BSByteStream::Encode::flush()
+{
+ if (bptr>0)
+ {
+ ASSERT(bptr<(int)blocksize);
+ memset(data+bptr, 0, OVERFLOW);
+ size = bptr+1;
+ encode();
+ }
+ size = bptr = 0;
+}
+
+size_t
+BSByteStream::Encode::write(const void *buffer, size_t sz)
+{
+ // Trivial checks
+ if (sz == 0)
+ return 0;
+ // Loop
+ int copied = 0;
+ while (sz > 0)
+ {
+ // Initialize
+ if (!data)
+ {
+ bptr = 0;
+ gdata.resize(blocksize+OVERFLOW);
+ }
+ // Compute remaining
+ int bytes = blocksize - 1 - bptr;
+ if (bytes > (int)sz)
+ bytes = sz;
+ // Store date (todo: rle)
+ memcpy(data+bptr, buffer, bytes);
+ buffer = (void*)((char*)buffer + bytes);
+ bptr += bytes;
+ sz -= bytes;
+ copied += bytes;
+ offset += bytes;
+ // Flush when needed
+ if (bptr + 1 >= (int)blocksize)
+ flush();
+ }
+ // return
+ return copied;
+}
+
+
+#ifdef HAVE_NAMESPACES
+}
+# ifndef NOT_USING_DJVU_NAMESPACE
+using namespace DJVU;
+# endif
+#endif
generated by cgit v1.2.1 (git 2.18.0) at 2024-11-28 13:53:23 +0000