text: /*-
   * Copyright 2003-2005 Colin Percival
   * All rights reserved
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted providing 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. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * 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.
  */
  
  #include "bsdiff.h"
  #include "../shared.h"
  
  static void split(off_t *I,off_t *V,off_t start,off_t len,off_t h)
  {
  	off_t i, j, k, x, tmp, jj, kk;
  
  	if(len < 16) 
  	{
  		for(k=start; k<start+len; k+=j) 
  		{
  			j=1;
  			x=V[I[k]+h];
  			for(i=1; k+i<start+len; i++) 
  			{
  				if(V[I[k+i]+h] < x) 
  				{
  					x=V[I[k+i]+h];
  					j=0;
  				}
  				if(V[I[k+i]+h] == x) 
  				{
  					tmp=I[k+j];
  					I[k+j]=I[k+i];
  					I[k+i]=tmp;
  					j++;
  				}
  			}
  			for(i=0; i<j; i++) 
  				V[I[k+i]]=k+j-1;
  			if(j == 1) 
  				I[k]=-1;
  		}
  		return;
  	}
  
  	x=V[I[start+len/2]+h];
  	jj=0;
  	kk=0;
  	for(i=start; i<start+len; i++) 
  	{
  		if(V[I[i]+h]<x) 
  			jj++;
  		if(V[I[i]+h]==x) 
  			kk++;
  	}
  	jj+=start;
  	kk+=jj;
  
  	i=start;
  	j=0;
  	k=0;
  	while(i < jj) 
  	{
  		if(V[I[i]+h] < x) 
  		{
  			i++;
  		} 
  		else if(V[I[i]+h] == x) 
  		{
  			tmp=I[i];
  			I[i]=I[jj+j];
  			I[jj+j]=tmp;
  
  			j++;
  		} 
  		else 
  		{
  			tmp=I[i];
  			I[i]=I[kk+k];
  			I[kk+k]=tmp;
  
  			k++;
  		}
  	}
  
  	while(jj+j < kk) 
  	{
  		if(V[I[jj+j]+h] == x) 
  			j++;
  		else 
  		{
  			tmp=I[jj+j];I[jj+j]=I[kk+k];I[kk+k]=tmp;
  			k++;
  		}
  	}
  
  	if(jj > start) 
  		split(I, V, start, jj-start, h);
  
  	for(i=0; i<kk-jj; i++) 
  		V[I[jj+i]] = kk-1;
  
  	if(jj == kk-1) 
  		I[jj] = -1;
  
  	if(start+len > kk) 
  		split(I, V, kk, start+len-kk, h);
  }
  
  static void qsufsort(off_t *I,off_t *V,u_char *old,off_t oldsize)
  {
  	off_t buckets[256];
  	off_t i,h,len;
  
  	for(i=0;i<256;i++) buckets[i] = 0;
  	for(i=0;i<oldsize;i++) buckets[old[i]]++;
  	for(i=1;i<256;i++) buckets[i]+=buckets[i-1];
  	for(i=255;i>0;i--) buckets[i]=buckets[i-1];
  	buckets[0] = 0;
  
  	for(i=0;i<oldsize;i++) I[++buckets[old[i]]]=i;
  	I[0] = oldsize;
  	for(i=0;i<oldsize;i++) V[i]=buckets[old[i]];
  	V[oldsize] = 0;
  	for(i=1;i<256;i++) if(buckets[i]==buckets[i-1]+1) I[buckets[i]]=-1;
  	I[0] = -1;
  
  	for(h=1;I[0]!=-(oldsize+1);h+=h) 
  	{
  		len=0;
  		for(i=0;i<oldsize+1;) 
  		{
  			if(I[i]<0) 
  			{
  				len-=I[i];
  				i-=I[i];
  			} 
  			else 
  			{
  				if(len) 
  					I[i-len]=-len;
  				
  				len=V[I[i]]+1-i;
  				split(I,V,i,len,h);
  				i+=len;
  				len=0;
  			}
  		}
  
  		if(len) 
  			I[i-len] = -len;
  	}
  
  	for(i=0; i<oldsize+1; i++) 
  		I[V[i]]=i;
  }
  
  static off_t matchlen(u_char *old,off_t oldsize,u_char *new,off_t newsize)
  {
  	off_t i;
  
  	for(i=0;(i<oldsize)&&(i<newsize);i++)
  		if(old[i]!=new[i]) 
  			break;
  
  	return i;
  }
  
  static off_t search(off_t *I,u_char *old,off_t oldsize, u_char *new,off_t newsize,off_t st,off_t en,off_t *pos)
  {
  	off_t x, y;
  
  	if(en-st < 2) 
  	{
  		x=matchlen(old+I[st],oldsize-I[st],new,newsize);
  		y=matchlen(old+I[en],oldsize-I[en],new,newsize);
  
  		if(x>y) 
  		{
  			*pos=I[st];
  			return x;
  		} 
  		else 
  		{
  			*pos=I[en];
  			return y;
  		}
  	}
  
  	x=st+(en-st)/2;
  	if(memcmp(old+I[x], new, (((oldsize-I[x])<(newsize)) ? (oldsize-I[x]) : (newsize))) < 0) 
  		return search(I, old, oldsize, new, newsize,x, en, pos);
  	else 
  		return search(I, old, oldsize, new, newsize, st, x, pos);
  }
  
  static void offtout(off_t x,u_char *buf)
  {
  	off_t y;
  
  	if(x<0) 
  		y=-x; 
  	else 
  		y=x;
  
  	buf[0]=y&0xff;y-=buf[0];
  	y=y>>8;buf[1]=y&0xff;y-=buf[1];
  	y=y>>8;buf[2]=y&0xff;y-=buf[2];
  	y=y>>8;buf[3]=y&0xff;y-=buf[3];
  	y=y>>8;buf[4]=y&0xff;y-=buf[4];
  	y=y>>8;buf[5]=y&0xff;y-=buf[5];
  	y=y>>8;buf[6]=y&0xff;y-=buf[6];
  	y=y>>8;buf[7]=y&0xff;
  
  	if(x < 0) 
  		buf[7]|= 0x80;
  }
  
  int bsdiff(const char* error, const char* oldfile, const char* newfile, const char* patchfile, void* progressWorker, void(*callback)(off_t, off_t, void*)) 
  {
  	int fd;
  	u_char *old,*new;
  	off_t oldsize,newsize;
  	off_t *I,*V;
  	off_t scan,pos,len;
  	off_t lastscan,lastpos,lastoffset;
  	off_t oldscore,scsc;
  	off_t s,Sf,lenf,Sb,lenb;
  	off_t overlap,Ss,lens;
  	off_t i;
  	off_t dblen,eblen;
  	u_char *db,*eb;
  	u_char buf[24];
  	t_header header;
  	FILE * pf;
  	BZFILE * pfbz2;
  	int bz2err;
  
  	/* Allocate oldsize+1 bytes instead of oldsize bytes to ensure
  		that we never try to malloc(0) and get a NULL pointer */
  	if(((fd=open(oldfile,OPEN_FLAGS,0)) < 0) ||
  		((oldsize=lseek(fd,0,SEEK_END))==-1) ||
  		((old=malloc(oldsize+1))==NULL) ||
  		(lseek(fd,0,SEEK_SET)!=0) ||
  		(read(fd,old,oldsize)!=oldsize) ||
  		(close(fd)==-1)) 
  	{
  			sprintf((char*)error, "\"%s\" %s", oldfile, strerror(errno));
  			return -1;
  	}
  
  	if(((I=malloc((oldsize+1)*sizeof(off_t)))==NULL) ||
  		((V=malloc((oldsize+1)*sizeof(off_t)))==NULL)) 
  	{
  		sprintf((char*)error, "%s", strerror(errno));
  		return -1;
  	}
  	
  	qsufsort(I,V,old,oldsize);
  
  	free(V);
  	
  	/* Allocate newsize+1 bytes instead of newsize bytes to ensure
  		that we never try to malloc(0) and get a NULL pointer */
  	if(((fd=open(newfile,OPEN_FLAGS,0))<0) ||
  		((newsize=lseek(fd,0,SEEK_END))==-1) ||
  		((new=malloc(newsize+1))==NULL) ||
  		(lseek(fd,0,SEEK_SET)!=0) ||
  		(read(fd,new,newsize)!=newsize) ||
  		(close(fd)==-1)) 
  	{
  			sprintf((char*)error, "\"%s\" %s", newfile, strerror(errno));
  			return -1;
  	}
  	
  	if(((db=malloc(newsize+1))==NULL) || ((eb=malloc(newsize+1))==NULL)) 
  		err(1,NULL);
  	
  	dblen=0;
  	eblen=0;
  		
  	/* Create the patch file */
  	if((pf = fopen(patchfile, FOPEN_WRITE_FLAGS)) == NULL) 
  	{
  		sprintf((char*)error, "\"%s\" %s", patchfile, strerror(errno));
  		return -1;
  	}	
  	
  	/* Header is
  		0	8	 "BSDIFF40"
  		8	8	length of bzip2ed ctrl block
  		16	8	length of bzip2ed diff block
  		24	8	length of new file */
  	/* File is
  		0	32	Header
  		32	??	Bzip2ed ctrl block
  		??	??	Bzip2ed diff block
  		??	??	Bzip2ed extra block */
  	memcpy(header.magic,"BSDIFF40",8);
  	offtout(0, (u_char*)&header.bzctrllen);
  	offtout(0, (u_char*)&header.bzdatalen);
  	offtout(newsize, (u_char*)&header.newsize);
  	if(fwrite(&header, 32, 1, pf) != 1) 
  	{
  		sprintf((char*)error, "\"%s\" %s", patchfile, strerror(errno));
  		return -1;
  	}		
  
  	/* Compute the differences, writing ctrl as we go */
  	if((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL) 
  	{
  		sprintf((char*)error, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
  		return -1;
  	}	
  	
  	scan=0;
  	len=0;
  	lastscan=0;
  	lastpos=0;
  	lastoffset=0;
  
  	while(scan<newsize) 
  	{
  		if(callback)
  			callback(scan, newsize, progressWorker);
  		oldscore=0;
  
  		for(scsc=scan+=len;scan<newsize;scan++) 
  		{
  			len=search(I,old,oldsize,new+scan,newsize-scan,
  					0,oldsize,&pos);
  
  			for(;scsc<scan+len;scsc++)
  			if((scsc+lastoffset<oldsize) && (old[scsc+lastoffset] == new[scsc]))
  				oldscore++;
  
  			if(((len==oldscore) && (len!=0)) || (len>oldscore+8)) 
  				break;
  
  			if((scan+lastoffset<oldsize) && (old[scan+lastoffset] == new[scan]))
  				oldscore--;
  		}
  
  		if((len!=oldscore) || (scan==newsize)) 
  		{
  			s=0;
  			Sf=0;
  			lenf=0;
  
  			for(i=0;(lastscan+i<scan)&&(lastpos+i<oldsize);) 
  			{
  				if(old[lastpos+i]==new[lastscan+i]) s++;
  				i++;
  				if(s*2-i>Sf*2-lenf) { Sf=s; lenf=i; }
  			}
  
  			lenb=0;
  			if(scan<newsize) 
  			{
  				s=0;Sb=0;
  				for(i=1;(scan>=lastscan+i)&&(pos>=i);i++) 
  				{
  					if(old[pos-i]==new[scan-i]) 
  						s++;
  					if(s*2-i>Sb*2-lenb) 
  					{ 
  						Sb=s; 
  						lenb=i; 
  					}
  				}
  			}
  
  			if(lastscan+lenf>scan-lenb) 
  			{
  				overlap=(lastscan+lenf)-(scan-lenb);
  				s=0;
  				Ss=0;
  				lens=0;
  				for(i=0;i<overlap;i++) 
  				{
  					if(new[lastscan+lenf-overlap+i] == old[lastpos+lenf-overlap+i]) 
  					s++;
  
  					if(new[scan-lenb+i] == old[pos-lenb+i]) 
  						s--;
  
  					if(s>Ss) 
  					{ 
  						Ss=s; 
  						lens=i+1; 
  					}
  				}
  
  				lenf+=lens-overlap;
  				lenb-=lens;
  			}
  
  			for(i=0;i<lenf;i++)
  				db[dblen+i]=new[lastscan+i]-old[lastpos+i];
  			if ((scan-lenb)-(lastscan+lenf) > 0)
  				memcpy(&eb[eblen], &new[lastscan+lenf], (scan-lenb)-(lastscan+lenf));
  
  			dblen+=lenf;
  			eblen+=(scan-lenb)-(lastscan+lenf);
  
  			offtout(lenf,&buf[0]);
  			offtout((scan-lenb)-(lastscan+lenf),&buf[8]);
  			offtout((pos-lenb)-(lastpos+lenf),&buf[16]);
  			BZ2_bzWrite(&bz2err, pfbz2, buf, 24);
  			if (bz2err != BZ_OK) 
  			{
  				sprintf((char*)error, "BZ2_bzWrite, bz2err = %d", bz2err);
  				return -1;
  			}
  
  			lastscan=scan-lenb;
  			lastpos=pos-lenb;
  			lastoffset=pos-scan;
  		}
  	}
  	BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
  	if (bz2err != BZ_OK) 
  	{
  		sprintf((char*)error, "BZ2_bzWriteClose, bz2err = %d", bz2err);
  		return -1;
  	}	
  
  	/* Compute size of compressed ctrl data */
  	if ((len = ftell(pf)) == -1) 
  	{
  		sprintf((char*)error, "\"ftell\" %s", strerror(errno));
  		return -1;
  	}		
  	offtout(len-32, (u_char*)&header.bzctrllen);
  
  	/* Write compressed diff data */
  	if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL) 
  	{
  		sprintf((char*)error, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
  		return -1;
  	}
  	
  	BZ2_bzWrite(&bz2err, pfbz2, db, dblen);
  	if (bz2err != BZ_OK) 
  	{
  		sprintf((char*)error, "BZ2_bzWrite, bz2err = %d", bz2err);
  		return -1;
  	}
  	
  	BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
  	if (bz2err != BZ_OK) 
  	{
  		sprintf((char*)error, "BZ2_bzWriteClose, bz2err = %d", bz2err);
  		return -1;
  	}	
  
  	/* Compute size of compressed diff data */
  	if ((newsize = ftell(pf)) == -1) 
  	{
  		sprintf((char*)error, "\"ftell\" %s", strerror(errno));
  		return -1;
  	}	
  	offtout(newsize - len, (u_char*)&header.bzdatalen);
  
  	/* Write compressed extra data */
  	if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL) 
  	{
  		sprintf((char*)error, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
  		return -1;
  	}
  	
  	BZ2_bzWrite(&bz2err, pfbz2, eb, eblen);
  	if (bz2err != BZ_OK) 
  	{
  		sprintf((char*)error, "BZ2_bzWrite, bz2err = %d", bz2err);
  		return -1;
  	}
  	
  	BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
  	if (bz2err != BZ_OK) 
  	{
  		sprintf((char*)error, "BZ2_bzWriteClose, bz2err = %d", bz2err);
  		return -1;
  	}		
  
  	/* Seek to the beginning, write the header, and close the file */
  	if (fseek(pf, 0, SEEK_SET)) 
  	{
  		sprintf((char*)error, "\"fseek\" %s", strerror(errno));
  		return -1;
  	}	
  	if (fwrite(&header, 32, 1, pf) != 1) 
  	{
  		sprintf((char*)error, "\"%s\" %s", patchfile, strerror(errno));
  		return -1;
  	}	
  	if (fclose(pf)) 
  	{
  		sprintf((char*)error, "\"fclose\" %s", strerror(errno));
  		return -1;
  	}
  	
  	/* Free the memory we used */
  	free(db);
  	free(eb);
  	free(I);
  	free(old);
  	free(new);
  
  	return 0;
  }