* Integrated bsdiff/bspatch 4.2 (from

  http://www.daemonology.net/bsdiff/bsdiff-4.2.tar.gz) into the source
  tree.  The license is a bit peculiar, but it does allow verbatim
  copying, which is what we do here (i.e., so don't make any changes
  to the sources).

7 files changed, 815 insertions, 0 deletions

diff --git a/src/bsdiff-4.2/LICENSE b/src/bsdiff-4.2/LICENSE
new file mode 100644
index 000000000..c146b5b39
--- /dev/null
+++ b/src/bsdiff-4.2/LICENSE
@@ -0,0 +1,121 @@
+BSD Protection License
+February 2002
+
+Preamble
+--------
+
+The Berkeley Software Distribution ("BSD") license has proven very effective
+over the years at allowing for a wide spread of work throughout both
+commercial and non-commercial products.  For programmers whose primary
+intention is to improve the general quality of available software, it is
+arguable that there is no better license than the BSD license, as it
+permits improvements to be used wherever they will help, without idealogical
+or metallic constraint.
+
+This is of particular value to those who produce reference implementations
+of proposed standards: The case of TCP/IP clearly illustrates that freely
+and universally available implementations leads the rapid acceptance of
+standards -- often even being used instead of a de jure standard (eg, OSI
+network models).
+
+With the rapid proliferation of software licensed under the GNU General
+Public License, however, the continued success of this role is called into
+question.  Given that the inclusion of a few lines of "GPL-tainted" work
+into a larger body of work will result in restricted distribution -- and
+given that further work will likely build upon the "tainted" portions,
+making them difficult to remove at a future date -- there are inevitable
+circumstances where authors would, in order to protect their goal of
+providing for the widespread usage of their work, wish to guard against
+such "GPL-taint".
+
+In addition, one can imagine that companies which operate by producing and
+selling (possibly closed-source) code would wish to protect themselves
+against the rise of a GPL-licensed competitor.  While under existing
+licenses this would mean not releasing their code under any form of open
+license, if a license existed under which they could incorporate any
+improvements back into their own (commercial) products then they might be
+far more willing to provide for non-closed distribution.
+
+For the above reasons, we put forth this "BSD Protection License": A
+license designed to retain the freedom granted by the BSD license to use
+licensed works in a wide variety of settings, both non-commercial and
+commercial, while protecting the work from having future contributors
+restrict that freedom.
+
+The precise terms and conditions for copying, distribution, and
+modification follow.
+
+BSD PROTECTION LICENSE
+TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION, AND MODIFICATION
+----------------------------------------------------------------
+
+0. Definitions.
+   a) "Program", below, refers to any program or work distributed under
+      the terms of this license.
+   b) A "work based on the Program", below, refers to either the Program
+      or any derivative work under copyright law.
+   c) "Modification", below, refers to the act of creating derivative works.
+   d) "You", below, refers to each licensee.
+
+1. Scope.
+   This license governs the copying, distribution, and modification of the
+   Program.  Other activities are outside the scope of this license; The
+   act of running the Program is not restricted, and the output from the
+   Program is covered only if its contents constitute a work based on the
+   Program.
+
+2. Verbatim copies.
+   You may copy and distribute verbatim copies of the Program as you
+   receive it, in any medium, provided that you conspicuously and
+   appropriately publish on each copy an appropriate copyright notice; keep
+   intact all the notices that refer to this License and to the absence of
+   any warranty; and give any other recipients of the Program a copy of this
+   License along with the Program.
+
+3. Modification and redistribution under closed license.
+   You may modify your copy or copies of the Program, and distribute
+   the resulting derivative works, provided that you meet the
+   following conditions:
+   a) The copyright notice and disclaimer on the Program must be reproduced
+      and included in the source code, documentation, and/or other materials
+      provided in a manner in which such notices are normally distributed.
+   b) The derivative work must be clearly identified as such, in order that
+      it may not be confused with the original work.
+   c) The license under which the derivative work is distributed must
+      expressly prohibit the distribution of further derivative works.
+
+4. Modification and redistribution under open license.
+   You may modify your copy or copies of the Program, and distribute
+   the resulting derivative works, provided that you meet the
+   following conditions:
+   a) The copyright notice and disclaimer on the Program must be reproduced
+      and included in the source code, documentation, and/or other materials
+      provided in a manner in which such notices are normally distributed.
+   b) You must clearly indicate the nature and date of any changes made
+      to the Program.  The full details need not necessarily be included in
+      the individual modified files, provided that each modified file is
+      clearly marked as such and instructions are included on where the
+      full details of the modifications may be found.
+   c) You must cause any work that you distribute or publish, that in whole
+      or in part contains or is derived from the Program or any part
+      thereof, to be licensed as a whole at no charge to all third
+      parties under the terms of this License.
+
+5. Implied acceptance.
+   You may not copy or distribute the Program or any derivative works except
+   as expressly provided under this license.  Consequently, any such action
+   will be taken as implied acceptance of the terms of this license.
+
+6. NO WARRANTY.
+   THIS SOFTWARE IS PROVIDED "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 COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+   REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE FOR ANY DIRECT,
+   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+   ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (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, EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+   POSSIBILITY OF SUCH DAMAGES.
diff --git a/src/bsdiff-4.2/Makefile.am b/src/bsdiff-4.2/Makefile.am
new file mode 100644
index 000000000..70f2ead7c
--- /dev/null
+++ b/src/bsdiff-4.2/Makefile.am
@@ -0,0 +1,7 @@
+libexec_PROGRAMS = bsdiff bspatch
+
+bsdiff_SOURCES = bsdiff.c
+
+bspatch_SOURCES = bspatch.c
+
+AM_CFLAGS = -O3 -DBZIP2=\"$(bzip2)\"
diff --git a/src/bsdiff-4.2/Makefile.old b/src/bsdiff-4.2/Makefile.old
new file mode 100644
index 000000000..ce5dd344d
--- /dev/null
+++ b/src/bsdiff-4.2/Makefile.old
@@ -0,0 +1,18 @@
+CFLAGS		+=	-O3
+.ifdef BZIP2
+CFLAGS		+=	-DBZIP2=\"${BZIP2}\"
+.endif
+
+PREFIX		?=	/usr/local
+INSTALL_PROGRAM	?=	${INSTALL} -c -s -m 555
+INSTALL_MAN	?=	${INSTALL} -c -m 444
+
+all:		bsdiff bspatch
+bsdiff:		bsdiff.c
+bspatch:	bspatch.c
+
+install:
+	${INSTALL_PROGRAM} bsdiff bspatch ${PREFIX}/bin
+.ifndef WITHOUT_MAN
+	${INSTALL_MAN} bsdiff.1 bspatch.1 ${PREFIX}/man/man1
+.endif
diff --git a/src/bsdiff-4.2/bsdiff.1 b/src/bsdiff-4.2/bsdiff.1
new file mode 100644
index 000000000..8d3926d32
--- /dev/null
+++ b/src/bsdiff-4.2/bsdiff.1
@@ -0,0 +1,36 @@
+.Dd May 18, 2003
+.Dt BSDIFF 1
+.Os FreeBSD
+.Sh NAME
+.Nm bsdiff
+.Nd generate a patch between two binary files
+.Sh SYNOPSIS
+.Nm
+.Ao Ar oldfile Ac Ao Ar newfile Ac Ao Ar patchfile Ac
+.Sh DESCRIPTION
+.Nm
+compares
+.Ao Ar oldfile Ac
+to
+.Ao Ar newfile Ac
+and writes to
+.Ao Ar patchfile Ac
+a binary patch suitable for use by bspatch(1).
+When
+.Ao Ar oldfile Ac
+and
+.Ao Ar newfile Ac
+are two versions of an executable program, the
+patches produced are on average a factor of five smaller
+than those produced by any other binary patch tool known
+to the author.
+.Pp
+.Nm
+uses memory equal to 17 times the size of 
+.Ao Ar oldfile Ac ,
+and requires
+an absolute minimum working set size of 8 times the size of oldfile.
+.Sh SEE ALSO
+.Xr bspatch 1
+.Sh AUTHORS
+.An Colin Percival Aq cperciva@daemonology.net
diff --git a/src/bsdiff-4.2/bsdiff.c b/src/bsdiff-4.2/bsdiff.c
new file mode 100644
index 000000000..f47226c1e
--- /dev/null
+++ b/src/bsdiff-4.2/bsdiff.c
@@ -0,0 +1,385 @@
+/*
+  bsdiff.c -- Binary patch generator.
+
+  Copyright 2003 Colin Percival
+
+  For the terms under which this work may be distributed, please see
+  the adjoining file "LICENSE".
+*/
+
+#ifndef BZIP2
+#define BZIP2 "/usr/bin/bzip2"
+#endif
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <err.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+
+#define MIN(x,y) (((x)<(y)) ? (x) : (y))
+
+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);
+}
+
+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;
+}
+
+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;
+}
+
+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,MIN(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);
+	};
+}
+
+void offtout(off_t x,u_char *buf)
+{
+	off_t y;
+
+	if(x<0) y=-x; else y=x;
+
+		buf[0]=y%256;y-=buf[0];
+	y=y/256;buf[1]=y%256;y-=buf[1];
+	y=y/256;buf[2]=y%256;y-=buf[2];
+	y=y/256;buf[3]=y%256;y-=buf[3];
+	y=y/256;buf[4]=y%256;y-=buf[4];
+	y=y/256;buf[5]=y%256;y-=buf[5];
+	y=y/256;buf[6]=y%256;y-=buf[6];
+	y=y/256;buf[7]=y%256;
+
+	if(x<0) buf[7]|=0x80;
+}
+
+int main(int argc,char *argv[])
+{
+	int fd,p[2];
+	pid_t pid;
+	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[8];
+	u_char header[32];
+
+	if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
+
+	/* 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(argv[1],O_RDONLY,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)) err(1,"%s",argv[1]);
+
+	if(((I=malloc((oldsize+1)*sizeof(off_t)))==NULL) ||
+		((V=malloc((oldsize+1)*sizeof(off_t)))==NULL)) err(1,NULL);
+
+	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(argv[2],O_RDONLY,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)) err(1,"%s",argv[2]);
+
+	if(((db=malloc(newsize+1))==NULL) ||
+		((eb=malloc(newsize+1))==NULL)) err(1,NULL);
+	dblen=0;
+	eblen=0;
+
+	if((fd=open(argv[3],O_CREAT|O_TRUNC|O_WRONLY,0666))<0)
+		err(1,"%s",argv[3]);
+
+	/* 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,"BSDIFF40",8);
+	memset(header+8,0,24);
+	if(write(fd,header,32)!=32) err(1,"%s",argv[3]);
+
+	if((pipe(p)==-1) || ((pid=fork())==-1)) err(1,NULL);
+	if(pid==0) {
+		if((close(0)==-1) || (close(1)==-1) || (dup2(fd,1)==-1) ||
+			(dup2(p[0],0)==-1) || (close(fd)==-1) ||
+			(close(p[0])==-1) || (close(p[1])==-1))
+			err(1,NULL);
+		execl(BZIP2,BZIP2,"-zc",NULL);
+		err(1,"%s",BZIP2);
+	};
+	if(close(p[0])==-1) err(1,NULL);
+
+	scan=0;len=0;
+	lastscan=0;lastpos=0;lastoffset=0;
+	while(scan<newsize) {
+		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];
+			for(i=0;i<(scan-lenb)-(lastscan+lenf);i++)
+				eb[eblen+i]=new[lastscan+lenf+i];
+
+			dblen+=lenf;
+			eblen+=(scan-lenb)-(lastscan+lenf);
+
+			offtout(lenf,buf);
+			if(write(p[1],buf,8)!=8) err(1,NULL);
+			offtout((scan-lenb)-(lastscan+lenf),buf);
+			if(write(p[1],buf,8)!=8) err(1,NULL);
+			offtout((pos-lenb)-(lastpos+lenf),buf);
+			if(write(p[1],buf,8)!=8) err(1,NULL);
+
+			lastscan=scan-lenb;
+			lastpos=pos-lenb;
+			lastoffset=pos-scan;
+		};
+	};
+
+	if((close(p[1])==-1) || (waitpid(pid,NULL,0)!=pid)) err(1,NULL);
+
+	if((len=lseek(fd,0,SEEK_END))==-1) err(1,"%s",argv[3]);
+	offtout(len-32,buf);
+	if((lseek(fd,8,SEEK_SET)!=8) || (write(fd,buf,8)!=8))
+		err(1,"%s",argv[3]);
+	offtout(newsize,buf);
+	if((lseek(fd,24,SEEK_SET)!=24) || (write(fd,buf,8)!=8))
+		err(1,"%s",argv[3]);
+
+	if(lseek(fd,0,SEEK_END)==-1) err(1,"%s",argv[3]);
+	if((pipe(p)==-1) || ((pid=fork())==-1)) err(1,NULL);
+	if(pid==0) {
+		if((close(0)==-1) || (close(1)==-1) || (dup2(fd,1)==-1) ||
+			(dup2(p[0],0)==-1) || (close(fd)==-1) ||
+			(close(p[0])==-1) || (close(p[1])==-1))
+			err(1,NULL);
+		execl(BZIP2,BZIP2,"-zc",NULL);
+		err(1,"%s",BZIP2);
+	};
+	if(close(p[0])==-1) err(1,NULL);
+	if(write(p[1],db,dblen)!=dblen) err(1,NULL);
+	if((close(p[1])==-1) || (waitpid(pid,NULL,0)!=pid)) err(1,NULL);
+
+	if((newsize=lseek(fd,0,SEEK_END))==-1) err(1,"%s",argv[3]);
+	offtout(newsize-len,buf);
+	if((lseek(fd,16,SEEK_SET)!=16) || (write(fd,buf,8)!=8))
+		err(1,"%s",argv[3]);
+
+	if(lseek(fd,0,SEEK_END)==-1) err(1,"%s",argv[3]);
+	if((pipe(p)==-1) || ((pid=fork())==-1)) err(1,NULL);
+	if(pid==0) {
+		if((close(0)==-1) || (close(1)==-1) || (dup2(fd,1)==-1) ||
+			(dup2(p[0],0)==-1) || (close(fd)==-1) ||
+			(close(p[0])==-1) || (close(p[1])==-1))
+			err(1,NULL);
+		execl(BZIP2,BZIP2,"-zc",NULL);
+		err(1,"%s",BZIP2);
+	};
+	if(close(p[0])==-1) err(1,NULL);
+	if(write(p[1],eb,eblen)!=eblen) err(1,NULL);
+	if((close(p[1])==-1) || (waitpid(pid,NULL,0)!=pid)) err(1,NULL);
+	if(close(fd)==-1) err(1,"%s",argv[3]);
+
+	free(db);
+	free(eb);
+	free(I);
+	free(old);
+	free(new);
+
+	return 0;
+}
diff --git a/src/bsdiff-4.2/bspatch.1 b/src/bsdiff-4.2/bspatch.1
new file mode 100644
index 000000000..b243f2b7b
--- /dev/null
+++ b/src/bsdiff-4.2/bspatch.1
@@ -0,0 +1,32 @@
+.Dd May 18, 2003
+.Dt BSPATCH 1
+.Os FreeBSD
+.Sh NAME
+.Nm bspatch
+.Nd apply a patch built with bsdiff(1)
+.Sh SYNOPSIS
+.Nm
+.Ao Ar oldfile Ac Ao Ar newfile Ac Ao Ar patchfile Ac
+.Sh DESCRIPTION
+.Nm
+generates
+.Ao Ar newfile Ac
+from
+.Ao Ar oldfile Ac
+and
+.Ao Ar patchfile Ac
+where
+.Ao Ar patchfile Ac
+is a binary patch built by bsdiff(1).
+.Pp
+.Nm
+uses memory equal to the size of 
+.Ao Ar oldfile Ac
+plus the size of 
+.Ao Ar newfile Ac ,
+but can tolerate a very small working set without a dramatic loss
+of performance.
+.Sh SEE ALSO
+.Xr bsdiff 1
+.Sh AUTHORS
+.An Colin Percival Aq cperciva@daemonology.net
diff --git a/src/bsdiff-4.2/bspatch.c b/src/bsdiff-4.2/bspatch.c
new file mode 100644
index 000000000..1386a7096
--- /dev/null
+++ b/src/bsdiff-4.2/bspatch.c
@@ -0,0 +1,216 @@
+/*
+  .c -- Binary patcher
+
+  Copyright 2003,2004 Colin Percival
+
+  For the terms under which this work may be distributed, please see
+  the adjoining file "LICENSE".
+*/
+
+#ifndef BZIP2
+#define BZIP2 "/usr/bin/bzip2"
+#endif
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <err.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+
+ssize_t loopread(int d,void *buf,size_t nbytes)
+{
+	ssize_t ptr,lenread;
+
+	for(ptr=0;ptr<nbytes;ptr+=lenread) {
+		lenread=read(d,buf+ptr,nbytes-ptr);
+		if(lenread==0) return ptr;
+		if(lenread==-1) return -1;
+	};
+	return ptr;
+}
+
+int bz2read(int fd,off_t offset,off_t len,char * fname,pid_t * pids)
+{
+	int p0[2],p1[2];
+	u_char * data;
+
+	if((pipe(p0)==-1) || (pipe(p1)==-1)) err(1,NULL);
+
+	if((pids[0]=fork())==-1) err(1,NULL);
+	if(pids[0]==0) {
+		if(close(0) || close(1) || close(p0[0]) ||
+			close(p1[0]) || close(p1[1])) err(1,NULL);
+		if((data=malloc(len+1))==NULL) err(1,NULL);
+		if((pread(fd,data,len,offset)!=len) || close(fd))
+			err(1,"%s",fname);
+		if((write(p0[1],data,len)!=len) || close(p0[1]))
+			err(1,NULL);
+		free(data);
+		_exit(0);
+	};
+
+	if((pids[1]=fork())==-1) err(1,NULL);
+	if(pids[1]==0) {
+		if(close(0) || close(1) || close(p0[1]) ||
+			close(p1[0])) err(1,NULL);
+		if((dup2(p0[0],0)==-1) || close(p0[0])) err(1,NULL);
+		if((dup2(p1[1],1)==-1) || close(p1[1])) err(1,NULL);
+		if(close(fd)==-1) err(1,"%s",fname);
+
+		execl(BZIP2,BZIP2,"-dc",NULL);
+		err(1,"%s",BZIP2);
+	};
+
+	if(close(p0[0]) || close(p0[1]) || close(p1[1])) err(1,NULL);
+
+	return p1[0];
+}
+
+off_t offtin(u_char *buf)
+{
+	off_t y;
+
+	y=buf[7]&0x7F;
+	y=y*256;y+=buf[6];
+	y=y*256;y+=buf[5];
+	y=y*256;y+=buf[4];
+	y=y*256;y+=buf[3];
+	y=y*256;y+=buf[2];
+	y=y*256;y+=buf[1];
+	y=y*256;y+=buf[0];
+
+	if(buf[7]&0x80) y=-y;
+
+	return y;
+}
+
+int main(int argc,char * argv[])
+{
+	int fd,ctrlpipe,diffpipe,extrapipe;
+	pid_t pids[6];
+	ssize_t patchsize,oldsize,newsize;
+	ssize_t bzctrllen,bzdatalen;
+	u_char header[32],buf[8];
+	int version=0;
+	u_char *old, *new;
+	off_t oldpos,newpos;
+	off_t ctrl[3];
+	off_t lenread;
+	off_t i;
+
+	if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
+
+	if(((fd=open(argv[3],O_RDONLY,0))<0) ||
+		((patchsize=lseek(fd,0,SEEK_END))==-1) ||
+		(lseek(fd,0,SEEK_SET)!=0)) err(1,"%s",argv[3]);
+	if(patchsize<32) errx(1,"Corrupt patch\n");
+
+	/*
+	  Ok, this is going to be messy.  There are two different patch
+	formats which we need to support.
+
+	  The old format (pre-4.0) is:
+		0	8	"QSUFDIFF" or "BSDIFF30"
+		8	8	X
+		16	8	Y
+		24	8	sizeof(newfile)
+		32	X	bzip2(control block)
+		32+X	Y	bzip2(data block)
+	with control block a set of pairs (x,y) meaning "seek forward
+	in oldfile by y bytes, and add the next x bytes to x bytes from
+	the data block".
+
+	  The new format (4.0) is:
+		0	8	"BSDIFF40"
+		8	8	X
+		16	8	Y
+		24	8	sizeof(newfile)
+		32	X	bzip2(control block)
+		32+X	Y	bzip2(diff block)
+		32+X+Y	???	bzip2(extra block)
+	with control block a set of triples (x,y,z) meaning "add x bytes
+	from oldfile to x bytes from the diff block; copy y bytes from the
+	extra block; seek forwards in oldfile by z bytes".
+	*/
+
+	if(read(fd,header,32)!=32) err(1,"%s",argv[3]);
+	if(memcmp(header,"QSUFDIFF",8)==0) version=1;
+	if(memcmp(header,"BSDIFF30",8)==0) version=1;
+	if(memcmp(header,"BSDIFF40",8)==0) version=2;
+
+	if(!version) errx(1,"Corrupt patch\n");
+
+	bzctrllen=offtin(header+8);
+	bzdatalen=offtin(header+16);
+	newsize=offtin(header+24);
+	if((bzctrllen<0) || (bzdatalen<0) || (newsize<0) ||
+		((version==1) && (32+bzctrllen+bzdatalen!=patchsize)))
+		errx(1,"Corrupt patch\n");
+
+	ctrlpipe=bz2read(fd,32,bzctrllen,argv[3],pids);
+	diffpipe=bz2read(fd,32+bzctrllen,bzdatalen,argv[3],pids+2);
+	if(version==2) {
+		extrapipe=bz2read(fd,32+bzctrllen+bzdatalen,
+			patchsize-(32+bzctrllen+bzdatalen),argv[3],pids+4);
+	};
+
+	if(close(fd)==-1) err(1,"%s",argv[3]);
+	if(((fd=open(argv[1],O_RDONLY,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)) err(1,"%s",argv[1]);
+	if((new=malloc(newsize+1))==NULL) err(1,NULL);
+
+	oldpos=0;newpos=0;
+	while(newpos<newsize) {
+		for(i=0;i<=version;i++) {
+			if((lenread=loopread(ctrlpipe,buf,8))<0) err(1,NULL);
+			if(lenread<8) errx(1,"Corrupt patch\n");
+			ctrl[i]=offtin(buf);
+		};
+
+		if(version==1) oldpos+=ctrl[1];
+
+		if(newpos+ctrl[0]>newsize) errx(1,"Corrupt patch\n");
+		if((lenread=loopread(diffpipe,new+newpos,ctrl[0]))<0)
+			err(1,NULL);
+		if(lenread!=ctrl[0]) errx(1,"Corrupt patch\n");
+		for(i=0;i<ctrl[0];i++)
+			if((oldpos+i>=0) && (oldpos+i<oldsize))
+				new[newpos+i]+=old[oldpos+i];
+		newpos+=ctrl[0];
+		oldpos+=ctrl[0];
+
+		if(version==2) {
+			if(newpos+ctrl[1]>newsize) errx(1,"Corrupt patch\n");
+			if((lenread=loopread(extrapipe,new+newpos,ctrl[1]))<0)
+				err(1,NULL);
+			if(lenread!=ctrl[1]) errx(1,"Corrupt patch\n");
+
+			newpos+=ctrl[1];
+			oldpos+=ctrl[2];
+		};
+	};
+
+	if(loopread(ctrlpipe,buf,1)!=0) errx(1,"Corrupt patch\n");
+	if(loopread(diffpipe,buf,1)!=0) errx(1,"Corrupt patch\n");
+	if(version==2)
+		if(loopread(extrapipe,buf,1)!=0) errx(1,"Corrupt patch\n");
+
+	if(close(ctrlpipe) || close(diffpipe) || 
+		((version==2) && close(extrapipe)))
+		err(1,NULL);
+	for(i=0;i<(version+1)*2;i++) waitpid(pids[i],NULL,0);
+
+	if(((fd=open(argv[2],O_CREAT|O_TRUNC|O_WRONLY,0666))<0) ||
+		(write(fd,new,newsize)!=newsize) || (close(fd)==-1))
+		err(1,"%s",argv[2]);
+
+	free(new);
+	free(old);
+
+	return 0;
+}