Add bsdiff and bspatch to the base system. These are tools for

constructing and applying binary patches; in particular, they perform
well (in the sense of constructing small patches) for executable code.
Both portsnap (coming to the base system Real Soon Now) and FreeBSD
Update (coming to the base system a bit later) use bspatch.

This is the same code as the bsdiff-4.2 which has been in the ports
tree (misc/bsdiff) for the past year, with the following exceptions:
1. The license is now the traditional 2-clause BSD;
2. Instead of forking and execing bzip2, the code now uses libbz2; and
3. Some minor changes have been made to fit this code into the base
system (adding $FreeBSD$ tags, putting bsdiff and bspatch into separate
directories, etc.)

This code is rather ugly and has lots of style bugs (mostly because I
wrote it before I had ever heard of style(9)).  Some day I'll come
back and clean it up.

Discussed on:	freebsd-arch
MFC before:	5.5-RELEASE
Tested by:	Several million users (earlier version).

9 files changed, 753 insertions, 0 deletions

diff --git a/usr.bin/Makefile b/usr.bin/Makefile
index 6528b7b..8848824 100644
--- a/usr.bin/Makefile
+++ b/usr.bin/Makefile
@@ -18,6 +18,7 @@ SUBDIR=	alias \
 	biff \
 	${_bluetooth} \
 	brandelf \
+	bsdiff \
 	bzip2 \
 	bzip2recover \
 	${_c89} \
diff --git a/usr.bin/bsdiff/Makefile b/usr.bin/bsdiff/Makefile
new file mode 100644
index 0000000..8a8bc31
--- /dev/null
+++ b/usr.bin/bsdiff/Makefile
@@ -0,0 +1,5 @@
+# $FreeBSD$
+
+SUBDIR=	bsdiff bspatch
+
+.include <bsd.subdir.mk>
diff --git a/usr.bin/bsdiff/Makefile.inc b/usr.bin/bsdiff/Makefile.inc
new file mode 100644
index 0000000..8eff734
--- /dev/null
+++ b/usr.bin/bsdiff/Makefile.inc
@@ -0,0 +1,3 @@
+# $FreeBSD$
+
+WARNS?=	6
diff --git a/usr.bin/bsdiff/bsdiff/Makefile b/usr.bin/bsdiff/bsdiff/Makefile
new file mode 100644
index 0000000..0e8498f
--- /dev/null
+++ b/usr.bin/bsdiff/bsdiff/Makefile
@@ -0,0 +1,8 @@
+# $FreeBSD$
+
+PROG=	bsdiff
+
+DPADD=	${LIBBZ2}
+LDADD=	-lbz2
+
+.include <bsd.prog.mk>
diff --git a/usr.bin/bsdiff/bsdiff/bsdiff.1 b/usr.bin/bsdiff/bsdiff/bsdiff.1
new file mode 100644
index 0000000..304285e
--- /dev/null
+++ b/usr.bin/bsdiff/bsdiff/bsdiff.1
@@ -0,0 +1,63 @@
+.\"-
+.\" 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.
+.\"
+.\" $FreeBSD$
+.\"
+.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@freebsd.org
diff --git a/usr.bin/bsdiff/bsdiff/bsdiff.c b/usr.bin/bsdiff/bsdiff/bsdiff.c
new file mode 100644
index 0000000..df9a058
--- /dev/null
+++ b/usr.bin/bsdiff/bsdiff/bsdiff.c
@@ -0,0 +1,403 @@
+/*-
+ * 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 <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+
+#include <bzlib.h>
+#include <err.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define MIN(x,y) (((x)<(y)) ? (x) : (y))
+
+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,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);
+	};
+}
+
+static 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;
+	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];
+	FILE * pf;
+	BZFILE * pfbz2;
+	int bz2err;
+
+	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;
+
+	/* Create the patch file */
+	if ((pf = fopen(argv[3], "w")) == NULL)
+		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);
+	offtout(0, header + 8);
+	offtout(0, header + 16);
+	offtout(newsize, header + 24);
+	if (fwrite(header, 32, 1, pf) != 1)
+		err(1, "fwrite(%s)", argv[3]);
+
+	/* Compute the differences, writing ctrl as we go */
+	if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
+		errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
+	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);
+			BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
+			if (bz2err != BZ_OK)
+				errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
+
+			offtout((scan-lenb)-(lastscan+lenf),buf);
+			BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
+			if (bz2err != BZ_OK)
+				errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
+
+			offtout((pos-lenb)-(lastpos+lenf),buf);
+			BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
+			if (bz2err != BZ_OK)
+				errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
+
+			lastscan=scan-lenb;
+			lastpos=pos-lenb;
+			lastoffset=pos-scan;
+		};
+	};
+	BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
+	if (bz2err != BZ_OK)
+		errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
+
+	/* Compute size of compressed ctrl data */
+	if ((len = ftello(pf)) == -1)
+		err(1, "ftello");
+	offtout(len-32, header + 8);
+
+	/* Write compressed diff data */
+	if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
+		errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
+	BZ2_bzWrite(&bz2err, pfbz2, db, dblen);
+	if (bz2err != BZ_OK)
+		errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
+	BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
+	if (bz2err != BZ_OK)
+		errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
+
+	/* Compute size of compressed diff data */
+	if ((newsize = ftello(pf)) == -1)
+		err(1, "ftello");
+	offtout(newsize - len, header + 16);
+
+	/* Write compressed extra data */
+	if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
+		errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
+	BZ2_bzWrite(&bz2err, pfbz2, eb, eblen);
+	if (bz2err != BZ_OK)
+		errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
+	BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
+	if (bz2err != BZ_OK)
+		errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
+
+	/* Seek to the beginning, write the header, and close the file */
+	if (fseeko(pf, 0, SEEK_SET))
+		err(1, "fseeko");
+	if (fwrite(header, 32, 1, pf) != 1)
+		err(1, "fwrite(%s)", argv[3]);
+	if (fclose(pf))
+		err(1, "fclose");
+
+	/* Free the memory we used */
+	free(db);
+	free(eb);
+	free(I);
+	free(old);
+	free(new);
+
+	return 0;
+}
diff --git a/usr.bin/bsdiff/bspatch/Makefile b/usr.bin/bsdiff/bspatch/Makefile
new file mode 100644
index 0000000..c0ed521
--- /dev/null
+++ b/usr.bin/bsdiff/bspatch/Makefile
@@ -0,0 +1,8 @@
+# $FreeBSD$
+
+PROG=	bspatch
+
+DPADD=	${LIBBZ2}
+LDADD=	-lbz2
+
+.include <bsd.prog.mk>
diff --git a/usr.bin/bsdiff/bspatch/bspatch.1 b/usr.bin/bsdiff/bspatch/bspatch.1
new file mode 100644
index 0000000..a428b84
--- /dev/null
+++ b/usr.bin/bsdiff/bspatch/bspatch.1
@@ -0,0 +1,59 @@
+.\"-
+.\" 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.
+.\"
+.\" $FreeBSD$
+.\"
+.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@freebsd.org
diff --git a/usr.bin/bsdiff/bspatch/bspatch.c b/usr.bin/bsdiff/bspatch/bspatch.c
new file mode 100644
index 0000000..bf6baa9
--- /dev/null
+++ b/usr.bin/bsdiff/bspatch/bspatch.c
@@ -0,0 +1,203 @@
+/*-
+ * 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 <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <bzlib.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <err.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+static 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[])
+{
+	FILE * f, * cpf, * dpf, * epf;
+	BZFILE * cpfbz2, * dpfbz2, * epfbz2;
+	int cbz2err, dbz2err, ebz2err;
+	int fd;
+	ssize_t oldsize,newsize;
+	ssize_t bzctrllen,bzdatalen;
+	u_char header[32],buf[8];
+	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]);
+
+	/* Open patch file */
+	if ((f = fopen(argv[3], "r")) == NULL)
+		err(1, "fopen(%s)", argv[3]);
+
+	/*
+	File format:
+		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".
+	*/
+
+	/* Read header */
+	if (fread(header, 1, 32, f) < 32) {
+		if (feof(f))
+			errx(1, "Corrupt patch\n");
+		err(1, "fread(%s)", argv[3]);
+	}
+
+	/* Check for appropriate magic */
+	if (memcmp(header, "BSDIFF40", 8) != 0)
+		errx(1, "Corrupt patch\n");
+
+	/* Read lengths from header */
+	bzctrllen=offtin(header+8);
+	bzdatalen=offtin(header+16);
+	newsize=offtin(header+24);
+	if((bzctrllen<0) || (bzdatalen<0) || (newsize<0))
+		errx(1,"Corrupt patch\n");
+
+	/* Close patch file and re-open it via libbzip2 at the right places */
+	if (fclose(f))
+		err(1, "fclose(%s)", argv[3]);
+	if ((cpf = fopen(argv[3], "r")) == NULL)
+		err(1, "fopen(%s)", argv[3]);
+	if (fseeko(cpf, 32, SEEK_SET))
+		err(1, "fseeko(%s, %lld)", argv[3],
+		    (long long)32);
+	if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL)
+		errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err);
+	if ((dpf = fopen(argv[3], "r")) == NULL)
+		err(1, "fopen(%s)", argv[3]);
+	if (fseeko(dpf, 32 + bzctrllen, SEEK_SET))
+		err(1, "fseeko(%s, %lld)", argv[3],
+		    (long long)(32 + bzctrllen));
+	if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL)
+		errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err);
+	if ((epf = fopen(argv[3], "r")) == NULL)
+		err(1, "fopen(%s)", argv[3]);
+	if (fseeko(epf, 32 + bzctrllen + bzdatalen, SEEK_SET))
+		err(1, "fseeko(%s, %lld)", argv[3],
+		    (long long)(32 + bzctrllen + bzdatalen));
+	if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
+		errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err);
+
+	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) {
+		/* Read control data */
+		for(i=0;i<=2;i++) {
+			lenread = BZ2_bzRead(&cbz2err, cpfbz2, buf, 8);
+			if ((lenread < 8) || ((cbz2err != BZ_OK) &&
+			    (cbz2err != BZ_STREAM_END)))
+				errx(1, "Corrupt patch\n");
+			ctrl[i]=offtin(buf);
+		};
+
+		/* Sanity-check */
+		if(newpos+ctrl[0]>newsize)
+			errx(1,"Corrupt patch\n");
+
+		/* Read diff string */
+		lenread = BZ2_bzRead(&dbz2err, dpfbz2, new + newpos, ctrl[0]);
+		if ((lenread < ctrl[0]) ||
+		    ((dbz2err != BZ_OK) && (dbz2err != BZ_STREAM_END)))
+			errx(1, "Corrupt patch\n");
+
+		/* Add old data to diff string */
+		for(i=0;i<ctrl[0];i++)
+			if((oldpos+i>=0) && (oldpos+i<oldsize))
+				new[newpos+i]+=old[oldpos+i];
+
+		/* Adjust pointers */
+		newpos+=ctrl[0];
+		oldpos+=ctrl[0];
+
+		/* Sanity-check */
+		if(newpos+ctrl[1]>newsize)
+			errx(1,"Corrupt patch\n");
+
+		/* Read extra string */
+		lenread = BZ2_bzRead(&ebz2err, epfbz2, new + newpos, ctrl[1]);
+		if ((lenread < ctrl[1]) ||
+		    ((ebz2err != BZ_OK) && (ebz2err != BZ_STREAM_END)))
+			errx(1, "Corrupt patch\n");
+
+		/* Adjust pointers */
+		newpos+=ctrl[1];
+		oldpos+=ctrl[2];
+	};
+
+	/* Clean up the bzip2 reads */
+	BZ2_bzReadClose(&cbz2err, cpfbz2);
+	BZ2_bzReadClose(&dbz2err, dpfbz2);
+	BZ2_bzReadClose(&ebz2err, epfbz2);
+	if (fclose(cpf) || fclose(dpf) || fclose(epf))
+		err(1, "fclose(%s)", argv[3]);
+
+	/* Write the new file */
+	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;
+}