interleaving control, diff and extra data

2 files changed, 37 insertions, 130 deletions

diff --git a/bsdiff.c b/bsdiff.c
index 88936aa..c4da099 100644
--- a/bsdiff.c
+++ b/bsdiff.c
@@ -249,13 +249,11 @@ static int bsdiff_internal(const struct bsdiff_request req)
 {
 	int64_t *I,*V;
 	int64_t scan,pos,len;
-	int64_t compresslen, filelen;
 	int64_t lastscan,lastpos,lastoffset;
 	int64_t oldscore,scsc;
 	int64_t s,Sf,lenf,Sb,lenb;
 	int64_t overlap,Ss,lens;
 	int64_t i;
-	int64_t dblen,eblen;
 	uint8_t *db,*eb;
 	uint8_t buf[8 * 3];
 
@@ -267,22 +265,6 @@ static int bsdiff_internal(const struct bsdiff_request req)
 
 	db = req.db;
 	eb = req.eb;
-	dblen=0;
-	eblen=0;
-	filelen=0;
-
-	/* 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(req.header->signature,"BSDIFF40",sizeof(req.header->signature));
-	req.header->new_file_length = req.newsize;
 
 	/* Compute the differences, writing ctrl as we go */
 	scan=0;len=0;
@@ -340,56 +322,31 @@ static int bsdiff_internal(const struct bsdiff_request req)
 			};
 
 			for(i=0;i<lenf;i++)
-				db[dblen+i]=req.new[lastscan+i]-req.old[lastpos+i];
+				db[i]=req.new[lastscan+i]-req.old[lastpos+i];
 			for(i=0;i<(scan-lenb)-(lastscan+lenf);i++)
-				eb[eblen+i]=req.new[lastscan+lenf+i];
-
-			dblen+=lenf;
-			eblen+=(scan-lenb)-(lastscan+lenf);
+				eb[i]=req.new[lastscan+lenf+i];
 
 			offtout(lenf,buf);
 			offtout((scan-lenb)-(lastscan+lenf),buf+8);
 			offtout((pos-lenb)-(lastpos+lenf),buf+16);
 
-			compresslen = writedata(req.stream, buf, sizeof(buf));
-			if (compresslen == -1)
+			/* Write control data */
+			if (writedata(req.stream, buf, sizeof(buf)))
+				return -1;
+
+			/* Write diff data */
+			if (writedata(req.stream, db, lenf))
+				return -1;
+
+			/* Write extra data */
+			if (writedata(req.stream, eb, (scan-lenb)-(lastscan+lenf)))
 				return -1;
-			filelen += compresslen;
 
 			lastscan=scan-lenb;
 			lastpos=pos-lenb;
 			lastoffset=pos-scan;
 		};
 	};
-	compresslen = req.stream->finish(req.stream);
-	if (compresslen == -1)
-		return -1;
-	filelen += compresslen;
-
-	/* Compute size of compressed ctrl data */
-	req.header->ctrl_block_length = filelen;
-
-	/* Write compressed diff data */
-	filelen = 0;
-	compresslen = writedata(req.stream, db, dblen);
-	if (compresslen == -1)
-		return -1;
-	filelen += compresslen;
-	compresslen = req.stream->finish(req.stream);
-	if (compresslen == -1)
-		return -1;
-	filelen += compresslen;
-
-	/* Compute size of compressed diff data */
-	req.header->diff_block_length = filelen;
-
-	/* Write compressed extra data */
-	compresslen = writedata(req.stream, eb, eblen);
-	if (compresslen == -1)
-		return -1;
-	compresslen = req.stream->finish(req.stream);
-	if (compresslen == -1)
-		return -1;
 
 	return 0;
 }
@@ -447,7 +404,6 @@ static int bz2_write(struct bsdiff_stream* stream, const void* buffer, int size)
 	bz_stream* bz2;
 	FILE* pf;
 	int err;
-	int totalwritten;
 	char compress_buffer[4096];
 
 	bz2 = (bz_stream*)stream->opaque;
@@ -462,7 +418,6 @@ static int bz2_write(struct bsdiff_stream* stream, const void* buffer, int size)
 	bz2->next_in = (char*)buffer;
 	bz2->avail_in = size;
 
-	totalwritten = 0;
 	for (;;)
 	{
 		bz2->next_out = compress_buffer;
@@ -475,19 +430,16 @@ static int bz2_write(struct bsdiff_stream* stream, const void* buffer, int size)
 			const size_t written = sizeof(compress_buffer) - bz2->avail_out;
 			if (written != fwrite(compress_buffer, 1, written, pf))
 				return -1;
-
-			totalwritten += written;
 		}
 
 		if (bz2->avail_in == 0)
-			return totalwritten;
+			return 0;
 	}
 }
 
 static int bz2_finish(struct bsdiff_stream* stream)
 {
 	int err;
-	int totalwritten;
 	bz_stream* bz2;
 	FILE* pf;
 	char compress_buffer[4096];
@@ -495,7 +447,6 @@ static int bz2_finish(struct bsdiff_stream* stream)
 	bz2 = (bz_stream*)stream->opaque;
 	pf = (FILE*)bz2->opaque;
 
-	totalwritten = 0;
 	for (;;)
 	{
 		bz2->next_out = compress_buffer;
@@ -510,8 +461,6 @@ static int bz2_finish(struct bsdiff_stream* stream)
 			const size_t written = sizeof(compress_buffer) - bz2->avail_out;
 			if (written != fwrite(compress_buffer, 1, written, pf))
 				return -1;
-
-			totalwritten += written;
 		}
 
 		if (BZ_STREAM_END == err)
@@ -519,7 +468,7 @@ static int bz2_finish(struct bsdiff_stream* stream)
 	}
 
 	BZ2_bzCompressEnd(bz2);
-	return totalwritten;
+	return 0;
 }
 
 int main(int argc,char *argv[])
@@ -573,6 +522,14 @@ int main(int argc,char *argv[])
 	if (bsdiff(old, oldsize, new, newsize, &stream, &header))
 		err(1, "bsdiff");
 
+	if (stream.finish(&stream))
+		err(1, "stream.finish");
+
+	memcpy(header.signature, "BSDIFF40", sizeof(header.signature));
+	header.ctrl_block_length = 0;
+	header.diff_block_length = 0;
+	header.new_file_length = newsize;
+
 	if (fseek(pf, 0, SEEK_SET) ||
 		fwrite(&header.signature, sizeof(header.signature), 1, pf) != 1)
 		err(1, "Failed to write header");
diff --git a/bspatch.c b/bspatch.c
index 3b7eab4..423283b 100644
--- a/bspatch.c
+++ b/bspatch.c
@@ -43,9 +43,7 @@ struct bspatch_request
 	int64_t oldsize;
 	uint8_t* new;
 	int64_t newsize;
-	struct bspatch_stream control;
-	struct bspatch_stream diff;
-	struct bspatch_stream extra;
+	struct bspatch_stream stream;
 };
 
 int bspatch(const struct bspatch_request req);
@@ -82,7 +80,7 @@ int bspatch(const struct bspatch_request req)
 	while(newpos<req.newsize) {
 		/* Read control data */
 		for(i=0;i<=2;i++) {
-			lenread = req.control.read(&req.control, buf, 8);
+			lenread = req.stream.read(&req.stream, buf, 8);
 			if (lenread != 8)
 				return -1;
 			ctrl[i]=offtin(buf);
@@ -93,7 +91,7 @@ int bspatch(const struct bspatch_request req)
 			return -1;
 
 		/* Read diff string */
-		lenread = req.diff.read(&req.diff, req.new + newpos, ctrl[0]);
+		lenread = req.stream.read(&req.stream, req.new + newpos, ctrl[0]);
 		if (lenread != ctrl[0])
 			return -1;
 
@@ -111,7 +109,7 @@ int bspatch(const struct bspatch_request req)
 			return -1;
 
 		/* Read extra string */
-		lenread = req.extra.read(&req.extra, req.new + newpos, ctrl[1]);
+		lenread = req.stream.read(&req.stream, req.new + newpos, ctrl[1]);
 		if (lenread != ctrl[1])
 			return -1;
 
@@ -185,19 +183,14 @@ int main(int argc,char * argv[])
 {
 	FILE * f;
 	int fd;
-	int cbz2err, dbz2err, ebz2err;
+	int bz2err;
 	ssize_t bzctrllen,bzdatalen;
 	uint8_t header[32];
 	uint8_t *old;
-	FILE *cpf, *dpf, *epf;
 	struct bspatch_request req;
-	struct bspatch_bz2_buffer cbz2;
-	struct bspatch_bz2_buffer dbz2;
-	struct bspatch_bz2_buffer ebz2;
+	struct bspatch_bz2_buffer bz2;
 
-	memset(&cbz2, 0, sizeof(cbz2));
-	memset(&dbz2, 0, sizeof(dbz2));
-	memset(&ebz2, 0, sizeof(ebz2));
+	memset(&bz2, 0, sizeof(bz2));
 
 	if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
 
@@ -205,20 +198,6 @@ int main(int argc,char * argv[])
 	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))
@@ -238,24 +217,6 @@ int main(int argc,char * argv[])
 		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, "fseeko64(%s, %lld)", argv[3],
-		    (long long)32);
-	if ((dpf = fopen(argv[3], "r")) == NULL)
-		err(1, "fopen(%s)", argv[3]);
-	if (fseeko(dpf, 32 + bzctrllen, SEEK_SET))
-		err(1, "fseeko64(%s, %lld)", argv[3],
-		    (long long)(32 + bzctrllen));
-	if ((epf = fopen(argv[3], "r")) == NULL)
-		err(1, "fopen(%s)", argv[3]);
-	if (fseeko(epf, 32 + bzctrllen + bzdatalen, SEEK_SET))
-		err(1, "fseeko64(%s, %lld)", argv[3],
-		    (long long)(32 + bzctrllen + bzdatalen));
-
 	if(((fd=open(argv[1],O_RDONLY,0))<0) ||
 		((req.oldsize=lseek(fd,0,SEEK_END))==-1) ||
 		((old=malloc(req.oldsize+1))==NULL) ||
@@ -265,30 +226,19 @@ int main(int argc,char * argv[])
 	req.old = old;
 	if((req.new=malloc(req.newsize+1))==NULL) err(1,NULL);
 
-	cbz2.pf = cpf;
-	req.control.opaque = &cbz2;
-	req.control.read = readcompress;
-	dbz2.pf = dpf;
-	req.diff.opaque = &dbz2;
-	req.diff.read = readcompress;
-	ebz2.pf = epf;
-	req.extra.opaque = &ebz2;
-	req.extra.read = readcompress;
-
-	if (BZ_OK != (cbz2err = BZ2_bzDecompressInit(&cbz2.bz2, 0, 0)))
-		errx(1, "BZ2_bzDecompressInit, bz2err = %d", cbz2err);
-	if (BZ_OK != (dbz2err = BZ2_bzDecompressInit(&dbz2.bz2, 0, 0)))
-		errx(1, "BZ2_bzDecompressInit, bz2err = %d", dbz2err);
-	if (BZ_OK != (ebz2err = BZ2_bzDecompressInit(&ebz2.bz2, 0, 0)))
-		errx(1, "BZ2_bzDecompressInit, bz2err = %d", ebz2err);
+	bz2.pf = f;
+	req.stream.opaque = &bz2;
+	req.stream.read = readcompress;
+
+	if (BZ_OK != (bz2err = BZ2_bzDecompressInit(&bz2.bz2, 0, 0)))
+		errx(1, "BZ2_bzDecompressInit, bz2err = %d", bz2err);
 
 	if (bspatch(req))
 		err(1, "bspatch");
 
 	/* Clean up the bzip2 reads */
-	BZ2_bzDecompressEnd(&cbz2.bz2);
-	BZ2_bzDecompressEnd(&dbz2.bz2);
-	BZ2_bzDecompressEnd(&ebz2.bz2);
+	BZ2_bzDecompressEnd(&bz2.bz2);
+	fclose(f);
 
 	/* Write the new file */
 	if(((fd=open(argv[2],O_CREAT|O_TRUNC|O_WRONLY,0666))<0) ||