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Use a header structure for reading / writing the header structure. #17

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Use a header structure for reading / writing the header structure. #17

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2e4df50
Fix split() pivoting to avoid Quicksort worst case causing stack over…
samuelhuang May 2, 2016
d1edc81
Use a header structure for reading / writing the header.
Dec 1, 2017
5ffee3d
Merge remote-tracking branch 'samuelhuang/master' into header
Dec 1, 2017
5bbb52a
WIP:BSDiff writes out patch in binary format rather than zipped format.
Jan 9, 2018
af79834
bspatch works.
Jan 9, 2018
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15 changes: 15 additions & 0 deletions bscommon.h
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Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
#ifndef BS_COMMON_H
#define BS_COMMON_H

# include <stdint.h>

#define HEADER_TXT ("ENDSLEY/BSDIFF44")
typedef struct BSHeader{
char header_txt[sizeof(HEADER_TXT)];
uint8_t new_size[8];
uint8_t old_size[8];
uint8_t new_chksum[2];
uint8_t old_chksum[2];
}BSHeader;

#endif
77 changes: 60 additions & 17 deletions bsdiff.c
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Original file line number Diff line number Diff line change
Expand Up @@ -26,15 +26,18 @@
*/

#include "bsdiff.h"

#include "bscommon.h"
#include <limits.h>
#include <string.h>

#define MIN(x,y) (((x)<(y)) ? (x) : (y))
#define MEDIAN3(a,b,c) (((a)<(b)) ? \
((b)<(c) ? (b) : ((a)<(c) ? (c) : (a))) : \
((b)>(c) ? (b) : ((a)>(c) ? (c) : (a))))

static void split(int64_t *I,int64_t *V,int64_t start,int64_t len,int64_t h)
{
int64_t i,j,k,x,tmp,jj,kk;
int64_t i,j,k,x,y,z,tmp,jj,kk;

if(len<16) {
for(k=start;k<start+len;k+=j) {
Expand All @@ -55,7 +58,20 @@ static void split(int64_t *I,int64_t *V,int64_t start,int64_t len,int64_t h)
return;
};

x=V[I[start+len/2]+h];
/* Select pivot, algorithm by Bentley & McIlroy */
j=start+len/2;
k=start+len-1;
x=V[I[j]+h];
y=V[I[start]+h];
z=V[I[k]+h];
if(len>40) { /* Big array: Pseudomedian of 9 */
tmp=len/8;
x=MEDIAN3(x,V[I[j-tmp]+h],V[I[j+tmp]+h]);
y=MEDIAN3(y,V[I[start+tmp]+h],V[I[start+tmp+tmp]+h]);
z=MEDIAN3(z,V[I[k-tmp]+h],V[I[k-tmp-tmp]+h]);
}; /* Else medium array: Pseudomedian of 3 */
x=MEDIAN3(x,y,z);

jj=0;kk=0;
for(i=start;i<start+len;i++) {
if(V[I[i]+h]<x) jj++;
Expand Down Expand Up @@ -373,22 +389,36 @@ static int bz2_write(struct bsdiff_stream* stream, const void* buffer, int size)
return 0;
}

static int raw_write(struct bsdiff_stream* stream, const void* buffer, int size)
{
int bz2err;
int bytes_wrote = fwrite ( buffer, 1, size, (FILE*) stream->opaque );
if ( bytes_wrote != size)
return -1;

return 0;
}

int main(int argc,char *argv[])
{
int use_bz2 = 0; /* Should wwe use bz2 or not ? */
int fd;
int bz2err;
uint8_t *old,*new;
off_t oldsize,newsize;
uint8_t buf[8];
off_t oldchksum, newchksum;
BSHeader header;
FILE * pf;
struct bsdiff_stream stream;
BZFILE* bz2;

memset(&bz2, 0, sizeof(bz2));
stream.malloc = malloc;
stream.free = free;
stream.write = bz2_write;

if(use_bz2)
stream.write = bz2_write;
else
stream.write = raw_write;
if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);

/* Allocate oldsize+1 bytes instead of oldsize bytes to ensure
Expand All @@ -414,23 +444,36 @@ int main(int argc,char *argv[])
if ((pf = fopen(argv[3], "w")) == NULL)
err(1, "%s", argv[3]);

/* Write header (signature+newsize)*/
offtout(newsize, buf);
if (fwrite("ENDSLEY/BSDIFF43", 16, 1, pf) != 1 ||
fwrite(buf, sizeof(buf), 1, pf) != 1)
err(1, "Failed to write header");
/* Write header (signature+newsize) */
strncpy(header.header_txt,HEADER_TXT, sizeof(header.header_txt));
offtout(newsize, header.new_size);
offtout(oldsize, header.old_size);
/* TODO Write out checksums */
offtout(newchksum, header.new_chksum);
offtout(oldchksum, header.old_chksum);

if( fwrite(&header,sizeof(header),1,pf) != 1)
err(1, "Failed to write header");

if (NULL == (bz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)))
errx(1, "BZ2_bzWriteOpen, bz2err=%d", bz2err);
if(use_bz2)
{
if (NULL == (bz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)))
errx(1, "BZ2_bzWriteOpen, bz2err=%d", bz2err);
stream.opaque = bz2;
}
else{
stream.opaque = pf;
}

stream.opaque = bz2;
if (bsdiff(old, oldsize, new, newsize, &stream))
err(1, "bsdiff");

BZ2_bzWriteClose(&bz2err, bz2, 0, NULL, NULL);
if (bz2err != BZ_OK)
err(1, "BZ2_bzWriteClose, bz2err=%d", bz2err);
if(use_bz2)
{
BZ2_bzWriteClose(&bz2err, bz2, 0, NULL, NULL);
if (bz2err != BZ_OK)
err(1, "BZ2_bzWriteClose, bz2err=%d", bz2err);
}

if (fclose(pf))
err(1, "fclose");
Expand Down
51 changes: 40 additions & 11 deletions bspatch.c
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Original file line number Diff line number Diff line change
Expand Up @@ -106,7 +106,7 @@ int bspatch(const uint8_t* old, int64_t oldsize, uint8_t* new, int64_t newsize,
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>

#include "bscommon.h"
static int bz2_read(const struct bspatch_stream* stream, void* buffer, int length)
{
int n;
Expand All @@ -121,12 +121,26 @@ static int bz2_read(const struct bspatch_stream* stream, void* buffer, int lengt
return 0;
}

static int raw_read(const struct bspatch_stream* stream, void* buffer, int length)
{
int n;
int bz2err;
BZFILE* bz2;
size_t bytes_read = fread ( buffer, 1, length, (FILE *) stream->opaque );

if (bytes_read != length)
return -1;

return 0;
}

int main(int argc,char * argv[])
{
int use_bz2 = 0;
FILE * f;
int fd;
int bz2err;
uint8_t header[24];
BSHeader header;
uint8_t *old, *new;
int64_t oldsize, newsize;
BZFILE* bz2;
Expand All @@ -140,20 +154,23 @@ int main(int argc,char * argv[])
err(1, "fopen(%s)", argv[3]);

/* Read header */
if (fread(header, 1, 24, f) != 24) {
if (fread(&header, sizeof(header), 1 , f) != 1) {
if (feof(f))
errx(1, "Corrupt patch\n");
err(1, "fread(%s)", argv[3]);
}

/* Check for appropriate magic */
if (memcmp(header, "ENDSLEY/BSDIFF43", 16) != 0)
if (memcmp(header.header_txt, HEADER_TXT, sizeof(HEADER_TXT)) != 0)
errx(1, "Corrupt patch\n");

/* Read lengths from header */
newsize=offtin(header+16);
newsize=offtin(header.new_size);
if(newsize<0)
errx(1,"Corrupt patch\n");
int oldsize_in = offtin(header.old_size);
if(oldsize_in != oldsize)
errx(1,"Corrupt patch Header oldsize %d != file %lld\n",oldsize_in, oldsize);

/* Close patch file and re-open it via libbzip2 at the right places */
if(((fd=open(argv[1],O_RDONLY,0))<0) ||
Expand All @@ -165,16 +182,28 @@ int main(int argc,char * argv[])
(close(fd)==-1)) err(1,"%s",argv[1]);
if((new=malloc(newsize+1))==NULL) err(1,NULL);

if (NULL == (bz2 = BZ2_bzReadOpen(&bz2err, f, 0, 0, NULL, 0)))
errx(1, "BZ2_bzReadOpen, bz2err=%d", bz2err);
if(use_bz2)
{
if (NULL == (bz2 = BZ2_bzReadOpen(&bz2err, f, 0, 0, NULL, 0)))
errx(1, "BZ2_bzReadOpen, bz2err=%d", bz2err);
stream.read = bz2_read;
stream.opaque = bz2;

}
else{
stream.read = raw_read;
stream.opaque = f;

}

stream.read = bz2_read;
stream.opaque = bz2;
if (bspatch(old, oldsize, new, newsize, &stream))
errx(1, "bspatch");

/* Clean up the bzip2 reads */
BZ2_bzReadClose(&bz2err, bz2);
if(use_bz2)
{
/* Clean up the bzip2 reads */
BZ2_bzReadClose(&bz2err, bz2);
}
fclose(f);

/* Write the new file */
Expand Down