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Merge pull request #4 from wiggy2k/FIX/Start-at-offset-0

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Fix compile on newer GCC and fix bug that missed matches starting at …
This commit is contained in:
Natalia Portillo
2025-03-02 17:20:52 +00:00
committed by GitHub
parent 2fd5f2caed f13954905a
commit 2e4a2eae85
2 changed files with 26 additions and 19 deletions
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2
Makefile
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@@ -74,7 +74,7 @@ $(BINARY): findcrcs.cc md5.c md5.h crcutil-1.0 crcutil.a
crcutil.a: crcutil-1.0
rm -rf *.o
$(BINPREFIX)g++ -O3 -Wall $(CXXFLAGS) -c crcutil-1.0/examples/interface.cc crcutil-1.0/code/*.cc -Icrcutil-1.0/code -Icrcutil-1.0/tests -Icrcutil-1.0/examples
$(BINPREFIX)g++ -O3 -Wall -msse4.2 $(CXXFLAGS) -c crcutil-1.0/examples/interface.cc crcutil-1.0/code/*.cc -Icrcutil-1.0/code -Icrcutil-1.0/tests -Icrcutil-1.0/examples
$(BINPREFIX)ar r crcutil.a *.o
rm -rf *.o

43
findcrcs.cc
View File

@@ -28,9 +28,6 @@
These changes are released under the same license as the original md5.c file.
*/
// Usage: findcrcs [-e] [-p PADDING] [-s SEEDFILE] [--] <FILE> <WINDOWSIZE> <CRC> [CRCS...]
// code comments not included (yet, if ever)
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
@@ -275,7 +272,7 @@ void usage() {
void findcrcs() {
unsigned int i1;
int i2, fd1, fd2, readbytes, done;
int i2, fd1, fd2, readbytes;
crcutil_interface::CRC *crcutil;
unsigned long long crc;
unsigned char buffer1[BUFFERSIZE], buffer2[BUFFERSIZE];
@@ -295,16 +292,30 @@ void findcrcs() {
crcutil->Compute(&buffer1, (windowsize % BUFFERSIZE), &crc);
}
done = 0;
if (!(single && checkcrcs((unsigned int)crc, 0))) {
for (i1 = 0; i1 < ((filesize - windowsize) / BUFFERSIZE) + 1; i1++) {
readbytes = read(fd1, &buffer1, BUFFERSIZE);
read(fd2, &buffer2, BUFFERSIZE);
for (i2 = 0; i2 < readbytes; i2++) {
crcutil->Roll(buffer2[i2], buffer1[i2], &crc, NULL);
if ((done = (single & checkcrcs((unsigned int)crc, (i1 * BUFFERSIZE) + i2 + 1))) == 1) break;
/* --- force check from offset 0 when not single --- */
if (checkcrcs((unsigned int)crc, 0)) {
if (single) {
close(fd2);
close(fd1);
crcutil->Delete();
return;
}
}
/* Continue scanning the rest of the file starting from offset 1 */
for (i1 = 0; i1 < ((filesize - windowsize) / BUFFERSIZE) + 1; i1++) {
readbytes = read(fd1, &buffer1, BUFFERSIZE);
read(fd2, &buffer2, BUFFERSIZE);
for (i2 = 0; i2 < readbytes; i2++) {
crcutil->Roll(buffer2[i2], buffer1[i2], &crc, NULL);
if (checkcrcs((unsigned int)crc, (i1 * BUFFERSIZE) + i2 + 1)) {
if (single) {
close(fd2);
close(fd1);
crcutil->Delete();
return;
}
}
if (done) break;
}
}
@@ -315,7 +326,6 @@ void findcrcs() {
int checkcrcs(unsigned int crc, int offset) {
int i;
for (i = 0; i < totalcrcs; i++) {
if (crc == crcs[i].crc) {
foundcrc(i, offset);
@@ -441,12 +451,10 @@ void extract_init(int offset) {
int extract_read(void *buffer, unsigned int size) {
unsigned int bytesread, returnvalue;
if (size == 0 || extract_bytesleft == 0) return 0;
if (size > extract_bytesleft) {
size = extract_bytesleft;
}
returnvalue = 0;
if (extract_offset < 0) {
if ((unsigned int)(extract_offset * -1) >= size) {
@@ -463,7 +471,6 @@ int extract_read(void *buffer, unsigned int size) {
extract_offset = 0;
}
}
lseek(fd, extract_offset, SEEK_SET);
bytesread = read(fd, buffer, size);
extract_bytesleft -= bytesread;
@@ -477,6 +484,6 @@ int extract_read(void *buffer, unsigned int size) {
extract_offset += size;
returnvalue += size;
}
return returnvalue;
}