PSET4 восстановление ошибки сегментации
В этом коде я хочу записать 50 jpg из файла.
(фактические инструкции: )[^]
This is the terminal output: ~/workspace/pset4/jpg/ $ make recover clang -fsanitize=integer -fsanitize=undefined -ggdb3 -O0 -std=c11 -Wall -Werror -Wextra -Wno-sign-compare -Wshadow recover.c -lcrypt -lcs50 -lm -o recover ~/workspace/pset4/jpg/ $ ./recover ---Segmentation fault--- With valgrind, I see that there are no leaks, but a line says that no memory allocations were made: Invalid read of size 4 ==17227== at 0x5E268D4: fclose@@GLIBC_2.2.5 (iofclose.c:54) ==17227== by 0x42DB5F: main (recover.c:85) ==17227== Address 0x0 is not stack'd, malloc'd or (recently) free'd ==17227== ==17227== ==17227== Process terminating with default action of signal 11 (SIGSEGV) ==17227== Access not within mapped region at address 0x0 ==17227== at 0x5E268D4: fclose@@GLIBC_2.2.5 (iofclose.c:54) ==17227== by 0x42DB5F: main (recover.c:85) ==17227== If you believe this happened as a result of a stack ==17227== overflow in your program's main thread (unlikely but ==17227== possible), you can try to increase the size of the ==17227== main thread stack using the --main-stacksize= flag. ==17227== The main thread stack size used in this run was 8388608. ==17227== ==17227== HEAP SUMMARY: ==17227== in use at exit: 0 bytes in 0 blocks ==17227== total heap usage: 1 allocs, 1 frees, 568 bytes allocated = =17227== ==17227== All heap blocks were freed -- no leaks are possible ==17227== ==17227== For counts of detected and suppressed errors, rerun with: -v ==17227== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0) Segmentation fault Thanks a lot,
Что я уже пробовал:
/**
* recover.c
*
* Computer Science 50
* Problem Set 4
*
* Recovers JPEGs from a forensic image.
*/
#include <stdio.h>
#include <cs50.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include <stdint.h>
int main()
{
typedef uint8_t BYTEINBITS;
int pictcount = 0;
FILE* input = fopen("card.raw", "r");
if ( input == NULL )
{
printf(" Could not open card.raw \n");
return 2;
}
FILE* output = NULL;
bool atend = false;
while ( atend == false)
{
BYTEINBITS buffer[512];
fread( &buffer, 512 * sizeof(char), 1, input);
bool jpg = true;
if ( !( ( buffer[0] == 255 ) && ( buffer[1] == 216 ) && ( buffer[2] == 255) && ( buffer[3] > 224 ) ) )
{
jpg = false;
}
if (jpg == true)
{
if (pictcount >= 1)
{
fclose(output);
}
pictcount++;
char title[8];
sprintf(title,"%03d.jpg", pictcount);
output = fopen("title", "w");
}
if (pictcount > 0)
{
fwrite( &buffer, 512 * sizeof(char), 1, output );
}
if ( fread( &buffer, 512*sizeof(char), 1, input) != 1)
{
atend = true;
}
}
fclose(input);
fclose(output);
}