I get a segmentation fault, specifically: load of null pointer of type 'BYTE' (aka 'unsigned char')' error when I try to compile my code.
Any assistance is kindly appreciated.
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include "bmp.h"
//#define BLOCK 512
// typedef uint8_t BYTE;
int main(int argc, char *argv[])
{
//ensure proper usuage
if(argc != 2)
{
fprintf(stderr, "Usuage: ./recover filename\n");
return 1;
}
// create file pointer
char *pfilename = argv[1];
/* open memory card file */
//If it isn't able to be opened return 2
FILE *pmem = fopen(pfilename, "r");
if (pmem == NULL)
{
fprintf(stderr, "Could not open %s\n", pfilename);
return 2;
}
// count parameter
int jpegCount = 0;
// holds the rea
int openedJpeg = 0;
char filename[50];
//create an array called buffer of size 512
//BYTE buffer[BLOCK];
BYTE *buffer = malloc(sizeof(BYTE) * 512);
if(buffer == NULL)
{
return 3;
}
//Provide a JPEG filename
sprintf(filename, "%03i.jpg", jpegCount);
//create JPEG file with established filename for writing
FILE *img = fopen(filename, "w");
if (img == NULL)
{
fclose(pmem);
fprintf(stderr, "Could not create %s.\n", filename);
return 3;
}
//read file
while(fread(&buffer, 1, 512, pmem) == 512)
{
/* find beginning of JPEG */
// are we at a start of a new JPEG? - first 4 bytes indicate the start of a new JPEG
if (buffer[0] == 0xff &&
buffer[1] == 0xd8 &&
buffer[2] == 0xff &&
(buffer[3] & 0xf0) == 0xe0)
{
/* open a new JPEG */
// a JPEG file isn't open
if(openedJpeg == 0)
{
openedJpeg = 1;
//write the bytes to the file
fwrite(&buffer, 1, 512, img);
}
//if a JPEG was already found
else
{
//close previous JPEG
fclose(img);
jpegCount++;
openedJpeg = 0;
//Provide a new JPEG filename
sprintf(filename, "%03i.jpg", jpegCount);
//create a new JPEG file with the established filename for writing
img = fopen(filename, "w");
if (img == NULL)
{
fclose(pmem);
fprintf(stderr, "Could not create %s.\n", filename);
return 3;
}
openedJpeg = 1;
//write the bytes to the file
fwrite(&buffer, 1, 512, img);
}
}
//first 4 bytes are not the start of a new JPEG
else
{
//JPEG is not open
if(openedJpeg == 0)
{
//discard the 512 bytes and continue loop
}
//JPEG is open
else
{
//write to the current JPEG file
fwrite(&buffer, 1, 512, img);
}
}
}
//free memory allocated
//free(buffer);
fclose(img);
openedJpeg = 0;
fclose(pmem);
}
My include file
/**
* BMP-related data types based on Microsoft's own.
*/
#include <stdint.h>
/**
* Common Data Types
*
* The data types in this section are essentially aliases for C/C++
* primitive data types.
*
* Adapted from https://msdn.microsoft.com/en-us/library/cc230309.aspx.
* See http://en.wikipedia.org/wiki/Stdint.h for more on stdint.h.
*/
typedef uint8_t BYTE;
