Created
September 2, 2019 20:28
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My solution to CS50 recover.
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| #include <stdio.h> | |
| #include <stdlib.h> | |
| #include <cs50.h> | |
| #include <stdint.h> | |
| #include <ctype.h> | |
| typedef uint8_t byte; | |
| bool isjpg(byte *block); | |
| int main(int argc, char *argv[]) | |
| { | |
| // ensure proper usage | |
| if (argc != 2) | |
| { | |
| fprintf(stderr, "Usage: recover forensicfilename.raw\n"); | |
| return 1; | |
| } | |
| // open input file | |
| FILE *inptr = fopen(argv[1], "r"); | |
| if (inptr == NULL) | |
| { | |
| fprintf(stderr, "Could not open %s.\n", argv[1]); | |
| return 2; | |
| } | |
| // Declare output file buffer ? | |
| FILE *JPG; | |
| // Declare temporary storage (buffer) for block. | |
| byte block[512]; | |
| // bool to see if we've found any jpgs yet | |
| bool foundjpg = false; | |
| int readblock; | |
| int jpgnum = 0; | |
| while (fread(block, sizeof(block), 1, inptr) == 1) | |
| { | |
| // If we found a header | |
| if (isjpg(block)) | |
| { | |
| // Filename will be three digits + .jpg and a null character | |
| char filename[8]; | |
| // filename is defined by jpgnum which only iterates when new jpgheader is found. | |
| sprintf(filename, "%03.3i.jpg", jpgnum); | |
| // For debugging | |
| printf("processing file: %s\n", filename); | |
| if (foundjpg == true) | |
| { | |
| // Already jpg in buffer. Close/finish it. | |
| fclose(JPG); | |
| } | |
| else | |
| { | |
| // First jpg! Set foundjpg to true. | |
| foundjpg = true; | |
| } | |
| // Open new and write first block in it | |
| JPG = fopen(filename, "w"); | |
| fwrite(block, sizeof(block), 1, JPG); | |
| jpgnum++; | |
| } | |
| // If we didn't find a header | |
| else | |
| { | |
| // Are we already working on a jpg? | |
| if (foundjpg == true) | |
| { | |
| // This is not a header and there is already a jpg, so write this block to current jpg. | |
| fwrite(block, sizeof(block), 1, JPG); | |
| } | |
| // We only land here if we're in the beginning and still haven't found a header. | |
| // We check again. If there happen to be zero headers in the whole file, loop exits and file closes. | |
| } | |
| } | |
| fclose(inptr); | |
| fclose(JPG); | |
| } | |
| bool isjpg(byte *block) | |
| { | |
| if (block[0] == 0xff && | |
| block[1] == 0xd8 && | |
| block[2] == 0xff && | |
| (block[3] & 0xf0) == 0xe0) | |
| { | |
| return true; | |
| } | |
| else | |
| { | |
| return false; | |
| } | |
| } |
line 38 "int readblock;" Seems is redundant.
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Excellent work