Created
November 16, 2014 21:07
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Counts the occurrences of each byte in a file
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// | |
// main.c | |
// byte count | |
// | |
// Created by kyle kersey on 11/16/14. | |
// Copyright (c) 2014 kyle kersey. All rights reserved. | |
// | |
#include <stdio.h> | |
#include <stdlib.h> | |
#include <sys/stat.h> | |
int main(int argc, const char * argv[]) { | |
if (argc < 2) { | |
fprintf(stderr, "Usage: file name\n"); | |
return 0; | |
} | |
/* get size of file */ | |
struct stat st; | |
stat(argv[1], &st); | |
uint32_t file_size = st.st_size; | |
/* allocate memory for file contents */ | |
unsigned char *file_contents; | |
file_contents = malloc(file_size); | |
/* open and read the file */ | |
FILE *fp = fopen(argv[1], "rb"); | |
if (fp == NULL) { | |
fprintf(stderr, "cannot open file '%s'\n", argv[1]); | |
return 0; | |
} | |
fread(file_contents, file_size, 1, fp); | |
fclose(fp); | |
/* array holding byte counts */ | |
uint32_t byte_list[0xFF]; | |
/* clear the array */ | |
memset(byte_list, 0, sizeof(byte_list)); | |
unsigned long file_index=0; | |
while (file_index<file_size) { | |
++byte_list[file_contents[file_index++]]; | |
} | |
int i; | |
for (i=0; i<=0xFF; i++) { | |
printf("%02X %d\n", i, byte_list[i]); | |
} | |
/* clear alocated memory */ | |
free(file_contents); | |
return 0; | |
} |
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