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#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "util.h"
// displays an error message and exits
void util_fatal_error(const char* msgfmt, ...) {
va_list args;
fputs(ERRMSG_START, stderr);
va_start(args, msgfmt);
vfprintf(stderr, msgfmt, args);
va_end(args);
fputs(ERRMSG_END "\n", stderr);
exit(1);
}
// reads a whole file into memory, and returns a malloc'd pointer to the data.
void* util_read_whole_file(const char* filename, size_t* pSize) {
FILE* file = fopen(filename, "rb");
uint8_t* buffer;
size_t size;
if (file == NULL)
util_fatal_error("failed to open file '%s' for reading: %s", filename, strerror(errno));
// get size
fseek(file, 0, SEEK_END);
size = ftell(file);
// allocate buffer
buffer = malloc(size + 1);
// read file
fseek(file, 0, SEEK_SET);
if (fread(buffer, size, 1, file) != 1)
util_fatal_error("error reading from file '%s': %s", filename, strerror(errno));
// null-terminate the buffer (in case of text files)
buffer[size] = 0;
fclose(file);
if (pSize != NULL)
*pSize = size;
return buffer;
}
// writes data to file
void util_write_whole_file(const char* filename, const void* data, size_t size) {
FILE* file = fopen(filename, "wb");
if (file == NULL)
util_fatal_error("failed to open file '%s' for writing: %s", filename, strerror(errno));
if (fwrite(data, size, 1, file) != 1)
util_fatal_error("error writing to file '%s': %s", filename, strerror(errno));
fclose(file);
}
uint32_t util_read_uint32_be(const uint8_t* data) {
return data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3] << 0;
}
// writes a big-endian 32-bit integer
void util_write_uint32_be(uint8_t* data, uint32_t val) {
data[0] = val >> 24;
data[1] = val >> 16;
data[2] = val >> 8;
data[3] = val >> 0;
}
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