First proper commit.

tools/util.c

@@ -0,0 +1,87 @@
+#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("error: ", stderr);
+
+    va_start(args, msgfmt);
+    vfprintf(stderr, msgfmt, args);
+    va_end(args);
+
+    fputc('\n', stderr);
+
+    exit(1);
+}
+
+// reads a whole file into memory, and returns a 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;
+}