/**
 * A simple GNUTLS NOP program that contains helper functions
 * to be used in the subsequent examples. It also calls GNUTLS
 * initialization function. That way it is possible that it is
 * possible to compile and execute programs that use GNUTLS
 * library.
 *
 * Written by Stjepan Gros <stjepan.gros@gmail.com>. Use this
 * code as it suites you.
 */
#include <stdio.h>

#include <gnutls/gnutls.h>
#include <gnutls/x509.h>

#include <glib.h>

/**
 * Load a given file into memory buffer
 *
 * @param file		File name and path to load
 *
 * \return Pointer to buffer, or NULL if any error occured
 */
gnutls_datum_t *load_file(const char *file)
{
	FILE *f;
	size_t filelen, size;
	void *ptr = NULL;
	gnutls_datum_t *loaded_file = NULL;

	if ((f = fopen(file, "r")) != NULL) {

		if (fseek(f, 0, SEEK_END) != 0) {
			perror("fseek");
			goto out;
		}

		if ((filelen = ftell(f)) < 0) {
			perror("ftell");
			goto out;
		}

		if (fseek(f, 0, SEEK_SET) != 0) {
			perror("fseek");
			goto out;
		}

		ptr = g_malloc(filelen);

		if ((size = fread(ptr, 1, filelen, f)) < filelen) {
			if (size < 0)
				perror("fread");

			goto out;
		}

		loaded_file = g_malloc0(sizeof(gnutls_datum_t));

		loaded_file->data = ptr;
		loaded_file->size = filelen;

out:
		fclose(f);
	} else
		perror ("fopen");

	return loaded_file;
}

/**
 * Free GNUTLS specific memory buffer
 *
 * @param buffer	Buffer to be free'd
 */
void unload_file(gnutls_datum_t *buffer)
{
	g_free(buffer->data);
	g_free(buffer);
}

/**
 * Given a buffer and it's size dump hex represetation to stdout
 *
 * @param buf	Pointer to a buffer
 * @param size	Size of the buffer in bytes
 *
 * This function prints 16 bytes per row of the buffer
 */
void dump_hex(unsigned char *buf, size_t size)
{
	int i, cols;
	unsigned int ch;

	for (i = 0, cols=0; i < size; i++, cols++) {

		if (cols == 16) {
			printf("\n");
			cols = 0;
		}

		ch = (unsigned int)((unsigned char)buf[i] & 0xF0) >> 4;

		if (ch < 10)
			ch += '0';
		else
			ch += 'A' - 10;

		printf("%c", ch);

		ch = (unsigned char)buf[i] & 0x0F;

		if (ch < 10)
			ch += '0';
		else
			ch += 'A' - 10;

		printf("%c ", ch);
	}

	printf ("\n");
}

int main(int argc, char **argv)
{
	gnutls_global_init();

	return 0;
}