/*
 * Here we implement the function that reads binary files
 * in our ad hoc format for TRAU testing.
 */

#include <sys/types.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "read_file.h"

static int check_magic(const uint8_t *buf, unsigned nframes, bool *got_fr,
			bool *got_efr)
{
	unsigned n;

	for (n = 0; n < nframes; n++) {
		switch (*buf & 0xF0) {
		case 0xC0:
			*got_efr = true;
			break;
		case 0xD0:
			*got_fr = true;
			break;
		default:
			return -1;
		}
		buf += 34;
	}
	return 0;
}

int read_binary_file(const char *filename, bool is_efr, uint8_t **bufret,
		     unsigned *size_ret)
{
	int fd, rc;
	struct stat st;
	uint8_t *buf;
	unsigned nframes;
	bool got_fr, got_efr;

	fd = open(filename, O_RDONLY);
	if (fd < 0) {
		perror(filename);
		return -1;
	}
	fstat(fd, &st);
	if (!S_ISREG(st.st_mode)) {
		close(fd);
		fprintf(stderr, "error: %s is not a regular file\n", filename);
		return -1;
	}
	if (!st.st_size) {
		close(fd);
		fprintf(stderr, "error: %s is an empty file\n", filename);
		return -1;
	}
	if (st.st_size % 34) {
		close(fd);
		fprintf(stderr,
			"error: size of %s is not a multiple of 34 bytes\n",
			filename);
		return -1;
	}
	buf = malloc(st.st_size);
	if (!buf) {
		close(fd);
		fprintf(stderr, "unable to malloc buffer for %s\n", filename);
		return -1;
	}
	read(fd, buf, st.st_size);
	close(fd);
	nframes = st.st_size / 34;

	got_fr = false;
	got_efr = false;
	rc = check_magic(buf, nframes, &got_fr, &got_efr);
	if (rc < 0 || got_fr && got_efr) {
		free(buf);
		fprintf(stderr, "error: %s is not a valid TRAU-UL test file\n",
			filename);
		return -1;
	}
	if (is_efr != got_efr) {
		free(buf);
		fprintf(stderr, "error: %s is for the wrong codec\n", filename);
		return -1;
	}
	*bufret = buf;
	*size_ret = nframes;
	return 0;
}