--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ater/read_file.c	Mon Jun 24 08:50:29 2024 +0000
@@ -0,0 +1,98 @@
+/*
+ * 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;
+}