--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/frtest/decode.c	Sun Nov 20 00:44:26 2022 +0000
@@ -0,0 +1,76 @@
+/*
+ * This file is the main module for gsmfr-decode utility.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <gsm.h>
+#include "../libgsmfrp/gsm_fr_preproc.h"
+#include "../libtest/binreader.h"
+#include "../libtest/wavwriter.h"
+#include "../libtest/pcmwrite.h"
+
+main(argc, argv)
+	char **argv;
+{
+	FILE *binf;
+	void *wav;
+	gsm dec_state;
+	struct gsmfr_preproc_state *pp_state;
+	uint8_t frame[BINFILE_MAX_FRAME];
+	int16_t pcm[160];
+	int rc, bfi, taf;
+
+	if (argc != 3) {
+		fprintf(stderr, "usage: %s input.gsm output.wav\n", argv[0]);
+		exit(1);
+	}
+	binf = fopen(argv[1], "r");
+	if (!binf) {
+		perror(argv[1]);
+		exit(1);
+	}
+	wav = wav_write_open(argv[2], 8000, 16, 1);
+	if (!wav) {
+		perror(argv[2]);
+		exit(1);
+	}
+	dec_state = gsm_create();
+	if (!dec_state) {
+		fprintf(stderr, "gsm_create() failed!\n");
+		exit(1);
+	}
+	pp_state = gsmfr_preproc_create();
+	if (!pp_state) {
+		fprintf(stderr, "gsmfr_preproc_create() failed!\n");
+		exit(1);
+	}
+	for (;;) {
+		rc = binfile_read_frame(binf, frame);
+		if (rc < 0) {
+			fprintf(stderr, "error: garbage in %s\n", argv[1]);
+			exit(1);
+		}
+		if (!rc)
+			break;
+		if (frame[0] == 0xBF) {
+			bfi = 1;
+			taf = frame[1] & 1;
+		} else if ((frame[0] & 0xF0) == 0xD)
+			bfi = 0;
+		else {
+			fprintf(stderr, "error: %s is not in FR codec format\n",
+				argv[1]);
+			exit(1);
+		}
+		if (bfi)
+			gsmfr_preproc_bfi(pp_state, taf, frame);
+		else
+			gsmfr_preproc_good_frame(pp_state, frame);
+		gsm_decode(dec_state, frame, pcm);
+		write_pcm_to_wav(wav, pcm);
+	}
+	wav_write_close(wav);
+	exit(0);
+}