1 files changed, 113 insertions, 0 deletions
diff --git a/src/ccitt-adpcm/decode.c b/src/ccitt-adpcm/decode.c
new file mode 100644
index 0000000..cf8c739
--- /dev/null
+++ b/src/ccitt-adpcm/decode.c
@@ -0,0 +1,113 @@
+/*
+ * decode.c
+ *
+ * CCITT ADPCM decoder
+ *
+ * Usage : decode [-3|4|5] [-a|u|l] < infile > outfile
+ */
+#include <stdio.h>
+#include "g72x.h"
+
+
+/*
+ * Unpack input codes and pass them back as bytes.
+ * Returns 1 if there is residual input, returns -1 if eof, else returns 0.
+ */
+int
+unpack_input(
+	unsigned char		*code,
+	int			bits)
+{
+	static unsigned int	in_buffer = 0;
+	static int		in_bits = 0;
+	unsigned char		in_byte;
+
+	if (in_bits < bits) {
+		if (fread(&in_byte, sizeof (char), 1, stdin) != 1) {
+			*code = 0;
+			return (-1);
+		}
+		in_buffer |= (in_byte << in_bits);
+		in_bits += 8;
+	}
+	*code = in_buffer & ((1 << bits) - 1);
+	in_buffer >>= bits;
+	in_bits -= bits;
+	return (in_bits > 0);
+}
+
+
+main(
+	int			argc,
+	char			**argv)
+{
+	short			sample;
+	unsigned char		code;
+	int			n;
+	struct g72x_state	state;
+	int			out_coding;
+	int			out_size;
+	int			(*dec_routine)();
+	int			dec_bits;
+
+	g72x_init_state(&state);
+	out_coding = AUDIO_ENCODING_ULAW;
+	out_size = sizeof (char);
+	dec_routine = g721_decoder;
+	dec_bits = 4;
+
+	/* Process encoding argument, if any */
+	while ((argc > 1) && (argv[1][0] == '-')) {
+		switch (argv[1][1]) {
+		case '3':
+			dec_routine = g723_24_decoder;
+			dec_bits = 3;
+			break;
+		case '4':
+			dec_routine = g721_decoder;
+			dec_bits = 4;
+			break;
+		case '5':
+			dec_routine = g723_40_decoder;
+			dec_bits = 5;
+			break;
+		case 'u':
+			out_coding = AUDIO_ENCODING_ULAW;
+			out_size = sizeof (char);
+			break;
+		case 'a':
+			out_coding = AUDIO_ENCODING_ALAW;
+			out_size = sizeof (char);
+			break;
+		case 'l':
+			out_coding = AUDIO_ENCODING_LINEAR;
+			out_size = sizeof (short);
+			break;
+		default:
+fprintf(stderr, "CCITT ADPCM Decoder -- usage:\n");
+fprintf(stderr, "\tdecode [-3|4|5] [-a|u|l] < infile > outfile\n");
+fprintf(stderr, "where:\n");
+fprintf(stderr, "\t-3\tProcess G.723 24kbps (3-bit) input data\n");
+fprintf(stderr, "\t-4\tProcess G.721 32kbps (4-bit) input data [default]\n");
+fprintf(stderr, "\t-5\tProcess G.723 40kbps (5-bit) input data\n");
+fprintf(stderr, "\t-a\tGenerate 8-bit A-law data\n");
+fprintf(stderr, "\t-u\tGenerate 8-bit u-law data [default]\n");
+fprintf(stderr, "\t-l\tGenerate 16-bit linear PCM data\n");
+			exit(1);
+		}
+		argc--;
+		argv++;
+	}
+
+	/* Read and unpack input codes and process them */
+	while (unpack_input(&code, dec_bits) >= 0) {
+		sample = (*dec_routine)(code, out_coding, &state);
+		if (out_size == 2) {
+			fwrite(&sample, out_size, 1, stdout);
+		} else {
+			code = (unsigned char)sample;
+			fwrite(&code, out_size, 1, stdout);
+		}
+	}
+	fclose(stdout);
+}