Performance optimizations for sbcenc utility

Read and write buffers sizes increased, memmove overhead eliminated.
Nonportable cast from 'unsigned char *' to 'struct au_header *' is
now also resolved as part of the changes.

1 files changed, 50 insertions, 72 deletions

diff --git a/sbc/sbcenc.c b/sbc/sbcenc.c
index 9cbfb871..388be2a4 100644
--- a/sbc/sbcenc.c
+++ b/sbc/sbcenc.c
@@ -40,45 +40,15 @@
 
 static int verbose = 0;
 
-static ssize_t __read(int fd, void *buf, size_t count)
-{
-	ssize_t len, pos = 0;
-
-	while (count > 0) {
-		len = read(fd, buf + pos, count);
-		if (len <= 0)
-			return pos > len ? pos : len;
-
-		count -= len;
-		pos   += len;
-	}
-
-	return pos;
-}
-
-static ssize_t __write(int fd, const void *buf, size_t count)
-{
-	ssize_t len, pos = 0;
-
-	while (count > 0) {
-		len = write(fd, buf + pos, count);
-		if (len <= 0)
-			return len;
-
-		count -= len;
-		pos   += len;
-	}
-
-	return pos;
-}
+#define BUF_SIZE 32768
+static unsigned char input[BUF_SIZE], output[BUF_SIZE + BUF_SIZE / 4];
 
 static void encode(char *filename, int subbands, int bitpool, int joint,
 					int dualchannel, int snr, int blocks)
 {
-	struct au_header *au_hdr;
-	unsigned char input[2048], output[2048];
+	struct au_header au_hdr;
 	sbc_t sbc;
-	int fd, len, size, count, encoded, srate;
+	int fd, len, size, count, encoded, srate, codesize, nframes;
 
 	if (strcmp(filename, "-")) {
 		fd = open(filename, O_RDONLY);
@@ -90,8 +60,8 @@ static void encode(char *filename, int subbands, int bitpool, int joint,
 	} else
 		fd = fileno(stdin);
 
-	len = __read(fd, input, sizeof(input));
-	if (len < sizeof(*au_hdr)) {
+	len = read(fd, &au_hdr, sizeof(au_hdr));
+	if (len < sizeof(au_hdr)) {
 		if (fd > fileno(stderr))
 			fprintf(stderr, "Can't read header from file %s: %s\n",
 						filename, strerror(errno));
@@ -100,19 +70,17 @@ static void encode(char *filename, int subbands, int bitpool, int joint,
 		goto done;
 	}
 
-	au_hdr = (struct au_header *) input;
-
-	if (au_hdr->magic != AU_MAGIC ||
-			BE_INT(au_hdr->hdr_size) > 128 ||
-			BE_INT(au_hdr->hdr_size) < 24 ||
-			BE_INT(au_hdr->encoding) != AU_FMT_LIN16) {
+	if (au_hdr.magic != AU_MAGIC ||
+			BE_INT(au_hdr.hdr_size) > 128 ||
+			BE_INT(au_hdr.hdr_size) < 24 ||
+			BE_INT(au_hdr.encoding) != AU_FMT_LIN16) {
 		fprintf(stderr, "Not in Sun/NeXT audio S16_BE format\n");
 		goto done;
 	}
 
 	sbc_init(&sbc, 0L);
 
-	switch (BE_INT(au_hdr->sample_rate)) {
+	switch (BE_INT(au_hdr.sample_rate)) {
 	case 16000:
 		sbc.frequency = SBC_FREQ_16000;
 		break;
@@ -127,11 +95,11 @@ static void encode(char *filename, int subbands, int bitpool, int joint,
 		break;
 	}
 
-	srate = BE_INT(au_hdr->sample_rate);
+	srate = BE_INT(au_hdr.sample_rate);
 
 	sbc.subbands = subbands == 4 ? SBC_SB_4 : SBC_SB_8;
 
-	if (BE_INT(au_hdr->channels) == 1) {
+	if (BE_INT(au_hdr.channels) == 1) {
 		sbc.mode = SBC_MODE_MONO;
 		if (joint || dualchannel) {
 			fprintf(stderr, "Audio is mono but joint or "
@@ -151,9 +119,9 @@ static void encode(char *filename, int subbands, int bitpool, int joint,
 	}
 
 	sbc.endian = SBC_BE;
-	count = BE_INT(au_hdr->data_size);
-	size = len - BE_INT(au_hdr->hdr_size);
-	memmove(input, input + BE_INT(au_hdr->hdr_size), size);
+	count = BE_INT(au_hdr.data_size);
+	size = len - BE_INT(au_hdr.hdr_size);
+	memmove(input, input + BE_INT(au_hdr.hdr_size), size);
 
 	sbc.bitpool = bitpool;
 	sbc.allocation = snr ? SBC_AM_SNR : SBC_AM_LOUDNESS;
@@ -172,37 +140,47 @@ static void encode(char *filename, int subbands, int bitpool, int joint,
 						"STEREO" : "JOINTSTEREO");
 	}
 
+	codesize = sbc_get_codesize(&sbc);
+	nframes = sizeof(input) / codesize;
 	while (1) {
-		if (size < sizeof(input)) {
-			len = __read(fd, input + size, sizeof(input) - size);
-			if (len == 0 && size == 0)
-				break;
-
-			if (len < 0) {
-				perror("Can't read audio data");
+		unsigned char *inp, *outp;
+		/* read data for up to 'nframes' frames of input data */
+		size = read(fd, input, codesize * nframes);
+		if (size < 0) {
+			/* Something really bad happened */
+			perror("Can't read audio data");
+			break;
+		}
+		if (size < codesize) {
+			/* Not enough data for encoding even a single frame */
+			break;
+		}
+		/* encode all the data from the input buffer in a loop */
+		inp = input;
+		outp = output;
+		while (size >= codesize) {
+			len = sbc_encode(&sbc, inp, codesize,
+				outp, sizeof(output) - (outp - output),
+				&encoded);
+			if (len != codesize || encoded <= 0) {
+				fprintf(stderr,
+					"sbc_encode fail, len=%d, encoded=%d\n",
+					len, encoded);
 				break;
 			}
-
-			size += len;
+			size -= len;
+			inp += len;
+			outp += encoded;
 		}
-
-		len = sbc_encode(&sbc, input, size,
-					output, sizeof(output), &encoded);
-		if (len <= 0)
-			break;
-		if (len < size)
-			memmove(input, input + len, size - len);
-
-		size -= len;
-
-		len = __write(fileno(stdout), output, encoded);
-		if (len == 0)
-			break;
-
-		if (len < 0 || len != encoded) {
+		len = write(fileno(stdout), output, outp - output);
+		if (len != outp - output) {
 			perror("Can't write SBC output");
 			break;
 		}
+		if (size >= codesize) {
+			/* sbc_encode failure has been detected earlier */
+			break;
+		}
 	}
 
 	sbc_finish(&sbc);