utils: added bitstream read/write helper

include/mediastreamer2/Makefile.am

@@ -36,7 +36,8 @@ mediastreamer2_include_HEADERS= ice.h \
 				bitratecontrol.h \
 				qualityindicator.h \
 				msconference.h \
-				videostarter.h
+				videostarter.h \
+				bits_rw.h
 
 EXTRA_DIST=$(mediastreamer2_include_HEADERS)
 

include/mediastreamer2/bits_rw.h

+/*
+mediastreamer2 library - modular sound and video processing and streaming
+Copyright (C) 2010  Belledonne Communications SARL
+Author: Simon Morlat <simon.morlat@linphone.org>
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+*/
+
+#if !defined(_BITS_RW_H_)
+#define _BITS_RW_H_
+
+#include <ortp/port.h>
+
+typedef struct ms_bits_reader{
+	const uint8_t *buffer;
+	size_t buf_size;
+	int bit_index;
+} MSBitsReader;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void ms_bits_reader_init(MSBitsReader *reader, const uint8_t *buffer, size_t bufsize);
+
+int ms_bits_reader_n_bits(MSBitsReader *reader, int count, unsigned int *ret, const char* symbol_name);
+
+int ms_bits_reader_ue(MSBitsReader *reader, unsigned int* ret, const char* symbol_name);
+
+int ms_bits_reader_se(MSBitsReader *reader, int* ret, const char* symbol_name);
+
+typedef struct ms_bits_writer {
+	uint8_t* buffer;
+	size_t buf_size;
+	int bit_index;
+} MSBitsWriter;
+
+void ms_bits_writer_init(MSBitsWriter *writer, size_t initialbufsize);
+
+int ms_bits_writer_n_bits(MSBitsWriter *writer, int count, unsigned int value, const char* symbol_name);
+
+int ms_bits_writer_ue(MSBitsWriter *writer, unsigned int value, const char* symbol_name);
+
+int ms_bits_writer_se(MSBitsWriter *writer, int value, const char* symbol_name);
+
+int ms_bits_writer_trailing_bits(MSBitsWriter *writer);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

src/Makefile.am

@@ -216,19 +216,19 @@ libmediastreamer_voip_la_SOURCES+=	videofilters/videoenc.c \
 					utils/ffmpeg-priv.h \
 					utils/ffmpeg-priv.c \
 					videofilters/h264dec.c \
-					videofilters/jpegwriter.c 
+					videofilters/jpegwriter.c
 endif
 
-if BUILD_AVCODEC 
-libmediastreamer_voip_la_SOURCES+= 	videofilters/nowebcam.c voip/nowebcam.h 
+if BUILD_AVCODEC
+libmediastreamer_voip_la_SOURCES+= 	videofilters/nowebcam.c voip/nowebcam.h
 else
 if BUILD_IOS
-libmediastreamer_voip_la_SOURCES+= 	videofilters/nowebcam.c voip/nowebcam.h 
+libmediastreamer_voip_la_SOURCES+= 	videofilters/nowebcam.c voip/nowebcam.h
 endif
 endif #might be better
 
 if BUILD_SDL
-libmediastreamer_voip_la_SOURCES+=	videofilters/videoout.c 
+libmediastreamer_voip_la_SOURCES+=	videofilters/videoout.c
 endif
 
 if BUILD_X11_XV
@@ -251,7 +251,8 @@ libmediastreamer_voip_la_SOURCES+=	voip/rfc2429.h \
 					voip/vp8rtpfmt.h \
 					videofilters/mire.c \
 					videofilters/extdisplay.c \
-					voip/layouts.c voip/layouts.h 
+					utils/bits_rw.c \
+					voip/layouts.c voip/layouts.h
 
 if ORTP_ENABLED
 libmediastreamer_voip_la_SOURCES+=	voip/videostream.c
@@ -261,7 +262,7 @@ endif BUILD_VIDEO
 
 endif MS2_FILTERS
 
-if BUILD_UPNP 
+if BUILD_UPNP
 libmediastreamer_voip_la_SOURCES+=	upnp/upnp_igd.c \
 					upnp/upnp_igd_private.h \
 					upnp/upnp_igd_cmd.c \
@@ -327,7 +328,7 @@ AM_CPPFLAGS=\
 	-I$(top_srcdir)/src/voip \
 	-I$(top_srcdir)/src/audiofilters \
 	-I$(top_srcdir)/src/otherfilters \
-	-I$(top_srcdir)/src/videofilters 	
+	-I$(top_srcdir)/src/videofilters
 
 AM_CFLAGS=\
 	$(STRICT_OPTIONS) \
@@ -339,7 +340,7 @@ AM_CFLAGS=\
 	$(SPANDSP_CFLAGS)  \
 	$(MSSILK_CFLAGS) \
 	$(PCAP_CFLAGS) \
-	$(OPUS_CFLAGS) 
+	$(OPUS_CFLAGS)
 
 AM_CXXFLAGS=\
 	$(STRICT_OPTIONS) \
@@ -396,7 +397,7 @@ AM_CFLAGS+=$(LIBUPNP_CFLAGS) -D_GNU_SOURCE
 libmediastreamer_voip_la_LIBADD+=	$(LIBUPNP_LIBS)
 endif
 
-if BUILD_IOS 
+if BUILD_IOS
 libmediastreamer_voip_la_LDFLAGS+=	-framework CoreGraphics
 endif
 

src/utils/bits_rw.c

+/*
+mediastreamer2 library - modular sound and video processing and streaming
+Copyright (C) 2010  Belledonne Communications SARL
+Author: Simon Morlat <simon.morlat@linphone.org>
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+*/
+
+#include "mediastreamer2/bits_rw.h"
+#include "mediastreamer2/mscommon.h"
+
+#include <math.h>
+
+void ms_bits_reader_init(MSBitsReader *reader, const uint8_t *buffer, size_t bufsize){
+	reader->buffer=buffer;
+	reader->buf_size=bufsize;
+	reader->bit_index=0;
+}
+
+int ms_bits_reader_n_bits(MSBitsReader *reader, int count, unsigned int *ret, const char* symbol_name){
+	unsigned int tmp;
+	size_t byte_index=reader->bit_index/8;
+	size_t bit_index=reader->bit_index % 8;
+	int shift=32-bit_index-count;
+
+	if (count>=24){
+		ms_error("This bit reader cannot read more than 24 bits at once.");
+		return -1;
+	}
+
+	if (byte_index<reader->buf_size)
+		tmp=((unsigned int)reader->buffer[byte_index++])<<24;
+	else{
+		ms_error("Bit reader goes end of stream.");
+		return -1;
+	}
+	if (byte_index<reader->buf_size)
+		tmp|=((unsigned int)reader->buffer[byte_index++])<<16;
+	if (byte_index<reader->buf_size)
+		tmp|=((unsigned int)reader->buffer[byte_index++])<<8;
+	if (byte_index<reader->buf_size)
+		tmp|=((unsigned int)reader->buffer[byte_index++]);
+
+	tmp=tmp>>shift;
+	tmp=tmp & ((1<<count)-1);
+	reader->bit_index+=count;
+
+	if (symbol_name)
+		ms_debug(".%s (u(%d)) : 0x%x | %u", symbol_name, count, tmp, tmp);
+	if (ret)
+		*ret=tmp;
+	return 0;
+}
+
+int ms_bits_reader_ue(MSBitsReader *reader, unsigned int* ret, const char* symbol_name){
+	unsigned int trail = 0;
+	unsigned int r = 0;
+	int leading_zeros_cnt = -1;
+
+	do {
+		leading_zeros_cnt++;
+		if (ms_bits_reader_n_bits(reader, 1, &r, 0) != 0)
+			return -1;
+	} while (r == 0);
+
+	if (leading_zeros_cnt == 0) {
+		if (symbol_name)
+			ms_debug(".%s (ue) : 0x%x", symbol_name, 0);
+		if (ret)
+			*ret = 0;
+	} else {
+		if (ms_bits_reader_n_bits(reader, leading_zeros_cnt, &trail, 0) != 0)
+			return -1;
+		unsigned int value = pow(2, leading_zeros_cnt) - 1 + trail;
+		if (symbol_name)
+			ms_debug(".%s (ue) : 0x%x | %u", symbol_name, value, value);
+		if (ret)
+			*ret = value;
+	}
+
+	return 0;
+}
+
+int ms_bits_reader_se(MSBitsReader *reader, int* ret, const char* symbol_name) {
+	unsigned int code_num;
+	int sign;
+	if (ms_bits_reader_ue(reader, &code_num, 0) != 0)
+		return -1;
+
+	sign = (code_num % 2) ? 1 : -1;
+	int value = sign * ceil(code_num / 2.0f);
+	if (symbol_name)
+		ms_debug(".%s (se) : 0x%x | %d [%x", symbol_name, value, value, code_num);
+	if (ret)
+		*ret = value;
+	return 0;
+}
+
+
+void ms_bits_writer_init(MSBitsWriter *writer, size_t initialbufsize) {
+	writer->buffer = (uint8_t*) malloc(initialbufsize);
+	writer->buf_size = initialbufsize;
+	writer->bit_index = 0;
+	memset(writer->buffer, 0, writer->buf_size);
+}
+
+int ms_bits_writer_n_bits(MSBitsWriter *writer, int count, unsigned int value, const char* symbol_name) {
+	uint8_t swap[4];
+	int i;
+	for (i=0; i<4; i++) {
+		swap[i] = (value >> (24 - 8 * i)) & 0xFF;
+	}
+
+	/* resize if necessary */
+	if (writer->bit_index + count > writer->buf_size * 8) {
+		int old_size = writer->buf_size;
+		writer->buf_size = MAX(2 * (writer->buf_size + 1), writer->buf_size + count / 8);
+		writer->buffer = (uint8_t*) realloc(writer->buffer, writer->buf_size);
+		memset(&writer->buffer[old_size], 0, writer->buf_size - old_size);
+	}
+
+	/* current byte */
+	int byte_index = writer->bit_index / 8;
+	/* bits available in current byte */
+	int bits_left = 8 - writer->bit_index % 8;
+
+	/* browse bytes containing bits to write */
+	int bytes = count == 32 ? 4 : (1 + count / 8);
+	for (i=0; i < bytes; i++) {
+		const uint8_t v = swap[4 - bytes + i];
+		int cnt = (i == 0) ? (count - (bytes - 1) * 8) : 8;
+		while (cnt) {
+			if (bits_left < cnt) {
+				writer->buffer[byte_index] |= v >> (cnt - bits_left);
+				byte_index++;
+				cnt -= bits_left;
+				bits_left = 8;
+			} else {
+				writer->buffer[byte_index] |= v << (bits_left - cnt);
+				bits_left -= cnt;
+				cnt = 0;
+				if (bits_left <= 0) {
+					bits_left = 8;
+					byte_index ++;
+				}
+			}
+		}
+	}
+
+	writer->bit_index += count;
+
+	return 0;
+}
+
+int ms_bits_writer_ue(MSBitsWriter *writer, unsigned int value, const char* symbol_name) {
+	int size_in_bits = 0;
+	int tmp_val = value + 1;
+
+	while (tmp_val) {
+		tmp_val >>= 1;
+		size_in_bits++;
+	}
+	size_in_bits --;
+
+	ms_bits_writer_n_bits(writer, size_in_bits, 0, NULL);
+	ms_bits_writer_n_bits(writer, 1, 1, NULL);
+	value = (value + 1) - (1 << size_in_bits);
+	ms_bits_writer_n_bits(writer, size_in_bits, value, NULL);
+
+	return 0;
+}
+
+int ms_bits_writer_se(MSBitsWriter *writer, int value, const char* symbol_name) {
+	unsigned int new_val;
+
+	if (value <= 0)
+		new_val = -2 * value;
+	else
+		new_val = 2 * value - 1;
+
+	return ms_bits_writer_ue(writer, new_val, symbol_name);
+}
+
+int ms_bits_writer_trailing_bits(MSBitsWriter *writer) {
+	ms_bits_writer_n_bits(writer, 1, 1, "trailing_bits");
+	// byte_aligning
+	if ((writer->bit_index % 8) == 0)
+		return 0;
+
+	ms_bits_writer_n_bits(writer, 8 - (writer->bit_index % 8), 0, "byte_aligning");
+	return 0;
+}