initial commit to new repo

decoder/bitstream.c

@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2009, 2010 by Nicole Faerber <nicole.faerber@dpin.de>
+ *
+ * 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.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "bitstream.h"
+
+static unsigned char *_BITBUF;
+static unsigned int _BITPOS;
+static unsigned int _BUFLEN;
+
+void printbits(unsigned int val)
+{
+unsigned char i=0;
+
+	while (i<32)
+		if (val & (1<<(31-i++)))
+			printf("1 ");
+		else
+			printf("0 ");
+//	printf("\n");
+}
+
+void printbuf_head(unsigned char *buf)
+{
+	//printbits(buf[3]<<24 | buf[2]<<16 | buf[1]<<8 | buf[0]);
+	printbits(buf[0]<<24 | buf[1]<<16 | buf[2]<<8 | buf[3]);
+}
+
+unsigned int bitstream_get_bits(unsigned char *data, unsigned int bitOffset, unsigned int numBits)
+{
+unsigned int val;
+unsigned int mask = (1 << numBits) - 1;
+
+	data += ((bitOffset / 8) -3);
+	val = *((int *)data);
+//	printf("0x%08x ", val);
+
+	val = val << (bitOffset % 8);
+//	printf("0x%08x ", val);
+
+	val = val >> (32-numBits);
+//	printf("0x%08x %d ", val, (32-numBits));
+
+	val &= mask;
+//	printf("0x%08x\n", val);
+
+return val;
+}
+
+int bitstream_bits_remaining(void)
+{
+	return (_BUFLEN - _BITPOS);
+}
+
+unsigned int bitstream_get_next_bits(unsigned int nbits)
+{
+unsigned int res;
+
+	res = bitstream_get_bits(_BITBUF, _BITPOS, nbits);
+	_BITPOS += nbits;
+
+	return res;
+}
+
+void bitstream_start(unsigned char *buf, unsigned int len)
+{
+	_BITBUF = buf;
+	_BITPOS = 0;
+	_BUFLEN = len;
+}
+
+