1 files changed, 126 insertions, 0 deletions
diff --git a/src/libmpg123/getbits.c b/src/libmpg123/getbits.c
new file mode 100755
index 0000000..a071b5e
--- /dev/null
+++ b/src/libmpg123/getbits.c
@@ -0,0 +1,126 @@
+#include "mpg123.h"
+
+#if 0
+static void check_buffer_range(int size)
+{
+	int pos = (bsi.wordpointer-bsbuf) + (size >> 3);
+
+	if( pos >= fsizeold) {
+		fprintf(stderr, "Pointer out of range (%d,%d)!\n", pos, fsizeold);
+	}
+}
+#endif
+
+void mpg123_backbits(int number_of_bits)
+{
+	bsi.bitindex    -= number_of_bits;
+	bsi.wordpointer += (bsi.bitindex>>3);
+	bsi.bitindex    &= 0x7;
+}
+
+int mpg123_getbitoffset(void) 
+{
+	return (-bsi.bitindex)&0x7;
+}
+
+int mpg123_getbyte(void)
+{
+#ifdef DEBUG_GETBITS
+	if(bsi.bitindex) 
+		fprintf(stderr,"getbyte called unsynched!\n");
+#endif
+	return *bsi.wordpointer++;
+}
+
+unsigned int mpg123_getbits(int number_of_bits)
+{
+	unsigned long rval;
+
+#ifdef DEBUG_GETBITS
+	fprintf(stderr, "g%d", number_of_bits);
+#endif
+
+	if(!number_of_bits)
+		return 0;
+
+#if 0
+	check_buffer_range(number_of_bits + bsi.bitindex);
+#endif
+
+	{
+		rval = bsi.wordpointer[0];
+		rval <<= 8;
+		rval |= bsi.wordpointer[1];
+		rval <<= 8;
+		rval |= bsi.wordpointer[2];
+
+		rval <<= bsi.bitindex;
+		rval &= 0xffffff;
+		
+		bsi.bitindex += number_of_bits;
+
+		rval >>= (24-number_of_bits);
+
+		bsi.wordpointer += (bsi.bitindex >> 3);
+		bsi.bitindex &= 7;
+	}
+
+#ifdef DEBUG_GETBITS
+	fprintf(stderr,":%x ",rval);
+#endif
+
+	return rval;
+}
+
+unsigned int mpg123_getbits_fast(int number_of_bits)
+{
+	unsigned int rval;
+#ifdef DEBUG_GETBITS
+	fprintf(stderr,"g%d",number_of_bits);
+#endif
+
+#if 0
+	check_buffer_range(number_of_bits+bsi.bitindex);
+#endif
+
+	rval =  (unsigned char) (bsi.wordpointer[0] << bsi.bitindex);
+	rval |= ((unsigned int) bsi.wordpointer[1] << bsi.bitindex) >> 8;
+	rval <<= number_of_bits;
+	rval >>= 8;
+
+	bsi.bitindex += number_of_bits;
+
+	bsi.wordpointer += (bsi.bitindex >> 3);
+	bsi.bitindex &= 7;
+
+#ifdef DEBUG_GETBITS
+	fprintf(stderr,":%x ",rval);
+#endif
+	return rval;
+}
+
+unsigned int mpg123_get1bit(void)
+{
+	unsigned char rval;
+
+#ifdef DEBUG_GETBITS
+	fprintf(stderr,"g%d",1);
+#endif
+
+#if 0
+	check_buffer_range(1+bsi.bitindex);
+#endif
+
+	rval = *bsi.wordpointer << bsi.bitindex;
+
+	bsi.bitindex++;
+	bsi.wordpointer += (bsi.bitindex >> 3);
+	bsi.bitindex &= 7;
+
+#ifdef DEBUG_GETBITS
+	fprintf(stderr,":%d ",rval >> 7);
+#endif
+
+	return rval>>7;
+}
+