Initial community commit

Src/replicant/nu/BitReader.cpp

@@ -0,0 +1,109 @@
+#include "BitReader.h"
+#include <string.h>
+
+static uint32_t mask[8]=
+{
+		0x1,
+		0x3,
+		0x7,
+		0xF,
+		0x1F,
+		0x3F,
+		0x7F,
+		0xFF
+};
+
+static uint32_t msk[33] =
+{
+  0x00000000,0x00000001,0x00000003,0x00000007,
+  0x0000000f,0x0000001f,0x0000003f,0x0000007f,
+  0x000000ff,0x000001ff,0x000003ff,0x000007ff,
+  0x00000fff,0x00001fff,0x00003fff,0x00007fff,
+  0x0000ffff,0x0001ffff,0x0003ffff,0x0007ffff,
+  0x000fffff,0x001fffff,0x003fffff,0x007fffff,
+  0x00ffffff,0x01ffffff,0x03ffffff,0x07ffffff,
+  0x0fffffff,0x1fffffff,0x3fffffff,0x7fffffff,
+  0xffffffff
+};
+
+void BitReader::alignbyte()
+{
+	flushbits(numBits&7);
+}
+
+void BitReader::getbytes(void *data, uint32_t n)
+{
+	memcpy(data, this->data, n);
+	flushbits(n*8);
+}
+
+uint8_t BitReader::getbits1()
+{
+	uint8_t byte = data[0];
+	uint32_t count = (numBits-1) & 7;
+	byte &= mask[count];
+	byte >>= count;
+
+	numBits--;
+	if ((numBits % 8) == 0)
+		data++;
+	return byte;
+}
+
+uint32_t BitReader::getbits(uint32_t n)
+{
+	uint32_t val = showbits(n);
+	flushbits(n);
+	return val;
+}
+
+uint8_t BitReader::showbits1() const
+{
+	uint8_t byte = data[0];
+	uint32_t count = (numBits-1) & 7;
+	byte &= mask[count];
+	byte >>= count;
+	return byte;
+}
+
+uint32_t BitReader::showbits(uint32_t n) const
+{
+	uint32_t val;
+	switch((numBits+7) >> 3)
+	{
+	case 0:
+		return 0;
+	case 1:
+		val=(data[0]<<24);
+		break;
+	case 2:
+		val=(data[0]<<24) | (data[1]<<16);
+		break;
+	case 3:
+		val=(data[0]<<24) | (data[1]<<16) | (data[2]<<8);
+		break;
+	default:
+		val=(data[0]<<24) | (data[1]<<16) | (data[2]<<8) | data[3];
+		break;
+	}
+	uint32_t c = ((numBits-1) & 7) + 25;
+	return (val>>(c-n)) & msk[n];
+}
+
+void BitReader::flushbits(uint32_t n)
+{
+	uint32_t oldpos = (numBits+7)>>3;
+	numBits-=n;
+	uint32_t newpos = (numBits+7)>>3;
+	data  += (oldpos - newpos);
+}
+
+bool BitReader::empty()
+{
+	return numBits==0;
+}
+
+uint32_t BitReader::size() const
+{
+	return numBits;
+}