bitbuffer.c

这是著名的TCPMP播放器在WINDWOWS,和WINCE下编译通过的源程序.笔者对其中的LIBMAD库做了针对ARM MPU的优化. 并增加了词幕功能.

		 */
		uval = (unsigned)(((-(++val)) << 1) + 1);
	else
		uval = (unsigned)(val << 1);

	msbs = uval >> parameter;

	return 1 + parameter + msbs;
}

#if 0 /* UNUSED */
unsigned FLAC__bitbuffer_golomb_bits_signed(int val, unsigned parameter)
{
	unsigned bits, msbs, uval;
	unsigned k;

	FLAC__ASSERT(parameter > 0);

	/* fold signed to unsigned */
	if(val < 0)
		/* equivalent to
		 *     (unsigned)(((--val) << 1) - 1);
		 * but without the overflow problem at MININT
		 */
		uval = (unsigned)(((-(++val)) << 1) + 1);
	else
		uval = (unsigned)(val << 1);

	k = FLAC__bitmath_ilog2(parameter);
	if(parameter == 1u<<k) {
		FLAC__ASSERT(k <= 30);

		msbs = uval >> k;
		bits = 1 + k + msbs;
	}
	else {
		unsigned q, r, d;

		d = (1 << (k+1)) - parameter;
		q = uval / parameter;
		r = uval - (q * parameter);

		bits = 1 + q + k;
		if(r >= d)
			bits++;
	}
	return bits;
}

unsigned FLAC__bitbuffer_golomb_bits_unsigned(unsigned uval, unsigned parameter)
{
	unsigned bits, msbs;
	unsigned k;

	FLAC__ASSERT(parameter > 0);

	k = FLAC__bitmath_ilog2(parameter);
	if(parameter == 1u<<k) {
		FLAC__ASSERT(k <= 30);

		msbs = uval >> k;
		bits = 1 + k + msbs;
	}
	else {
		unsigned q, r, d;

		d = (1 << (k+1)) - parameter;
		q = uval / parameter;
		r = uval - (q * parameter);

		bits = 1 + q + k;
		if(r >= d)
			bits++;
	}
	return bits;
}
#endif /* UNUSED */

#ifdef FLAC__SYMMETRIC_RICE
FLAC__bool FLAC__bitbuffer_write_symmetric_rice_signed(FLAC__BitBuffer *bb, int val, unsigned parameter)
{
	unsigned total_bits, interesting_bits, msbs;
	FLAC__uint32 pattern;

	FLAC__ASSERT(0 != bb);
	FLAC__ASSERT(0 != bb->buffer);
	FLAC__ASSERT(parameter <= 31);

	/* init pattern with the unary end bit and the sign bit */
	if(val < 0) {
		pattern = 3;
		val = -val;
	}
	else
		pattern = 2;

	msbs = val >> parameter;
	interesting_bits = 2 + parameter;
	total_bits = interesting_bits + msbs;
	pattern <<= parameter;
	pattern |= (val & ((1<<parameter)-1)); /* the binary LSBs */

	if(total_bits <= 32) {
		if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, total_bits))
			return false;
	}
	else {
		/* write the unary MSBs */
		if(!FLAC__bitbuffer_write_zeroes(bb, msbs))
			return false;
		/* write the unary end bit, the sign bit, and binary LSBs */
		if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, interesting_bits))
			return false;
	}
	return true;
}

#if 0 /* UNUSED */
FLAC__bool FLAC__bitbuffer_write_symmetric_rice_signed_guarded(FLAC__BitBuffer *bb, int val, unsigned parameter, unsigned max_bits, FLAC__bool *overflow)
{
	unsigned total_bits, interesting_bits, msbs;
	FLAC__uint32 pattern;

	FLAC__ASSERT(0 != bb);
	FLAC__ASSERT(0 != bb->buffer);
	FLAC__ASSERT(parameter <= 31);

	*overflow = false;

	/* init pattern with the unary end bit and the sign bit */
	if(val < 0) {
		pattern = 3;
		val = -val;
	}
	else
		pattern = 2;

	msbs = val >> parameter;
	interesting_bits = 2 + parameter;
	total_bits = interesting_bits + msbs;
	pattern <<= parameter;
	pattern |= (val & ((1<<parameter)-1)); /* the binary LSBs */

	if(total_bits <= 32) {
		if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, total_bits))
			return false;
	}
	else if(total_bits > max_bits) {
		*overflow = true;
		return true;
	}
	else {
		/* write the unary MSBs */
		if(!FLAC__bitbuffer_write_zeroes(bb, msbs))
			return false;
		/* write the unary end bit, the sign bit, and binary LSBs */
		if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, interesting_bits))
			return false;
	}
	return true;
}
#endif /* UNUSED */

FLAC__bool FLAC__bitbuffer_write_symmetric_rice_signed_escape(FLAC__BitBuffer *bb, int val, unsigned parameter)
{
	unsigned total_bits, val_bits;
	FLAC__uint32 pattern;

	FLAC__ASSERT(0 != bb);
	FLAC__ASSERT(0 != bb->buffer);
	FLAC__ASSERT(parameter <= 31);

	val_bits = FLAC__bitmath_silog2(val);
	total_bits = 2 + parameter + 5 + val_bits;

	if(total_bits <= 32) {
		pattern = 3;
		pattern <<= (parameter + 5);
		pattern |= val_bits;
		pattern <<= val_bits;
		pattern |= (val & ((1 << val_bits) - 1));
		if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, total_bits))
			return false;
	}
	else {
		/* write the '-0' escape code first */
		if(!FLAC__bitbuffer_write_raw_uint32(bb, 3u << parameter, 2+parameter))
			return false;
		/* write the length */
		if(!FLAC__bitbuffer_write_raw_uint32(bb, val_bits, 5))
			return false;
		/* write the value */
		if(!FLAC__bitbuffer_write_raw_int32(bb, val, val_bits))
			return false;
	}
	return true;
}
#endif /* ifdef FLAC__SYMMETRIC_RICE */

FLAC__bool FLAC__bitbuffer_write_rice_signed(FLAC__BitBuffer *bb, int val, unsigned parameter)
{
	unsigned total_bits, interesting_bits, msbs, uval;
	FLAC__uint32 pattern;

	FLAC__ASSERT(0 != bb);
	FLAC__ASSERT(0 != bb->buffer);
	FLAC__ASSERT(parameter <= 30);

	/* fold signed to unsigned */
	if(val < 0)
		/* equivalent to
		 *     (unsigned)(((--val) << 1) - 1);
		 * but without the overflow problem at MININT
		 */
		uval = (unsigned)(((-(++val)) << 1) + 1);
	else
		uval = (unsigned)(val << 1);

	msbs = uval >> parameter;
	interesting_bits = 1 + parameter;
	total_bits = interesting_bits + msbs;
	pattern = 1 << parameter; /* the unary end bit */
	pattern |= (uval & ((1<<parameter)-1)); /* the binary LSBs */

	if(total_bits <= 32) {
		if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, total_bits))
			return false;
	}
	else {
		/* write the unary MSBs */
		if(!FLAC__bitbuffer_write_zeroes(bb, msbs))
			return false;
		/* write the unary end bit and binary LSBs */
		if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, interesting_bits))
			return false;
	}
	return true;
}

#if 0 /* UNUSED */
FLAC__bool FLAC__bitbuffer_write_rice_signed_guarded(FLAC__BitBuffer *bb, int val, unsigned parameter, unsigned max_bits, FLAC__bool *overflow)
{
	unsigned total_bits, interesting_bits, msbs, uval;
	FLAC__uint32 pattern;

	FLAC__ASSERT(0 != bb);
	FLAC__ASSERT(0 != bb->buffer);
	FLAC__ASSERT(parameter <= 30);

	*overflow = false;

	/* fold signed to unsigned */
	if(val < 0)
		/* equivalent to
		 *     (unsigned)(((--val) << 1) - 1);
		 * but without the overflow problem at MININT
		 */
		uval = (unsigned)(((-(++val)) << 1) + 1);
	else
		uval = (unsigned)(val << 1);

	msbs = uval >> parameter;
	interesting_bits = 1 + parameter;
	total_bits = interesting_bits + msbs;
	pattern = 1 << parameter; /* the unary end bit */
	pattern |= (uval & ((1<<parameter)-1)); /* the binary LSBs */

	if(total_bits <= 32) {
		if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, total_bits))
			return false;
	}
	else if(total_bits > max_bits) {
		*overflow = true;
		return true;
	}
	else {
		/* write the unary MSBs */
		if(!FLAC__bitbuffer_write_zeroes(bb, msbs))
			return false;
		/* write the unary end bit and binary LSBs */
		if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, interesting_bits))
			return false;
	}
	return true;
}
#endif /* UNUSED */

#if 0 /* UNUSED */
FLAC__bool FLAC__bitbuffer_write_golomb_signed(FLAC__BitBuffer *bb, int val, unsigned parameter)
{
	unsigned total_bits, msbs, uval;
	unsigned k;

	FLAC__ASSERT(0 != bb);
	FLAC__ASSERT(0 != bb->buffer);
	FLAC__ASSERT(parameter > 0);

	/* fold signed to unsigned */
	if(val < 0)
		/* equivalent to
		 *     (unsigned)(((--val) << 1) - 1);
		 * but without the overflow problem at MININT
		 */
		uval = (unsigned)(((-(++val)) << 1) + 1);
	else
		uval = (unsigned)(val << 1);

	k = FLAC__bitmath_ilog2(parameter);
	if(parameter == 1u<<k) {
		unsigned pattern;

		FLAC__ASSERT(k <= 30);

		msbs = uval >> k;
		total_bits = 1 + k + msbs;
		pattern = 1 << k; /* the unary end bit */
		pattern |= (uval & ((1u<<k)-1)); /* the binary LSBs */

		if(total_bits <= 32) {
			if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, total_bits))
				return false;
		}
		else {
			/* write the unary MSBs */
			if(!FLAC__bitbuffer_write_zeroes(bb, msbs))
				return false;
			/* write the unary end bit and binary LSBs */
			if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, k+1))
				return false;
		}
	}
	else {
		unsigned q, r, d;

		d = (1 << (k+1)) - parameter;
		q = uval / parameter;
		r = uval - (q * parameter);
		/* write the unary MSBs */
		if(!FLAC__bitbuffer_write_zeroes(bb, q))
			return false;
		/* write the unary end bit */
		if(!FLAC__bitbuffer_write_raw_uint32(bb, 1, 1))
			return false;
		/* write the binary LSBs */
		if(r >= d) {
			if(!FLAC__bitbuffer_write_raw_uint32(bb, r+d, k+1))
				return false;
		}
		else {
			if(!FLAC__bitbuffer_write_raw_uint32(bb, r, k))
				return false;
		}
	}
	return true;
}

FLAC__bool FLAC__bitbuffer_write_golomb_unsigned(FLAC__BitBuffer *bb, unsigned uval, unsigned parameter)
{
	unsigned total_bits, msbs;
	unsigned k;

	FLAC__ASSERT(0 != bb);
	FLAC__ASSERT(0 != bb->buffer);
	FLAC__ASSERT(parameter > 0);

	k = FLAC__bitmath_ilog2(parameter);
	if(parameter == 1u<<k) {
		unsigned pattern;

		FLAC__ASSERT(k <= 30);

		msbs = uval >> k;
		total_bits = 1 + k + msbs;
		pattern = 1 << k; /* the unary end bit */
		pattern |= (uval & ((1u<<k)-1)); /* the binary LSBs */

		if(total_bits <= 32) {
			if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, total_bits))
				return false;
		}
		else {
			/* write the unary MSBs */
			if(!FLAC__bitbuffer_write_zeroes(bb, msbs))
				return false;
			/* write the unary end bit and binary LSBs */
			if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, k+1))
				return false;
		}
	}
	else {
		unsigned q, r, d;

		d = (1 << (k+1)) - parameter;
		q = uval / parameter;
		r = uval - (q * parameter);
		/* write the unary MSBs */
		if(!FLAC__bitbuffer_write_zeroes(bb, q))
			return false;
		/* write the unary end bit */
		if(!FLAC__bitbuffer_write_raw_uint32(bb, 1, 1))
			return false;
		/* write the binary LSBs */
		if(r >= d) {
			if(!FLAC__bitbuffer_write_raw_uint32(bb, r+d, k+1))
				return false;
		}
		else {
			if(!FLAC__bitbuffer_write_raw_uint32(bb, r, k))
				return false;
		}
	}
	return true;
}
#endif /* UNUSED */

FLAC__bool FLAC__bitbuffer_write_utf8_uint32(FLAC__BitBuffer *bb, FLAC__uint32 val)