Adding upstream version 5.4.1.upstream/5.4.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 784 insertions, 0 deletions

diff --git a/src/common/tuklib_integer.h b/src/common/tuklib_integer.h
new file mode 100644
index 0000000..b58ef68
--- /dev/null
+++ b/src/common/tuklib_integer.h
@@ -0,0 +1,784 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       tuklib_integer.h
+/// \brief      Various integer and bit operations
+///
+/// This file provides macros or functions to do some basic integer and bit
+/// operations.
+///
+/// Native endian inline functions (XX = 16, 32, or 64):
+///   - Unaligned native endian reads: readXXne(ptr)
+///   - Unaligned native endian writes: writeXXne(ptr, num)
+///   - Aligned native endian reads: aligned_readXXne(ptr)
+///   - Aligned native endian writes: aligned_writeXXne(ptr, num)
+///
+/// Endianness-converting integer operations (these can be macros!)
+/// (XX = 16, 32, or 64; Y = b or l):
+///   - Byte swapping: bswapXX(num)
+///   - Byte order conversions to/from native (byteswaps if Y isn't
+///     the native endianness): convXXYe(num)
+///   - Unaligned reads: readXXYe(ptr)
+///   - Unaligned writes: writeXXYe(ptr, num)
+///   - Aligned reads: aligned_readXXYe(ptr)
+///   - Aligned writes: aligned_writeXXYe(ptr, num)
+///
+/// Since the above can macros, the arguments should have no side effects
+/// because they may be evaluated more than once.
+///
+/// Bit scan operations for non-zero 32-bit integers (inline functions):
+///   - Bit scan reverse (find highest non-zero bit): bsr32(num)
+///   - Count leading zeros: clz32(num)
+///   - Count trailing zeros: ctz32(num)
+///   - Bit scan forward (simply an alias for ctz32()): bsf32(num)
+///
+/// The above bit scan operations return 0-31. If num is zero,
+/// the result is undefined.
+//
+//  Authors:    Lasse Collin
+//              Joachim Henke
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef TUKLIB_INTEGER_H
+#define TUKLIB_INTEGER_H
+
+#include "tuklib_common.h"
+#include <string.h>
+
+// Newer Intel C compilers require immintrin.h for _bit_scan_reverse()
+// and such functions.
+#if defined(__INTEL_COMPILER) && (__INTEL_COMPILER >= 1500)
+#	include <immintrin.h>
+#endif
+
+
+///////////////////
+// Byte swapping //
+///////////////////
+
+#if defined(HAVE___BUILTIN_BSWAPXX)
+	// GCC >= 4.8 and Clang
+#	define bswap16(n) __builtin_bswap16(n)
+#	define bswap32(n) __builtin_bswap32(n)
+#	define bswap64(n) __builtin_bswap64(n)
+
+#elif defined(HAVE_BYTESWAP_H)
+	// glibc, uClibc, dietlibc
+#	include <byteswap.h>
+#	ifdef HAVE_BSWAP_16
+#		define bswap16(num) bswap_16(num)
+#	endif
+#	ifdef HAVE_BSWAP_32
+#		define bswap32(num) bswap_32(num)
+#	endif
+#	ifdef HAVE_BSWAP_64
+#		define bswap64(num) bswap_64(num)
+#	endif
+
+#elif defined(HAVE_SYS_ENDIAN_H)
+	// *BSDs and Darwin
+#	include <sys/endian.h>
+
+#elif defined(HAVE_SYS_BYTEORDER_H)
+	// Solaris
+#	include <sys/byteorder.h>
+#	ifdef BSWAP_16
+#		define bswap16(num) BSWAP_16(num)
+#	endif
+#	ifdef BSWAP_32
+#		define bswap32(num) BSWAP_32(num)
+#	endif
+#	ifdef BSWAP_64
+#		define bswap64(num) BSWAP_64(num)
+#	endif
+#	ifdef BE_16
+#		define conv16be(num) BE_16(num)
+#	endif
+#	ifdef BE_32
+#		define conv32be(num) BE_32(num)
+#	endif
+#	ifdef BE_64
+#		define conv64be(num) BE_64(num)
+#	endif
+#	ifdef LE_16
+#		define conv16le(num) LE_16(num)
+#	endif
+#	ifdef LE_32
+#		define conv32le(num) LE_32(num)
+#	endif
+#	ifdef LE_64
+#		define conv64le(num) LE_64(num)
+#	endif
+#endif
+
+#ifndef bswap16
+#	define bswap16(n) (uint16_t)( \
+		  (((n) & 0x00FFU) << 8) \
+		| (((n) & 0xFF00U) >> 8) \
+	)
+#endif
+
+#ifndef bswap32
+#	define bswap32(n) (uint32_t)( \
+		  (((n) & UINT32_C(0x000000FF)) << 24) \
+		| (((n) & UINT32_C(0x0000FF00)) << 8) \
+		| (((n) & UINT32_C(0x00FF0000)) >> 8) \
+		| (((n) & UINT32_C(0xFF000000)) >> 24) \
+	)
+#endif
+
+#ifndef bswap64
+#	define bswap64(n) (uint64_t)( \
+		  (((n) & UINT64_C(0x00000000000000FF)) << 56) \
+		| (((n) & UINT64_C(0x000000000000FF00)) << 40) \
+		| (((n) & UINT64_C(0x0000000000FF0000)) << 24) \
+		| (((n) & UINT64_C(0x00000000FF000000)) << 8) \
+		| (((n) & UINT64_C(0x000000FF00000000)) >> 8) \
+		| (((n) & UINT64_C(0x0000FF0000000000)) >> 24) \
+		| (((n) & UINT64_C(0x00FF000000000000)) >> 40) \
+		| (((n) & UINT64_C(0xFF00000000000000)) >> 56) \
+	)
+#endif
+
+// Define conversion macros using the basic byte swapping macros.
+#ifdef WORDS_BIGENDIAN
+#	ifndef conv16be
+#		define conv16be(num) ((uint16_t)(num))
+#	endif
+#	ifndef conv32be
+#		define conv32be(num) ((uint32_t)(num))
+#	endif
+#	ifndef conv64be
+#		define conv64be(num) ((uint64_t)(num))
+#	endif
+#	ifndef conv16le
+#		define conv16le(num) bswap16(num)
+#	endif
+#	ifndef conv32le
+#		define conv32le(num) bswap32(num)
+#	endif
+#	ifndef conv64le
+#		define conv64le(num) bswap64(num)
+#	endif
+#else
+#	ifndef conv16be
+#		define conv16be(num) bswap16(num)
+#	endif
+#	ifndef conv32be
+#		define conv32be(num) bswap32(num)
+#	endif
+#	ifndef conv64be
+#		define conv64be(num) bswap64(num)
+#	endif
+#	ifndef conv16le
+#		define conv16le(num) ((uint16_t)(num))
+#	endif
+#	ifndef conv32le
+#		define conv32le(num) ((uint32_t)(num))
+#	endif
+#	ifndef conv64le
+#		define conv64le(num) ((uint64_t)(num))
+#	endif
+#endif
+
+
+////////////////////////////////
+// Unaligned reads and writes //
+////////////////////////////////
+
+// The traditional way of casting e.g. *(const uint16_t *)uint8_pointer
+// is bad even if the uint8_pointer is properly aligned because this kind
+// of casts break strict aliasing rules and result in undefined behavior.
+// With unaligned pointers it's even worse: compilers may emit vector
+// instructions that require aligned pointers even if non-vector
+// instructions work with unaligned pointers.
+//
+// Using memcpy() is the standard compliant way to do unaligned access.
+// Many modern compilers inline it so there is no function call overhead.
+// For those compilers that don't handle the memcpy() method well, the
+// old casting method (that violates strict aliasing) can be requested at
+// build time. A third method, casting to a packed struct, would also be
+// an option but isn't provided to keep things simpler (it's already a mess).
+// Hopefully this is flexible enough in practice.
+
+static inline uint16_t
+read16ne(const uint8_t *buf)
+{
+#if defined(TUKLIB_FAST_UNALIGNED_ACCESS) \
+		&& defined(TUKLIB_USE_UNSAFE_TYPE_PUNNING)
+	return *(const uint16_t *)buf;
+#else
+	uint16_t num;
+	memcpy(&num, buf, sizeof(num));
+	return num;
+#endif
+}
+
+
+static inline uint32_t
+read32ne(const uint8_t *buf)
+{
+#if defined(TUKLIB_FAST_UNALIGNED_ACCESS) \
+		&& defined(TUKLIB_USE_UNSAFE_TYPE_PUNNING)
+	return *(const uint32_t *)buf;
+#else
+	uint32_t num;
+	memcpy(&num, buf, sizeof(num));
+	return num;
+#endif
+}
+
+
+static inline uint64_t
+read64ne(const uint8_t *buf)
+{
+#if defined(TUKLIB_FAST_UNALIGNED_ACCESS) \
+		&& defined(TUKLIB_USE_UNSAFE_TYPE_PUNNING)
+	return *(const uint64_t *)buf;
+#else
+	uint64_t num;
+	memcpy(&num, buf, sizeof(num));
+	return num;
+#endif
+}
+
+
+static inline void
+write16ne(uint8_t *buf, uint16_t num)
+{
+#if defined(TUKLIB_FAST_UNALIGNED_ACCESS) \
+		&& defined(TUKLIB_USE_UNSAFE_TYPE_PUNNING)
+	*(uint16_t *)buf = num;
+#else
+	memcpy(buf, &num, sizeof(num));
+#endif
+	return;
+}
+
+
+static inline void
+write32ne(uint8_t *buf, uint32_t num)
+{
+#if defined(TUKLIB_FAST_UNALIGNED_ACCESS) \
+		&& defined(TUKLIB_USE_UNSAFE_TYPE_PUNNING)
+	*(uint32_t *)buf = num;
+#else
+	memcpy(buf, &num, sizeof(num));
+#endif
+	return;
+}
+
+
+static inline void
+write64ne(uint8_t *buf, uint64_t num)
+{
+#if defined(TUKLIB_FAST_UNALIGNED_ACCESS) \
+		&& defined(TUKLIB_USE_UNSAFE_TYPE_PUNNING)
+	*(uint64_t *)buf = num;
+#else
+	memcpy(buf, &num, sizeof(num));
+#endif
+	return;
+}
+
+
+static inline uint16_t
+read16be(const uint8_t *buf)
+{
+#if defined(WORDS_BIGENDIAN) || defined(TUKLIB_FAST_UNALIGNED_ACCESS)
+	uint16_t num = read16ne(buf);
+	return conv16be(num);
+#else
+	uint16_t num = ((uint16_t)buf[0] << 8) | (uint16_t)buf[1];
+	return num;
+#endif
+}
+
+
+static inline uint16_t
+read16le(const uint8_t *buf)
+{
+#if !defined(WORDS_BIGENDIAN) || defined(TUKLIB_FAST_UNALIGNED_ACCESS)
+	uint16_t num = read16ne(buf);
+	return conv16le(num);
+#else
+	uint16_t num = ((uint16_t)buf[0]) | ((uint16_t)buf[1] << 8);
+	return num;
+#endif
+}
+
+
+static inline uint32_t
+read32be(const uint8_t *buf)
+{
+#if defined(WORDS_BIGENDIAN) || defined(TUKLIB_FAST_UNALIGNED_ACCESS)
+	uint32_t num = read32ne(buf);
+	return conv32be(num);
+#else
+	uint32_t num = (uint32_t)buf[0] << 24;
+	num |= (uint32_t)buf[1] << 16;
+	num |= (uint32_t)buf[2] << 8;
+	num |= (uint32_t)buf[3];
+	return num;
+#endif
+}
+
+
+static inline uint32_t
+read32le(const uint8_t *buf)
+{
+#if !defined(WORDS_BIGENDIAN) || defined(TUKLIB_FAST_UNALIGNED_ACCESS)
+	uint32_t num = read32ne(buf);
+	return conv32le(num);
+#else
+	uint32_t num = (uint32_t)buf[0];
+	num |= (uint32_t)buf[1] << 8;
+	num |= (uint32_t)buf[2] << 16;
+	num |= (uint32_t)buf[3] << 24;
+	return num;
+#endif
+}
+
+
+static inline uint64_t
+read64be(const uint8_t *buf)
+{
+#if defined(WORDS_BIGENDIAN) || defined(TUKLIB_FAST_UNALIGNED_ACCESS)
+	uint64_t num = read64ne(buf);
+	return conv64be(num);
+#else
+	uint64_t num = (uint64_t)buf[0] << 56;
+	num |= (uint64_t)buf[1] << 48;
+	num |= (uint64_t)buf[2] << 40;
+	num |= (uint64_t)buf[3] << 32;
+	num |= (uint64_t)buf[4] << 24;
+	num |= (uint64_t)buf[5] << 16;
+	num |= (uint64_t)buf[6] << 8;
+	num |= (uint64_t)buf[7];
+	return num;
+#endif
+}
+
+
+static inline uint64_t
+read64le(const uint8_t *buf)
+{
+#if !defined(WORDS_BIGENDIAN) || defined(TUKLIB_FAST_UNALIGNED_ACCESS)
+	uint64_t num = read64ne(buf);
+	return conv64le(num);
+#else
+	uint64_t num = (uint64_t)buf[0];
+	num |= (uint64_t)buf[1] << 8;
+	num |= (uint64_t)buf[2] << 16;
+	num |= (uint64_t)buf[3] << 24;
+	num |= (uint64_t)buf[4] << 32;
+	num |= (uint64_t)buf[5] << 40;
+	num |= (uint64_t)buf[6] << 48;
+	num |= (uint64_t)buf[7] << 56;
+	return num;
+#endif
+}
+
+
+// NOTE: Possible byte swapping must be done in a macro to allow the compiler
+// to optimize byte swapping of constants when using glibc's or *BSD's
+// byte swapping macros. The actual write is done in an inline function
+// to make type checking of the buf pointer possible.
+#if defined(WORDS_BIGENDIAN) || defined(TUKLIB_FAST_UNALIGNED_ACCESS)
+#	define write16be(buf, num) write16ne(buf, conv16be(num))
+#	define write32be(buf, num) write32ne(buf, conv32be(num))
+#	define write64be(buf, num) write64ne(buf, conv64be(num))
+#endif
+
+#if !defined(WORDS_BIGENDIAN) || defined(TUKLIB_FAST_UNALIGNED_ACCESS)
+#	define write16le(buf, num) write16ne(buf, conv16le(num))
+#	define write32le(buf, num) write32ne(buf, conv32le(num))
+#	define write64le(buf, num) write64ne(buf, conv64le(num))
+#endif
+
+
+#ifndef write16be
+static inline void
+write16be(uint8_t *buf, uint16_t num)
+{
+	buf[0] = (uint8_t)(num >> 8);
+	buf[1] = (uint8_t)num;
+	return;
+}
+#endif
+
+
+#ifndef write16le
+static inline void
+write16le(uint8_t *buf, uint16_t num)
+{
+	buf[0] = (uint8_t)num;
+	buf[1] = (uint8_t)(num >> 8);
+	return;
+}
+#endif
+
+
+#ifndef write32be
+static inline void
+write32be(uint8_t *buf, uint32_t num)
+{
+	buf[0] = (uint8_t)(num >> 24);
+	buf[1] = (uint8_t)(num >> 16);
+	buf[2] = (uint8_t)(num >> 8);
+	buf[3] = (uint8_t)num;
+	return;
+}
+#endif
+
+
+#ifndef write32le
+static inline void
+write32le(uint8_t *buf, uint32_t num)
+{
+	buf[0] = (uint8_t)num;
+	buf[1] = (uint8_t)(num >> 8);
+	buf[2] = (uint8_t)(num >> 16);
+	buf[3] = (uint8_t)(num >> 24);
+	return;
+}
+#endif
+
+
+//////////////////////////////
+// Aligned reads and writes //
+//////////////////////////////
+
+// Separate functions for aligned reads and writes are provided since on
+// strict-align archs aligned access is much faster than unaligned access.
+//
+// Just like in the unaligned case, memcpy() is needed to avoid
+// strict aliasing violations. However, on archs that don't support
+// unaligned access the compiler cannot know that the pointers given
+// to memcpy() are aligned which results in slow code. As of C11 there is
+// no standard way to tell the compiler that we know that the address is
+// aligned but some compilers have language extensions to do that. With
+// such language extensions the memcpy() method gives excellent results.
+//
+// What to do on a strict-align system when no known language extentensions
+// are available? Falling back to byte-by-byte access would be safe but ruin
+// optimizations that have been made specifically with aligned access in mind.
+// As a compromise, aligned reads will fall back to non-compliant type punning
+// but aligned writes will be byte-by-byte, that is, fast reads are preferred
+// over fast writes. This obviously isn't great but hopefully it's a working
+// compromise for now.
+//
+// __builtin_assume_aligned is support by GCC >= 4.7 and clang >= 3.6.
+#ifdef HAVE___BUILTIN_ASSUME_ALIGNED
+#	define tuklib_memcpy_aligned(dest, src, size) \
+		memcpy(dest, __builtin_assume_aligned(src, size), size)
+#else
+#	define tuklib_memcpy_aligned(dest, src, size) \
+		memcpy(dest, src, size)
+#	ifndef TUKLIB_FAST_UNALIGNED_ACCESS
+#		define TUKLIB_USE_UNSAFE_ALIGNED_READS 1
+#	endif
+#endif
+
+
+static inline uint16_t
+aligned_read16ne(const uint8_t *buf)
+{
+#if defined(TUKLIB_USE_UNSAFE_TYPE_PUNNING) \
+		|| defined(TUKLIB_USE_UNSAFE_ALIGNED_READS)
+	return *(const uint16_t *)buf;
+#else
+	uint16_t num;
+	tuklib_memcpy_aligned(&num, buf, sizeof(num));
+	return num;
+#endif
+}
+
+
+static inline uint32_t
+aligned_read32ne(const uint8_t *buf)
+{
+#if defined(TUKLIB_USE_UNSAFE_TYPE_PUNNING) \
+		|| defined(TUKLIB_USE_UNSAFE_ALIGNED_READS)
+	return *(const uint32_t *)buf;
+#else
+	uint32_t num;
+	tuklib_memcpy_aligned(&num, buf, sizeof(num));
+	return num;
+#endif
+}
+
+
+static inline uint64_t
+aligned_read64ne(const uint8_t *buf)
+{
+#if defined(TUKLIB_USE_UNSAFE_TYPE_PUNNING) \
+		|| defined(TUKLIB_USE_UNSAFE_ALIGNED_READS)
+	return *(const uint64_t *)buf;
+#else
+	uint64_t num;
+	tuklib_memcpy_aligned(&num, buf, sizeof(num));
+	return num;
+#endif
+}
+
+
+static inline void
+aligned_write16ne(uint8_t *buf, uint16_t num)
+{
+#ifdef TUKLIB_USE_UNSAFE_TYPE_PUNNING
+	*(uint16_t *)buf = num;
+#else
+	tuklib_memcpy_aligned(buf, &num, sizeof(num));
+#endif
+	return;
+}
+
+
+static inline void
+aligned_write32ne(uint8_t *buf, uint32_t num)
+{
+#ifdef TUKLIB_USE_UNSAFE_TYPE_PUNNING
+	*(uint32_t *)buf = num;
+#else
+	tuklib_memcpy_aligned(buf, &num, sizeof(num));
+#endif
+	return;
+}
+
+
+static inline void
+aligned_write64ne(uint8_t *buf, uint64_t num)
+{
+#ifdef TUKLIB_USE_UNSAFE_TYPE_PUNNING
+	*(uint64_t *)buf = num;
+#else
+	tuklib_memcpy_aligned(buf, &num, sizeof(num));
+#endif
+	return;
+}
+
+
+static inline uint16_t
+aligned_read16be(const uint8_t *buf)
+{
+	uint16_t num = aligned_read16ne(buf);
+	return conv16be(num);
+}
+
+
+static inline uint16_t
+aligned_read16le(const uint8_t *buf)
+{
+	uint16_t num = aligned_read16ne(buf);
+	return conv16le(num);
+}
+
+
+static inline uint32_t
+aligned_read32be(const uint8_t *buf)
+{
+	uint32_t num = aligned_read32ne(buf);
+	return conv32be(num);
+}
+
+
+static inline uint32_t
+aligned_read32le(const uint8_t *buf)
+{
+	uint32_t num = aligned_read32ne(buf);
+	return conv32le(num);
+}
+
+
+static inline uint64_t
+aligned_read64be(const uint8_t *buf)
+{
+	uint64_t num = aligned_read64ne(buf);
+	return conv64be(num);
+}
+
+
+static inline uint64_t
+aligned_read64le(const uint8_t *buf)
+{
+	uint64_t num = aligned_read64ne(buf);
+	return conv64le(num);
+}
+
+
+// These need to be macros like in the unaligned case.
+#define aligned_write16be(buf, num) aligned_write16ne((buf), conv16be(num))
+#define aligned_write16le(buf, num) aligned_write16ne((buf), conv16le(num))
+#define aligned_write32be(buf, num) aligned_write32ne((buf), conv32be(num))
+#define aligned_write32le(buf, num) aligned_write32ne((buf), conv32le(num))
+#define aligned_write64be(buf, num) aligned_write64ne((buf), conv64be(num))
+#define aligned_write64le(buf, num) aligned_write64ne((buf), conv64le(num))
+
+
+////////////////////
+// Bit operations //
+////////////////////
+
+static inline uint32_t
+bsr32(uint32_t n)
+{
+	// Check for ICC first, since it tends to define __GNUC__ too.
+#if defined(__INTEL_COMPILER)
+	return _bit_scan_reverse(n);
+
+#elif TUKLIB_GNUC_REQ(3, 4) && UINT_MAX == UINT32_MAX
+	// GCC >= 3.4 has __builtin_clz(), which gives good results on
+	// multiple architectures. On x86, __builtin_clz() ^ 31U becomes
+	// either plain BSR (so the XOR gets optimized away) or LZCNT and
+	// XOR (if -march indicates that SSE4a instructions are supported).
+	return (uint32_t)__builtin_clz(n) ^ 31U;
+
+#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+	uint32_t i;
+	__asm__("bsrl %1, %0" : "=r" (i) : "rm" (n));
+	return i;
+
+#elif defined(_MSC_VER)
+	unsigned long i;
+	_BitScanReverse(&i, n);
+	return i;
+
+#else
+	uint32_t i = 31;
+
+	if ((n & 0xFFFF0000) == 0) {
+		n <<= 16;
+		i = 15;
+	}
+
+	if ((n & 0xFF000000) == 0) {
+		n <<= 8;
+		i -= 8;
+	}
+
+	if ((n & 0xF0000000) == 0) {
+		n <<= 4;
+		i -= 4;
+	}
+
+	if ((n & 0xC0000000) == 0) {
+		n <<= 2;
+		i -= 2;
+	}
+
+	if ((n & 0x80000000) == 0)
+		--i;
+
+	return i;
+#endif
+}
+
+
+static inline uint32_t
+clz32(uint32_t n)
+{
+#if defined(__INTEL_COMPILER)
+	return _bit_scan_reverse(n) ^ 31U;
+
+#elif TUKLIB_GNUC_REQ(3, 4) && UINT_MAX == UINT32_MAX
+	return (uint32_t)__builtin_clz(n);
+
+#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+	uint32_t i;
+	__asm__("bsrl %1, %0\n\t"
+		"xorl $31, %0"
+		: "=r" (i) : "rm" (n));
+	return i;
+
+#elif defined(_MSC_VER)
+	unsigned long i;
+	_BitScanReverse(&i, n);
+	return i ^ 31U;
+
+#else
+	uint32_t i = 0;
+
+	if ((n & 0xFFFF0000) == 0) {
+		n <<= 16;
+		i = 16;
+	}
+
+	if ((n & 0xFF000000) == 0) {
+		n <<= 8;
+		i += 8;
+	}
+
+	if ((n & 0xF0000000) == 0) {
+		n <<= 4;
+		i += 4;
+	}
+
+	if ((n & 0xC0000000) == 0) {
+		n <<= 2;
+		i += 2;
+	}
+
+	if ((n & 0x80000000) == 0)
+		++i;
+
+	return i;
+#endif
+}
+
+
+static inline uint32_t
+ctz32(uint32_t n)
+{
+#if defined(__INTEL_COMPILER)
+	return _bit_scan_forward(n);
+
+#elif TUKLIB_GNUC_REQ(3, 4) && UINT_MAX >= UINT32_MAX
+	return (uint32_t)__builtin_ctz(n);
+
+#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+	uint32_t i;
+	__asm__("bsfl %1, %0" : "=r" (i) : "rm" (n));
+	return i;
+
+#elif defined(_MSC_VER)
+	unsigned long i;
+	_BitScanForward(&i, n);
+	return i;
+
+#else
+	uint32_t i = 0;
+
+	if ((n & 0x0000FFFF) == 0) {
+		n >>= 16;
+		i = 16;
+	}
+
+	if ((n & 0x000000FF) == 0) {
+		n >>= 8;
+		i += 8;
+	}
+
+	if ((n & 0x0000000F) == 0) {
+		n >>= 4;
+		i += 4;
+	}
+
+	if ((n & 0x00000003) == 0) {
+		n >>= 2;
+		i += 2;
+	}
+
+	if ((n & 0x00000001) == 0)
+		++i;
+
+	return i;
+#endif
+}
+
+#define bsf32 ctz32
+
+#endif