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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 01:47:29 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 01:47:29 +0000
commit0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d (patch)
treea31f07c9bcca9d56ce61e9a1ffd30ef350d513aa /third_party/jpeg-xl/lib/jxl/base/bits.h
parentInitial commit. (diff)
downloadfirefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.tar.xz
firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.zip
Adding upstream version 115.8.0esr.upstream/115.8.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/jpeg-xl/lib/jxl/base/bits.h')
-rw-r--r--third_party/jpeg-xl/lib/jxl/base/bits.h147
1 files changed, 147 insertions, 0 deletions
diff --git a/third_party/jpeg-xl/lib/jxl/base/bits.h b/third_party/jpeg-xl/lib/jxl/base/bits.h
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+++ b/third_party/jpeg-xl/lib/jxl/base/bits.h
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+// Copyright (c) the JPEG XL Project Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#ifndef LIB_JXL_BASE_BITS_H_
+#define LIB_JXL_BASE_BITS_H_
+
+// Specialized instructions for processing register-sized bit arrays.
+
+#include "lib/jxl/base/compiler_specific.h"
+#include "lib/jxl/base/status.h"
+
+#if JXL_COMPILER_MSVC
+#include <intrin.h>
+#endif
+
+#include <stddef.h>
+#include <stdint.h>
+
+namespace jxl {
+
+// Empty struct used as a size tag type.
+template <size_t N>
+struct SizeTag {};
+
+template <typename T>
+constexpr bool IsSigned() {
+ return T(0) > T(-1);
+}
+
+// Undefined results for x == 0.
+static JXL_INLINE JXL_MAYBE_UNUSED size_t
+Num0BitsAboveMS1Bit_Nonzero(SizeTag<4> /* tag */, const uint32_t x) {
+ JXL_DASSERT(x != 0);
+#if JXL_COMPILER_MSVC
+ unsigned long index;
+ _BitScanReverse(&index, x);
+ return 31 - index;
+#else
+ return static_cast<size_t>(__builtin_clz(x));
+#endif
+}
+static JXL_INLINE JXL_MAYBE_UNUSED size_t
+Num0BitsAboveMS1Bit_Nonzero(SizeTag<8> /* tag */, const uint64_t x) {
+ JXL_DASSERT(x != 0);
+#if JXL_COMPILER_MSVC
+#if JXL_ARCH_X64
+ unsigned long index;
+ _BitScanReverse64(&index, x);
+ return 63 - index;
+#else // JXL_ARCH_X64
+ // _BitScanReverse64 not available
+ uint32_t msb = static_cast<uint32_t>(x >> 32u);
+ unsigned long index;
+ if (msb == 0) {
+ uint32_t lsb = static_cast<uint32_t>(x & 0xFFFFFFFF);
+ _BitScanReverse(&index, lsb);
+ return 63 - index;
+ } else {
+ _BitScanReverse(&index, msb);
+ return 31 - index;
+ }
+#endif // JXL_ARCH_X64
+#else
+ return static_cast<size_t>(__builtin_clzll(x));
+#endif
+}
+template <typename T>
+static JXL_INLINE JXL_MAYBE_UNUSED size_t
+Num0BitsAboveMS1Bit_Nonzero(const T x) {
+ static_assert(!IsSigned<T>(), "Num0BitsAboveMS1Bit_Nonzero: use unsigned");
+ return Num0BitsAboveMS1Bit_Nonzero(SizeTag<sizeof(T)>(), x);
+}
+
+// Undefined results for x == 0.
+static JXL_INLINE JXL_MAYBE_UNUSED size_t
+Num0BitsBelowLS1Bit_Nonzero(SizeTag<4> /* tag */, const uint32_t x) {
+ JXL_DASSERT(x != 0);
+#if JXL_COMPILER_MSVC
+ unsigned long index;
+ _BitScanForward(&index, x);
+ return index;
+#else
+ return static_cast<size_t>(__builtin_ctz(x));
+#endif
+}
+static JXL_INLINE JXL_MAYBE_UNUSED size_t
+Num0BitsBelowLS1Bit_Nonzero(SizeTag<8> /* tag */, const uint64_t x) {
+ JXL_DASSERT(x != 0);
+#if JXL_COMPILER_MSVC
+#if JXL_ARCH_X64
+ unsigned long index;
+ _BitScanForward64(&index, x);
+ return index;
+#else // JXL_ARCH_64
+ // _BitScanForward64 not available
+ uint32_t lsb = static_cast<uint32_t>(x & 0xFFFFFFFF);
+ unsigned long index;
+ if (lsb == 0) {
+ uint32_t msb = static_cast<uint32_t>(x >> 32u);
+ _BitScanForward(&index, msb);
+ return 32 + index;
+ } else {
+ _BitScanForward(&index, lsb);
+ return index;
+ }
+#endif // JXL_ARCH_X64
+#else
+ return static_cast<size_t>(__builtin_ctzll(x));
+#endif
+}
+template <typename T>
+static JXL_INLINE JXL_MAYBE_UNUSED size_t Num0BitsBelowLS1Bit_Nonzero(T x) {
+ static_assert(!IsSigned<T>(), "Num0BitsBelowLS1Bit_Nonzero: use unsigned");
+ return Num0BitsBelowLS1Bit_Nonzero(SizeTag<sizeof(T)>(), x);
+}
+
+// Returns bit width for x == 0.
+template <typename T>
+static JXL_INLINE JXL_MAYBE_UNUSED size_t Num0BitsAboveMS1Bit(const T x) {
+ return (x == 0) ? sizeof(T) * 8 : Num0BitsAboveMS1Bit_Nonzero(x);
+}
+
+// Returns bit width for x == 0.
+template <typename T>
+static JXL_INLINE JXL_MAYBE_UNUSED size_t Num0BitsBelowLS1Bit(const T x) {
+ return (x == 0) ? sizeof(T) * 8 : Num0BitsBelowLS1Bit_Nonzero(x);
+}
+
+// Returns base-2 logarithm, rounded down.
+template <typename T>
+static JXL_INLINE JXL_MAYBE_UNUSED size_t FloorLog2Nonzero(const T x) {
+ return (sizeof(T) * 8 - 1) ^ Num0BitsAboveMS1Bit_Nonzero(x);
+}
+
+// Returns base-2 logarithm, rounded up.
+template <typename T>
+static JXL_INLINE JXL_MAYBE_UNUSED size_t CeilLog2Nonzero(const T x) {
+ const size_t floor_log2 = FloorLog2Nonzero(x);
+ if ((x & (x - 1)) == 0) return floor_log2; // power of two
+ return floor_log2 + 1;
+}
+
+} // namespace jxl
+
+#endif // LIB_JXL_BASE_BITS_H_