diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /other-licenses/snappy/src/snappy-stubs-internal.h | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'other-licenses/snappy/src/snappy-stubs-internal.h')
-rw-r--r-- | other-licenses/snappy/src/snappy-stubs-internal.h | 492 |
1 files changed, 492 insertions, 0 deletions
diff --git a/other-licenses/snappy/src/snappy-stubs-internal.h b/other-licenses/snappy/src/snappy-stubs-internal.h new file mode 100644 index 0000000000..c2a838f38f --- /dev/null +++ b/other-licenses/snappy/src/snappy-stubs-internal.h @@ -0,0 +1,492 @@ +// Copyright 2011 Google Inc. All Rights Reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +// +// Various stubs for the open-source version of Snappy. + +#ifndef THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_STUBS_INTERNAL_H_ +#define THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_STUBS_INTERNAL_H_ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <stdint.h> + +#include <cassert> +#include <cstdlib> +#include <cstring> +#include <limits> +#include <string> + +#ifdef HAVE_SYS_MMAN_H +#include <sys/mman.h> +#endif + +#ifdef HAVE_UNISTD_H +#include <unistd.h> +#endif + +#if defined(_MSC_VER) +#include <intrin.h> +#endif // defined(_MSC_VER) + +#ifndef __has_feature +#define __has_feature(x) 0 +#endif + +#if __has_feature(memory_sanitizer) +#include <sanitizer/msan_interface.h> +#define SNAPPY_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \ + __msan_unpoison((address), (size)) +#else +#define SNAPPY_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) /* empty */ +#endif // __has_feature(memory_sanitizer) + +#include "snappy-stubs-public.h" + +// Used to enable 64-bit optimized versions of some routines. +#if defined(__PPC64__) || defined(__powerpc64__) +#define ARCH_PPC 1 +#elif defined(__aarch64__) || defined(_M_ARM64) +#define ARCH_ARM 1 +#endif + +// Needed by OS X, among others. +#ifndef MAP_ANONYMOUS +#define MAP_ANONYMOUS MAP_ANON +#endif + +// The size of an array, if known at compile-time. +// Will give unexpected results if used on a pointer. +// We undefine it first, since some compilers already have a definition. +#ifdef ARRAYSIZE +#undef ARRAYSIZE +#endif +#define ARRAYSIZE(a) int{sizeof(a) / sizeof(*(a))} + +// Static prediction hints. +#ifdef HAVE_BUILTIN_EXPECT +#define SNAPPY_PREDICT_FALSE(x) (__builtin_expect(x, 0)) +#define SNAPPY_PREDICT_TRUE(x) (__builtin_expect(!!(x), 1)) +#else +#define SNAPPY_PREDICT_FALSE(x) x +#define SNAPPY_PREDICT_TRUE(x) x +#endif + +// Inlining hints. +#ifdef HAVE_ATTRIBUTE_ALWAYS_INLINE +#define SNAPPY_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline)) +#else +#define SNAPPY_ATTRIBUTE_ALWAYS_INLINE +#endif + +// Stubbed version of ABSL_FLAG. +// +// In the open source version, flags can only be changed at compile time. +#define SNAPPY_FLAG(flag_type, flag_name, default_value, help) \ + flag_type FLAGS_ ## flag_name = default_value + +namespace snappy { + +// Stubbed version of absl::GetFlag(). +template <typename T> +inline T GetFlag(T flag) { return flag; } + +static const uint32_t kuint32max = std::numeric_limits<uint32_t>::max(); +static const int64_t kint64max = std::numeric_limits<int64_t>::max(); + +// Potentially unaligned loads and stores. + +inline uint16_t UNALIGNED_LOAD16(const void *p) { + // Compiles to a single movzx/ldrh on clang/gcc/msvc. + uint16_t v; + std::memcpy(&v, p, sizeof(v)); + return v; +} + +inline uint32_t UNALIGNED_LOAD32(const void *p) { + // Compiles to a single mov/ldr on clang/gcc/msvc. + uint32_t v; + std::memcpy(&v, p, sizeof(v)); + return v; +} + +inline uint64_t UNALIGNED_LOAD64(const void *p) { + // Compiles to a single mov/ldr on clang/gcc/msvc. + uint64_t v; + std::memcpy(&v, p, sizeof(v)); + return v; +} + +inline void UNALIGNED_STORE16(void *p, uint16_t v) { + // Compiles to a single mov/strh on clang/gcc/msvc. + std::memcpy(p, &v, sizeof(v)); +} + +inline void UNALIGNED_STORE32(void *p, uint32_t v) { + // Compiles to a single mov/str on clang/gcc/msvc. + std::memcpy(p, &v, sizeof(v)); +} + +inline void UNALIGNED_STORE64(void *p, uint64_t v) { + // Compiles to a single mov/str on clang/gcc/msvc. + std::memcpy(p, &v, sizeof(v)); +} + +// Convert to little-endian storage, opposite of network format. +// Convert x from host to little endian: x = LittleEndian.FromHost(x); +// convert x from little endian to host: x = LittleEndian.ToHost(x); +// +// Store values into unaligned memory converting to little endian order: +// LittleEndian.Store16(p, x); +// +// Load unaligned values stored in little endian converting to host order: +// x = LittleEndian.Load16(p); +class LittleEndian { + public: + // Functions to do unaligned loads and stores in little-endian order. + static inline uint16_t Load16(const void *ptr) { + const uint8_t* const buffer = reinterpret_cast<const uint8_t*>(ptr); + + // Compiles to a single mov/str on recent clang and gcc. + return (static_cast<uint16_t>(buffer[0])) | + (static_cast<uint16_t>(buffer[1]) << 8); + } + + static inline uint32_t Load32(const void *ptr) { + const uint8_t* const buffer = reinterpret_cast<const uint8_t*>(ptr); + + // Compiles to a single mov/str on recent clang and gcc. + return (static_cast<uint32_t>(buffer[0])) | + (static_cast<uint32_t>(buffer[1]) << 8) | + (static_cast<uint32_t>(buffer[2]) << 16) | + (static_cast<uint32_t>(buffer[3]) << 24); + } + + static inline uint64_t Load64(const void *ptr) { + const uint8_t* const buffer = reinterpret_cast<const uint8_t*>(ptr); + + // Compiles to a single mov/str on recent clang and gcc. + return (static_cast<uint64_t>(buffer[0])) | + (static_cast<uint64_t>(buffer[1]) << 8) | + (static_cast<uint64_t>(buffer[2]) << 16) | + (static_cast<uint64_t>(buffer[3]) << 24) | + (static_cast<uint64_t>(buffer[4]) << 32) | + (static_cast<uint64_t>(buffer[5]) << 40) | + (static_cast<uint64_t>(buffer[6]) << 48) | + (static_cast<uint64_t>(buffer[7]) << 56); + } + + static inline void Store16(void *dst, uint16_t value) { + uint8_t* const buffer = reinterpret_cast<uint8_t*>(dst); + + // Compiles to a single mov/str on recent clang and gcc. + buffer[0] = static_cast<uint8_t>(value); + buffer[1] = static_cast<uint8_t>(value >> 8); + } + + static void Store32(void *dst, uint32_t value) { + uint8_t* const buffer = reinterpret_cast<uint8_t*>(dst); + + // Compiles to a single mov/str on recent clang and gcc. + buffer[0] = static_cast<uint8_t>(value); + buffer[1] = static_cast<uint8_t>(value >> 8); + buffer[2] = static_cast<uint8_t>(value >> 16); + buffer[3] = static_cast<uint8_t>(value >> 24); + } + + static void Store64(void* dst, uint64_t value) { + uint8_t* const buffer = reinterpret_cast<uint8_t*>(dst); + + // Compiles to a single mov/str on recent clang and gcc. + buffer[0] = static_cast<uint8_t>(value); + buffer[1] = static_cast<uint8_t>(value >> 8); + buffer[2] = static_cast<uint8_t>(value >> 16); + buffer[3] = static_cast<uint8_t>(value >> 24); + buffer[4] = static_cast<uint8_t>(value >> 32); + buffer[5] = static_cast<uint8_t>(value >> 40); + buffer[6] = static_cast<uint8_t>(value >> 48); + buffer[7] = static_cast<uint8_t>(value >> 56); + } + + static inline constexpr bool IsLittleEndian() { +#if defined(SNAPPY_IS_BIG_ENDIAN) + return false; +#else + return true; +#endif // defined(SNAPPY_IS_BIG_ENDIAN) + } +}; + +// Some bit-manipulation functions. +class Bits { + public: + // Return floor(log2(n)) for positive integer n. + static int Log2FloorNonZero(uint32_t n); + + // Return floor(log2(n)) for positive integer n. Returns -1 iff n == 0. + static int Log2Floor(uint32_t n); + + // Return the first set least / most significant bit, 0-indexed. Returns an + // undefined value if n == 0. FindLSBSetNonZero() is similar to ffs() except + // that it's 0-indexed. + static int FindLSBSetNonZero(uint32_t n); + + static int FindLSBSetNonZero64(uint64_t n); + + private: + // No copying + Bits(const Bits&); + void operator=(const Bits&); +}; + +#if defined(HAVE_BUILTIN_CTZ) + +inline int Bits::Log2FloorNonZero(uint32_t n) { + assert(n != 0); + // (31 ^ x) is equivalent to (31 - x) for x in [0, 31]. An easy proof + // represents subtraction in base 2 and observes that there's no carry. + // + // GCC and Clang represent __builtin_clz on x86 as 31 ^ _bit_scan_reverse(x). + // Using "31 ^" here instead of "31 -" allows the optimizer to strip the + // function body down to _bit_scan_reverse(x). + return 31 ^ __builtin_clz(n); +} + +inline int Bits::Log2Floor(uint32_t n) { + return (n == 0) ? -1 : Bits::Log2FloorNonZero(n); +} + +inline int Bits::FindLSBSetNonZero(uint32_t n) { + assert(n != 0); + return __builtin_ctz(n); +} + +#elif defined(_MSC_VER) + +inline int Bits::Log2FloorNonZero(uint32_t n) { + assert(n != 0); + // NOLINTNEXTLINE(runtime/int): The MSVC intrinsic demands unsigned long. + unsigned long where; + _BitScanReverse(&where, n); + return static_cast<int>(where); +} + +inline int Bits::Log2Floor(uint32_t n) { + // NOLINTNEXTLINE(runtime/int): The MSVC intrinsic demands unsigned long. + unsigned long where; + if (_BitScanReverse(&where, n)) + return static_cast<int>(where); + return -1; +} + +inline int Bits::FindLSBSetNonZero(uint32_t n) { + assert(n != 0); + // NOLINTNEXTLINE(runtime/int): The MSVC intrinsic demands unsigned long. + unsigned long where; + if (_BitScanForward(&where, n)) + return static_cast<int>(where); + return 32; +} + +#else // Portable versions. + +inline int Bits::Log2FloorNonZero(uint32_t n) { + assert(n != 0); + + int log = 0; + uint32_t value = n; + for (int i = 4; i >= 0; --i) { + int shift = (1 << i); + uint32_t x = value >> shift; + if (x != 0) { + value = x; + log += shift; + } + } + assert(value == 1); + return log; +} + +inline int Bits::Log2Floor(uint32_t n) { + return (n == 0) ? -1 : Bits::Log2FloorNonZero(n); +} + +inline int Bits::FindLSBSetNonZero(uint32_t n) { + assert(n != 0); + + int rc = 31; + for (int i = 4, shift = 1 << 4; i >= 0; --i) { + const uint32_t x = n << shift; + if (x != 0) { + n = x; + rc -= shift; + } + shift >>= 1; + } + return rc; +} + +#endif // End portable versions. + +#if defined(HAVE_BUILTIN_CTZ) + +inline int Bits::FindLSBSetNonZero64(uint64_t n) { + assert(n != 0); + return __builtin_ctzll(n); +} + +#elif defined(_MSC_VER) && (defined(_M_X64) || defined(_M_ARM64)) +// _BitScanForward64() is only available on x64 and ARM64. + +inline int Bits::FindLSBSetNonZero64(uint64_t n) { + assert(n != 0); + // NOLINTNEXTLINE(runtime/int): The MSVC intrinsic demands unsigned long. + unsigned long where; + if (_BitScanForward64(&where, n)) + return static_cast<int>(where); + return 64; +} + +#else // Portable version. + +// FindLSBSetNonZero64() is defined in terms of FindLSBSetNonZero(). +inline int Bits::FindLSBSetNonZero64(uint64_t n) { + assert(n != 0); + + const uint32_t bottombits = static_cast<uint32_t>(n); + if (bottombits == 0) { + // Bottom bits are zero, so scan the top bits. + return 32 + FindLSBSetNonZero(static_cast<uint32_t>(n >> 32)); + } else { + return FindLSBSetNonZero(bottombits); + } +} + +#endif // End portable version. + +// Variable-length integer encoding. +class Varint { + public: + // Maximum lengths of varint encoding of uint32_t. + static const int kMax32 = 5; + + // Attempts to parse a varint32 from a prefix of the bytes in [ptr,limit-1]. + // Never reads a character at or beyond limit. If a valid/terminated varint32 + // was found in the range, stores it in *OUTPUT and returns a pointer just + // past the last byte of the varint32. Else returns NULL. On success, + // "result <= limit". + static const char* Parse32WithLimit(const char* ptr, const char* limit, + uint32_t* OUTPUT); + + // REQUIRES "ptr" points to a buffer of length sufficient to hold "v". + // EFFECTS Encodes "v" into "ptr" and returns a pointer to the + // byte just past the last encoded byte. + static char* Encode32(char* ptr, uint32_t v); + + // EFFECTS Appends the varint representation of "value" to "*s". + static void Append32(std::string* s, uint32_t value); +}; + +inline const char* Varint::Parse32WithLimit(const char* p, + const char* l, + uint32_t* OUTPUT) { + const unsigned char* ptr = reinterpret_cast<const unsigned char*>(p); + const unsigned char* limit = reinterpret_cast<const unsigned char*>(l); + uint32_t b, result; + if (ptr >= limit) return NULL; + b = *(ptr++); result = b & 127; if (b < 128) goto done; + if (ptr >= limit) return NULL; + b = *(ptr++); result |= (b & 127) << 7; if (b < 128) goto done; + if (ptr >= limit) return NULL; + b = *(ptr++); result |= (b & 127) << 14; if (b < 128) goto done; + if (ptr >= limit) return NULL; + b = *(ptr++); result |= (b & 127) << 21; if (b < 128) goto done; + if (ptr >= limit) return NULL; + b = *(ptr++); result |= (b & 127) << 28; if (b < 16) goto done; + return NULL; // Value is too long to be a varint32 + done: + *OUTPUT = result; + return reinterpret_cast<const char*>(ptr); +} + +inline char* Varint::Encode32(char* sptr, uint32_t v) { + // Operate on characters as unsigneds + uint8_t* ptr = reinterpret_cast<uint8_t*>(sptr); + static const uint8_t B = 128; + if (v < (1 << 7)) { + *(ptr++) = static_cast<uint8_t>(v); + } else if (v < (1 << 14)) { + *(ptr++) = static_cast<uint8_t>(v | B); + *(ptr++) = static_cast<uint8_t>(v >> 7); + } else if (v < (1 << 21)) { + *(ptr++) = static_cast<uint8_t>(v | B); + *(ptr++) = static_cast<uint8_t>((v >> 7) | B); + *(ptr++) = static_cast<uint8_t>(v >> 14); + } else if (v < (1 << 28)) { + *(ptr++) = static_cast<uint8_t>(v | B); + *(ptr++) = static_cast<uint8_t>((v >> 7) | B); + *(ptr++) = static_cast<uint8_t>((v >> 14) | B); + *(ptr++) = static_cast<uint8_t>(v >> 21); + } else { + *(ptr++) = static_cast<uint8_t>(v | B); + *(ptr++) = static_cast<uint8_t>((v>>7) | B); + *(ptr++) = static_cast<uint8_t>((v>>14) | B); + *(ptr++) = static_cast<uint8_t>((v>>21) | B); + *(ptr++) = static_cast<uint8_t>(v >> 28); + } + return reinterpret_cast<char*>(ptr); +} + +// If you know the internal layout of the std::string in use, you can +// replace this function with one that resizes the string without +// filling the new space with zeros (if applicable) -- +// it will be non-portable but faster. +inline void STLStringResizeUninitialized(std::string* s, size_t new_size) { + s->resize(new_size); +} + +// Return a mutable char* pointing to a string's internal buffer, +// which may not be null-terminated. Writing through this pointer will +// modify the string. +// +// string_as_array(&str)[i] is valid for 0 <= i < str.size() until the +// next call to a string method that invalidates iterators. +// +// As of 2006-04, there is no standard-blessed way of getting a +// mutable reference to a string's internal buffer. However, issue 530 +// (http://www.open-std.org/JTC1/SC22/WG21/docs/lwg-defects.html#530) +// proposes this as the method. It will officially be part of the standard +// for C++0x. This should already work on all current implementations. +inline char* string_as_array(std::string* str) { + return str->empty() ? NULL : &*str->begin(); +} + +} // namespace snappy + +#endif // THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_STUBS_INTERNAL_H_ |