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Diffstat (limited to 'modules/woff2/src/port.h')
| -rw-r--r-- | modules/woff2/src/port.h | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/modules/woff2/src/port.h b/modules/woff2/src/port.h new file mode 100644 index 0000000000..8b60fee8bc --- /dev/null +++ b/modules/woff2/src/port.h @@ -0,0 +1,66 @@ +/* Copyright 2013 Google Inc. All Rights Reserved. + + Distributed under MIT license. + See file LICENSE for detail or copy at https://opensource.org/licenses/MIT +*/ + +/* Helper function for bit twiddling and macros for branch prediction. */ + +#ifndef WOFF2_PORT_H_ +#define WOFF2_PORT_H_ + +#include <assert.h> + +namespace woff2 { + +typedef unsigned int uint32; + +inline int Log2Floor(uint32 n) { +#if defined(__GNUC__) + return n == 0 ? -1 : 31 ^ __builtin_clz(n); +#else + if (n == 0) + return -1; + int log = 0; + uint32 value = n; + for (int i = 4; i >= 0; --i) { + int shift = (1 << i); + uint32 x = value >> shift; + if (x != 0) { + value = x; + log += shift; + } + } + assert(value == 1); + return log; +#endif +} + +} // namespace woff2 + +/* Compatibility with non-clang compilers. */ +#ifndef __has_builtin +#define __has_builtin(x) 0 +#endif + +#if (__GNUC__ > 2) || (__GNUC__ == 2 && __GNUC_MINOR__ > 95) || \ + (defined(__llvm__) && __has_builtin(__builtin_expect)) +#define PREDICT_FALSE(x) (__builtin_expect(x, 0)) +#define PREDICT_TRUE(x) (__builtin_expect(!!(x), 1)) +#else +#define PREDICT_FALSE(x) (x) +#define PREDICT_TRUE(x) (x) +#endif + +#if (defined(__ARM_ARCH) && (__ARM_ARCH == 7)) || \ + (defined(M_ARM) && (M_ARM == 7)) || \ + defined(__aarch64__) || defined(__ARM64_ARCH_8__) || defined(__i386) || \ + defined(_M_IX86) || defined(__x86_64__) || defined(_M_X64) +#if defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) +#define WOFF_LITTLE_ENDIAN +#elif defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) +#define WOFF_BIG_ENDIAN +#endif /* endianness */ +#endif /* CPU whitelist */ + +#endif // WOFF2_PORT_H_ |