41 lines
839 B
C++
41 lines
839 B
C++
#pragma once
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#include <cmath>
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#include <cstdint>
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#include <type_traits>
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#if defined(__ANDROID__)
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#include <android/api-level.h>
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#endif
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namespace mbgl {
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namespace util {
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/// Computes the log2(x) rounded up to the next integer.
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/// (== number of bits required to store x)
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uint32_t ceil_log2(uint64_t x);
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template <typename T>
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T log2(T x) {
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// log2() is producing wrong results on ARMv5 binaries
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// running on ARMv7+ CPUs.
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#if defined(__ANDROID__)
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return ::log(x) / M_LN2;
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#else
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return ::log2(x);
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#endif
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}
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} // namespace util
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} // namespace mbgl
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// log2 is not available on Android before API 18.
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#if defined(__ANDROID__) && defined(__GNUC__) && defined(__ANDROID_API__) && __ANDROID_API__ < 18
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template <typename T>
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typename std::enable_if_t<std::is_floating_point_v<T>, T> log2(T x) {
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return ::log(x) / M_LN2;
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}
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#endif
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