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Diffstat (limited to 'lib/libcxx/src/charconv.cpp')
| -rw-r--r-- | lib/libcxx/src/charconv.cpp | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/lib/libcxx/src/charconv.cpp b/lib/libcxx/src/charconv.cpp new file mode 100644 index 00000000000..ec241db7447 --- /dev/null +++ b/lib/libcxx/src/charconv.cpp @@ -0,0 +1,233 @@ +//===------------------------- charconv.cpp -------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is dual licensed under the MIT and the University of Illinois Open +// Source Licenses. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#include "charconv" +#include <string.h> + +_LIBCPP_BEGIN_NAMESPACE_STD + +namespace __itoa +{ + +static constexpr char cDigitsLut[200] = { + '0', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '0', '6', '0', + '7', '0', '8', '0', '9', '1', '0', '1', '1', '1', '2', '1', '3', '1', '4', + '1', '5', '1', '6', '1', '7', '1', '8', '1', '9', '2', '0', '2', '1', '2', + '2', '2', '3', '2', '4', '2', '5', '2', '6', '2', '7', '2', '8', '2', '9', + '3', '0', '3', '1', '3', '2', '3', '3', '3', '4', '3', '5', '3', '6', '3', + '7', '3', '8', '3', '9', '4', '0', '4', '1', '4', '2', '4', '3', '4', '4', + '4', '5', '4', '6', '4', '7', '4', '8', '4', '9', '5', '0', '5', '1', '5', + '2', '5', '3', '5', '4', '5', '5', '5', '6', '5', '7', '5', '8', '5', '9', + '6', '0', '6', '1', '6', '2', '6', '3', '6', '4', '6', '5', '6', '6', '6', + '7', '6', '8', '6', '9', '7', '0', '7', '1', '7', '2', '7', '3', '7', '4', + '7', '5', '7', '6', '7', '7', '7', '8', '7', '9', '8', '0', '8', '1', '8', + '2', '8', '3', '8', '4', '8', '5', '8', '6', '8', '7', '8', '8', '8', '9', + '9', '0', '9', '1', '9', '2', '9', '3', '9', '4', '9', '5', '9', '6', '9', + '7', '9', '8', '9', '9'}; + +template <typename T> +inline _LIBCPP_INLINE_VISIBILITY char* +append1(char* buffer, T i) +{ + *buffer = '0' + static_cast<char>(i); + return buffer + 1; +} + +template <typename T> +inline _LIBCPP_INLINE_VISIBILITY char* +append2(char* buffer, T i) +{ + memcpy(buffer, &cDigitsLut[(i)*2], 2); + return buffer + 2; +} + +template <typename T> +inline _LIBCPP_INLINE_VISIBILITY char* +append3(char* buffer, T i) +{ + return append2(append1(buffer, (i) / 100), (i) % 100); +} + +template <typename T> +inline _LIBCPP_INLINE_VISIBILITY char* +append4(char* buffer, T i) +{ + return append2(append2(buffer, (i) / 100), (i) % 100); +} + +char* +__u32toa(uint32_t value, char* buffer) +{ + if (value < 10000) + { + if (value < 100) + { + if (value < 10) + buffer = append1(buffer, value); + else + buffer = append2(buffer, value); + } + else + { + if (value < 1000) + buffer = append3(buffer, value); + else + buffer = append4(buffer, value); + } + } + else if (value < 100000000) + { + // value = bbbbcccc + const uint32_t b = value / 10000; + const uint32_t c = value % 10000; + + if (value < 1000000) + { + if (value < 100000) + buffer = append1(buffer, b); + else + buffer = append2(buffer, b); + } + else + { + if (value < 10000000) + buffer = append3(buffer, b); + else + buffer = append4(buffer, b); + } + + buffer = append4(buffer, c); + } + else + { + // value = aabbbbcccc in decimal + const uint32_t a = value / 100000000; // 1 to 42 + value %= 100000000; + + if (a < 10) + buffer = append1(buffer, a); + else + buffer = append2(buffer, a); + + buffer = append4(buffer, value / 10000); + buffer = append4(buffer, value % 10000); + } + + return buffer; +} + +char* +__u64toa(uint64_t value, char* buffer) +{ + if (value < 100000000) + { + uint32_t v = static_cast<uint32_t>(value); + if (v < 10000) + { + if (v < 100) + { + if (v < 10) + buffer = append1(buffer, v); + else + buffer = append2(buffer, v); + } + else + { + if (v < 1000) + buffer = append3(buffer, v); + else + buffer = append4(buffer, v); + } + } + else + { + // value = bbbbcccc + const uint32_t b = v / 10000; + const uint32_t c = v % 10000; + + if (v < 1000000) + { + if (v < 100000) + buffer = append1(buffer, b); + else + buffer = append2(buffer, b); + } + else + { + if (v < 10000000) + buffer = append3(buffer, b); + else + buffer = append4(buffer, b); + } + + buffer = append4(buffer, c); + } + } + else if (value < 10000000000000000) + { + const uint32_t v0 = static_cast<uint32_t>(value / 100000000); + const uint32_t v1 = static_cast<uint32_t>(value % 100000000); + + const uint32_t b0 = v0 / 10000; + const uint32_t c0 = v0 % 10000; + + if (v0 < 1000000) + { + if (v0 < 100000) + buffer = append1(buffer, b0); + else + buffer = append2(buffer, b0); + } + else + { + if (v0 < 10000000) + buffer = append3(buffer, b0); + else + buffer = append4(buffer, b0); + } + + buffer = append4(buffer, c0); + buffer = append4(buffer, v1 / 10000); + buffer = append4(buffer, v1 % 10000); + } + else + { + const uint32_t a = + static_cast<uint32_t>(value / 10000000000000000); // 1 to 1844 + value %= 10000000000000000; + + if (a < 100) + { + if (a < 10) + buffer = append1(buffer, a); + else + buffer = append2(buffer, a); + } + else + { + if (a < 1000) + buffer = append3(buffer, a); + else + buffer = append4(buffer, a); + } + + const uint32_t v0 = static_cast<uint32_t>(value / 100000000); + const uint32_t v1 = static_cast<uint32_t>(value % 100000000); + buffer = append4(buffer, v0 / 10000); + buffer = append4(buffer, v0 % 10000); + buffer = append4(buffer, v1 / 10000); + buffer = append4(buffer, v1 % 10000); + } + + return buffer; +} + +} // namespace __itoa + +_LIBCPP_END_NAMESPACE_STD |