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Merge pull request #67 from cppalliance/table
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Remove duplicate table
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@mborland
mborland authored Aug 8, 2023
2 parents bbcb97f + 187f233 commit b3935e5
Showing 1 changed file with 9 additions and 31 deletions.
40 changes: 9 additions & 31 deletions src/to_chars.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -22,28 +22,6 @@ namespace boost { namespace charconv { namespace detail { namespace to_chars_det
// These "//"'s are to prevent clang-format to ruin this nice alignment.
// Thanks to reddit user u/mcmcc:
// https://www.reddit.com/r/cpp/comments/so3wx9/dragonbox_110_is_released_a_fast_floattostring/hw8z26r/?context=3
static constexpr char radix_100_table[] = {
'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' //
};
static constexpr char radix_100_head_table[] = {
'0', '.', '1', '.', '2', '.', '3', '.', '4', '.', //
'5', '.', '6', '.', '7', '.', '8', '.', '9', '.', //
Expand Down Expand Up @@ -74,7 +52,7 @@ namespace boost { namespace charconv { namespace detail { namespace to_chars_det

static void print_2_digits(std::uint32_t n, char* buffer) noexcept
{
std::memcpy(buffer, radix_100_table + n * 2, 2);
std::memcpy(buffer, radix_table + n * 2, 2);
}

// These digit generation routines are inspired by James Anhalt's itoa algorithm:
Expand Down Expand Up @@ -132,7 +110,7 @@ namespace boost { namespace charconv { namespace detail { namespace to_chars_det
// Write the first digit and the decimal point.
std::memcpy(buffer, radix_100_head_table + head_digits * 2, 2);
// This third character may be overwritten later but we don't care.
buffer[2] = radix_100_table[head_digits * 2 + 1];
buffer[2] = radix_table[head_digits * 2 + 1];

// Remaining 6 digits are all zero?
if (std::uint32_t(prod) <= std::uint32_t((std::uint64_t(1) << 32) / 1000000))
Expand Down Expand Up @@ -198,7 +176,7 @@ namespace boost { namespace charconv { namespace detail { namespace to_chars_det
// Write the first digit and the decimal point.
std::memcpy(buffer, radix_100_head_table + head_digits * 2, 2);
// This third character may be overwritten later but we don't care.
buffer[2] = radix_100_table[head_digits * 2 + 1];
buffer[2] = radix_table[head_digits * 2 + 1];

// Remaining 4 digits are all zero?
if (std::uint32_t(prod) <= std::uint32_t((std::uint64_t(1) << 32) / 10000))
Expand Down Expand Up @@ -246,7 +224,7 @@ namespace boost { namespace charconv { namespace detail { namespace to_chars_det
// Write the first digit and the decimal point.
std::memcpy(buffer, radix_100_head_table + head_digits * 2, 2);
// This third character may be overwritten later but we don't care.
buffer[2] = radix_100_table[head_digits * 2 + 1];
buffer[2] = radix_table[head_digits * 2 + 1];

// Remaining 2 digits are all zero?
if (std::uint32_t(prod) <= std::uint32_t((std::uint64_t(1) << 32) / 100))
Expand Down Expand Up @@ -277,7 +255,7 @@ namespace boost { namespace charconv { namespace detail { namespace to_chars_det
// Write the first digit and the decimal point.
std::memcpy(buffer, radix_100_head_table + s32 * 2, 2);
// This third character may be overwritten later but we don't care.
buffer[2] = radix_100_table[s32 * 2 + 1];
buffer[2] = radix_table[s32 * 2 + 1];

// The number of characters actually written is 1 or 3, similarly to the case of
// 7 or 8 digits.
Expand Down Expand Up @@ -392,7 +370,7 @@ namespace boost { namespace charconv { namespace detail { namespace to_chars_det
const auto head_digits = std::uint32_t(prod >> 32);

std::memcpy(buffer, radix_100_head_table + head_digits * 2, 2);
buffer[2] = radix_100_table[head_digits * 2 + 1];
buffer[2] = radix_table[head_digits * 2 + 1];

exponent += (6 + unsigned(head_digits >= 10));
buffer += unsigned(head_digits >= 10);
Expand All @@ -415,7 +393,7 @@ namespace boost { namespace charconv { namespace detail { namespace to_chars_det
const auto head_digits = std::uint32_t(prod >> 32);

std::memcpy(buffer, radix_100_head_table + head_digits * 2, 2);
buffer[2] = radix_100_table[head_digits * 2 + 1];
buffer[2] = radix_table[head_digits * 2 + 1];

exponent += (4 + unsigned(head_digits >= 10));
buffer += unsigned(head_digits >= 10);
Expand All @@ -436,7 +414,7 @@ namespace boost { namespace charconv { namespace detail { namespace to_chars_det
const auto head_digits = std::uint32_t(prod >> 32);

std::memcpy(buffer, radix_100_head_table + head_digits * 2, 2);
buffer[2] = radix_100_table[head_digits * 2 + 1];
buffer[2] = radix_table[head_digits * 2 + 1];

exponent += (2 + unsigned(head_digits >= 10));
buffer += unsigned(head_digits >= 10);
Expand All @@ -451,7 +429,7 @@ namespace boost { namespace charconv { namespace detail { namespace to_chars_det
{
// 1 or 2 digits.
std::memcpy(buffer, radix_100_head_table + first_block * 2, 2);
buffer[2] = radix_100_table[first_block * 2 + 1];
buffer[2] = radix_table[first_block * 2 + 1];

exponent += unsigned(first_block >= 10);
buffer += (2 + unsigned(first_block >= 10));
Expand Down

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