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Added missing return in format_decimal(); Added first support for negative numbers

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This commit is contained in:
Andreas Tsouchlos 2021-11-27 16:41:38 +01:00
parent 50024240ef
commit 0db75bbdd8
3 changed files with 62 additions and 53 deletions
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11
inc/format.h
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@ -40,21 +40,16 @@ constexpr inline void check_fmt_params() {
*
*/
// TODO: Error handling
template <fmt_data_t fmt_data, std::integral arg_t>
constexpr inline void format_arg(char* dest, arg_t arg) {
constexpr auto error_array = get_init_array<fmt_data.length>('f');
detail::format_int(dest, arg, fmt_data);
};
// TODO: Error handling
template <fmt_data_t fmt_data, std::floating_point arg_t>
constexpr inline void format_arg(char* dest, arg_t arg) {
*(dest) = 'f';
*(dest + fmt_data.length - fmt_data.precision - 1) = '.';
//detail::format_float(dest, arg, fmt_data);
};
// TODO: Error handling
template<fmt_data_t fmt_data>
constexpr inline void format_arg(char* dest, const char* arg) {
@ -87,7 +82,7 @@ constexpr inline void format_args(char* dest, first_arg_t first_arg, args_t... a
template <auto ast>
consteval inline std::array<char, get_ast_output_len<ast>()> get_preproc_string() {
auto result = get_init_array<get_ast_output_len<ast>()>('0');
auto result = get_init_array<get_ast_output_len<ast>()>('f');
int i = 0;

99
inc/format_impl.h
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@ -26,10 +26,44 @@ namespace detail {
*/
#define FMT_POWERS_OF_10(factor) \
factor * 10, (factor)*100, (factor)*1000, (factor)*10000, (factor)*100000, \
(factor)*1000000, (factor)*10000000, (factor)*100000000, \
(factor)*1000000000
#define FMT_POWERS_OF_10(factor) \
factor * 10, (factor)*100, (factor)*1000, (factor)*10000, (factor)*100000, \
(factor)*1000000, (factor)*10000000, (factor)*100000000, \
(factor)*1000000000
template <typename T>
constexpr int count_digits_fallback(T n) {
int count = 1;
for (;;) {
if (n < 10) return count;
if (n < 100) return count + 1;
if (n < 1000) return count + 2;
if (n < 10000) return count + 3;
n /= 10000u;
count += 4;
}
}
inline int do_count_digits(uint64_t n) {
// Maps bsr(n) to ceil(log10(pow(2, bsr(n) + 1) - 1)).
static constexpr uint8_t bsr2log10[] = {
1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5,
6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10,
10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 15, 15,
15, 16, 16, 16, 16, 17, 17, 17, 18, 18, 18, 19, 19, 19, 19, 20};
auto t = bsr2log10[__builtin_clzll(n | 1) ^ 63];
static constexpr const uint64_t zero_or_powers_of_10[] = {
0, 0, FMT_POWERS_OF_10(1U), FMT_POWERS_OF_10(1000000000ULL),
10000000000000000000ULL};
return t - (n < zero_or_powers_of_10[t]);
}
constexpr inline auto count_digits(uint64_t n) -> int {
if (!std::is_constant_evaluated()) {
return do_count_digits(n);
}
return count_digits_fallback(n);
}
// Converts value in the range [0, 100) to a string.
@ -54,6 +88,8 @@ constexpr inline void copy2(char* dst, const char* src) {
template <typename uint_t>
constexpr inline void format_decimal(char* out, uint_t value, int size) {
if (count_digits(value) > size) return;
out += size;
while (value >= 100) {
out -= 2;
@ -61,46 +97,15 @@ constexpr inline void format_decimal(char* out, uint_t value, int size) {
value /= 100;
}
if (value < 10) *--out = static_cast<char>('0' + value);
if (value < 10) {
*--out = static_cast<char>('0' + value);
return;
}
out -= 2;
copy2(out, digits2(static_cast<size_t>(value)));
}
template <typename T>
constexpr int count_digits_fallback(T n) {
int count = 1;
for (;;) {
if (n < 10) return count;
if (n < 100) return count + 1;
if (n < 1000) return count + 2;
if (n < 10000) return count + 3;
n /= 10000u;
count += 4;
}
}
inline int do_count_digits(uint64_t n) {
// Maps bsr(n) to ceil(log10(pow(2, bsr(n) + 1) - 1)).
static constexpr uint8_t bsr2log10[] = {
1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5,
6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10,
10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 15, 15,
15, 16, 16, 16, 16, 17, 17, 17, 18, 18, 18, 19, 19, 19, 19, 20};
auto t = bsr2log10[__builtin_clzll(n | 1) ^ 63];
static constexpr const uint64_t zero_or_powers_of_10[] = {
0, 0, FMT_POWERS_OF_10(1U), FMT_POWERS_OF_10(1000000000ULL),
10000000000000000000ULL};
return t - (n < zero_or_powers_of_10[t]);
}
constexpr inline auto count_digits(uint64_t n) -> int {
if (!std::is_constant_evaluated()) {
return do_count_digits(n);
}
return count_digits_fallback(n);
}
/*
*
@ -116,8 +121,14 @@ constexpr inline void format_int(char* out, uint_t value, fmt_data_t fmt_node) {
template <std::signed_integral uint_t>
constexpr inline void format_int(char* out, uint_t value, fmt_data_t fmt_node) {
if (value < 0) value = -value;
format_decimal(out, value, fmt_node.length);
auto abs_value = static_cast<uint64_t>(value);
const bool negative = value < 0;
if (negative) abs_value = 0 - abs_value;
format_decimal(out + 1 * (negative), abs_value,
fmt_node.length - 1 * (negative));
if (negative) *out = '-';
}
@ -130,8 +141,10 @@ constexpr inline void format_int(char* out, uint_t value, fmt_data_t fmt_node) {
template <std::floating_point float_t>
constexpr inline void format_float(char* out, float_t value,
fmt_data_t fmt_node) {
// TODO
fmt_data_t fmt_data) {
*(out) = 'f';
*(out + fmt_data.length - fmt_data.precision - 1) = '.';
}

5
src/main.cpp
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@ -4,11 +4,12 @@
int main(int argc, char* argv[]) {
auto formatted = "Test: {:12} {:012.5} {:8}"_fmt(argv[0], argc, -1234);
auto formatted = "Test: {:12} {:012.5} {:8}"_fmt(argv[0], 123.45, -1234567);
for (const auto& c : formatted)
std::cout << c;
std::cout << std::endl;
return formatted[6];
// return formatted[6];
return 0;
}