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ladybird/AK/PrintfImplementation.h
Peter Elliott b217045f8f AK: Don't write trailing zeros with %g
2023-01-19 12:22:24 +01:00

626 lines
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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Format.h>
#include <AK/StdLibExtras.h>
#include <AK/Types.h>
#include <stdarg.h>
#include <wchar.h>
#ifndef KERNEL
# include <math.h>
#endif
#ifdef AK_OS_SERENITY
extern "C" size_t strlen(char const*);
#else
# include <string.h>
#endif
namespace PrintfImplementation {
template<typename PutChFunc, typename T, typename CharType>
ALWAYS_INLINE int print_hex(PutChFunc putch, CharType*& bufptr, T number, bool upper_case, bool alternate_form, bool left_pad, bool zero_pad, u32 field_width, bool has_precision, u32 precision)
{
constexpr char const* printf_hex_digits_lower = "0123456789abcdef";
constexpr char const* printf_hex_digits_upper = "0123456789ABCDEF";
u32 digits = 0;
for (T n = number; n > 0; n >>= 4)
++digits;
if (digits == 0)
digits = 1;
bool not_zero = number != 0;
char buf[16];
char* p = buf;
if (!(has_precision && precision == 0 && !not_zero)) {
if (number == 0) {
(*p++) = '0';
if (precision > 0)
precision--;
} else {
u8 shift_count = digits * 4;
while (shift_count) {
shift_count -= 4;
(*p++) = upper_case
? printf_hex_digits_upper[(number >> shift_count) & 0x0f]
: printf_hex_digits_lower[(number >> shift_count) & 0x0f];
if (precision > 0)
precision--;
}
}
}
size_t numlen = p - buf;
if (!field_width || field_width < (numlen + has_precision * precision + (alternate_form * 2 * not_zero)))
field_width = numlen + has_precision * precision + alternate_form * 2 * not_zero;
if ((zero_pad && !has_precision) && (alternate_form && not_zero)) {
putch(bufptr, '0');
putch(bufptr, 'x');
}
if (!left_pad) {
for (unsigned i = 0; i < field_width - numlen - has_precision * precision - alternate_form * 2 * not_zero; ++i) {
putch(bufptr, (zero_pad && !has_precision) ? '0' : ' ');
}
}
if (!(zero_pad && !has_precision) && (alternate_form && not_zero)) {
putch(bufptr, '0');
putch(bufptr, 'x');
}
if (has_precision) {
for (u32 i = 0; i < precision; ++i) {
putch(bufptr, '0');
}
}
for (unsigned i = 0; i < numlen; ++i) {
putch(bufptr, buf[i]);
}
if (left_pad) {
for (unsigned i = 0; i < field_width - numlen - has_precision * precision - alternate_form * 2 * not_zero; ++i) {
putch(bufptr, ' ');
}
}
return field_width;
}
template<typename PutChFunc, typename CharType>
ALWAYS_INLINE int print_decimal(PutChFunc putch, CharType*& bufptr, u64 number, bool sign, bool always_sign, bool left_pad, bool zero_pad, u32 field_width, bool has_precision, u32 precision)
{
u64 divisor = 10000000000000000000LLU;
char ch;
char padding = 1;
char buf[21];
char* p = buf;
if (!(has_precision && precision == 0 && number == 0)) {
for (;;) {
ch = '0' + (number / divisor);
number %= divisor;
if (ch != '0')
padding = 0;
if (!padding || divisor == 1) {
*(p++) = ch;
if (precision > 0)
precision--;
}
if (divisor == 1)
break;
divisor /= 10;
}
}
size_t numlen = p - buf;
if (!field_width || field_width < (numlen + has_precision * precision + (sign || always_sign)))
field_width = numlen + has_precision * precision + (sign || always_sign);
if ((zero_pad && !has_precision) && (sign || always_sign)) {
putch(bufptr, sign ? '-' : '+');
}
if (!left_pad) {
for (unsigned i = 0; i < field_width - numlen - has_precision * precision - (sign || always_sign); ++i) {
putch(bufptr, (zero_pad && !has_precision) ? '0' : ' ');
}
}
if (!(zero_pad && !has_precision) && (sign || always_sign)) {
putch(bufptr, sign ? '-' : '+');
}
if (has_precision) {
for (u32 i = 0; i < precision; ++i) {
putch(bufptr, '0');
}
}
for (unsigned i = 0; i < numlen; ++i) {
putch(bufptr, buf[i]);
}
if (left_pad) {
for (unsigned i = 0; i < field_width - numlen - has_precision * precision - (sign || always_sign); ++i) {
putch(bufptr, ' ');
}
}
return field_width;
}
#ifndef KERNEL
template<typename PutChFunc, typename CharType>
ALWAYS_INLINE int print_double(PutChFunc putch, CharType*& bufptr, double number, bool always_sign, bool left_pad, bool zero_pad, u32 field_width, u32 precision, bool trailing_zeros)
{
int length = 0;
u32 whole_width = (field_width >= precision + 1) ? field_width - precision - 1 : 0;
bool sign = signbit(number);
bool nan = isnan(number);
bool inf = isinf(number);
if (nan || inf) {
for (unsigned i = 0; i < field_width - 3 - sign; i++) {
putch(bufptr, ' ');
length++;
}
if (sign) {
putch(bufptr, '-');
length++;
}
if (nan) {
putch(bufptr, 'n');
putch(bufptr, 'a');
putch(bufptr, 'n');
} else {
putch(bufptr, 'i');
putch(bufptr, 'n');
putch(bufptr, 'f');
}
return length + 3;
}
if (sign)
number = -number;
length = print_decimal(putch, bufptr, (i64)number, sign, always_sign, left_pad, zero_pad, whole_width, false, 1);
if (precision > 0) {
double fraction = number - (i64)number;
for (u32 i = 0; i < precision; ++i)
fraction = fraction * 10;
if (trailing_zeros || fraction) {
length++;
putch(bufptr, '.');
i64 ifraction = fraction;
while (!trailing_zeros && ifraction % 10 == 0) {
ifraction /= 10;
precision--;
}
return length + print_decimal(putch, bufptr, ifraction, false, false, false, true, precision, false, 1);
}
}
return length;
}
#endif
template<typename PutChFunc, typename CharType>
ALWAYS_INLINE int print_octal_number(PutChFunc putch, CharType*& bufptr, u64 number, bool alternate_form, bool left_pad, bool zero_pad, u32 field_width, bool has_precision, u32 precision)
{
u32 divisor = 134217728;
char ch;
char padding = 1;
char buf[32];
char* p = buf;
if (alternate_form) {
(*p++) = '0';
if (precision > 0)
precision--;
}
if (!(has_precision && precision == 0 && number == 0)) {
for (;;) {
ch = '0' + (number / divisor);
number %= divisor;
if (ch != '0')
padding = 0;
if (!padding || divisor == 1) {
*(p++) = ch;
if (precision > 0)
precision--;
}
if (divisor == 1)
break;
divisor /= 8;
}
}
size_t numlen = p - buf;
if (!field_width || field_width < (numlen + has_precision * precision))
field_width = numlen + has_precision * precision;
if (!left_pad) {
for (unsigned i = 0; i < field_width - numlen - has_precision * precision; ++i) {
putch(bufptr, (zero_pad && !has_precision) ? '0' : ' ');
}
}
if (has_precision) {
for (u32 i = 0; i < precision; ++i) {
putch(bufptr, '0');
}
}
for (unsigned i = 0; i < numlen; ++i) {
putch(bufptr, buf[i]);
}
if (left_pad) {
for (unsigned i = 0; i < field_width - numlen - has_precision * precision; ++i) {
putch(bufptr, ' ');
}
}
return field_width;
}
template<typename PutChFunc, typename T, typename CharType>
ALWAYS_INLINE int print_string(PutChFunc putch, CharType*& bufptr, T str, size_t len, bool left_pad, size_t field_width, bool dot, size_t precision, bool has_fraction)
{
if (has_fraction)
len = min(len, precision);
if (!dot && (!field_width || field_width < len))
field_width = len;
if (has_fraction && !field_width)
field_width = len;
size_t pad_amount = field_width > len ? field_width - len : 0;
if (!left_pad) {
for (size_t i = 0; i < pad_amount; ++i)
putch(bufptr, ' ');
}
for (size_t i = 0; i < min(len, field_width); ++i) {
putch(bufptr, str[i]);
}
if (left_pad) {
for (size_t i = 0; i < pad_amount; ++i)
putch(bufptr, ' ');
}
return field_width;
}
template<typename PutChFunc, typename CharType>
ALWAYS_INLINE int print_signed_number(PutChFunc putch, CharType*& bufptr, i64 number, bool always_sign, bool left_pad, bool zero_pad, u32 field_width, bool has_precision, u32 precision)
{
// FIXME: `0 - number` overflows if we are trying to negate the smallest possible value.
return print_decimal(putch, bufptr, (number < 0) ? 0 - number : number, number < 0, always_sign, left_pad, zero_pad, field_width, has_precision, precision);
}
struct ModifierState {
bool left_pad { false };
bool zero_pad { false };
bool dot { false };
unsigned field_width { 0 };
bool has_precision { false };
unsigned precision { 6 };
unsigned short_qualifiers { 0 }; // TODO: Unimplemented.
unsigned long_qualifiers { 0 };
bool intmax_qualifier { false }; // TODO: Unimplemented.
bool ptrdiff_qualifier { false }; // TODO: Unimplemented.
bool long_double_qualifier { false }; // TODO: Unimplemented.
bool size_qualifier { false }; // TODO: Unimplemented.
bool alternate_form { 0 };
bool always_sign { false };
};
template<typename PutChFunc, typename ArgumentListRefT, template<typename T, typename U = ArgumentListRefT> typename NextArgument, typename CharType = char>
struct PrintfImpl {
ALWAYS_INLINE PrintfImpl(PutChFunc& putch, CharType*& bufptr, int const& nwritten)
: m_bufptr(bufptr)
, m_nwritten(nwritten)
, m_putch(putch)
{
}
ALWAYS_INLINE int format_s(ModifierState const& state, ArgumentListRefT ap) const
{
// FIXME: Narrow characters should be converted to wide characters on the fly and vice versa.
// https://pubs.opengroup.org/onlinepubs/9699919799/functions/printf.html
// https://pubs.opengroup.org/onlinepubs/9699919799/functions/wprintf.html
#ifndef KERNEL
if (state.long_qualifiers) {
wchar_t const* sp = NextArgument<wchar_t const*>()(ap);
if (!sp)
sp = L"(null)";
return print_string(m_putch, m_bufptr, sp, wcslen(sp), state.left_pad, state.field_width, state.dot, state.precision, state.has_precision);
}
#endif
char const* sp = NextArgument<char const*>()(ap);
if (!sp)
sp = "(null)";
return print_string(m_putch, m_bufptr, sp, strlen(sp), state.left_pad, state.field_width, state.dot, state.precision, state.has_precision);
}
ALWAYS_INLINE int format_d(ModifierState const& state, ArgumentListRefT ap) const
{
i64 number = [&]() -> i64 {
if (state.long_qualifiers >= 2)
return NextArgument<long long int>()(ap);
if (state.long_qualifiers == 1)
return NextArgument<long int>()(ap);
return NextArgument<int>()(ap);
}();
return print_signed_number(m_putch, m_bufptr, number, state.always_sign, state.left_pad, state.zero_pad, state.field_width, state.has_precision, state.precision);
}
ALWAYS_INLINE int format_i(ModifierState const& state, ArgumentListRefT ap) const
{
return format_d(state, ap);
}
ALWAYS_INLINE int format_u(ModifierState const& state, ArgumentListRefT ap) const
{
u64 number = [&]() -> u64 {
if (state.long_qualifiers >= 2)
return NextArgument<unsigned long long int>()(ap);
if (state.long_qualifiers == 1)
return NextArgument<unsigned long int>()(ap);
return NextArgument<unsigned int>()(ap);
}();
return print_decimal(m_putch, m_bufptr, number, false, false, state.left_pad, state.zero_pad, state.field_width, state.has_precision, state.precision);
}
ALWAYS_INLINE int format_Q(ModifierState const& state, ArgumentListRefT ap) const
{
return print_decimal(m_putch, m_bufptr, NextArgument<u64>()(ap), false, false, state.left_pad, state.zero_pad, state.field_width, state.has_precision, state.precision);
}
ALWAYS_INLINE int format_q(ModifierState const& state, ArgumentListRefT ap) const
{
return print_hex(m_putch, m_bufptr, NextArgument<u64>()(ap), false, false, state.left_pad, state.zero_pad, 16, false, 1);
}
#ifndef KERNEL
ALWAYS_INLINE int format_g(ModifierState const& state, ArgumentListRefT ap) const
{
// FIXME: Exponent notation
return print_double(m_putch, m_bufptr, NextArgument<double>()(ap), state.always_sign, state.left_pad, state.zero_pad, state.field_width, state.precision, false);
}
ALWAYS_INLINE int format_f(ModifierState const& state, ArgumentListRefT ap) const
{
return print_double(m_putch, m_bufptr, NextArgument<double>()(ap), state.always_sign, state.left_pad, state.zero_pad, state.field_width, state.precision, true);
}
#endif
ALWAYS_INLINE int format_o(ModifierState const& state, ArgumentListRefT ap) const
{
return print_octal_number(m_putch, m_bufptr, NextArgument<u32>()(ap), state.alternate_form, state.left_pad, state.zero_pad, state.field_width, state.has_precision, state.precision);
}
ALWAYS_INLINE int format_unsigned_hex(ModifierState const& state, ArgumentListRefT ap, bool uppercase) const
{
u64 number = [&]() -> u64 {
if (state.long_qualifiers >= 2)
return NextArgument<unsigned long long int>()(ap);
if (state.long_qualifiers == 1)
return NextArgument<unsigned long int>()(ap);
return NextArgument<unsigned int>()(ap);
}();
return print_hex(m_putch, m_bufptr, number, uppercase, state.alternate_form, state.left_pad, state.zero_pad, state.field_width, state.has_precision, state.precision);
}
ALWAYS_INLINE int format_x(ModifierState const& state, ArgumentListRefT ap) const
{
return format_unsigned_hex(state, ap, false);
}
ALWAYS_INLINE int format_X(ModifierState const& state, ArgumentListRefT ap) const
{
return format_unsigned_hex(state, ap, true);
}
ALWAYS_INLINE int format_n(ModifierState const&, ArgumentListRefT ap) const
{
*NextArgument<int*>()(ap) = m_nwritten;
return 0;
}
ALWAYS_INLINE int format_p(ModifierState const&, ArgumentListRefT ap) const
{
return print_hex(m_putch, m_bufptr, NextArgument<FlatPtr>()(ap), false, true, false, true, 8, false, 1);
}
ALWAYS_INLINE int format_P(ModifierState const&, ArgumentListRefT ap) const
{
return print_hex(m_putch, m_bufptr, NextArgument<FlatPtr>()(ap), true, true, false, true, 8, false, 1);
}
ALWAYS_INLINE int format_percent(ModifierState const&, ArgumentListRefT) const
{
m_putch(m_bufptr, '%');
return 1;
}
ALWAYS_INLINE int format_c(ModifierState const& state, ArgumentListRefT ap) const
{
char c = NextArgument<int>()(ap);
return print_string(m_putch, m_bufptr, &c, 1, state.left_pad, state.field_width, state.dot, state.precision, state.has_precision);
}
ALWAYS_INLINE int format_unrecognized(CharType format_op, CharType const* fmt, ModifierState const&, ArgumentListRefT) const
{
dbgln("printf_internal: Unimplemented format specifier {} (fmt: {})", format_op, fmt);
return 0;
}
protected:
CharType*& m_bufptr;
int const& m_nwritten;
PutChFunc& m_putch;
};
template<typename T, typename V>
struct VaArgNextArgument {
ALWAYS_INLINE T operator()(V ap) const
{
#ifdef AK_OS_WINDOWS
// GCC on msys2 complains about the type of ap,
// so let's force the compiler to believe it's a
// va_list.
return va_arg((va_list&)ap, T);
#else
return va_arg(ap, T);
#endif
}
};
#define PRINTF_IMPL_DELEGATE_TO_IMPL(c) \
case *#c: \
ret += impl.format_##c(state, ap); \
break;
template<typename PutChFunc, template<typename T, typename U, template<typename X, typename Y> typename V, typename C = char> typename Impl = PrintfImpl, typename ArgumentListT = va_list, template<typename T, typename V = decltype(declval<ArgumentListT&>())> typename NextArgument = VaArgNextArgument, typename CharType = char>
ALWAYS_INLINE int printf_internal(PutChFunc putch, IdentityType<CharType>* buffer, CharType const*& fmt, ArgumentListT ap)
{
int ret = 0;
CharType* bufptr = buffer;
Impl<PutChFunc, ArgumentListT&, NextArgument, CharType> impl { putch, bufptr, ret };
for (CharType const* p = fmt; *p; ++p) {
ModifierState state;
if (*p == '%' && *(p + 1)) {
one_more:
++p;
if (*p == '.') {
state.dot = true;
if (*(p + 1))
goto one_more;
}
if (*p == '-') {
state.left_pad = true;
if (*(p + 1))
goto one_more;
}
if (*p == '+') {
state.always_sign = true;
if (*(p + 1))
goto one_more;
}
if (!state.zero_pad && !state.field_width && !state.dot && *p == '0') {
state.zero_pad = true;
if (*(p + 1))
goto one_more;
}
if (*p >= '0' && *p <= '9') {
if (!state.dot) {
state.field_width *= 10;
state.field_width += *p - '0';
if (*(p + 1))
goto one_more;
} else {
if (!state.has_precision) {
state.has_precision = true;
state.precision = 0;
}
state.precision *= 10;
state.precision += *p - '0';
if (*(p + 1))
goto one_more;
}
}
if (*p == '*') {
if (state.dot) {
state.has_precision = true;
state.zero_pad = true;
state.precision = NextArgument<int>()(ap);
} else {
state.field_width = NextArgument<int>()(ap);
}
if (*(p + 1))
goto one_more;
}
if (*p == 'h') {
++state.short_qualifiers;
if (*(p + 1))
goto one_more;
}
if (*p == 'l') {
++state.long_qualifiers;
if (*(p + 1))
goto one_more;
}
if (*p == 'j') {
state.intmax_qualifier = true;
if (*(p + 1))
goto one_more;
}
if (*p == 't') {
state.ptrdiff_qualifier = true;
if (*(p + 1))
goto one_more;
}
if (*p == 'L') {
state.long_double_qualifier = true;
if (*(p + 1))
goto one_more;
}
if (*p == 'z') {
state.size_qualifier = true;
if (*(p + 1))
goto one_more;
}
if (*p == '#') {
state.alternate_form = true;
if (*(p + 1))
goto one_more;
}
switch (*p) {
case '%':
ret += impl.format_percent(state, ap);
break;
PRINTF_IMPL_DELEGATE_TO_IMPL(P);
PRINTF_IMPL_DELEGATE_TO_IMPL(Q);
PRINTF_IMPL_DELEGATE_TO_IMPL(X);
PRINTF_IMPL_DELEGATE_TO_IMPL(c);
PRINTF_IMPL_DELEGATE_TO_IMPL(d);
#ifndef KERNEL
PRINTF_IMPL_DELEGATE_TO_IMPL(f);
PRINTF_IMPL_DELEGATE_TO_IMPL(g);
#endif
PRINTF_IMPL_DELEGATE_TO_IMPL(i);
PRINTF_IMPL_DELEGATE_TO_IMPL(n);
PRINTF_IMPL_DELEGATE_TO_IMPL(o);
PRINTF_IMPL_DELEGATE_TO_IMPL(p);
PRINTF_IMPL_DELEGATE_TO_IMPL(q);
PRINTF_IMPL_DELEGATE_TO_IMPL(s);
PRINTF_IMPL_DELEGATE_TO_IMPL(u);
PRINTF_IMPL_DELEGATE_TO_IMPL(x);
default:
ret += impl.format_unrecognized(*p, fmt, state, ap);
break;
}
} else {
putch(bufptr, *p);
++ret;
}
}
return ret;
}
#undef PRINTF_IMPL_DELEGATE_TO_IMPL
}
using PrintfImplementation::printf_internal;
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