fmtlib/fmt
1
0
Fork 1
mirror of https://github.com/fmtlib/fmt.git synced 2025-11-27 21:00:01 +01:00
Code Issues Packages Projects Releases Wiki Activity

Supporting ? as a string presentation type (#2674)

Browse Source 
* Supporting ? as a string presentation type.

* Supporting ? as a char presentation type.

* Adding iterator_category to counting_iterator.
This commit is contained in:
Barry Revzin
2022-01-30 10:55:28 -06:00
committed by GitHub
parent ae1aaaee5f
commit a34a97cc1d
7 changed files with 421 additions and 354 deletions
Download Patch File Download Diff File Expand all files Collapse all files

238
include/fmt/format.h
View File

@@ -1367,11 +1367,173 @@ auto write_ptr(OutputIt out, UIntPtr value,
: base_iterator(out, write(reserve(out, size)));
}
// Returns true iff the code point cp is printable.
FMT_API auto is_printable(uint32_t cp) -> bool;
inline auto needs_escape(uint32_t cp) -> bool {
return cp < 0x20 || cp == 0x7f || cp == '"' || cp == '\\' ||
!is_printable(cp);
}
template <typename Char> struct find_escape_result {
const Char* begin;
const Char* end;
uint32_t cp;
};
template <typename Char>
using make_unsigned_char =
typename conditional_t<std::is_integral<Char>::value,
std::make_unsigned<Char>,
type_identity<uint32_t>>::type;
template <typename Char>
auto find_escape(const Char* begin, const Char* end)
-> find_escape_result<Char> {
for (; begin != end; ++begin) {
uint32_t cp = static_cast<make_unsigned_char<Char>>(*begin);
if (sizeof(Char) == 1 && cp >= 0x80) continue;
if (needs_escape(cp)) return {begin, begin + 1, cp};
}
return {begin, nullptr, 0};
}
inline auto find_escape(const char* begin, const char* end)
-> find_escape_result<char> {
if (!is_utf8()) return find_escape<char>(begin, end);
auto result = find_escape_result<char>{end, nullptr, 0};
for_each_codepoint(string_view(begin, to_unsigned(end - begin)),
[&](uint32_t cp, string_view sv) {
if (needs_escape(cp)) {
result = {sv.begin(), sv.end(), cp};
return false;
}
return true;
});
return result;
}
#define FMT_STRING_IMPL(s, base, explicit) \
[] { \
/* Use the hidden visibility as a workaround for a GCC bug (#1973). */ \
/* Use a macro-like name to avoid shadowing warnings. */ \
struct FMT_GCC_VISIBILITY_HIDDEN FMT_COMPILE_STRING : base { \
using char_type = fmt::remove_cvref_t<decltype(s[0])>; \
FMT_MAYBE_UNUSED FMT_CONSTEXPR explicit \
operator fmt::basic_string_view<char_type>() const { \
return fmt::detail_exported::compile_string_to_view<char_type>(s); \
} \
}; \
return FMT_COMPILE_STRING(); \
}()
/**
\rst
Constructs a compile-time format string from a string literal *s*.
**Example**::
// A compile-time error because 'd' is an invalid specifier for strings.
std::string s = fmt::format(FMT_STRING("{:d}"), "foo");
\endrst
*/
#define FMT_STRING(s) FMT_STRING_IMPL(s, fmt::compile_string, )
template <typename Char, typename OutputIt>
auto write_escaped_string(OutputIt out, basic_string_view<Char> str)
-> OutputIt {
return copy_str<Char>(str.data(), str.data() + str.size(), out);
}
template <typename OutputIt, typename Char>
auto write_escaped_cp(OutputIt out, const find_escape_result<Char>& escape)
-> OutputIt {
auto c = static_cast<Char>(escape.cp);
switch (escape.cp) {
case '\n':
*out++ = '\\';
c = 'n';
break;
case '\r':
*out++ = '\\';
c = 'r';
break;
case '\t':
*out++ = '\\';
c = 't';
break;
case '"':
FMT_FALLTHROUGH;
case '\'':
FMT_FALLTHROUGH;
case '\\':
*out++ = '\\';
break;
default:
if (is_utf8()) {
if (escape.cp < 0x100) {
return format_to(out, FMT_STRING("\\x{:02x}"), escape.cp);
}
if (escape.cp < 0x10000) {
return format_to(out, FMT_STRING("\\u{:04x}"), escape.cp);
}
if (escape.cp < 0x110000) {
return format_to(out, FMT_STRING("\\U{:08x}"), escape.cp);
}
}
for (char escape_char : basic_string_view<Char>(
escape.begin, to_unsigned(escape.end - escape.begin))) {
out = format_to(out, FMT_STRING("\\x{:02x}"),
static_cast<make_unsigned_char<Char>>(escape_char));
}
return out;
}
*out++ = c;
return out;
}
template <typename OutputIt>
auto write_escaped_string(OutputIt out, basic_string_view<char> str)
-> OutputIt {
*out++ = '"';
auto begin = str.begin(), end = str.end();
do {
auto escape = find_escape(begin, end);
out = copy_str<char>(begin, escape.begin, out);
begin = escape.end;
if (!begin) break;
out = write_escaped_cp(out, escape);
} while (begin != end);
*out++ = '"';
return out;
}
template <typename Char, typename OutputIt>
auto write_escaped_char(OutputIt out, Char v) -> OutputIt {
*out++ = v;
return out;
}
template <typename OutputIt>
auto write_escaped_char(OutputIt out, char v) -> OutputIt {
*out++ = '\'';
if ((needs_escape(static_cast<uint32_t>(v)) && v != '"') || v == '\'') {
out = write_escaped_cp(
out, find_escape_result<char>{&v, &v + 1, static_cast<uint32_t>(v)});
} else {
*out++ = v;
}
*out++ = '\'';
return out;
}
template <typename Char, typename OutputIt>
FMT_CONSTEXPR auto write_char(OutputIt out, Char value,
const basic_format_specs<Char>& specs)
-> OutputIt {
bool is_debug = specs.type == presentation_type::debug;
return write_padded(out, specs, 1, [=](reserve_iterator<OutputIt> it) {
if (is_debug) return write_escaped_char(it, value);
*it++ = value;
return it;
});
@@ -1637,6 +1799,45 @@ FMT_CONSTEXPR FMT_INLINE auto write(OutputIt out, T value,
return write_int(out, make_write_int_arg(value, specs.sign), specs, loc);
}
// An output iterator that counts the number of objects written to it and
// discards them.
class counting_iterator {
private:
size_t count_;
public:
using iterator_category = std::output_iterator_tag;
using difference_type = std::ptrdiff_t;
using pointer = void;
using reference = void;
using _Unchecked_type = counting_iterator; // Mark iterator as checked.
struct value_type {
template <typename T> void operator=(const T&) {}
};
counting_iterator() : count_(0) {}
size_t count() const { return count_; }
counting_iterator& operator++() {
++count_;
return *this;
}
counting_iterator operator++(int) {
auto it = *this;
++*this;
return it;
}
friend counting_iterator operator+(counting_iterator it, difference_type n) {
it.count_ += static_cast<size_t>(n);
return it;
}
value_type operator*() const { return {}; }
};
template <typename Char, typename OutputIt>
FMT_CONSTEXPR auto write(OutputIt out, basic_string_view<Char> s,
const basic_format_specs<Char>& specs) -> OutputIt {
@@ -1644,10 +1845,17 @@ FMT_CONSTEXPR auto write(OutputIt out, basic_string_view<Char> s,
auto size = s.size();
if (specs.precision >= 0 && to_unsigned(specs.precision) < size)
size = code_point_index(s, to_unsigned(specs.precision));
auto width =
specs.width != 0 ? compute_width(basic_string_view<Char>(data, size)) : 0;
bool is_debug = specs.type == presentation_type::debug;
size_t width = 0;
if (specs.width != 0) {
if (is_debug)
width = write_escaped_string(counting_iterator{}, s).count();
else
width = compute_width(basic_string_view<Char>(data, size));
}
return write_padded(out, specs, size, width,
[=](reserve_iterator<OutputIt> it) {
if (is_debug) return write_escaped_string(it, s);
return copy_str<Char>(data, data + size, it);
});
}
@@ -2346,32 +2554,6 @@ FMT_CONSTEXPR void handle_dynamic_spec(int& value,
}
}
#define FMT_STRING_IMPL(s, base, explicit) \
[] { \
/* Use the hidden visibility as a workaround for a GCC bug (#1973). */ \
/* Use a macro-like name to avoid shadowing warnings. */ \
struct FMT_GCC_VISIBILITY_HIDDEN FMT_COMPILE_STRING : base { \
using char_type = fmt::remove_cvref_t<decltype(s[0])>; \
FMT_MAYBE_UNUSED FMT_CONSTEXPR explicit \
operator fmt::basic_string_view<char_type>() const { \
return fmt::detail_exported::compile_string_to_view<char_type>(s); \
} \
}; \
return FMT_COMPILE_STRING(); \
}()
/**
\rst
Constructs a compile-time format string from a string literal *s*.
**Example**::
// A compile-time error because 'd' is an invalid specifier for strings.
std::string s = fmt::format(FMT_STRING("{:d}"), "foo");
\endrst
*/
#define FMT_STRING(s) FMT_STRING_IMPL(s, fmt::compile_string, )
#if FMT_USE_USER_DEFINED_LITERALS
template <typename Char> struct udl_formatter {
basic_string_view<Char> str;