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// Copyright 2025 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/strings/internal/generic_printer.h"
#include <cstddef>
#include <cstdlib>
#include <ostream>
#include <string>
#include "absl/base/config.h"
#include "absl/strings/ascii.h"
#include "absl/strings/escaping.h"
#include "absl/strings/str_format.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace internal_generic_printer {
// Out-of-line helper for PrintAsStringWithEscaping.
std::ostream& PrintEscapedString(std::ostream& os, absl::string_view v) {
return os << "\"" << absl::CHexEscape(v) << "\"";
}
// Retuns a string representation of 'v', shortened if possible.
template <class T, class F>
std::string TryShorten(T v, F strtox) {
std::string printed =
absl::StrFormat("%.*g", std::numeric_limits<T>::max_digits10 / 2, v);
T parsed = strtox(printed.data());
if (parsed != v) {
printed =
absl::StrFormat("%.*g", std::numeric_limits<T>::max_digits10 + 1, v);
}
return printed;
}
// Out-of-line helpers for floating point values. These don't necessarily
// ensure that values are precise, but rather that they are wide enough to
// represent distinct values. go/c++17std/numeric.limits.members.html
std::ostream& PrintPreciseFP(std::ostream& os, float v) {
return os << TryShorten(v, [](const char* buf) {
char* unused;
return std::strtof(buf, &unused);
}) << "f";
}
std::ostream& PrintPreciseFP(std::ostream& os, double v) {
return os << TryShorten(v, [](const char* buf) {
char* unused;
return std::strtod(buf, &unused);
});
}
std::ostream& PrintPreciseFP(std::ostream& os, long double v) {
return os << TryShorten(v, [](const char* buf) {
char* unused;
return std::strtold(buf, &unused);
}) << "L";
}
// Prints a nibble of 'v' in hexadecimal.
inline char hexnib(int v) {
return static_cast<char>((v < 10 ? '0' : ('a' - 10)) + v);
}
template <typename T>
static std::ostream& PrintCharImpl(std::ostream& os, T v) {
// Specialization for chars: print as 'c' if printable, otherwise
// hex-escaped.
return (absl::ascii_isprint(static_cast<unsigned char>(v))
? (os << (v == '\'' ? "'\\" : "'") << v)
: (os << "'\\x" << hexnib((v >> 4) & 0xf) << hexnib(v & 0xf)))
<< "' (0x" << hexnib((v >> 4) & 0xf) << hexnib(v & 0xf) << " "
<< static_cast<int>(v) << ")";
}
std::ostream& PrintChar(std::ostream& os, char c) {
return PrintCharImpl(os, c);
}
std::ostream& PrintChar(std::ostream& os, signed char c) {
return PrintCharImpl(os, c);
}
std::ostream& PrintChar(std::ostream& os, unsigned char c) {
return PrintCharImpl(os, c);
}
std::ostream& PrintByte(std::ostream& os, std::byte b) {
auto v = std::to_integer<int>(b);
os << "0x" << hexnib((v >> 4) & 0xf) << hexnib(v & 0xf);
return os;
}
} // namespace internal_generic_printer
ABSL_NAMESPACE_END
} // namespace absl
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