llvm/libc/src/__support/StringUtil/error_to_string.cpp

//===-- Implementation of a class for mapping errors to strings -----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "error_to_string.h"
#include "platform_errors.h"

#include "src/__support/CPP/span.h"
#include "src/__support/CPP/string_view.h"
#include "src/__support/CPP/stringstream.h"
#include "src/__support/StringUtil/message_mapper.h"
#include "src/__support/integer_to_string.h"
#include "src/__support/macros/attributes.h"
#include "src/__support/macros/config.h"

#include <stddef.h>

namespace LIBC_NAMESPACE_DECL {
namespace internal {

constexpr size_t max_buff_size() { … }

// This is to hold error strings that have to be custom built. It may be
// rewritten on every call to strerror (or other error to string function).
constexpr size_t ERR_BUFFER_SIZE = …;
LIBC_THREAD_LOCAL char error_buffer[ERR_BUFFER_SIZE];

constexpr size_t TOTAL_STR_LEN = …;

// Since the StringMappings array is a map from error numbers to their
// corresponding strings, we have to have an array large enough we can use the
// error numbers as indexes. The current linux configuration has 132 values with
// the maximum value being 133 (41 and 58 are skipped). If other platforms use
// negative numbers or discontiguous ranges, then the array should be turned
// into a proper hashmap.
constexpr size_t ERR_ARRAY_SIZE = …;

constexpr MessageMapper<ERR_ARRAY_SIZE, TOTAL_STR_LEN>
    error_mapper(PLATFORM_ERRORS);

cpp::string_view build_error_string(int err_num, cpp::span<char> buffer) { … }

} // namespace internal

cpp::string_view get_error_string(int err_num) { … }

cpp::string_view get_error_string(int err_num, cpp::span<char> buffer) { … }

} // namespace LIBC_NAMESPACE_DECL