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1//===-- A class for number to string mappings -------------------*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef LLVM_LIBC_SRC___SUPPORT_STRINGUTIL_MESSAGE_MAPPER_H10#define LLVM_LIBC_SRC___SUPPORT_STRINGUTIL_MESSAGE_MAPPER_H11 12#include "src/__support/CPP/array.h"13#include "src/__support/CPP/optional.h"14#include "src/__support/CPP/string_view.h"15#include "src/__support/macros/config.h"16#include <stddef.h>17 18namespace LIBC_NAMESPACE_DECL {19 20struct MsgMapping {21 int num;22 cpp::string_view msg;23 24 constexpr MsgMapping() : num(0), msg() { ; }25 26 constexpr MsgMapping(int init_num, const char *init_msg)27 : num(init_num), msg(init_msg) {28 ;29 }30};31 32template <size_t N> using MsgTable = cpp::array<MsgMapping, N>;33 34template <size_t N> constexpr size_t total_str_len(const MsgTable<N> &table) {35 size_t total = 0;36 for (size_t i = 0; i < table.size(); ++i) {37 // add 1 for the null terminator.38 total += table[i].msg.size() + 1;39 }40 return total;41}42 43template <size_t N> constexpr size_t max_key_val(const MsgTable<N> &table) {44 int max = 0;45 for (size_t i = 0; i < table.size(); ++i) {46 if (table[i].num > max) {47 max = table[i].num;48 }49 }50 // max will never be negative since the starting value is 0. This is good,51 // since it's used as a length.52 return static_cast<size_t>(max);53}54 55template <size_t ARR_SIZE, size_t TOTAL_STR_LEN> class MessageMapper {56 int msg_offsets[ARR_SIZE] = {-1};57 char string_array[TOTAL_STR_LEN] = {'\0'};58 59public:60 template <size_t N> constexpr MessageMapper(const MsgTable<N> &table) {61 cpp::string_view string_mappings[ARR_SIZE] = {""};62 for (size_t i = 0; i < table.size(); ++i)63 string_mappings[table[i].num] = table[i].msg;64 65 int string_array_index = 0;66 for (size_t cur_num = 0; cur_num < ARR_SIZE; ++cur_num) {67 if (string_mappings[cur_num].size() != 0) {68 msg_offsets[cur_num] = string_array_index;69 // No need to replace with proper strcpy, this is evaluated at compile70 // time.71 for (size_t i = 0; i < string_mappings[cur_num].size() + 1;72 ++i, ++string_array_index) {73 string_array[string_array_index] = string_mappings[cur_num][i];74 }75 } else {76 msg_offsets[cur_num] = -1;77 }78 }79 }80 81 cpp::optional<cpp::string_view> get_str(int num) const {82 if (num >= 0 && static_cast<size_t>(num) < ARR_SIZE &&83 msg_offsets[num] != -1) {84 return {string_array + msg_offsets[num]};85 } else {86 return cpp::optional<cpp::string_view>();87 }88 }89};90 91template <size_t N1, size_t N2>92constexpr MsgTable<N1 + N2> operator+(const MsgTable<N1> &t1,93 const MsgTable<N2> &t2) {94 MsgTable<N1 + N2> res{};95 for (size_t i = 0; i < N1; ++i)96 res[i] = t1[i];97 for (size_t i = 0; i < N2; ++i)98 res[N1 + i] = t2[i];99 return res;100}101 102} // namespace LIBC_NAMESPACE_DECL103 104#endif // LLVM_LIBC_SRC___SUPPORT_STRINGUTIL_MESSAGE_MAPPER_H105