source/to_string.cpp

   1 // Copyright (c) 2024 Google LLC
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6 //
   7 //     http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14
  15 #include "source/to_string.h"
  16
  17 #include <cassert>
  18
  19 namespace spvtools {
  20
  21 std::string to_string(uint32_t n) {
  22   // This implementation avoids using standard library features that access
  23   // the locale.  Using the locale requires taking a mutex which causes
  24   // annoying serialization.
  25
  26   constexpr int max_digits = 10;  // max uint has 10 digits
  27   // Contains the resulting digits, with least significant digit in the last
  28   // entry.
  29   char buf[max_digits];
  30   int write_index = max_digits - 1;
  31   if (n == 0) {
  32     buf[write_index] = '0';
  33   } else {
  34     while (n > 0) {
  35       int units = n % 10;
  36       buf[write_index--] = "0123456789"[units];
  37       n = (n - units) / 10;
  38     }
  39     write_index++;
  40   }
  41   assert(write_index >= 0);
  42   return std::string(buf + write_index, max_digits - write_index);
  43 }
  44 }  // namespace spvtools