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  1. #include <string>
  2. #include <cstring>
  3. #include <iostream>
  4.  
  5. bool validateUTF8(std::string const& _input, size_t& _invalidPosition)
  6. {
  7. 	const size_t length = _input.length();
  8. 	bool valid = true;
  9. 	size_t i = 0;
  10.  
  11. 	for (; i < length; i++)
  12. 	{
  13. 		if ((unsigned char)_input[i] < 0x80)
  14. 			continue;
  15.  
  16. 		size_t count = 0;
  17. 		switch(_input[i] & 0xe0) {
  18. 			case 0xc0: count = 1; break;
  19. 			case 0xe0: count = 2; break;
  20. 			case 0xf0: count = 3; break;
  21. 			default: break;
  22. 		}
  23.  
  24. 		if (count == 0)
  25. 		{
  26. 			valid = false;
  27. 			break;
  28. 		}
  29.  
  30. 		if ((i + count) >= length)
  31. 		{
  32. 			valid = false;
  33. 			break;
  34. 		}
  35.  
  36. 		for (size_t j = 0; j < count; j++)
  37. 		{
  38. 			i++;
  39. 			if ((_input[i] & 0xc0) != 0x80)
  40. 			{
  41. 				valid = false;
  42. 				break;
  43. 			}
  44. 		}
  45. 	}
  46.  
  47. 	if (valid)
  48. 		return true;
  49.  
  50. 	_invalidPosition = i;
  51. 	return false;
  52. }
  53.  
  54. int main() {
  55. 	const std::string input = "\xF0\x9F\xA6\x84";
  56. 	size_t position = 0;
  57.  
  58. 	bool ret = validateUTF8(input, position);
  59. 	std::cout << "Final Position:" << position << std::endl;
  60. 	std::cout << "OK:" << ret << std::endl;
  61.  
  62. 	return 0;
  63. }
Success #stdin #stdout 0s 16064KB
comments (?)
stdin
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Standard input is empty
stdout
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Final Position:3
OK:0
https://ideone.com/sO8fwT
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
public

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