Files
mqtt5/include/async_mqtt5/detail/utf8_mqtt.hpp
Korina Šimičević 9af32a942b Properties & string validation
Summary: related to T13318

Reviewers: ivica

Reviewed By: ivica

Subscribers: miljen, iljazovic

Differential Revision: https://repo.mireo.local/D26975
2023-12-14 15:29:40 +01:00

100 lines
2.4 KiB
C++

#ifndef ASYNC_MQTT5_UTF8_MQTT_HPP
#define ASYNC_MQTT5_UTF8_MQTT_HPP
#include <string>
namespace async_mqtt5::detail {
enum class validation_result : uint8_t {
valid = 0,
has_wildcard_character,
invalid
};
inline int pop_front_unichar(std::string_view& s) {
// assuming that s.length() is > 0
int n = s[0] & 0xF0;
int ch = -1;
if ((n & 0x80) == 0) {
ch = s[0];
s.remove_prefix(1);
}
else if ((n == 0xC0 || n == 0xD0) && s.size() > 1) {
ch = ((s[0] & 0x1F) << 6) | (s[1] & 0x3F);
s.remove_prefix(2);
}
else if ((n == 0xE0) && s.size() > 2) {
ch = ((s[0] & 0x1F) << 12) | ((s[1] & 0x3F) << 6) | (s[2] & 0x3F);
s.remove_prefix(3);
}
else if ((n == 0xF0) && s.size() > 3) {
ch = ((s[0] & 0x1F) << 18) | ((s[1] & 0x3F) << 12) |
((s[2] & 0x3F) << 6) | (s[3] & 0x3F);
s.remove_prefix(4);
}
return ch;
}
inline validation_result validate_mqtt_utf8_char(int c) {
constexpr int fe_flag = 0xFE;
constexpr int ff_flag = 0xFF;
constexpr int multi_lvl_wildcard = '#';
constexpr int single_lvl_wildcard = '+';
if (c == multi_lvl_wildcard || c == single_lvl_wildcard)
return validation_result::has_wildcard_character;
if (c > 0x001F && // U+0000...U+001F control characters
(c < 0x007F || c > 0x009F) && // U+007F...0+009F control characters
(c < 0xD800 || c > 0xDFFF) && // U+D800...U+DFFF surrogates
(c < 0xFDD0 || c > 0xFDEF) && // U+FDD0...U+FDEF non-characters
(c & fe_flag) != fe_flag && // non-characters
(c & ff_flag) != ff_flag
)
return validation_result::valid;
return validation_result::invalid;
}
inline bool is_valid_string_size(size_t sz) {
constexpr size_t max_sz = 65535;
return sz <= max_sz;
}
inline bool is_utf8(validation_result result) {
return result == validation_result::valid ||
result == validation_result::has_wildcard_character;
}
template <typename ValidSizeCondition, typename ValidCondition>
validation_result validate_impl(
std::string_view str,
ValidSizeCondition&& size_condition, ValidCondition&& condition
) {
if (!size_condition(str.size()))
return validation_result::invalid;
validation_result result;
while (!str.empty()) {
int c = pop_front_unichar(str);
result = validate_mqtt_utf8_char(c);
if (!condition(result))
return result;
}
return validation_result::valid;
}
inline validation_result validate_mqtt_utf8(std::string_view str) {
return validate_impl(str, is_valid_string_size, is_utf8);
}
} // namespace async_mqtt5::detail
#endif //ASYNC_MQTT5_UTF8_MQTT_HPP