Merge duplicate byte-to-hex helper and drop stale '| 0' promotions

serializer::hex_bytes() and binary_writer::hex_byte() had identical
bodies. Keep one, detail::hex_byte() in string_utils.hpp, and use it
from both. Also drop the `| 0` at the two serializer call sites
(hex_bytes(byte | 0) and hex_bytes(s.back() | 0)): #3088 (7440786b8)
added it so that `ss << std::hex << (byte | 0)` printed a number
rather than a char with the old stringstream writer; the int result
just narrows back to uint8_t now, so it was a no-op.

Behavior is unchanged: unit-serialization, unit-bon8 (whose
type_error.316 messages exercise this code) and unit-diagnostics
pass, and both headers still compile standalone with -Werror.

Part of #5709

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann
2026-09-30 10:03:02 +02:00
parent 58250e9b3f
commit 23febcee51
4 changed files with 29 additions and 54 deletions
@@ -29,6 +29,7 @@
#include <nlohmann/detail/macro_scope.hpp>
#include <nlohmann/detail/output/output_adapters.hpp>
#include <nlohmann/detail/string_concat.hpp>
#include <nlohmann/detail/string_utils.hpp>
NLOHMANN_JSON_NAMESPACE_BEGIN
namespace detail
@@ -2278,20 +2279,10 @@ class binary_writer
const std::size_t valid = valid_utf8_prefix(data, s.size());
if (JSON_HEDLEY_UNLIKELY(valid != s.size()))
{
JSON_THROW(type_error::create(316, concat("invalid UTF-8 byte at index ", std::to_string(valid), ": 0x", hex_byte(data[valid])), &context));
JSON_THROW(type_error::create(316, concat("invalid UTF-8 byte at index ", std::to_string(valid), ": 0x", detail::hex_byte(data[valid])), &context));
}
}
/// @return a byte as two uppercase hexadecimal digits
static std::string hex_byte(const std::uint8_t byte)
{
std::string result = "00";
constexpr const char* nibble_to_hex = "0123456789ABCDEF";
result[0] = nibble_to_hex[byte / 16];
result[1] = nibble_to_hex[byte % 16];
return result;
}
/*!
@brief write an integer in the shortest encoding
+2 -16
View File
@@ -882,7 +882,7 @@ class serializer
{
case error_handler_t::strict:
{
JSON_THROW(type_error::create(316, concat("invalid UTF-8 byte at index ", std::to_string(i), ": 0x", hex_bytes(byte | 0)), nullptr));
JSON_THROW(type_error::create(316, concat("invalid UTF-8 byte at index ", std::to_string(i), ": 0x", detail::hex_byte(byte)), nullptr));
}
case error_handler_t::ignore:
@@ -974,7 +974,7 @@ class serializer
{
case error_handler_t::strict:
{
JSON_THROW(type_error::create(316, concat("incomplete UTF-8 string; last byte: 0x", hex_bytes(static_cast<std::uint8_t>(s[s.size() - 1] | 0))), nullptr));
JSON_THROW(type_error::create(316, concat("incomplete UTF-8 string; last byte: 0x", detail::hex_byte(static_cast<std::uint8_t>(s[s.size() - 1]))), nullptr));
}
case error_handler_t::ignore:
@@ -1195,20 +1195,6 @@ class serializer
}
}
/*!
* @brief convert a byte to a uppercase hex representation
* @param[in] byte byte to represent
* @return representation ("00".."FF")
*/
static std::string hex_bytes(std::uint8_t byte)
{
std::string result = "FF";
constexpr const char* nibble_to_hex = "0123456789ABCDEF";
result[0] = nibble_to_hex[byte / 16];
result[1] = nibble_to_hex[byte % 16];
return result;
}
/*!
* @brief write a lowercase "\uXXXX" escape sequence into @a string_buffer
*
+10
View File
@@ -36,6 +36,16 @@ StringType to_string(std::size_t value)
return result;
}
/// @return a byte as two uppercase hexadecimal digits
inline std::string hex_byte(const std::uint8_t byte)
{
std::string result = "00";
constexpr const char* nibble_to_hex = "0123456789ABCDEF";
result[0] = nibble_to_hex[byte / 16];
result[1] = nibble_to_hex[byte % 16];
return result;
}
///////////////////
// UTF-8 decoding //
///////////////////
+15 -27
View File
@@ -6234,6 +6234,16 @@ StringType to_string(std::size_t value)
return result;
}
/// @return a byte as two uppercase hexadecimal digits
inline std::string hex_byte(const std::uint8_t byte)
{
std::string result = "00";
constexpr const char* nibble_to_hex = "0123456789ABCDEF";
result[0] = nibble_to_hex[byte / 16];
result[1] = nibble_to_hex[byte % 16];
return result;
}
///////////////////
// UTF-8 decoding //
///////////////////
@@ -20358,6 +20368,8 @@ NLOHMANN_JSON_NAMESPACE_END
// #include <nlohmann/detail/string_concat.hpp>
// #include <nlohmann/detail/string_utils.hpp>
NLOHMANN_JSON_NAMESPACE_BEGIN
namespace detail
@@ -22607,20 +22619,10 @@ class binary_writer
const std::size_t valid = valid_utf8_prefix(data, s.size());
if (JSON_HEDLEY_UNLIKELY(valid != s.size()))
{
JSON_THROW(type_error::create(316, concat("invalid UTF-8 byte at index ", std::to_string(valid), ": 0x", hex_byte(data[valid])), &context));
JSON_THROW(type_error::create(316, concat("invalid UTF-8 byte at index ", std::to_string(valid), ": 0x", detail::hex_byte(data[valid])), &context));
}
}
/// @return a byte as two uppercase hexadecimal digits
static std::string hex_byte(const std::uint8_t byte)
{
std::string result = "00";
constexpr const char* nibble_to_hex = "0123456789ABCDEF";
result[0] = nibble_to_hex[byte / 16];
result[1] = nibble_to_hex[byte % 16];
return result;
}
/*!
@brief write an integer in the shortest encoding
@@ -24961,7 +24963,7 @@ class serializer
{
case error_handler_t::strict:
{
JSON_THROW(type_error::create(316, concat("invalid UTF-8 byte at index ", std::to_string(i), ": 0x", hex_bytes(byte | 0)), nullptr));
JSON_THROW(type_error::create(316, concat("invalid UTF-8 byte at index ", std::to_string(i), ": 0x", detail::hex_byte(byte)), nullptr));
}
case error_handler_t::ignore:
@@ -25053,7 +25055,7 @@ class serializer
{
case error_handler_t::strict:
{
JSON_THROW(type_error::create(316, concat("incomplete UTF-8 string; last byte: 0x", hex_bytes(static_cast<std::uint8_t>(s[s.size() - 1] | 0))), nullptr));
JSON_THROW(type_error::create(316, concat("incomplete UTF-8 string; last byte: 0x", detail::hex_byte(static_cast<std::uint8_t>(s[s.size() - 1]))), nullptr));
}
case error_handler_t::ignore:
@@ -25274,20 +25276,6 @@ class serializer
}
}
/*!
* @brief convert a byte to a uppercase hex representation
* @param[in] byte byte to represent
* @return representation ("00".."FF")
*/
static std::string hex_bytes(std::uint8_t byte)
{
std::string result = "FF";
constexpr const char* nibble_to_hex = "0123456789ABCDEF";
result[0] = nibble_to_hex[byte / 16];
result[1] = nibble_to_hex[byte % 16];
return result;
}
/*!
* @brief write a lowercase "\uXXXX" escape sequence into @a string_buffer
*