sascha/esphome
1
0
Fork 0
mirror of https://github.com/esphome/esphome.git synced 2026-02-08 00:31:58 +00:00
Code Issues Releases Wiki Activity

[helpers] Add format_hex_prefixed_to for "0x" prefixed hex formatting (#13115)

Browse Source
This commit is contained in:
J. Nick Koston
2026-01-10 17:07:21 -10:00
committed by GitHub
parent 6222fae907
commit a1395af763
3 changed files with 29 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
esphome/components/one_wire/one_wire.cpp
View File

@@ -6,8 +6,10 @@ namespace one_wire {
static const char *const TAG = "one_wire";
const std::string &OneWireDevice::get_address_name() {
if (this->address_name_.empty())
this->address_name_ = std::string("0x") + format_hex(this->address_);
if (this->address_name_.empty()) {
char hex_buf[19]; // "0x" + 16 hex chars + null
this->address_name_ = format_hex_prefixed_to(hex_buf, this->address_);
}
return this->address_name_;
}

6
esphome/components/sml/text_sensor/sml_text_sensor.cpp
View File

@@ -24,11 +24,9 @@ void SmlTextSensor::publish_val(const ObisInfo &obis_info) {
case SML_HEX: {
// Buffer for "0x" + up to 32 bytes as hex + null
char buf[67];
buf[0] = '0';
buf[1] = 'x';
// Max 32 bytes of data fit in remaining buffer ((65-1)/2)
// Max 32 bytes of data fit in buffer ((67-3)/2)
size_t hex_bytes = std::min(obis_info.value.size(), size_t(32));
format_hex_to(buf + 2, sizeof(buf) - 2, obis_info.value.begin(), hex_bytes);
format_hex_prefixed_to(buf, obis_info.value.begin(), hex_bytes);
publish_state(buf, 2 + hex_bytes * 2);
break;
}

23
esphome/core/helpers.h
View File

@@ -759,6 +759,29 @@ inline char *format_hex_to(char (&buffer)[N], T val) {
/// Calculate buffer size needed for format_hex_to: "XXXXXXXX...\0" = bytes * 2 + 1
constexpr size_t format_hex_size(size_t byte_count) { return byte_count * 2 + 1; }
/// Calculate buffer size needed for format_hex_prefixed_to: "0xXXXXXXXX...\0" = bytes * 2 + 3
constexpr size_t format_hex_prefixed_size(size_t byte_count) { return byte_count * 2 + 3; }
/// Format an unsigned integer as "0x" prefixed lowercase hex to buffer.
template<size_t N, typename T, enable_if_t<std::is_unsigned<T>::value, int> = 0>
inline char *format_hex_prefixed_to(char (&buffer)[N], T val) {
static_assert(N >= sizeof(T) * 2 + 3, "Buffer too small for prefixed hex");
buffer[0] = '0';
buffer[1] = 'x';
val = convert_big_endian(val);
format_hex_to(buffer + 2, N - 2, reinterpret_cast<const uint8_t *>(&val), sizeof(T));
return buffer;
}
/// Format byte array as "0x" prefixed lowercase hex to buffer.
template<size_t N> inline char *format_hex_prefixed_to(char (&buffer)[N], const uint8_t *data, size_t length) {
static_assert(N >= 5, "Buffer must hold at least '0x' + one hex byte + null");
buffer[0] = '0';
buffer[1] = 'x';
format_hex_to(buffer + 2, N - 2, data, length);
return buffer;
}
/// Calculate buffer size needed for format_hex_pretty_to with separator: "XX:XX:...:XX\0"
constexpr size_t format_hex_pretty_size(size_t byte_count) { return byte_count * 3; }