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[unicode][font] move extract_unicode_codepoint to new component (#19969)

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This commit is contained in:
Samuel Sieb
2026-10-05 17:40:06 +00:00
committed by GitHub
parent 4a47a984a0
commit fc441646f4
6 changed files with 123 additions and 104 deletions
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CODEOWNERS
+1
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@@ -609,6 +609,7 @@ esphome/components/ufire_ec/* @pvizeli
esphome/components/ufire_ise/* @pvizeli
esphome/components/ufm01/* @ljungqvist
esphome/components/ultrasonic/* @ssieb @swoboda1337
esphome/components/unicode/* @esphome/core
esphome/components/update/* @jesserockz
esphome/components/uponor_smatrix/* @kroimon
esphome/components/usb_cdc_acm/* @kbx81
esphome/components/font/__init__.py
+1
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@@ -41,6 +41,7 @@ _LOGGER = logging.getLogger(__name__)
DOMAIN = "font"
MULTI_CONF = True
AUTO_LOAD = ["unicode"]
CODEOWNERS = ["@esphome/core", "@clydebarrow"]
esphome/components/font/font.cpp
+3 -104
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@@ -3,6 +3,7 @@
#include "esphome/core/color.h"
#include "esphome/core/hal.h"
#include "esphome/core/log.h"
#include "esphome/components/unicode/unicode.h"
namespace esphome::font {
static const char *const TAG = "font";
@@ -121,108 +122,6 @@ const Glyph *Font::get_glyph_data_(uint32_t unicode_letter) {
}
#endif
/**
* Attempt to extract a 32 bit Unicode codepoint from a UTF-8 string.
* If successful, return the codepoint and set the length to the number of bytes read.
* If the end of the string has been reached and a valid codepoint has not been found, return 0 and set the length to
* 0.
*
* @param utf8_str The input string
* @param length Pointer to length storage
* @return The extracted code point
*/
static uint32_t extract_unicode_codepoint(const char *utf8_str, size_t *length) {
// Safely cast to uint8_t* for correct bitwise operations on bytes
const uint8_t *current = reinterpret_cast<const uint8_t *>(utf8_str);
uint32_t code_point = 0;
uint8_t c1 = *current++;
// check for end of string
if (c1 == 0) {
*length = 0;
return 0;
}
// --- 1-Byte Sequence: 0xxxxxxx (ASCII) ---
if (c1 < 0x80) {
// Valid ASCII byte.
code_point = c1;
// Optimization: No need to check for continuation bytes.
}
// --- 2-Byte Sequence: 110xxxxx 10xxxxxx ---
else if ((c1 & 0xE0) == 0xC0) {
uint8_t c2 = *current++;
// Error Check 1: Check if c2 is a valid continuation byte (10xxxxxx)
if ((c2 & 0xC0) != 0x80) {
*length = 0;
return 0;
}
code_point = (c1 & 0x1F) << 6;
code_point |= (c2 & 0x3F);
// Error Check 2: Overlong check (2-byte must be > 0x7F)
if (code_point <= 0x7F) {
*length = 0;
return 0;
}
}
// --- 3-Byte Sequence: 1110xxxx 10xxxxxx 10xxxxxx ---
else if ((c1 & 0xF0) == 0xE0) {
uint8_t c2 = *current++;
uint8_t c3 = *current++;
// Error Check 1: Check continuation bytes
if (((c2 & 0xC0) != 0x80) || ((c3 & 0xC0) != 0x80)) {
*length = 0;
return 0;
}
code_point = (c1 & 0x0F) << 12;
code_point |= (c2 & 0x3F) << 6;
code_point |= (c3 & 0x3F);
// Error Check 2: Overlong check (3-byte must be > 0x7FF)
// Also check for surrogates (0xD800-0xDFFF)
if (code_point <= 0x7FF || (code_point >= 0xD800 && code_point <= 0xDFFF)) {
*length = 0;
return 0;
}
}
// --- 4-Byte Sequence: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx ---
else if ((c1 & 0xF8) == 0xF0) {
uint8_t c2 = *current++;
uint8_t c3 = *current++;
uint8_t c4 = *current++;
// Error Check 1: Check continuation bytes
if (((c2 & 0xC0) != 0x80) || ((c3 & 0xC0) != 0x80) || ((c4 & 0xC0) != 0x80)) {
*length = 0;
return 0;
}
code_point = (c1 & 0x07) << 18;
code_point |= (c2 & 0x3F) << 12;
code_point |= (c3 & 0x3F) << 6;
code_point |= (c4 & 0x3F);
// Error Check 2: Overlong check (4-byte must be > 0xFFFF)
// Also check for valid Unicode range (must be <= 0x10FFFF)
if (code_point <= 0xFFFF || code_point > 0x10FFFF) {
*length = 0;
return 0;
}
}
// --- Invalid leading byte (e.g., 10xxxxxx or 11111xxx) ---
else {
*length = 0;
return 0;
}
*length = current - reinterpret_cast<const uint8_t *>(utf8_str);
return code_point;
}
Font::Font(const Glyph *data, int data_nr, int baseline, int height, int descender, int xheight, int capheight,
uint8_t bpp)
: glyphs_(ConstVector(data, data_nr)),
@@ -271,7 +170,7 @@ void Font::measure(const char *str, int *width, int *x_offset, int *baseline, in
int x = 0;
for (;;) {
size_t length;
auto code_point = extract_unicode_codepoint(str, &length);
auto code_point = unicode::extract_unicode_codepoint(str, &length);
if (length == 0)
break;
str += length;
@@ -300,7 +199,7 @@ void Font::print(int x_start, int y_start, display::Display *display, Color colo
int x_at = x_start;
for (;;) {
size_t length;
auto code_point = extract_unicode_codepoint(text, &length);
auto code_point = unicode::extract_unicode_codepoint(text, &length);
if (length == 0)
break;
text += length;
esphome/components/unicode/__init__.py
+1
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@@ -0,0 +1 @@
CODEOWNERS = ["@esphome/core"]
esphome/components/unicode/unicode.cpp
+97
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@@ -0,0 +1,97 @@
#include "unicode.h"
namespace esphome::unicode {
uint32_t extract_unicode_codepoint(const char *utf8_str, size_t *length) {
// Safely cast to uint8_t* for correct bitwise operations on bytes
const uint8_t *current = reinterpret_cast<const uint8_t *>(utf8_str);
uint32_t code_point = 0;
uint8_t c1 = *current++;
// check for end of string
if (c1 == 0) {
*length = 0;
return 0;
}
// --- 1-Byte Sequence: 0xxxxxxx (ASCII) ---
if (c1 < 0x80) {
// Valid ASCII byte.
code_point = c1;
// Optimization: No need to check for continuation bytes.
}
// --- 2-Byte Sequence: 110xxxxx 10xxxxxx ---
else if ((c1 & 0xE0) == 0xC0) {
uint8_t c2 = *current++;
// Error Check 1: Check if c2 is a valid continuation byte (10xxxxxx)
if ((c2 & 0xC0) != 0x80) {
*length = 0;
return 0;
}
code_point = (c1 & 0x1F) << 6;
code_point |= (c2 & 0x3F);
// Error Check 2: Overlong check (2-byte must be > 0x7F)
if (code_point <= 0x7F) {
*length = 0;
return 0;
}
}
// --- 3-Byte Sequence: 1110xxxx 10xxxxxx 10xxxxxx ---
else if ((c1 & 0xF0) == 0xE0) {
uint8_t c2 = *current++;
uint8_t c3 = *current++;
// Error Check 1: Check continuation bytes
if (((c2 & 0xC0) != 0x80) || ((c3 & 0xC0) != 0x80)) {
*length = 0;
return 0;
}
code_point = (c1 & 0x0F) << 12;
code_point |= (c2 & 0x3F) << 6;
code_point |= (c3 & 0x3F);
// Error Check 2: Overlong check (3-byte must be > 0x7FF)
// Also check for surrogates (0xD800-0xDFFF)
if (code_point <= 0x7FF || (code_point >= 0xD800 && code_point <= 0xDFFF)) {
*length = 0;
return 0;
}
}
// --- 4-Byte Sequence: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx ---
else if ((c1 & 0xF8) == 0xF0) {
uint8_t c2 = *current++;
uint8_t c3 = *current++;
uint8_t c4 = *current++;
// Error Check 1: Check continuation bytes
if (((c2 & 0xC0) != 0x80) || ((c3 & 0xC0) != 0x80) || ((c4 & 0xC0) != 0x80)) {
*length = 0;
return 0;
}
code_point = (c1 & 0x07) << 18;
code_point |= (c2 & 0x3F) << 12;
code_point |= (c3 & 0x3F) << 6;
code_point |= (c4 & 0x3F);
// Error Check 2: Overlong check (4-byte must be > 0xFFFF)
// Also check for valid Unicode range (must be <= 0x10FFFF)
if (code_point <= 0xFFFF || code_point > 0x10FFFF) {
*length = 0;
return 0;
}
}
// --- Invalid leading byte (e.g., 10xxxxxx or 11111xxx) ---
else {
*length = 0;
return 0;
}
*length = current - reinterpret_cast<const uint8_t *>(utf8_str);
return code_point;
}
} // namespace esphome::unicode
esphome/components/unicode/unicode.h
+20
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@@ -0,0 +1,20 @@
#pragma once
#include <cstddef>
#include <cstdint>
namespace esphome::unicode {
/**
* Attempt to extract a 32 bit Unicode codepoint from a UTF-8 string.
* If successful, return the codepoint and set the length to the number of bytes read.
* If the end of the string has been reached and a valid codepoint has not been found, return 0 and set the length to
* 0.
*
* @param utf8_str The input string
* @param length Pointer to length storage
* @return The extracted code point
*/
uint32_t extract_unicode_codepoint(const char *utf8_str, size_t *length);
} // namespace esphome::unicode