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-rw-r--r--src/string_utils.h58
1 files changed, 38 insertions, 20 deletions
diff --git a/src/string_utils.h b/src/string_utils.h
index 07941325..5eeabc6b 100644
--- a/src/string_utils.h
+++ b/src/string_utils.h
@@ -112,25 +112,44 @@ serd_strncasecmp(const char* s1, const char* s2, size_t n)
}
static inline uint32_t
-utf8_num_bytes(const uint8_t c)
+utf8_num_bytes(const uint8_t leading)
{
- if ((c & 0x80) == 0) { // Starts with `0'
- return 1;
- }
-
- if ((c & 0xE0) == 0xC0) { // Starts with `110'
- return 2;
- }
-
- if ((c & 0xF0) == 0xE0) { // Starts with `1110'
- return 3;
- }
-
- if ((c & 0xF8) == 0xF0) { // Starts with `11110'
- return 4;
- }
-
- return 0;
+ static const uint8_t lengths[32] = {
+ 1u, // 00000xxx
+ 1u, // 00001xxx
+ 1u, // 00010xxx
+ 1u, // 00011xxx
+ 1u, // 00100xxx
+ 1u, // 00101xxx
+ 1u, // 00110xxx
+ 1u, // 00111xxx
+ 1u, // 01000xxx
+ 1u, // 01001xxx
+ 1u, // 01010xxx
+ 1u, // 01011xxx
+ 1u, // 01100xxx
+ 1u, // 01101xxx
+ 1u, // 01110xxx
+ 1u, // 01111xxx
+ 0u, // 10000xxx
+ 0u, // 10001xxx
+ 0u, // 10010xxx
+ 0u, // 10011xxx
+ 0u, // 10100xxx
+ 0u, // 10101xxx
+ 0u, // 10110xxx
+ 0u, // 10111xxx
+ 2u, // 11000xxx
+ 2u, // 11001xxx
+ 2u, // 11010xxx
+ 2u, // 11011xxx
+ 3u, // 11100xxx
+ 3u, // 11101xxx
+ 4u, // 11110xxx
+ 0u // 11111xxx
+ };
+
+ return lengths[leading >> 3u];
}
/// Return the code point of a UTF-8 character with known length
@@ -139,8 +158,7 @@ parse_counted_utf8_char(const uint8_t* utf8, size_t size)
{
uint32_t c = utf8[0] & ((1u << (8u - size)) - 1u);
for (size_t i = 1; i < size; ++i) {
- const uint8_t in = utf8[i] & 0x3Fu;
- c = (c << 6) | in;
+ c = (c << 6) | (utf8[i] & 0x3Fu);
}
return c;
}