| 44,6 → 44,12 |
|---|
| |
| char invalch = '?'; |
| |
| /** Byte mask consisting of bits 0 - (@n - 1) */ |
| #define LO_MASK_8(n) ((uint8_t)((1 << (n)) - 1)) |
| |
| /** Number of data bits in a UTF-8 continuation byte. */ |
| #define CONT_BITS 6 |
| |
| /** Decode a single UTF-8 character from a NULL-terminated string. |
| * |
| * Decode a single UTF-8 character from a plain char NULL-terminated |
| 60,76 → 66,62 |
|---|
| */ |
| wchar_t utf8_decode(const char *str, index_t *index, index_t limit) |
| { |
| uint8_t c1; /* First plain character from str */ |
| uint8_t c2; /* Second plain character from str */ |
| uint8_t c3; /* Third plain character from str */ |
| uint8_t c4; /* Fourth plain character from str */ |
| |
| uint8_t b0, b; /* Bytes read from str. */ |
| wchar_t ch; |
| |
| int b0_bits; /* Data bits in first byte. */ |
| int cbytes; /* Number of continuation bytes. */ |
| |
| if (*index > limit) |
| return invalch; |
| |
| c1 = (uint8_t) str[*index]; |
| |
| if ((c1 & 0x80) == 0) { |
| /* Plain ASCII (code points 0 .. 127) */ |
| return (wchar_t) c1; |
| |
| b0 = (uint8_t) str[*index]; |
| |
| /* Determine code length. */ |
| |
| if ((b0 & 0x80) == 0) { |
| /* 0xxxxxxx (Plain ASCII) */ |
| b0_bits = 7; |
| cbytes = 0; |
| } else if ((b0 & 0xe0) == 0xc0) { |
| /* 110xxxxx 10xxxxxx */ |
| b0_bits = 5; |
| cbytes = 1; |
| } else if ((b0 & 0xf0) == 0xe0) { |
| /* 1110xxxx 10xxxxxx 10xxxxxx */ |
| b0_bits = 4; |
| cbytes = 2; |
| } else if ((b0 & 0xf8) == 0xf0) { |
| /* 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */ |
| b0_bits = 3; |
| cbytes = 3; |
| } else { |
| /* 10xxxxxx -- unexpected continuation byte. */ |
| return invalch; |
| } |
| |
| if ((c1 & 0xe0) == 0xc0) { |
| /* Code points 128 .. 2047 */ |
| if (*index + 1 > limit) |
| return invalch; |
| |
| c2 = (uint8_t) str[*index + 1]; |
| if ((c2 & 0xc0) == 0x80) { |
| (*index)++; |
| return ((wchar_t) ((c1 & 0x1f) << 6) | (c2 & 0x3f)); |
| } else |
| return invalch; |
| |
| if (*index + cbytes > limit) { |
| return invalch; |
| } |
| |
| if ((c1 & 0xf0) == 0xe0) { |
| /* Code points 2048 .. 65535 */ |
| if (*index + 2 > limit) |
| |
| ch = b0 & LO_MASK_8(b0_bits); |
| |
| /* Decode continuation bytes. */ |
| while (cbytes > 0) { |
| b = (uint8_t) str[*index + 1]; |
| ++(*index); |
| |
| /* Must be 10xxxxxx. */ |
| if ((b & 0xc0) != 0x80) { |
| return invalch; |
| |
| c2 = (uint8_t) str[*index + 1]; |
| if ((c2 & 0xc0) == 0x80) { |
| (*index)++; |
| c3 = (uint8_t) str[*index + 1]; |
| if ((c3 & 0xc0) == 0x80) { |
| (*index)++; |
| return ((wchar_t) ((c1 & 0x0f) << 12) | ((c2 & 0x3f) << 6) | (c3 & 0x3f)); |
| } else |
| return invalch; |
| } else |
| return invalch; |
| } |
| |
| /* Shift data bits to ch. */ |
| ch = (ch << CONT_BITS) | (wchar_t) (b & LO_MASK_8(CONT_BITS)); |
| --cbytes; |
| } |
| |
| if ((c1 & 0xf8) == 0xf0) { |
| /* Code points 65536 .. 1114111 */ |
| if (*index + 3 > limit) |
| return invalch; |
| |
| c2 = (uint8_t) str[*index + 1]; |
| if ((c2 & 0xc0) == 0x80) { |
| (*index)++; |
| c3 = (uint8_t) str[*index + 1]; |
| if ((c3 & 0xc0) == 0x80) { |
| (*index)++; |
| c4 = (uint8_t) str[*index + 1]; |
| if ((c4 & 0xc0) == 0x80) { |
| (*index)++; |
| return ((wchar_t) ((c1 & 0x07) << 18) | ((c2 & 0x3f) << 12) | ((c3 & 0x3f) << 6) | (c4 & 0x3f)); |
| } else |
| return invalch; |
| } else |
| return invalch; |
| } else |
| return invalch; |
| } |
| |
| return invalch; |
| |
| return ch; |
| } |
| |
| /** Encode a single UTF-32 character as UTF-8 |