--- /dev/null
+#include "gmqcc.h"
+
+static unsigned char utf8_lengths[256] = {
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* ascii characters */
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x80 - 0xBF are within multibyte sequences
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, * they could be interpreted as 2-byte starts but
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, * the codepoint would be < 127
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, *
+ 0, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, * C0 and C1 would also result in overlong encodings
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, */
+ 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+ 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+ /* with F5 the codepoint is above 0x10FFFF,
+ * F8-FB would start 5-byte sequences
+ * FC-FD would start 6-byte sequences
+ * ...
+ */
+};
+
+static Uchar utf8_range[5] = {
+ 1, /* invalid - let's not allow the creation of 0-bytes :P
+ 1, * ascii minimum
+ 0x80, * 2-byte minimum
+ 0x800, * 3-byte minimum
+ 0x10000, * 4-byte minimum */
+};
+
+/** Analyze the next character and return various information if requested.
+ * @param _s An utf-8 string.
+ * @param _start Filled with the start byte-offset of the next valid character
+ * @param _len Fileed with the length of the next valid character
+ * @param _ch Filled with the unicode value of the next character
+ * @param _maxlen Maximum number of bytes to read from _s
+ * @return Whether or not another valid character is in the string
+ */
+static bool u8_analyze(const char *_s, size_t *_start, size_t *_len, Uchar *_ch, size_t _maxlen)
+{
+ const unsigned char *s = (const unsigned char*)_s;
+ size_t i, j;
+ size_t bits = 0;
+ Uchar ch;
+
+ i = 0;
+findchar:
+ while (i < _maxlen && s[i] && (bits = utf8_lengths[s[i]]) == 0)
+ ++i;
+
+ if (i >= _maxlen || !s[i]) {
+ if (_start) *_start = i;
+ if (_len) *_len = 0;
+ return false;
+ }
+
+ if (bits == 1) { /* ascii */
+ if (_start) *_start = i;
+ if (_len) *_len = 1;
+ if (_ch) *_ch = (Uchar)s[i];
+ return true;
+ }
+
+ ch = (s[i] & (0xFF >> bits));
+ for (j = 1; j < bits; ++j)
+ {
+ if ( (s[i+j] & 0xC0) != 0x80 )
+ {
+ i += j;
+ goto findchar;
+ }
+ ch = (ch << 6) | (s[i+j] & 0x3F);
+ }
+ if (ch < utf8_range[bits] || ch >= 0x10FFFF)
+ {
+ i += bits;
+ goto findchar;
+ }
+
+ if (_start)
+ *_start = i;
+ if (_len)
+ *_len = bits;
+ if (_ch)
+ *_ch = ch;
+ return true;
+}
+
+/* might come in handy */
+size_t u8_strlen(const char *_s)
+{
+ size_t st, ln;
+ size_t len = 0;
+ const unsigned char *s = (const unsigned char*)_s;
+
+ while (*s)
+ {
+ /* ascii char, skip u8_analyze */
+ if (*s < 0x80)
+ {
+ ++len;
+ ++s;
+ continue;
+ }
+
+ /* invalid, skip u8_analyze */
+ if (*s < 0xC2)
+ {
+ ++s;
+ continue;
+ }
+
+ if (!u8_analyze((const char*)s, &st, &ln, NULL, 0x10))
+ break;
+ /* valid character, skip after it */
+ s += st + ln;
+ ++len;
+ }
+ return len;
+}
+
+size_t u8_strnlen(const char *_s, size_t n)
+{
+ size_t st, ln;
+ size_t len = 0;
+ const unsigned char *s = (const unsigned char*)_s;
+
+ while (*s && n)
+ {
+ /* ascii char, skip u8_analyze */
+ if (*s < 0x80)
+ {
+ ++len;
+ ++s;
+ --n;
+ continue;
+ }
+
+ /* invalid, skip u8_analyze */
+ if (*s < 0xC2)
+ {
+ ++s;
+ --n;
+ continue;
+ }
+
+ if (!u8_analyze((const char*)s, &st, &ln, NULL, n))
+ break;
+ /* valid character, see if it's still inside the range specified by n: */
+ if (n < st + ln)
+ return len;
+ ++len;
+ n -= st + ln;
+ s += st + ln;
+ }
+ return len;
+}
+
+/* Required for character constants */
+Uchar u8_getchar(const char *_s, const char **_end)
+{
+ size_t st, ln;
+ Uchar ch;
+
+ if (!u8_analyze(_s, &st, &ln, &ch, 0x10))
+ ch = 0;
+ if (_end)
+ *_end = _s + st + ln;
+ return ch;
+}
+
+Uchar u8_getnchar(const char *_s, const char **_end, size_t _maxlen)
+{
+ size_t st, ln;
+ Uchar ch;
+
+ if (!u8_analyze(_s, &st, &ln, &ch, _maxlen))
+ ch = 0;
+ if (_end)
+ *_end = _s + st + ln;
+ return ch;
+}
+
+/* required for \x{asdf}-like string escape sequences */
+int u8_fromchar(Uchar w, char *to, size_t maxlen)
+{
+ if (maxlen < 1)
+ return 0;
+
+ if (!w)
+ return 0;
+
+/* We may want an -f flag for this behaviour...
+ if (w >= 0xE000)
+ w -= 0xE000;
+*/
+
+ if (w < 0x80)
+ {
+ to[0] = (char)w;
+ if (maxlen < 2)
+ return -1;
+ to[1] = 0;
+ return 1;
+ }
+ /* for a little speedup */
+ if (w < 0x800)
+ {
+ if (maxlen < 3)
+ {
+ to[0] = 0;
+ return -1;
+ }
+ to[2] = 0;
+ to[1] = 0x80 | (w & 0x3F); w >>= 6;
+ to[0] = 0xC0 | w;
+ return 2;
+ }
+ if (w < 0x10000)
+ {
+ if (maxlen < 4)
+ {
+ to[0] = 0;
+ return -1;
+ }
+ to[3] = 0;
+ to[2] = 0x80 | (w & 0x3F); w >>= 6;
+ to[1] = 0x80 | (w & 0x3F); w >>= 6;
+ to[0] = 0xE0 | w;
+ return 3;
+ }
+
+ /* RFC 3629 */
+ if (w <= 0x10FFFF)
+ {
+ if (maxlen < 5)
+ {
+ to[0] = 0;
+ return -1;
+ }
+ to[4] = 0;
+ to[3] = 0x80 | (w & 0x3F); w >>= 6;
+ to[2] = 0x80 | (w & 0x3F); w >>= 6;
+ to[1] = 0x80 | (w & 0x3F); w >>= 6;
+ to[0] = 0xF0 | w;
+ return 4;
+ }
+ return 0;
+}