ref: d0ab3a0dd8f6355b3603d0fb04043a9ae867639b
dir: /libkern/utfrune.c/
#include "lib9.h" char* utfrune(char *s, long c) { long c1; Rune r; int n; if(c < Runesync) /* not part of utf sequence */ return strchr(s, c); for(;;) { c1 = *(uchar*)s; if(c1 < Runeself) { /* one byte rune */ if(c1 == 0) return 0; if(c1 == c) return s; s++; continue; } n = chartorune(&r, s); if(r == c) return s; s += n; } }