ref: 5c448c618a89ab8933838da1b5b97ed7c4a42e08
dir: /sys/src/ape/lib/ap/gen/mbwc.c/
#include <stdlib.h> #include <utf.h> /* * Use the FSS-UTF transformation proposed by posix. * We define 7 byte types: * T0 0xxxxxxx 7 free bits * Tx 10xxxxxx 6 free bits * T1 110xxxxx 5 free bits * T2 1110xxxx 4 free bits * T3 11110xxx 3 free bits * * Encoding is as follows. * From hex Thru hex Sequence Bits * 00000000 0000007F T0 7 * 00000080 000007FF T1 Tx 11 * 00000800 0000FFFF T2 Tx Tx 16 * 00010000 0010FFFF T3 Tx Tx Tx 20 (and change) */ int mblen(const char *s, size_t n) { return mbtowc(0, s, n); } int mbtowc(wchar_t *pwc, const char *s, size_t n) { int c, c1, c2, c3; long l; if(!s) return 0; if(n < 1) goto bad; c = s[0] & 0xff; if((c & 0x80) == 0x00) { if(pwc) *pwc = c; if(c == 0) return 0; return 1; } if(n < 2) goto bad; c1 = (s[1] ^ 0x80) & 0xff; if((c1 & 0xC0) != 0x00) goto bad; if((c & 0xE0) == 0xC0) { l = ((c << 6) | c1) & 0x7FF; if(l < 0x080) goto bad; if(pwc) *pwc = l; return 2; } if(n < 3) goto bad; c2 = (s[2] ^ 0x80) & 0xff; if((c2 & 0xC0) != 0x00) goto bad; if((c & 0xF0) == 0xE0) { l = ((((c << 6) | c1) << 6) | c2) & 0xFFFF; if(l < 0x0800) goto bad; if(pwc) *pwc = l; return 3; } if(n < 4) goto bad; if(UTFmax >= 4) { c3 = (s[3] ^ 0x80) & 0xff; if(c3 & 0xC0) goto bad; if(c < 0xf8) { l = ((((((c << 6) | c1) << 6) | c2) << 6) | c3) & 0x3fffff; if(l <= 0x10000) goto bad; if(l > Runemax) goto bad; if(pwc) *pwc = l; return 4; } } /* * bad decoding */ bad: return -1; } int wctomb(char *s, wchar_t wchar) { long c; if(!s) return 0; c = wchar; if(c > Runemax) c = Runeerror; if(c < 0x80) { s[0] = c; return 1; } if(c < 0x800) { s[0] = 0xC0 | (c >> 6); s[1] = 0x80 | (c & 0x3F); return 2; } if(c < 0x10000) { s[0] = 0xE0 | (c >> 12); s[1] = 0x80 | ((c >> 6) & 0x3F); s[2] = 0x80 | (c & 0x3F); return 3; } s[0] = 0xf0 | c >> 18; s[1] = 0x80 | (c >> 12) & 0x3F; s[2] = 0x80 | (c >> 6) & 0x3F; s[3] = 0x80 | (c & 0x3F); return 4; } size_t mbstowcs(wchar_t *pwcs, const char *s, size_t n) { int i, d, c; for(i=0; i < n; i++) { c = *s & 0xff; if(c < 0x80) { *pwcs = c; if(c == 0) break; s++; } else { d = mbtowc(pwcs, s, UTFmax); if(d <= 0) return (size_t)((d<0) ? -1 : i); s += d; } pwcs++; } return i; } size_t wcstombs(char *s, const wchar_t *pwcs, size_t n) { int i, d; long c; char *p, *pe; char buf[UTFmax]; p = s; pe = p+n-UTFmax; while(p < pe) { c = *pwcs++; if(c < 0x80) *p++ = c; else p += wctomb(p, c); if(c == 0) return p-s; } while(p < pe+UTFmax) { c = *pwcs++; d = wctomb(buf, c); if(p+d <= pe+UTFmax) { for(i = 0; i < d; i++) p[i] = buf[i]; p += d; } if(c == 0) break; } return p-s; }