ref: ee93b99842546dc501a383e06fd0ba4af904e150
dir: /sys/src/libc/9sys/idn.c/
#include <u.h> #include <libc.h> enum { base = 36, tmin = 1, tmax = 26, skew = 38, damp = 700, initial_bias = 72, initial_n = 0x80, Domlen = 256, }; static uint maxint = ~0; static uint decode_digit(uint cp) { if((cp - '0') < 10) return cp - ('0' - 26); if((cp - 'A') < 26) return cp - 'A'; if((cp - 'a') < 26) return cp - 'a'; return base; } static char encode_digit(uint d, int flag) { if(d < 26) return d + (flag ? 'A' : 'a'); return d + ('0' - 26); } static uint adapt(uint delta, uint numpoints, int firsttime) { uint k; delta = firsttime ? delta / damp : delta >> 1; delta += delta / numpoints; for (k = 0; delta > ((base - tmin) * tmax) / 2; k += base) delta /= base - tmin; return k + (base - tmin + 1) * delta / (delta + skew); } static int punyencode(uint input_length, Rune input[], uint max_out, char output[]) { uint n, delta, h, b, out, bias, j, m, q, k, t; n = initial_n; delta = out = 0; bias = initial_bias; for (j = 0; j < input_length; ++j) { if ((uint)input[j] < 0x80) { if (max_out - out < 2) return -1; output[out++] = input[j]; } } h = b = out; if (b > 0) output[out++] = '-'; while (h < input_length) { for (m = maxint, j = 0; j < input_length; ++j) { if (input[j] >= n && input[j] < m) m = input[j]; } if (m - n > (maxint - delta) / (h + 1)) return -1; delta += (m - n) * (h + 1); n = m; for (j = 0; j < input_length; ++j) { if (input[j] < n) { if (++delta == 0) return -1; } if (input[j] == n) { for (q = delta, k = base;; k += base) { if (out >= max_out) return -1; if (k <= bias) t = tmin; else if (k >= bias + tmax) t = tmax; else t = k - bias; if (q < t) break; output[out++] = encode_digit(t + (q - t) % (base - t), 0); q = (q - t) / (base - t); } output[out++] = encode_digit(q, isupperrune(input[j])); bias = adapt(delta, h + 1, h == b); delta = 0; ++h; } } ++delta, ++n; } return (int)out; } static int punydecode(uint input_length, char input[], uint max_out, Rune output[]) { uint n, out, i, bias, b, j, in, oldi, w, k, digit, t; n = initial_n; out = i = 0; bias = initial_bias; for (b = j = 0; j < input_length; ++j) if (input[j] == '-') b = j; if (b > max_out) return -1; for (j = 0; j < b; ++j) { if (input[j] & 0x80) return -1; output[out++] = input[j]; } for (in = b > 0 ? b + 1 : 0; in < input_length; ++out) { for (oldi = i, w = 1, k = base;; k += base) { if (in >= input_length) return -1; digit = decode_digit(input[in++]); if (digit >= base) return -1; if (digit > (maxint - i) / w) return -1; i += digit * w; if (k <= bias) t = tmin; else if (k >= bias + tmax) t = tmax; else t = k - bias; if (digit < t) break; if (w > maxint / (base - t)) return -1; w *= (base - t); } bias = adapt(i - oldi, out + 1, oldi == 0); if (i / (out + 1) > maxint - n) return -1; n += i / (out + 1); i %= (out + 1); if (out >= max_out) return -1; memmove(output + i + 1, output + i, (out - i) * sizeof *output); if(((uint)input[in-1] - 'A') < 26) output[i++] = toupperrune(n); else output[i++] = tolowerrune(n); } return (int)out; } /* * convert punycode encoded internationalized * domain name to unicode string */ int idn2utf(char *name, char *buf, int nbuf) { char *dp, *de, *cp; Rune rb[Domlen], r; int nc, nr, n; if(nbuf < 1) return -1; cp = name; dp = buf; de = dp+nbuf-1; for(;;){ nc = nr = 0; while(cp[nc] != 0){ n = chartorune(&r, cp+nc); if(r == '.') break; if(nr >= nelem(rb)) return -1; rb[nr++] = r; nc += n; } if(cistrncmp(cp, "xn--", 4) == 0) if((nr = punydecode(nc-4, cp+4, nelem(rb), rb)) < 0) return -1; dp = seprint(dp, de, "%.*S", nr, rb); if(dp >= de) return -1; if(cp[nc] == 0) break; *dp++ = '.'; cp += nc+1; } *dp = 0; return dp - buf; } /* * convert unicode string to punycode * encoded internationalized domain name */ int utf2idn(char *name, char *buf, int nbuf) { char *dp, *de, *cp; Rune rb[Domlen], r; int nc, nr, n; if(nbuf < 1) return -1; dp = buf; de = dp+nbuf-1; cp = name; for(;;){ nc = nr = 0; while(cp[nc] != 0){ n = chartorune(&r, cp+nc); if(r == '.') break; if(nr >= nelem(rb)) return -1; rb[nr++] = r; nc += n; } if(nc == nr) dp = seprint(dp, de, "%.*s", nc, cp); else { dp = seprint(dp, de, "xn--"); if((n = punyencode(nr, rb, de - dp, dp)) < 0) return -1; dp += n; } if(dp >= de) return -1; if(cp[nc] == 0) break; *dp++ = '.'; cp += nc+1; } *dp = 0; return dp - buf; }