ref: 4821c261c4cea895ddcbd7c70bc71103c9a2763b
dir: /sys/src/cmd/ip/imap4d/mutf7.c/
#include <u.h> #include <libc.h> #include <bio.h> #include <auth.h> #include "imap4d.h" /* * modified utf-7, as per imap4 spec * like utf-7, but substitues , for / in base 64, * does not allow escaped ascii characters. * * /lib/rfc/rfc2152 is utf-7 * /lib/rfc/rfc1642 is obsolete utf-7 * * test sequences from rfc1642 * 'A≢Α.' 'A&ImIDkQ-.' * 'Hi Mom ☺!" 'Hi Mom &Jjo-!' * '日本語' '&ZeVnLIqe-' */ static uchar mt64d[256]; static char mt64e[64]; static void initm64(void) { int c, i; memset(mt64d, 255, 256); memset(mt64e, '=', 64); i = 0; for(c = 'A'; c <= 'Z'; c++){ mt64e[i] = c; mt64d[c] = i++; } for(c = 'a'; c <= 'z'; c++){ mt64e[i] = c; mt64d[c] = i++; } for(c = '0'; c <= '9'; c++){ mt64e[i] = c; mt64d[c] = i++; } mt64e[i] = '+'; mt64d['+'] = i++; mt64e[i] = ','; mt64d[','] = i; } int encmutf7(char *out, int lim, char *in) { Rune rr; ulong r, b; char *start = out; char *e = out + lim; int nb; if(mt64e[0] == 0) initm64(); for(;;){ r = *(uchar*)in; if(r < ' ' || r >= Runeself){ if(r == '\0') break; if(out + 1 >= e) return -1; *out++ = '&'; b = 0; nb = 0; for(;;){ in += chartorune(&rr, in); r = rr; if(r == '\0' || r >= ' ' && r < Runeself) break; b = (b << 16) | r; for(nb += 16; nb >= 6; nb -= 6){ if(out + 1 >= e) return -1; *out++ = mt64e[(b>>(nb-6))&0x3f]; } } for(; nb >= 6; nb -= 6){ if(out + 1 >= e) return -1; *out++ = mt64e[(b>>(nb-6))&0x3f]; } if(nb){ if(out + 1 >= e) return -1; *out++ = mt64e[(b<<(6-nb))&0x3f]; } if(out + 1 >= e) return -1; *out++ = '-'; if(r == '\0') break; }else in++; if(out + 1 >= e) return -1; *out = r; out++; if(r == '&') *out++ = '-'; } if(out >= e) return -1; *out = '\0'; return out - start; } int decmutf7(char *out, int lim, char *in) { Rune rr; char *start = out; char *e = out + lim; int c, b, nb; if(mt64e[0] == 0) initm64(); for(;;){ c = *in; if(c < ' ' || c >= Runeself){ if(c == '\0') break; return -1; } if(c != '&'){ if(out + 1 >= e) return -1; *out++ = c; in++; continue; } in++; if(*in == '-'){ if(out + 1 >= e) return -1; *out++ = '&'; in++; continue; } b = 0; nb = 0; while((c = *in++) != '-'){ c = mt64d[c]; if(c >= 64) return -1; b = (b << 6) | c; nb += 6; if(nb >= 16){ rr = b >> (nb - 16); nb -= 16; if(out + UTFmax + 1 >= e && out + runelen(rr) + 1 >= e) return -1; out += runetochar(out, &rr); } } if(b & ((1 << nb) - 1)) return -1; } if(out >= e) return -1; *out = '\0'; return out - start; }