Subversion Repositories planix.SVN

#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 * /lib/rfc/rfc1642 is obsolete utf-7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;
}