450 lines
14 KiB
C
450 lines
14 KiB
C
/* ========================================================================
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* Copyright 1988-2007 University of Washington
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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*
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* ========================================================================
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*/
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/*
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* Program: UTF-8 auxillary routines (c-client and MIME2 support)
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*
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* Author: Mark Crispin
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* Networks and Distributed Computing
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* Computing & Communications
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* University of Washington
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* Administration Building, AG-44
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* Seattle, WA 98195
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* Internet: MRC@CAC.Washington.EDU
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*
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* Date: 11 June 1997
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* Last Edited: 12 October 2007
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*/
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#include <stdio.h>
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#include <ctype.h>
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#include "c-client.h"
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/* Convert charset labelled stringlist to UTF-8 in place
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* Accepts: string list
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* charset
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*/
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static void utf8_stringlist (STRINGLIST *st,char *charset)
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{
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SIZEDTEXT txt;
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/* convert entire stringstruct */
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if (st) do if (utf8_text (&st->text,charset,&txt,U8T_CANONICAL)) {
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fs_give ((void **) &st->text.data);
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st->text.data = txt.data; /* transfer this text */
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st->text.size = txt.size;
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} while (st = st->next);
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}
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/* Convert charset labelled searchpgm to UTF-8 in place
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* Accepts: search program
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* charset
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*/
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void utf8_searchpgm (SEARCHPGM *pgm,char *charset)
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{
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SIZEDTEXT txt;
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SEARCHHEADER *hl;
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SEARCHOR *ol;
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SEARCHPGMLIST *pl;
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if (pgm) { /* must have a search program */
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utf8_stringlist (pgm->bcc,charset);
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utf8_stringlist (pgm->cc,charset);
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utf8_stringlist (pgm->from,charset);
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utf8_stringlist (pgm->to,charset);
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utf8_stringlist (pgm->subject,charset);
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for (hl = pgm->header; hl; hl = hl->next) {
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if (utf8_text (&hl->line,charset,&txt,U8T_CANONICAL)) {
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fs_give ((void **) &hl->line.data);
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hl->line.data = txt.data;
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hl->line.size = txt.size;
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}
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if (utf8_text (&hl->text,charset,&txt,U8T_CANONICAL)) {
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fs_give ((void **) &hl->text.data);
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hl->text.data = txt.data;
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hl->text.size = txt.size;
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}
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}
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utf8_stringlist (pgm->body,charset);
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utf8_stringlist (pgm->text,charset);
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for (ol = pgm->or; ol; ol = ol->next) {
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utf8_searchpgm (ol->first,charset);
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utf8_searchpgm (ol->second,charset);
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}
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for (pl = pgm->not; pl; pl = pl->next) utf8_searchpgm (pl->pgm,charset);
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utf8_stringlist (pgm->return_path,charset);
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utf8_stringlist (pgm->sender,charset);
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utf8_stringlist (pgm->reply_to,charset);
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utf8_stringlist (pgm->in_reply_to,charset);
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utf8_stringlist (pgm->message_id,charset);
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utf8_stringlist (pgm->newsgroups,charset);
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utf8_stringlist (pgm->followup_to,charset);
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utf8_stringlist (pgm->references,charset);
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}
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}
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/* Convert MIME-2 sized text to UTF-8
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* Accepts: source sized text
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* charset
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* flags (same as utf8_text())
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* Returns: T if successful, NIL if failure
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*/
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#define MINENCWORD 9
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#define MAXENCWORD 75
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/* This resizing algorithm is stupid, but hopefully it should never be triggered
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* except for a pathological header. The main concern is that we don't get a
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* buffer overflow.
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*/
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#define DSIZE 65536 /* real headers should never be this big */
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#define FUZZ 10 /* paranoia fuzz */
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long utf8_mime2text (SIZEDTEXT *src,SIZEDTEXT *dst,long flags)
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{
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unsigned char *s,*se,*e,*ee,*t,*te;
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char *cs,*ce,*ls;
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SIZEDTEXT txt,rtxt;
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unsigned long i;
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size_t dsize = min (DSIZE,((src->size / 4) + 1) * 9);
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/* always create buffer if canonicalizing */
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dst->data = (flags & U8T_CANONICAL) ?
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(unsigned char *) fs_get ((size_t) dsize) : NIL;
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dst->size = 0; /* nothing written yet */
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/* look for encoded words */
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for (s = src->data, se = src->data + src->size; s < se; s++) {
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if (((se - s) > MINENCWORD) && (*s == '=') && (s[1] == '?') &&
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(cs = (char *) mime2_token (s+2,se,(unsigned char **) &ce)) &&
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(e = mime2_token ((unsigned char *) ce+1,se,&ee)) &&
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(te = mime2_text (t = e+2,se)) && (ee == e + 1) &&
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((te - s) < MAXENCWORD)) {
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if (mime2_decode (e,t,te,&txt)) {
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*ce = '\0'; /* temporarily tie off charset */
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if (ls = strchr (cs,'*')) *ls = '\0';
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/* convert to UTF-8 as best we can */
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if (!utf8_text (&txt,cs,&rtxt,flags)) utf8_text (&txt,NIL,&rtxt,flags);
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if (dst->data) { /* make sure existing buffer fits */
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while (dsize <= (dst->size + rtxt.size + FUZZ)) {
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dsize += DSIZE; /* kick it up */
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fs_resize ((void **) &dst->data,dsize);
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}
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}
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else { /* make a new buffer */
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while (dsize <= (dst->size + rtxt.size)) dsize += DSIZE;
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memcpy (dst->data = (unsigned char *) fs_get (dsize),src->data,
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dst->size = s - src->data);
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}
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for (i = 0; i < rtxt.size; i++) dst->data[dst->size++] = rtxt.data[i];
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/* all done with converted text */
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if (rtxt.data != txt.data) fs_give ((void **) &rtxt.data);
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if (ls) *ls = '*'; /* restore language tag delimiter */
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*ce = '?'; /* restore charset delimiter */
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/* all done with decoded text */
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fs_give ((void **) &txt.data);
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s = te+1; /* continue scan after encoded word */
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/* skip leading whitespace */
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for (t = s + 1; (t < se) && ((*t == ' ') || (*t == '\t')); t++);
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/* see if likely continuation encoded word */
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if (t < (se - MINENCWORD)) switch (*t) {
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case '=': /* possible encoded word? */
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if (t[1] == '?') s = t - 1;
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break;
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case '\015': /* CR, eat a following LF */
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if (t[1] == '\012') t++;
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case '\012': /* possible end of logical line */
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if ((t[1] == ' ') || (t[1] == '\t')) {
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do t++;
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while ((t < (se - MINENCWORD)) && ((t[1] == ' ')||(t[1] == '\t')));
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if ((t < (se - MINENCWORD)) && (t[1] == '=') && (t[2] == '?'))
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s = t; /* definitely looks like continuation */
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}
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}
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}
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else { /* restore original text */
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if (dst->data) fs_give ((void **) &dst->data);
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dst->data = src->data;
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dst->size = src->size;
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return NIL; /* syntax error: MIME-2 decoding failure */
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}
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}
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else do if (dst->data) { /* stash ASCII characters until LWSP */
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if (dsize < (dst->size + FUZZ)) {
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dsize += DSIZE; /* kick it up */
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fs_resize ((void **) &dst->data,dsize);
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}
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/* kludge: assumes ASCII doesn't decompose and titlecases to one byte */
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dst->data[dst->size++] = (flags & U8T_CASECANON) ?
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(unsigned char) ucs4_titlecase (*s) : *s;
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}
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while ((*s != ' ') && (*s != '\t') && (*s != '\015') && (*s != '\012') &&
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(++s < se));
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}
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if (dst->data) dst->data[dst->size] = '\0';
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else { /* nothing converted, return identity */
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dst->data = src->data;
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dst->size = src->size;
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}
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return T; /* success */
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}
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/* Decode MIME-2 text
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* Accepts: Encoding
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* text
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* text end
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* destination sized text
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* Returns: T if successful, else NIL
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*/
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long mime2_decode (unsigned char *e,unsigned char *t,unsigned char *te,
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SIZEDTEXT *txt)
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{
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unsigned char *q;
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txt->data = NIL; /* initially no returned data */
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switch (*e) { /* dispatch based upon encoding */
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case 'Q': case 'q': /* sort-of QUOTED-PRINTABLE */
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txt->data = (unsigned char *) fs_get ((size_t) (te - t) + 1);
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for (q = t,txt->size = 0; q < te; q++) switch (*q) {
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case '=': /* quoted character */
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/* both must be hex */
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if (!isxdigit (q[1]) || !isxdigit (q[2])) {
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fs_give ((void **) &txt->data);
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return NIL; /* syntax error: bad quoted character */
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}
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/* assemble character */
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txt->data[txt->size++] = hex2byte (q[1],q[2]);
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q += 2; /* advance past quoted character */
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break;
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case '_': /* convert to space */
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txt->data[txt->size++] = ' ';
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break;
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default: /* ordinary character */
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txt->data[txt->size++] = *q;
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break;
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}
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txt->data[txt->size] = '\0';
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break;
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case 'B': case 'b': /* BASE64 */
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if (txt->data = (unsigned char *) rfc822_base64 (t,te - t,&txt->size))
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break;
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default: /* any other encoding is unknown */
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return NIL; /* syntax error: unknown encoding */
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}
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return T;
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}
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/* Get MIME-2 token from encoded word
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* Accepts: current text pointer
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* text limit pointer
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* pointer to returned end pointer
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* Returns: current text pointer & end pointer if success, else NIL
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*/
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unsigned char *mime2_token (unsigned char *s,unsigned char *se,
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unsigned char **t)
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{
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for (*t = s; **t != '?'; ++*t) {
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if ((*t < se) && isgraph (**t)) switch (**t) {
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case '(': case ')': case '<': case '>': case '@': case ',': case ';':
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case ':': case '\\': case '"': case '/': case '[': case ']': case '.':
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case '=':
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return NIL; /* none of these are valid in tokens */
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}
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else return NIL; /* out of text or CTL or space */
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}
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return s;
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}
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/* Get MIME-2 text from encoded word
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* Accepts: current text pointer
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* text limit pointer
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* pointer to returned end pointer
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* Returns: end pointer if success, else NIL
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*/
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unsigned char *mime2_text (unsigned char *s,unsigned char *se)
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{
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unsigned char *t = se - 1;
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/* search for closing ?, make sure valid */
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while ((s < t) && (*s != '?') && isgraph (*s++));
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return ((s < t) && (*s == '?') && (s[1] == '=') &&
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((se == (s + 2)) || (s[2] == ' ') || (s[2] == '\t') ||
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(s[2] == '\015') || (s[2] == '\012'))) ? s : NIL;
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}
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/* Convert UTF-16 string to Modified Base64
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* Accepts: destination pointer
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* source string
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* source length in octets
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* Returns: updated destination pointer
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*/
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static unsigned char *utf16_to_mbase64 (unsigned char *t,unsigned char *s,
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size_t i)
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{
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char *v = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
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*t++ = '&'; /* write shift-in */
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while (i >= 3) { /* process tuplets */
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*t++ = v[s[0] >> 2]; /* byte 1: high 6 bits (1) */
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/* byte 2: low 2 bits (1), high 4 bits (2) */
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*t++ = v[((s[0] << 4) + (s[1] >> 4)) & 0x3f];
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/* byte 3: low 4 bits (2), high 2 bits (3) */
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*t++ = v[((s[1] << 2) + (s[2] >> 6)) & 0x3f];
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*t++ = v[s[2] & 0x3f]; /* byte 4: low 6 bits (3) */
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s += 3;
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i -= 3;
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}
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if (i) {
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*t++ = v[s[0] >> 2]; /* byte 1: high 6 bits (1) */
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/* byte 2: low 2 bits (1), high 4 bits (2) */
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*t++ = v[((s[0] << 4) + (--i ? (s[1] >> 4) : 0)) & 0x3f];
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/* byte 3: low 4 bits (2) */
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if (i) *t++ = v[(s[1] << 2) & 0x3f];
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}
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*t++ = '-'; /* write shift-out */
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return t;
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}
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/* Poot a UTF-16 value to a buffer
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* Accepts: buffer pointer
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* value
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* Returns: updated pointer
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*/
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static unsigned char *utf16_poot (unsigned char *s,unsigned long c)
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{
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*s++ = (unsigned char) (c >> 8);
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*s++ = (unsigned char) (c & 0xff);
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return s;
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}
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/* Convert UTF-8 to Modified UTF-7
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* Accepts: UTF-8 string
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* Returns: Modified UTF-7 string on success, NIL if invalid UTF-8
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*/
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#define MAXUNIUTF8 4 /* maximum length of Unicode UTF-8 sequence */
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unsigned char *utf8_to_mutf7 (unsigned char *src)
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{
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unsigned char *u16buf,*utf16;
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unsigned char *ret,*t;
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unsigned long j,c;
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unsigned char *s = src;
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unsigned long i = 0;
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int nonascii = 0;
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while (*s) { /* pass one: count destination octets */
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if (*s & 0x80) { /* non-ASCII character? */
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j = MAXUNIUTF8; /* get single UCS-4 codepoint */
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if ((c = utf8_get (&s,&j)) & U8G_ERROR) return NIL;
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/* tally number of UTF-16 octets */
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nonascii += (c & U8GM_NONBMP) ? 4 : 2;
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}
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else { /* ASCII character */
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if (nonascii) { /* add pending Modified BASE64 size + shifts */
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i += ((nonascii / 3) * 4) + ((j = nonascii % 3) ? j + 1 : 0) + 2;
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nonascii = 0; /* back to ASCII */
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}
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if (*s == '&') i += 2; /* two octets if the escape */
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else ++i; /* otherwise just count another octet */
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++s; /* advance to next source octet */
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}
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}
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if (nonascii) /* add pending Modified BASE64 size + shifts */
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i += ((nonascii / 3) * 4) + ((j = nonascii % 3) ? j + 1 : 0) + 2;
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/* create return buffer */
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t = ret = (unsigned char *) fs_get (i + 1);
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/* and scratch buffer */
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utf16 = u16buf = (unsigned char *) fs_get (i + 1);
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for (s = src; *s;) { /* pass two: copy destination octets */
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if (*s & 0x80) { /* non-ASCII character? */
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j = MAXUNIUTF8; /* get single UCS-4 codepoint */
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if ((c = utf8_get (&s,&j)) & U8G_ERROR) return NIL;
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if (c & U8GM_NONBMP) { /* non-BMP? */
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c -= UTF16_BASE; /* yes, convert to surrogate */
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utf16 = utf16_poot (utf16_poot (utf16,(c >> UTF16_SHIFT)+UTF16_SURRH),
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(c & UTF16_MASK) + UTF16_SURRL);
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}
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else utf16 = utf16_poot (utf16,c);
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}
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else { /* ASCII character */
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if (utf16 != u16buf) { /* add pending Modified BASE64 size + shifts */
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t = utf16_to_mbase64 (t,u16buf,utf16 - u16buf);
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utf16 = u16buf; /* reset buffer */
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}
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*t++ = *s; /* copy the character */
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if (*s == '&') *t++ = '-';/* special sequence if the escape */
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++s; /* advance to next source octet */
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}
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}
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/* add pending Modified BASE64 size + shifts */
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if (utf16 != u16buf) t = utf16_to_mbase64 (t,u16buf,utf16 - u16buf);
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*t = '\0'; /* tie off destination */
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if (i != (t - ret)) fatal ("utf8_to_mutf7 botch");
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fs_give ((void **) &u16buf);
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return ret;
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}
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/* Convert Modified UTF-7 to UTF-8
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* Accepts: Modified UTF-7 string
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* Returns: UTF-8 string on success, NIL if invalid Modified UTF-7
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*/
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unsigned char *utf8_from_mutf7 (unsigned char *src)
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{
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SIZEDTEXT utf8,utf7;
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unsigned char *s;
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int mbase64 = 0;
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/* disallow bogus strings */
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if (mail_utf7_valid (src)) return NIL;
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/* initialize SIZEDTEXTs */
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memset (&utf7,0,sizeof (SIZEDTEXT));
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memset (&utf8,0,sizeof (SIZEDTEXT));
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/* make copy of source */
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for (s = cpytxt (&utf7,src,strlen (src)); *s; ++s) switch (*s) {
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case '&': /* Modified UTF-7 uses & instead of + */
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*s = '+';
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mbase64 = T; /* note that we are in Modified BASE64 */
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break;
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case '+': /* temporarily swap text + to & */
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if (!mbase64) *s = '&';
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break;
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case '-': /* shift back to ASCII */
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mbase64 = NIL;
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break;
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case ',': /* Modified UTF-7 uses , instead of / ... */
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if (mbase64) *s = '/'; /* ...in Modified BASE64 */
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break;
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}
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/* do the conversion */
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utf8_text_utf7 (&utf7,&utf8,NIL,NIL);
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/* no longer need copy of source */
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fs_give ((void **) &utf7.data);
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/* post-process: switch & and + */
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for (s = utf8.data; *s; ++s) switch (*s) {
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case '&':
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*s = '+';
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break;
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case '+':
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*s = '&';
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break;
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}
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return utf8.data;
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}
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