mdw@git.distorted.org.uk Git - ezmlm/blob - decodeQ.c

   1 /*$Id: decodeQ.c,v 1.3 1998/10/29 21:48:24 lindberg Exp $*/
   2 /*$Name: ezmlm-idx-040 $*/
   3
   4 #include "stralloc.h"
   5 #include "strerr.h"
   6 #include "errtxt.h"
   7 #include "mime.h"
   8
   9 /* takes a string pointed to by cpfrom and adds the next 'n' bytes to        */
  10 /* outdata, replacing any Quoted-Printable codes with the real characters.   */
  11 /* NUL and LF in the input are allowed, but anything that decodes to these   */
  12 /* values is ignored. */
  13
  14 static char char16table[128] = {
  15     -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
  16     -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
  17     -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
  18      0, 1, 2, 3,  4, 5, 6, 7,  8, 9,-1,-1, -1,-1,-1,-1,
  19     -1,10,11,12, 13,14,15,-1, -1,-1,-1,-1, -1,-1,-1,-1,
  20     -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
  21     -1,10,11,12, 13,14,15,-1, -1,-1,-1,-1, -1,-1,-1,-1,
  22     -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1
  23 };
  24
  25 #define char16enc(c)  (((c) & 0x80) ? -1 : char16table[(c)])
  26
  27 static void die_nomem(fatal)
  28   char *fatal;
  29 {
  30   strerr_die2x(111,fatal,ERR_NOMEM);
  31 }
  32
  33 void decodeQ(cpfrom,n,outdata,fatal)
  34 char *cpfrom;
  35 unsigned int n;
  36 stralloc *outdata;
  37 char *fatal;
  38 /* does Q decoding of the string pointed to by cpfrom up to the character */
  39 /* before the one pointed to by cpnext, and appends the results to mimeline*/
  40 {
  41   char *cp,*cpnext,*cpmore;
  42   char holdch[2];
  43   char ch1,ch2;         /* need to be signed */
  44
  45   cpmore = cpfrom;
  46   cp = cpfrom;
  47   cpnext = cp + n;
  48   if (!stralloc_readyplus(outdata,n)) die_nomem(fatal);
  49
  50   while (cp < cpnext) {
  51     if (*cp == '_') *cp = ' ';          /* '_' -> space */
  52     else if (*cp == '=') {              /* "=F8" -> '\xF8' */
  53                                         /* copy stuff before */
  54       if (!stralloc_catb(outdata,cpmore,cp-cpmore)) die_nomem(fatal);
  55       cpmore = cp;
  56       ++cp;
  57       if (*cp == '\n') {                /* skip soft line break */
  58         ++cp;
  59         cpmore = cp;
  60         continue;
  61       }
  62       ch1 = char16enc(*cp);
  63       if (++cp >= cpnext)
  64         break;
  65       ch2 = char16enc(*cp);
  66       if (ch1 >= 0 && ch2 >= 0) {       /* ignore illegals */
  67         holdch[0] = (ch1 << 4 | ch2) & 0xff;
  68         if (!stralloc_catb(outdata,holdch,1)) die_nomem(fatal);
  69         cpmore += 3;
  70       }
  71     }
  72     ++cp;
  73   }                                     /* copy stuff after */
  74   if (!stralloc_catb(outdata,cpmore,cpnext-cpmore)) die_nomem(fatal);
  75 }
  76
  77