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

   1 #include "stralloc.h"
   2 #include "strerr.h"
   3 #include "uint32.h"
   4 #include "errtxt.h"
   5
   6         /* Characters and translation as per rfc2047. */
   7 static char char64table[128] = {
   8     -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
   9     -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
  10     -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,62, -1,-1,-1,63,
  11     52,53,54,55, 56,57,58,59, 60,61,-1,-1, -1,-1,-1,-1,
  12     -1, 0, 1, 2,  3, 4, 5, 6,  7, 8, 9,10, 11,12,13,14,
  13     15,16,17,18, 19,20,21,22, 23,24,25,-1, -1,-1,-1,-1,
  14     -1,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
  15     41,42,43,44, 45,46,47,48, 49,50,51,-1, -1,-1,-1,-1
  16 };
  17
  18 #define char64enc(c)  (((c) & 0x80) ? -1 : char64table[(c)])
  19
  20 static void die_nomem(fatal)
  21   char *fatal;
  22 {
  23   strerr_die2x(111,fatal,ERR_NOMEM);
  24 }
  25
  26 void decodeB(cpfrom,n,outdata,fatal)
  27 char *cpfrom;
  28 unsigned int n;
  29 stralloc *outdata;
  30 char *fatal;
  31 /* does B decoding of the string pointed to by cpfrom up to the character */
  32 /* before the one pointed to by cpnext, and appends the results to mimeline*/
  33 {
  34   uint32 hold32;
  35   char holdch[4] = "???";
  36   int i,j;
  37   char c;       /* needs to be signed */
  38   char *cp, *cpnext;
  39
  40   cp = cpfrom;
  41   cpnext = cp + n;
  42   i = 0;
  43   hold32 = 0L;
  44   if (!stralloc_readyplus(outdata,n)) die_nomem(fatal);
  45   for (;;) {
  46     if (i == 4) {
  47       for (j = 2; j >= 0; --j) {
  48         holdch[j] = hold32 & 0xff;
  49         hold32 = hold32 >> 8;
  50       }
  51       if (!stralloc_cats(outdata,holdch)) die_nomem(fatal);
  52       if (cp >= cpnext)
  53         break;
  54       hold32 = 0L;
  55       i = 0;
  56     }
  57     if (cp >= cpnext) { /* pad */
  58       c = 0;
  59     } else {
  60       c = char64enc(*cp);
  61       ++cp;
  62     }
  63     if (c < 0)          /* ignore illegal characters */
  64       continue;
  65     else {
  66       hold32 = (hold32 << 6) | (c & 0x7f);
  67       ++i;
  68     }
  69   }
  70 }
  71