lib/uudecode.c

   1 /*
   2  * Copyright (C) 1996-2017 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #include "squid.h"
  10 #include "uudecode.h"
  11
  12 /* aaaack but it's fast and const should make it shared text page. */
  13 const int pr2six[256] = {
  14     64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
  15     64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
  16     52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64, 64, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
  17     10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 64, 64, 64, 64, 64, 64, 26, 27,
  18     28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,
  19     64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
  20     64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
  21     64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
  22     64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
  23     64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
  24     64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
  25 };
  26
  27 char *
  28 uudecode(const char *bufcoded)
  29 {
  30     int nbytesdecoded;
  31     const unsigned char *bufin;
  32     char *bufplain;
  33     unsigned char *bufout;
  34     int nprbytes;
  35
  36     /* Strip leading whitespace. */
  37
  38     while (*bufcoded == ' ' || *bufcoded == '\t')
  39         bufcoded++;
  40
  41     /* Figure out how many characters are in the input buffer.
  42      * Allocate this many from the per-transaction pool for the result.
  43      */
  44     bufin = (const unsigned char *) bufcoded;
  45     while (pr2six[*(bufin++)] <= 63);
  46     nprbytes = (const char *) bufin - bufcoded - 1;
  47     nbytesdecoded = ((nprbytes + 3) / 4) * 3;
  48
  49     bufplain = xmalloc(nbytesdecoded + 1);
  50     bufout = (unsigned char *) bufplain;
  51     bufin = (const unsigned char *) bufcoded;
  52
  53     while (nprbytes > 0) {
  54         *(bufout++) =
  55             (unsigned char) (pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
  56         *(bufout++) =
  57             (unsigned char) (pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
  58         *(bufout++) =
  59             (unsigned char) (pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
  60         bufin += 4;
  61         nprbytes -= 4;
  62     }
  63
  64     if (nprbytes & 03) {
  65         if (pr2six[bufin[-2]] > 63)
  66             nbytesdecoded -= 2;
  67         else
  68             nbytesdecoded -= 1;
  69     }
  70     bufplain[nbytesdecoded] = '\0';
  71     return bufplain;
  72 }
  73