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/* MODULE HTUU.c
** UUENCODE AND UUDECODE
**
** ACKNOWLEDGEMENT:
** This code is taken from rpem distribution, and was originally
** written by Mark Riordan.
**
** AUTHORS:
** MR Mark Riordan riordanmr@clvax1.cl.msu.edu
** AL Ari Luotonen luotonen@dxcern.cern.ch
**
** HISTORY:
** Added as part of the WWW library and edited to conform
** with the WWW project coding standards by: AL 5 Aug 1993
** Originally written by: MR 12 Aug 1990
** Original header text:
** -------------------------------------------------------------
** File containing routines to convert a buffer
** of bytes to/from RFC 1113 printable encoding format.
**
** This technique is similar to the familiar Unix uuencode
** format in that it maps 6 binary bits to one ASCII
** character (or more aptly, 3 binary bytes to 4 ASCII
** characters). However, RFC 1113 does not use the same
** mapping to printable characters as uuencode.
**
** Mark Riordan 12 August 1990 and 17 Feb 1991.
** This code is hereby placed in the public domain.
** -------------------------------------------------------------
**
** BUGS:
**
**
*/
#include "HTUtils.h"
#include "HTUU.h"
PRIVATE char six2pr[64] = {
'A','B','C','D','E','F','G','H','I','J','K','L','M',
'N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
'a','b','c','d','e','f','g','h','i','j','k','l','m',
'n','o','p','q','r','s','t','u','v','w','x','y','z',
'0','1','2','3','4','5','6','7','8','9','+','/'
};
PRIVATE unsigned char pr2six[256];
/*--- function HTUU_encode -----------------------------------------------
*
* Encode a single line of binary data to a standard format that
* uses only printing ASCII characters (but takes up 33% more bytes).
*
* Entry bufin points to a buffer of bytes. If nbytes is not
* a multiple of three, then the byte just beyond
* the last byte in the buffer must be 0.
* nbytes is the number of bytes in that buffer.
* This cannot be more than 48.
* bufcoded points to an output buffer. Be sure that this
* can hold at least 1 + (4*nbytes)/3 characters.
*
* Exit bufcoded contains the coded line. The first 4*nbytes/3 bytes
* contain printing ASCII characters representing
* those binary bytes. This may include one or
* two '=' characters used as padding at the end.
* The last byte is a zero byte.
* Returns the number of ASCII characters in "bufcoded".
*/
PUBLIC int HTUU_encode ARGS3(unsigned char *, bufin,
unsigned int, nbytes,
char *, bufcoded)
{
/* ENC is the basic 1 character encoding function to make a char printing */
#define ENC(c) six2pr[c]
register char *outptr = bufcoded;
unsigned int i;
for (i=0; i<nbytes; i += 3) {
*(outptr++) = ENC(*bufin >> 2); /* c1 */
*(outptr++) = ENC(((*bufin << 4) & 060) | ((bufin[1] >> 4) & 017)); /*c2*/
*(outptr++) = ENC(((bufin[1] << 2) & 074) | ((bufin[2] >> 6) & 03));/*c3*/
*(outptr++) = ENC(bufin[2] & 077); /* c4 */
bufin += 3;
}
/* If nbytes was not a multiple of 3, then we have encoded too
* many characters. Adjust appropriately.
*/
if(i == nbytes+1) {
/* There were only 2 bytes in that last group */
outptr[-1] = '=';
} else if(i == nbytes+2) {
/* There was only 1 byte in that last group */
outptr[-1] = '=';
outptr[-2] = '=';
}
*outptr = '\0';
return(outptr - bufcoded);
}
/*--- function HTUU_decode ------------------------------------------------
*
* Decode an ASCII-encoded buffer back to its original binary form.
*
* Entry bufcoded points to a uuencoded string. It is
* terminated by any character not in
* the printable character table six2pr, but
* leading whitespace is stripped.
* bufplain points to the output buffer; must be big
* enough to hold the decoded string (generally
* shorter than the encoded string) plus
* as many as two extra bytes used during
* the decoding process.
* outbufsize is the maximum number of bytes that
* can fit in bufplain.
*
* Exit Returns the number of binary bytes decoded.
* bufplain contains these bytes.
*/
PUBLIC int HTUU_decode ARGS3(char *, bufcoded,
unsigned char *, bufplain,
int, outbufsize)
{
/* single character decode */
#define DEC(c) pr2six[(int)c]
#define MAXVAL 63
static int first = 1;
int nbytesdecoded, j;
register char *bufin = bufcoded;
register unsigned char *bufout = bufplain;
register int nprbytes;
/* If this is the first call, initialize the mapping table.
* This code should work even on non-ASCII machines.
*/
if(first) {
first = 0;
for(j=0; j<256; j++) pr2six[j] = MAXVAL+1;
for(j=0; j<64; j++) pr2six[(int)six2pr[j]] = (unsigned char) j;
#if 0
pr2six['A']= 0; pr2six['B']= 1; pr2six['C']= 2; pr2six['D']= 3;
pr2six['E']= 4; pr2six['F']= 5; pr2six['G']= 6; pr2six['H']= 7;
pr2six['I']= 8; pr2six['J']= 9; pr2six['K']=10; pr2six['L']=11;
pr2six['M']=12; pr2six['N']=13; pr2six['O']=14; pr2six['P']=15;
pr2six['Q']=16; pr2six['R']=17; pr2six['S']=18; pr2six['T']=19;
pr2six['U']=20; pr2six['V']=21; pr2six['W']=22; pr2six['X']=23;
pr2six['Y']=24; pr2six['Z']=25; pr2six['a']=26; pr2six['b']=27;
pr2six['c']=28; pr2six['d']=29; pr2six['e']=30; pr2six['f']=31;
pr2six['g']=32; pr2six['h']=33; pr2six['i']=34; pr2six['j']=35;
pr2six['k']=36; pr2six['l']=37; pr2six['m']=38; pr2six['n']=39;
pr2six['o']=40; pr2six['p']=41; pr2six['q']=42; pr2six['r']=43;
pr2six['s']=44; pr2six['t']=45; pr2six['u']=46; pr2six['v']=47;
pr2six['w']=48; pr2six['x']=49; pr2six['y']=50; pr2six['z']=51;
pr2six['0']=52; pr2six['1']=53; pr2six['2']=54; pr2six['3']=55;
pr2six['4']=56; pr2six['5']=57; pr2six['6']=58; pr2six['7']=59;
pr2six['8']=60; pr2six['9']=61; pr2six['+']=62; pr2six['/']=63;
#endif
}
/* Strip leading whitespace. */
while(*bufcoded==' ' || *bufcoded == '\t') bufcoded++;
/* Figure out how many characters are in the input buffer.
* If this would decode into more bytes than would fit into
* the output buffer, adjust the number of input bytes downwards.
*/
bufin = bufcoded;
while(pr2six[(int)*(bufin++)] <= MAXVAL);
nprbytes = bufin - bufcoded - 1;
nbytesdecoded = ((nprbytes+3)/4) * 3;
if(nbytesdecoded > outbufsize) {
nprbytes = (outbufsize*4)/3;
}
bufin = bufcoded;
while (nprbytes > 0) {
*(bufout++) = (unsigned char) (DEC(*bufin) << 2 | DEC(bufin[1]) >> 4);
*(bufout++) = (unsigned char) (DEC(bufin[1]) << 4 | DEC(bufin[2]) >> 2);
*(bufout++) = (unsigned char) (DEC(bufin[2]) << 6 | DEC(bufin[3]));
bufin += 4;
nprbytes -= 4;
}
if(nprbytes & 03) {
if(pr2six[(int)bufin[-2]] > MAXVAL) {
nbytesdecoded -= 2;
} else {
nbytesdecoded -= 1;
}
}
return(nbytesdecoded);
}
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