/*
* $LynxId: HTUU.c,v 1.11 2010/09/21 23:55:12 tom Exp $
*
* 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.
* -------------------------------------------------------------
*/
#include <HTUtils.h>
#include <HTUU.h>
#include <LYLeaks.h>
static 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', '+', '/'
};
static 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".
*/
int HTUU_encode(unsigned char *bufin,
size_t 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;
size_t i;
/* This doesn't seem to be needed (AL): register unsigned char *inptr = bufin; */
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 (int) (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.
*/
int HTUU_decode(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;
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[UCH(six2pr[j])] = UCH(j);
#if 0
/* *INDENT-OFF* */
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;
/* *INDENT-ON* */
#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[UCH(*(bufin++))] <= MAXVAL) ;
nprbytes = (int) (bufin - bufcoded - 1);
nbytesdecoded = ((nprbytes + 3) / 4) * 3;
if (nbytesdecoded > outbufsize) {
nprbytes = (outbufsize * 4) / 3;
}
bufin = bufcoded;
while (nprbytes > 0) {
*(bufout++) = UCH((DEC(bufin[0]) << 2) | (DEC(bufin[1]) >> 4));
*(bufout++) = UCH((DEC(bufin[1]) << 4) | (DEC(bufin[2]) >> 2));
*(bufout++) = UCH((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);
}