Annotation of libwww/Library/src/HTUU.c, revision 2.12
2.6 frystyk 1: /* HTUU.c
2: ** UUENCODE AND UUDECODE
3: **
2.9 frystyk 4: ** (c) COPYRIGHT MIT 1995.
2.6 frystyk 5: ** Please first read the full copyright statement in the file COPYRIGH.
2.12 ! frystyk 6: ** @(#) $Id: Date Author State $
2.1 luotonen 7: **
8: ** ACKNOWLEDGEMENT:
9: ** This code is taken from rpem distribution, and was originally
10: ** written by Mark Riordan.
11: **
12: ** AUTHORS:
13: ** MR Mark Riordan riordanmr@clvax1.cl.msu.edu
14: ** AL Ari Luotonen luotonen@dxcern.cern.ch
15: **
16: ** HISTORY:
17: ** Added as part of the WWW library and edited to conform
18: ** with the WWW project coding standards by: AL 5 Aug 1993
19: ** Originally written by: MR 12 Aug 1990
20: ** Original header text:
21: ** -------------------------------------------------------------
22: ** File containing routines to convert a buffer
23: ** of bytes to/from RFC 1113 printable encoding format.
24: **
25: ** This technique is similar to the familiar Unix uuencode
26: ** format in that it maps 6 binary bits to one ASCII
27: ** character (or more aptly, 3 binary bytes to 4 ASCII
28: ** characters). However, RFC 1113 does not use the same
29: ** mapping to printable characters as uuencode.
30: **
31: ** Mark Riordan 12 August 1990 and 17 Feb 1991.
32: ** This code is hereby placed in the public domain.
33: ** -------------------------------------------------------------
34: **
35: ** BUGS:
36: **
37: **
38: */
39:
2.8 frystyk 40: /* Library include files */
2.11 frystyk 41: #include "sysdep.h"
2.1 luotonen 42: #include "HTUtils.h"
43: #include "HTUU.h"
44:
45:
46: PRIVATE char six2pr[64] = {
47: 'A','B','C','D','E','F','G','H','I','J','K','L','M',
48: 'N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
49: 'a','b','c','d','e','f','g','h','i','j','k','l','m',
50: 'n','o','p','q','r','s','t','u','v','w','x','y','z',
51: '0','1','2','3','4','5','6','7','8','9','+','/'
52: };
53:
54: PRIVATE unsigned char pr2six[256];
55:
56:
57: /*--- function HTUU_encode -----------------------------------------------
58: *
59: * Encode a single line of binary data to a standard format that
60: * uses only printing ASCII characters (but takes up 33% more bytes).
61: *
62: * Entry bufin points to a buffer of bytes. If nbytes is not
63: * a multiple of three, then the byte just beyond
64: * the last byte in the buffer must be 0.
65: * nbytes is the number of bytes in that buffer.
66: * This cannot be more than 48.
67: * bufcoded points to an output buffer. Be sure that this
68: * can hold at least 1 + (4*nbytes)/3 characters.
69: *
70: * Exit bufcoded contains the coded line. The first 4*nbytes/3 bytes
71: * contain printing ASCII characters representing
72: * those binary bytes. This may include one or
73: * two '=' characters used as padding at the end.
74: * The last byte is a zero byte.
75: * Returns the number of ASCII characters in "bufcoded".
76: */
2.10 frystyk 77: PUBLIC int HTUU_encode (unsigned char * bufin,
78: unsigned int nbytes,
79: char * bufcoded)
2.1 luotonen 80: {
81: /* ENC is the basic 1 character encoding function to make a char printing */
82: #define ENC(c) six2pr[c]
83:
84: register char *outptr = bufcoded;
85: unsigned int i;
2.4 luotonen 86:
2.1 luotonen 87: for (i=0; i<nbytes; i += 3) {
88: *(outptr++) = ENC(*bufin >> 2); /* c1 */
2.2 luotonen 89: *(outptr++) = ENC(((*bufin << 4) & 060) | ((bufin[1] >> 4) & 017)); /*c2*/
90: *(outptr++) = ENC(((bufin[1] << 2) & 074) | ((bufin[2] >> 6) & 03));/*c3*/
2.1 luotonen 91: *(outptr++) = ENC(bufin[2] & 077); /* c4 */
92:
93: bufin += 3;
94: }
95:
96: /* If nbytes was not a multiple of 3, then we have encoded too
97: * many characters. Adjust appropriately.
98: */
99: if(i == nbytes+1) {
100: /* There were only 2 bytes in that last group */
101: outptr[-1] = '=';
102: } else if(i == nbytes+2) {
103: /* There was only 1 byte in that last group */
104: outptr[-1] = '=';
105: outptr[-2] = '=';
106: }
107: *outptr = '\0';
108: return(outptr - bufcoded);
109: }
110:
111:
112: /*--- function HTUU_decode ------------------------------------------------
113: *
114: * Decode an ASCII-encoded buffer back to its original binary form.
115: *
116: * Entry bufcoded points to a uuencoded string. It is
117: * terminated by any character not in
118: * the printable character table six2pr, but
119: * leading whitespace is stripped.
120: * bufplain points to the output buffer; must be big
121: * enough to hold the decoded string (generally
122: * shorter than the encoded string) plus
123: * as many as two extra bytes used during
124: * the decoding process.
125: * outbufsize is the maximum number of bytes that
126: * can fit in bufplain.
127: *
128: * Exit Returns the number of binary bytes decoded.
129: * bufplain contains these bytes.
130: */
2.10 frystyk 131: PUBLIC int HTUU_decode (char * bufcoded,
132: unsigned char * bufplain,
133: int outbufsize)
2.1 luotonen 134: {
135: /* single character decode */
2.3 luotonen 136: #define DEC(c) pr2six[(int)c]
2.1 luotonen 137: #define MAXVAL 63
138:
139: static int first = 1;
140:
141: int nbytesdecoded, j;
142: register char *bufin = bufcoded;
143: register unsigned char *bufout = bufplain;
144: register int nprbytes;
145:
146: /* If this is the first call, initialize the mapping table.
147: * This code should work even on non-ASCII machines.
148: */
149: if(first) {
150: first = 0;
151: for(j=0; j<256; j++) pr2six[j] = MAXVAL+1;
152:
2.3 luotonen 153: for(j=0; j<64; j++) pr2six[(int)six2pr[j]] = (unsigned char) j;
2.1 luotonen 154: #if 0
155: pr2six['A']= 0; pr2six['B']= 1; pr2six['C']= 2; pr2six['D']= 3;
156: pr2six['E']= 4; pr2six['F']= 5; pr2six['G']= 6; pr2six['H']= 7;
157: pr2six['I']= 8; pr2six['J']= 9; pr2six['K']=10; pr2six['L']=11;
158: pr2six['M']=12; pr2six['N']=13; pr2six['O']=14; pr2six['P']=15;
159: pr2six['Q']=16; pr2six['R']=17; pr2six['S']=18; pr2six['T']=19;
160: pr2six['U']=20; pr2six['V']=21; pr2six['W']=22; pr2six['X']=23;
161: pr2six['Y']=24; pr2six['Z']=25; pr2six['a']=26; pr2six['b']=27;
162: pr2six['c']=28; pr2six['d']=29; pr2six['e']=30; pr2six['f']=31;
163: pr2six['g']=32; pr2six['h']=33; pr2six['i']=34; pr2six['j']=35;
164: pr2six['k']=36; pr2six['l']=37; pr2six['m']=38; pr2six['n']=39;
165: pr2six['o']=40; pr2six['p']=41; pr2six['q']=42; pr2six['r']=43;
166: pr2six['s']=44; pr2six['t']=45; pr2six['u']=46; pr2six['v']=47;
167: pr2six['w']=48; pr2six['x']=49; pr2six['y']=50; pr2six['z']=51;
168: pr2six['0']=52; pr2six['1']=53; pr2six['2']=54; pr2six['3']=55;
169: pr2six['4']=56; pr2six['5']=57; pr2six['6']=58; pr2six['7']=59;
170: pr2six['8']=60; pr2six['9']=61; pr2six['+']=62; pr2six['/']=63;
171: #endif
172: }
173:
174: /* Strip leading whitespace. */
175:
176: while(*bufcoded==' ' || *bufcoded == '\t') bufcoded++;
177:
178: /* Figure out how many characters are in the input buffer.
179: * If this would decode into more bytes than would fit into
180: * the output buffer, adjust the number of input bytes downwards.
181: */
182: bufin = bufcoded;
2.3 luotonen 183: while(pr2six[(int)*(bufin++)] <= MAXVAL);
2.1 luotonen 184: nprbytes = bufin - bufcoded - 1;
185: nbytesdecoded = ((nprbytes+3)/4) * 3;
186: if(nbytesdecoded > outbufsize) {
187: nprbytes = (outbufsize*4)/3;
188: }
189:
190: bufin = bufcoded;
191:
192: while (nprbytes > 0) {
193: *(bufout++) = (unsigned char) (DEC(*bufin) << 2 | DEC(bufin[1]) >> 4);
194: *(bufout++) = (unsigned char) (DEC(bufin[1]) << 4 | DEC(bufin[2]) >> 2);
195: *(bufout++) = (unsigned char) (DEC(bufin[2]) << 6 | DEC(bufin[3]));
196: bufin += 4;
197: nprbytes -= 4;
198: }
199:
200: if(nprbytes & 03) {
2.3 luotonen 201: if(pr2six[(int)bufin[-2]] > MAXVAL) {
2.1 luotonen 202: nbytesdecoded -= 2;
203: } else {
204: nbytesdecoded -= 1;
205: }
206: }
207:
208: return(nbytesdecoded);
209: }
210:
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