Annotation of libwww/Library/src/HTUU.c, revision 2.2
2.1 luotonen 1:
2: /* MODULE HTUU.c
3: ** UUENCODE AND UUDECODE
4: **
5: ** ACKNOWLEDGEMENT:
6: ** This code is taken from rpem distribution, and was originally
7: ** written by Mark Riordan.
8: **
9: ** AUTHORS:
10: ** MR Mark Riordan riordanmr@clvax1.cl.msu.edu
11: ** AL Ari Luotonen luotonen@dxcern.cern.ch
12: **
13: ** HISTORY:
14: ** Added as part of the WWW library and edited to conform
15: ** with the WWW project coding standards by: AL 5 Aug 1993
16: ** Originally written by: MR 12 Aug 1990
17: ** Original header text:
18: ** -------------------------------------------------------------
19: ** File containing routines to convert a buffer
20: ** of bytes to/from RFC 1113 printable encoding format.
21: **
22: ** This technique is similar to the familiar Unix uuencode
23: ** format in that it maps 6 binary bits to one ASCII
24: ** character (or more aptly, 3 binary bytes to 4 ASCII
25: ** characters). However, RFC 1113 does not use the same
26: ** mapping to printable characters as uuencode.
27: **
28: ** Mark Riordan 12 August 1990 and 17 Feb 1991.
29: ** This code is hereby placed in the public domain.
30: ** -------------------------------------------------------------
31: **
32: ** BUGS:
33: **
34: **
35: */
36:
37: #include "HTUtils.h"
38: #include "HTUU.h"
39:
40:
41: PRIVATE char six2pr[64] = {
42: 'A','B','C','D','E','F','G','H','I','J','K','L','M',
43: 'N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
44: 'a','b','c','d','e','f','g','h','i','j','k','l','m',
45: 'n','o','p','q','r','s','t','u','v','w','x','y','z',
46: '0','1','2','3','4','5','6','7','8','9','+','/'
47: };
48:
49: PRIVATE unsigned char pr2six[256];
50:
51:
52: /*--- function HTUU_encode -----------------------------------------------
53: *
54: * Encode a single line of binary data to a standard format that
55: * uses only printing ASCII characters (but takes up 33% more bytes).
56: *
57: * Entry bufin points to a buffer of bytes. If nbytes is not
58: * a multiple of three, then the byte just beyond
59: * the last byte in the buffer must be 0.
60: * nbytes is the number of bytes in that buffer.
61: * This cannot be more than 48.
62: * bufcoded points to an output buffer. Be sure that this
63: * can hold at least 1 + (4*nbytes)/3 characters.
64: *
65: * Exit bufcoded contains the coded line. The first 4*nbytes/3 bytes
66: * contain printing ASCII characters representing
67: * those binary bytes. This may include one or
68: * two '=' characters used as padding at the end.
69: * The last byte is a zero byte.
70: * Returns the number of ASCII characters in "bufcoded".
71: */
72: PUBLIC int HTUU_encode ARGS3(unsigned char *, bufin,
73: unsigned int, nbytes,
74: char *, bufcoded)
75: {
76: /* ENC is the basic 1 character encoding function to make a char printing */
77: #define ENC(c) six2pr[c]
78:
79: register char *outptr = bufcoded;
80: unsigned int i;
81: /* This doesn't seem to be needed (AL): register unsigned char *inptr = bufin; */
82:
83: for (i=0; i<nbytes; i += 3) {
84: *(outptr++) = ENC(*bufin >> 2); /* c1 */
2.2 ! luotonen 85: *(outptr++) = ENC(((*bufin << 4) & 060) | ((bufin[1] >> 4) & 017)); /*c2*/
! 86: *(outptr++) = ENC(((bufin[1] << 2) & 074) | ((bufin[2] >> 6) & 03));/*c3*/
2.1 luotonen 87: *(outptr++) = ENC(bufin[2] & 077); /* c4 */
88:
89: bufin += 3;
90: }
91:
92: /* If nbytes was not a multiple of 3, then we have encoded too
93: * many characters. Adjust appropriately.
94: */
95: if(i == nbytes+1) {
96: /* There were only 2 bytes in that last group */
97: outptr[-1] = '=';
98: } else if(i == nbytes+2) {
99: /* There was only 1 byte in that last group */
100: outptr[-1] = '=';
101: outptr[-2] = '=';
102: }
103: *outptr = '\0';
104: return(outptr - bufcoded);
105: }
106:
107:
108: /*--- function HTUU_decode ------------------------------------------------
109: *
110: * Decode an ASCII-encoded buffer back to its original binary form.
111: *
112: * Entry bufcoded points to a uuencoded string. It is
113: * terminated by any character not in
114: * the printable character table six2pr, but
115: * leading whitespace is stripped.
116: * bufplain points to the output buffer; must be big
117: * enough to hold the decoded string (generally
118: * shorter than the encoded string) plus
119: * as many as two extra bytes used during
120: * the decoding process.
121: * outbufsize is the maximum number of bytes that
122: * can fit in bufplain.
123: *
124: * Exit Returns the number of binary bytes decoded.
125: * bufplain contains these bytes.
126: */
127: PUBLIC int HTUU_decode ARGS3(char *, bufcoded,
128: unsigned char *, bufplain,
129: int, outbufsize)
130: {
131: /* single character decode */
132: #define DEC(c) pr2six[c]
133: #define MAXVAL 63
134:
135: static int first = 1;
136:
137: int nbytesdecoded, j;
138: register char *bufin = bufcoded;
139: register unsigned char *bufout = bufplain;
140: register int nprbytes;
141:
142: /* If this is the first call, initialize the mapping table.
143: * This code should work even on non-ASCII machines.
144: */
145: if(first) {
146: first = 0;
147: for(j=0; j<256; j++) pr2six[j] = MAXVAL+1;
148:
149: for(j=0; j<64; j++) pr2six[six2pr[j]] = (unsigned char) j;
150: #if 0
151: pr2six['A']= 0; pr2six['B']= 1; pr2six['C']= 2; pr2six['D']= 3;
152: pr2six['E']= 4; pr2six['F']= 5; pr2six['G']= 6; pr2six['H']= 7;
153: pr2six['I']= 8; pr2six['J']= 9; pr2six['K']=10; pr2six['L']=11;
154: pr2six['M']=12; pr2six['N']=13; pr2six['O']=14; pr2six['P']=15;
155: pr2six['Q']=16; pr2six['R']=17; pr2six['S']=18; pr2six['T']=19;
156: pr2six['U']=20; pr2six['V']=21; pr2six['W']=22; pr2six['X']=23;
157: pr2six['Y']=24; pr2six['Z']=25; pr2six['a']=26; pr2six['b']=27;
158: pr2six['c']=28; pr2six['d']=29; pr2six['e']=30; pr2six['f']=31;
159: pr2six['g']=32; pr2six['h']=33; pr2six['i']=34; pr2six['j']=35;
160: pr2six['k']=36; pr2six['l']=37; pr2six['m']=38; pr2six['n']=39;
161: pr2six['o']=40; pr2six['p']=41; pr2six['q']=42; pr2six['r']=43;
162: pr2six['s']=44; pr2six['t']=45; pr2six['u']=46; pr2six['v']=47;
163: pr2six['w']=48; pr2six['x']=49; pr2six['y']=50; pr2six['z']=51;
164: pr2six['0']=52; pr2six['1']=53; pr2six['2']=54; pr2six['3']=55;
165: pr2six['4']=56; pr2six['5']=57; pr2six['6']=58; pr2six['7']=59;
166: pr2six['8']=60; pr2six['9']=61; pr2six['+']=62; pr2six['/']=63;
167: #endif
168: }
169:
170: /* Strip leading whitespace. */
171:
172: while(*bufcoded==' ' || *bufcoded == '\t') bufcoded++;
173:
174: /* Figure out how many characters are in the input buffer.
175: * If this would decode into more bytes than would fit into
176: * the output buffer, adjust the number of input bytes downwards.
177: */
178: bufin = bufcoded;
179: while(pr2six[*(bufin++)] <= MAXVAL);
180: nprbytes = bufin - bufcoded - 1;
181: nbytesdecoded = ((nprbytes+3)/4) * 3;
182: if(nbytesdecoded > outbufsize) {
183: nprbytes = (outbufsize*4)/3;
184: }
185:
186: bufin = bufcoded;
187:
188: while (nprbytes > 0) {
189: *(bufout++) = (unsigned char) (DEC(*bufin) << 2 | DEC(bufin[1]) >> 4);
190: *(bufout++) = (unsigned char) (DEC(bufin[1]) << 4 | DEC(bufin[2]) >> 2);
191: *(bufout++) = (unsigned char) (DEC(bufin[2]) << 6 | DEC(bufin[3]));
192: bufin += 4;
193: nprbytes -= 4;
194: }
195:
196: if(nprbytes & 03) {
197: if(pr2six[bufin[-2]] > MAXVAL) {
198: nbytesdecoded -= 2;
199: } else {
200: nbytesdecoded -= 1;
201: }
202: }
203:
204: return(nbytesdecoded);
205: }
206:
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