1/*++
2/* NAME
3/*	xtext 3
4/* SUMMARY
5/*	quote/unquote text, xtext style.
6/* SYNOPSIS
7/*	#include <xtext.h>
8/*
9/*	VSTRING	*xtext_quote(quoted, unquoted, special)
10/*	VSTRING	*quoted;
11/*	const char *unquoted;
12/*	const char *special;
13/*
14/*	VSTRING	*xtext_quote_append(unquoted, quoted, special)
15/*	VSTRING	*unquoted;
16/*	const char *quoted;
17/*	const char *special;
18/*
19/*	VSTRING	*xtext_unquote(unquoted, quoted)
20/*	VSTRING	*unquoted;
21/*	const char *quoted;
22/*
23/*	VSTRING	*xtext_unquote_append(unquoted, quoted)
24/*	VSTRING	*unquoted;
25/*	const char *quoted;
26/* DESCRIPTION
27/*	xtext_quote() takes a null-terminated string and replaces characters
28/*	+, <33(10) and >126(10), as well as characters specified with "special"
29/*	by +XX, XX being the two-digit uppercase hexadecimal equivalent.
30/*
31/*	xtext_quote_append() is like xtext_quote(), but appends the conversion
32/*	result to the result buffer.
33/*
34/*	xtext_unquote() performs the opposite transformation. This function
35/*	understands lowercase, uppercase, and mixed case +XX sequences. The
36/*	result value is the unquoted argument in case of success, a null pointer
37/*	otherwise.
38/*
39/*	xtext_unquote_append() is like xtext_unquote(), but appends
40/*	the conversion result to the result buffer.
41/* BUGS
42/*	This module cannot process null characters in data.
43/* LICENSE
44/* .ad
45/* .fi
46/*	The Secure Mailer license must be distributed with this software.
47/* AUTHOR(S)
48/*	Wietse Venema
49/*	IBM T.J. Watson Research
50/*	P.O. Box 704
51/*	Yorktown Heights, NY 10598, USA
52/*--*/
53
54/* System library. */
55
56#include <sys_defs.h>
57#include <string.h>
58#include <ctype.h>
59
60/* Utility library. */
61
62#include "msg.h"
63#include "vstring.h"
64#include "xtext.h"
65
66/* Application-specific. */
67
68#define STR(x)	vstring_str(x)
69#define LEN(x)	VSTRING_LEN(x)
70
71/* xtext_quote_append - append unquoted data to quoted data */
72
73VSTRING *xtext_quote_append(VSTRING *quoted, const char *unquoted,
74			            const char *special)
75{
76    const char *cp;
77    int     ch;
78
79    for (cp = unquoted; (ch = *(unsigned const char *) cp) != 0; cp++) {
80	if (ch != '+' && ch > 32 && ch < 127
81	    && (*special == 0 || strchr(special, ch) == 0)) {
82	    VSTRING_ADDCH(quoted, ch);
83	} else {
84	    vstring_sprintf_append(quoted, "+%02X", ch);
85	}
86    }
87    VSTRING_TERMINATE(quoted);
88    return (quoted);
89}
90
91/* xtext_quote - unquoted data to quoted */
92
93VSTRING *xtext_quote(VSTRING *quoted, const char *unquoted, const char *special)
94{
95    VSTRING_RESET(quoted);
96    xtext_quote_append(quoted, unquoted, special);
97    return (quoted);
98}
99
100/* xtext_unquote_append - quoted data to unquoted */
101
102VSTRING *xtext_unquote_append(VSTRING *unquoted, const char *quoted)
103{
104    const char *cp;
105    int     ch;
106
107    for (cp = quoted; (ch = *cp) != 0; cp++) {
108	if (ch == '+') {
109	    if (ISDIGIT(cp[1]))
110		ch = (cp[1] - '0') << 4;
111	    else if (cp[1] >= 'a' && cp[1] <= 'f')
112		ch = (cp[1] - 'a' + 10) << 4;
113	    else if (cp[1] >= 'A' && cp[1] <= 'F')
114		ch = (cp[1] - 'A' + 10) << 4;
115	    else
116		return (0);
117	    if (ISDIGIT(cp[2]))
118		ch |= (cp[2] - '0');
119	    else if (cp[2] >= 'a' && cp[2] <= 'f')
120		ch |= (cp[2] - 'a' + 10);
121	    else if (cp[2] >= 'A' && cp[2] <= 'F')
122		ch |= (cp[2] - 'A' + 10);
123	    else
124		return (0);
125	    cp += 2;
126	}
127	VSTRING_ADDCH(unquoted, ch);
128    }
129    VSTRING_TERMINATE(unquoted);
130    return (unquoted);
131}
132/* xtext_unquote - quoted data to unquoted */
133
134VSTRING *xtext_unquote(VSTRING *unquoted, const char *quoted)
135{
136    VSTRING_RESET(unquoted);
137    xtext_unquote_append(unquoted, quoted);
138    return (unquoted);
139}
140
141#ifdef TEST
142
143 /*
144  * Proof-of-concept test program: convert to quoted and back.
145  */
146#include <vstream.h>
147
148#define BUFLEN 1024
149
150static ssize_t read_buf(VSTREAM *fp, VSTRING *buf)
151{
152    ssize_t len;
153
154    VSTRING_RESET(buf);
155    len = vstream_fread(fp, STR(buf), vstring_avail(buf));
156    VSTRING_AT_OFFSET(buf, len);		/* XXX */
157    VSTRING_TERMINATE(buf);
158    return (len);
159}
160
161int     main(int unused_argc, char **unused_argv)
162{
163    VSTRING *unquoted = vstring_alloc(BUFLEN);
164    VSTRING *quoted = vstring_alloc(100);
165    ssize_t len;
166
167    while ((len = read_buf(VSTREAM_IN, unquoted)) > 0) {
168	xtext_quote(quoted, STR(unquoted), "+=");
169	if (xtext_unquote(unquoted, STR(quoted)) == 0)
170	    msg_fatal("bad input: %.100s", STR(quoted));
171	if (LEN(unquoted) != len)
172	    msg_fatal("len %ld != unquoted len %ld",
173		      (long) len, (long) LEN(unquoted));
174	if (vstream_fwrite(VSTREAM_OUT, STR(unquoted), LEN(unquoted)) != LEN(unquoted))
175	    msg_fatal("write error: %m");
176    }
177    vstream_fflush(VSTREAM_OUT);
178    vstring_free(unquoted);
179    vstring_free(quoted);
180    return (0);
181}
182
183#endif
184