1 /*
2  * The authors of this software are Rob Pike and Ken Thompson.
3  *              Copyright (c) 2002 by Lucent Technologies.
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose without fee is hereby granted, provided that this entire notice
6  * is included in all copies of any software which is or includes a copy
7  * or modification of this software and in all copies of the supporting
8  * documentation for such software.
9  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
10  * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
11  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
12  * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
13  */
14 #include <u.h>
15 #include <libc.h>
16 #include "fmt.h"
17 #include "fmtdef.h"
18 
19 extern int (*doquote)(int);
20 
21 /*
22  * How many bytes of output UTF will be produced by quoting (if necessary) this string?
23  * How many runes? How much of the input will be consumed?
24  * The parameter q is filled in by _quotesetup.
25  * The string may be UTF or Runes (s or r).
26  * Return count does not include NUL.
27  * Terminate the scan at the first of:
28  *	NUL in input
29  *	count exceeded in input
30  *	count exceeded on output
31  * *ninp is set to number of input bytes accepted.
32  * nin may be <0 initially, to avoid checking input by count.
33  */
34 void
35 __quotesetup(char *s, int nin, int nout, Quoteinfo *q, int sharp)
36 {
37 	int c;
38 
39 	q->quoted = 0;
40 	q->nbytesout = 0;
41 	q->nrunesout = 0;
42 	q->nbytesin = 0;
43 	q->nrunesin = 0;
44 	if(sharp || nin==0 || *s=='\0'){
45 		if(nout < 2)
46 			return;
47 		q->quoted = 1;
48 		q->nbytesout = 2;
49 		q->nrunesout = 2;
50 	}
51 	for(; nin!=0; nin-=1){
52 		c = *s;
53 
54 		if(c == '\0')
55 			break;
56 		if(q->nrunesout+1 > nout)
57 			break;
58 
59 		if((c <= L' ') || (c == L'\'') || (doquote!=nil && doquote(c))){
60 			if(!q->quoted){
61 				if(1+q->nrunesout+1+1 > nout)	/* no room for quotes */
62 					break;
63 				q->nrunesout += 2;	/* include quotes */
64 				q->nbytesout += 2;	/* include quotes */
65 				q->quoted = 1;
66 			}
67 			if(c == '\'')	{
68 				q->nbytesout++;
69 				q->nrunesout++;	/* quotes reproduce as two characters */
70 			}
71 		}
72 
73 		/* advance input */
74 		s++;
75 		q->nbytesin++;
76 		q->nrunesin++;
77 
78 		/* advance output */
79 		q->nbytesout++;
80 		q->nrunesout++;
81 	}
82 }
83 
84 static int
85 qstrfmt(char *sin, Quoteinfo *q, Fmt *f)
86 {
87 	int r;
88 	char *t, *s, *m, *me;
89 	ulong fl;
90 	int nc, w;
91 
92 	m = sin;
93 	me = m + q->nbytesin;
94 
95 	w = f->width;
96 	fl = f->flags;
97 	if(!(fl & FmtLeft) && __fmtpad(f, w - q->nbytesout) < 0)
98 		return -1;
99 	t = f->to;
100 	s = f->stop;
101 	FMTCHAR(f, t, s, '\'');
102 	for(nc = q->nrunesin; nc > 0; nc--){
103 		r = *(uchar*)m++;
104 		FMTCHAR(f, t, s, r);
105 		if(r == '\'')
106 			FMTCHAR(f, t, s, r);
107 	}
108 
109 	FMTCHAR(f, t, s, '\'');
110 	f->nfmt += t - (char *)f->to;
111 	f->to = t;
112 	if(fl & FmtLeft && __fmtpad(f, w - q->nbytesout) < 0)
113 		return -1;
114 	return 0;
115 }
116 
117 int
118 __quotestrfmt(int runesin, Fmt *f)
119 {
120 	int outlen;
121 	char *s;
122 	Quoteinfo q;
123 
124 	f->flags &= ~FmtPrec;	/* ignored for %q %Q, so disable for %s %S in easy case */
125 	s = va_arg(f->args, char *);
126 	if(!s)
127 		return __fmtcpy(f, "<nil>", 5, 5);
128 
129 	if(f->flush)
130 		outlen = 0x7FFFFFFF;	/* if we can flush, no output limit */
131 	else
132 		outlen = (char*)f->stop - (char*)f->to;
133 
134 	__quotesetup(s, -1, outlen, &q, f->flags&FmtSharp);
135 
136 	if(!q.quoted)
137 		return __fmtcpy(f, s, q.nrunesin, q.nbytesin);
138 	return qstrfmt(s, &q, f);
139 }
140 
141 int
142 quotestrfmt(Fmt *f)
143 {
144 	return __quotestrfmt(0, f);
145 }
146 
147 void
148 quotefmtinstall(void)
149 {
150 	fmtinstall('q', quotestrfmt);
151 }
152 
153 int
154 __needsquotes(char *s, int *quotelenp)
155 {
156 	Quoteinfo q;
157 
158 	__quotesetup(s, -1, 0x7FFFFFFF, &q, 0);
159 	*quotelenp = q.nbytesout;
160 
161 	return q.quoted;
162 }