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	fmtquote.c - 9base - revived minimalist port of Plan 9 userland to Unix
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	fmtquote.c (3609B)
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	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 noti…
	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 IMPLI…
	10 * WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES…
	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 necessar…
	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 && doquo…
	60 if(!q->quoted){
	61 if(1+q->nrunesout+1+1 > nout) /* …
	62 break;
	63 q->nrunesout += 2; /* include quo…
	64 q->nbytesout += 2; /* include quo…
	65 q->quoted = 1;
	66 }
	67 if(c == '\'') {
	68 q->nbytesout++;
	69 q->nrunesout++; /* quotes reprodu…
	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 fo…
	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 outpu…
	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 }