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	fmt.c - 9base - revived minimalist port of Plan 9 userland to Unix
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	---
	fmt.c (3575B)
	---
	1 /* Copyright (c) 2002-2006 Lucent Technologies; see LICENSE */
	2 #include <stdarg.h>
	3 #include <string.h>
	4 #include "plan9.h"
	5 #include "fmt.h"
	6 #include "fmtdef.h"
	7
	8 enum
	9 {
	10 Maxfmt = 64
	11 };
	12
	13 typedef struct Convfmt Convfmt;
	14 struct Convfmt
	15 {
	16 int c;
	17 volatile Fmts fmt; /* for spin lock in fmtf…
	18 };
	19
	20 static struct
	21 {
	22 /* lock by calling __fmtlock, __fmtunlock */
	23 int nfmt;
	24 Convfmt fmt[Maxfmt];
	25 } fmtalloc;
	26
	27 static Convfmt knownfmt[] = {
	28 ' ', __flagfmt,
	29 '#', __flagfmt,
	30 '%', __percentfmt,
	31 '\'', __flagfmt,
	32 '+', __flagfmt,
	33 ',', __flagfmt,
	34 '-', __flagfmt,
	35 'C', __runefmt, /* Plan 9 addition */
	36 'E', __efgfmt,
	37 #ifndef PLAN9PORT
	38 'F', __efgfmt, /* ANSI only */
	39 #endif
	40 'G', __efgfmt,
	41 #ifndef PLAN9PORT
	42 'L', __flagfmt, /* ANSI only */
	43 #endif
	44 'S', __runesfmt, /* Plan 9 addition */
	45 'X', __ifmt,
	46 'b', __ifmt, /* Plan 9 addition */
	47 'c', __charfmt,
	48 'd', __ifmt,
	49 'e', __efgfmt,
	50 'f', __efgfmt,
	51 'g', __efgfmt,
	52 'h', __flagfmt,
	53 #ifndef PLAN9PORT
	54 'i', __ifmt, /* ANSI only */
	55 #endif
	56 'l', __flagfmt,
	57 'n', __countfmt,
	58 'o', __ifmt,
	59 'p', __ifmt,
	60 'r', __errfmt,
	61 's', __strfmt,
	62 #ifdef PLAN9PORT
	63 'u', __flagfmt,
	64 #else
	65 'u', __ifmt,
	66 #endif
	67 'x', __ifmt,
	68 0, nil,
	69 };
	70
	71
	72 int (*fmtdoquote)(int);
	73
	74 /*
	75 * __fmtlock() must be set
	76 */
	77 static int
	78 __fmtinstall(int c, Fmts f)
	79 {
	80 Convfmt p, ep;
	81
	82 if(c<=0 \|\| c>=65536)
	83 return -1;
	84 if(!f)
	85 f = __badfmt;
	86
	87 ep = &fmtalloc.fmt[fmtalloc.nfmt];
	88 for(p=fmtalloc.fmt; p<ep; p++)
	89 if(p->c == c)
	90 break;
	91
	92 if(p == &fmtalloc.fmt[Maxfmt])
	93 return -1;
	94
	95 p->fmt = f;
	96 if(p == ep){ /* installing a new format character */
	97 fmtalloc.nfmt++;
	98 p->c = c;
	99 }
	100
	101 return 0;
	102 }
	103
	104 int
	105 fmtinstall(int c, int (f)(Fmt))
	106 {
	107 int ret;
	108
	109 __fmtlock();
	110 ret = __fmtinstall(c, f);
	111 __fmtunlock();
	112 return ret;
	113 }
	114
	115 static Fmts
	116 fmtfmt(int c)
	117 {
	118 Convfmt p, ep;
	119
	120 ep = &fmtalloc.fmt[fmtalloc.nfmt];
	121 for(p=fmtalloc.fmt; p<ep; p++)
	122 if(p->c == c){
	123 while(p->fmt == nil) /* loop until value …
	124 ;
	125 return p->fmt;
	126 }
	127
	128 /* is this a predefined format char? */
	129 __fmtlock();
	130 for(p=knownfmt; p->c; p++)
	131 if(p->c == c){
	132 __fmtinstall(p->c, p->fmt);
	133 __fmtunlock();
	134 return p->fmt;
	135 }
	136 __fmtunlock();
	137
	138 return __badfmt;
	139 }
	140
	141 void*
	142 __fmtdispatch(Fmt f, void fmt, int isrunes)
	143 {
	144 Rune rune, r;
	145 int i, n;
	146
	147 f->flags = 0;
	148 f->width = f->prec = 0;
	149
	150 for(;;){
	151 if(isrunes){
	152 r = (Rune)fmt;
	153 fmt = (Rune*)fmt + 1;
	154 }else{
	155 fmt = (char)fmt + chartorune(&rune, (char)fmt);
	156 r = rune;
	157 }
	158 f->r = r;
	159 switch(r){
	160 case '\0':
	161 return nil;
	162 case '.':
	163 f->flags \|= FmtWidth\|FmtPrec;
	164 continue;
	165 case '0':
	166 if(!(f->flags & FmtWidth)){
	167 f->flags \|= FmtZero;
	168 continue;
	169 }
	170 /* fall through */
	171 case '1': case '2': case '3': case '4':
	172 case '5': case '6': case '7': case '8': case '9':
	173 i = 0;
	174 while(r >= '0' && r <= '9'){
	175 i = i * 10 + r - '0';
	176 if(isrunes){
	177 r = (Rune)fmt;
	178 fmt = (Rune*)fmt + 1;
	179 }else{
	180 r = (char)fmt;
	181 fmt = (char*)fmt + 1;
	182 }
	183 }
	184 if(isrunes)
	185 fmt = (Rune*)fmt - 1;
	186 else
	187 fmt = (char*)fmt - 1;
	188 numflag:
	189 if(f->flags & FmtWidth){
	190 f->flags \|= FmtPrec;
	191 f->prec = i;
	192 }else{
	193 f->flags \|= FmtWidth;
	194 f->width = i;
	195 }
	196 continue;
	197 case '*':
	198 i = va_arg(f->args, int);
	199 if(i < 0){
	200 /*
	201 * negative precision =>
	202 * ignore the precision.
	203 */
	204 if(f->flags & FmtPrec){
	205 f->flags &= ~FmtPrec;
	206 f->prec = 0;
	207 continue;
	208 }
	209 i = -i;
	210 f->flags \|= FmtLeft;
	211 }
	212 goto numflag;
	213 }
	214 n = (*fmtfmt(r))(f);
	215 if(n < 0)
	216 return nil;
	217 if(n == 0)
	218 return fmt;
	219 }
	220 }