a

libc/fmt.c

@@ -0,0 +1,193 @@
+#include <u.h>
+#include <libc.h>
+#include "fmtdef.h"
+
+enum
+{
+	Maxfmt = 64
+};
+
+typedef struct Convfmt Convfmt;
+struct Convfmt
+{
+	int	c;
+	volatile	Fmts	fmt;	/* for spin lock in fmtfmt; avoids race due to write order */
+};
+
+struct
+{
+	/* lock by calling _fmtlock, _fmtunlock */
+	int	nfmt;
+	Convfmt	fmt[Maxfmt];
+} fmtalloc;
+
+static Convfmt knownfmt[] = {
+	' ',	_flagfmt,
+	'#',	_flagfmt,
+	'%',	_percentfmt,
+	'+',	_flagfmt,
+	',',	_flagfmt,
+	'-',	_flagfmt,
+	'C',	_runefmt,
+	'E',	_efgfmt,
+	'G',	_efgfmt,
+	'S',	_runesfmt,
+	'X',	_ifmt,
+	'b',	_ifmt,
+	'c',	_charfmt,
+	'd',	_ifmt,
+	'e',	_efgfmt,
+	'f',	_efgfmt,
+	'g',	_efgfmt,
+	'h',	_flagfmt,
+	'l',	_flagfmt,
+	'n',	_countfmt,
+	'o',	_ifmt,
+	'p',	_ifmt,
+/*	'r',	errfmt, */
+	's',	_strfmt,
+	'u',	_flagfmt,
+	'x',	_ifmt,
+	0,	nil,
+};
+
+int	(*doquote)(int);
+
+/*
+ * _fmtlock() must be set
+ */
+static int
+_fmtinstall(int c, Fmts f)
+{
+	Convfmt *p, *ep;
+
+	if(c<=0 || c>=65536)
+		return -1;
+	if(!f)
+		f = _badfmt;
+
+	ep = &fmtalloc.fmt[fmtalloc.nfmt];
+	for(p=fmtalloc.fmt; p<ep; p++)
+		if(p->c == c)
+			break;
+
+	if(p == &fmtalloc.fmt[Maxfmt])
+		return -1;
+
+	p->fmt = f;
+	if(p == ep){	/* installing a new format character */
+		fmtalloc.nfmt++;
+		p->c = c;
+	}
+
+	return 0;
+}
+
+int
+fmtinstall(int c, Fmts f)
+{
+	int ret;
+
+	_fmtlock();
+	ret = _fmtinstall(c, f);
+	_fmtunlock();
+	return ret;
+}
+
+static Fmts
+fmtfmt(int c)
+{
+	Convfmt *p, *ep;
+
+	ep = &fmtalloc.fmt[fmtalloc.nfmt];
+	for(p=fmtalloc.fmt; p<ep; p++)
+		if(p->c == c){
+			while(p->fmt == nil)	/* loop until value is updated */
+				;
+			return p->fmt;
+		}
+
+	/* is this a predefined format char? */
+	_fmtlock();
+	for(p=knownfmt; p->c; p++)
+		if(p->c == c){
+			_fmtinstall(p->c, p->fmt);
+			_fmtunlock();
+			return p->fmt;
+		}
+	_fmtunlock();
+
+	return _badfmt;
+}
+
+void*
+_fmtdispatch(Fmt *f, void *fmt, int isrunes)
+{
+	Rune rune, r;
+	int i, n;
+
+	f->flags = 0;
+	f->width = f->prec = 0;
+
+	for(;;){
+		if(isrunes){
+			r = *(Rune*)fmt;
+			fmt = (Rune*)fmt + 1;
+		}else{
+			fmt = (char*)fmt + chartorune(&rune, fmt);
+			r = rune;
+		}
+		f->r = r;
+		switch(r){
+		case '\0':
+			return nil;
+		case '.':
+			f->flags |= FmtWidth|FmtPrec;
+			continue;
+		case '0':
+			if(!(f->flags & FmtWidth)){
+				f->flags |= FmtZero;
+				continue;
+			}
+			/* fall through */
+		case '1': case '2': case '3': case '4':
+		case '5': case '6': case '7': case '8': case '9':
+			i = 0;
+			while(r >= '0' && r <= '9'){
+				i = i * 10 + r - '0';
+				if(isrunes){
+					r = *(Rune*)fmt;
+					fmt = (Rune*)fmt + 1;
+				}else{
+					r = *(char*)fmt;
+					fmt = (char*)fmt + 1;
+				}
+			}
+			if(isrunes)
+				fmt = (Rune*)fmt - 1;
+			else
+				fmt = (char*)fmt - 1;
+		numflag:
+			if(f->flags & FmtWidth){
+				f->flags |= FmtPrec;
+				f->prec = i;
+			}else{
+				f->flags |= FmtWidth;
+				f->width = i;
+			}
+			continue;
+		case '*':
+			i = va_arg(f->args, int);
+			if(i < 0){
+				i = -i;
+				f->flags |= FmtLeft;
+			}
+			goto numflag;
+		}
+		n = (*fmtfmt(r))(f);
+		if(n < 0)
+			return nil;
+		if(n == 0)
+			return fmt;
+	}
+}