updates from p9p

libc/fltfmt.c

@@ -1,15 +1,97 @@
-#include <u.h>
-#include <libc.h>
+/*
+ * The authors of this software are Rob Pike and Ken Thompson.
+ *              Copyright (c) 2002 by Lucent Technologies.
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose without fee is hereby granted, provided that this entire notice
+ * is included in all copies of any software which is or includes a copy
+ * or modification of this software and in all copies of the supporting
+ * documentation for such software.
+ * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE
+ * ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
+ * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
+ */
+#include <stdio.h>
+#include <math.h>
+#include <float.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdarg.h>
 #include <ctype.h>
+#include <fmt.h>
+#include "plan9.h"
+#include "fmt.h"
 #include "fmtdef.h"
 
 enum
 {
 	FDIGIT	= 30,
 	FDEFLT	= 6,
-	NSIGNIF	= 17,
+	NSIGNIF	= 17
 };
 
+/*
+ * first few powers of 10, enough for about 1/2 of the
+ * total space for doubles.
+ */
+static double pows10[] =
+{
+	  1e0,   1e1,   1e2,   1e3,   1e4,   1e5,   1e6,   1e7,   1e8,   1e9,  
+	 1e10,  1e11,  1e12,  1e13,  1e14,  1e15,  1e16,  1e17,  1e18,  1e19,  
+	 1e20,  1e21,  1e22,  1e23,  1e24,  1e25,  1e26,  1e27,  1e28,  1e29,  
+	 1e30,  1e31,  1e32,  1e33,  1e34,  1e35,  1e36,  1e37,  1e38,  1e39,  
+	 1e40,  1e41,  1e42,  1e43,  1e44,  1e45,  1e46,  1e47,  1e48,  1e49,  
+	 1e50,  1e51,  1e52,  1e53,  1e54,  1e55,  1e56,  1e57,  1e58,  1e59,  
+	 1e60,  1e61,  1e62,  1e63,  1e64,  1e65,  1e66,  1e67,  1e68,  1e69,  
+	 1e70,  1e71,  1e72,  1e73,  1e74,  1e75,  1e76,  1e77,  1e78,  1e79,  
+	 1e80,  1e81,  1e82,  1e83,  1e84,  1e85,  1e86,  1e87,  1e88,  1e89,  
+	 1e90,  1e91,  1e92,  1e93,  1e94,  1e95,  1e96,  1e97,  1e98,  1e99,  
+	1e100, 1e101, 1e102, 1e103, 1e104, 1e105, 1e106, 1e107, 1e108, 1e109, 
+	1e110, 1e111, 1e112, 1e113, 1e114, 1e115, 1e116, 1e117, 1e118, 1e119, 
+	1e120, 1e121, 1e122, 1e123, 1e124, 1e125, 1e126, 1e127, 1e128, 1e129, 
+	1e130, 1e131, 1e132, 1e133, 1e134, 1e135, 1e136, 1e137, 1e138, 1e139, 
+	1e140, 1e141, 1e142, 1e143, 1e144, 1e145, 1e146, 1e147, 1e148, 1e149, 
+	1e150, 1e151, 1e152, 1e153, 1e154, 1e155, 1e156, 1e157, 1e158, 1e159, 
+};
+
+#define  pow10(x)  fmtpow10(x)
+
+static double
+pow10(int n)
+{
+	double d;
+	int neg;
+
+	neg = 0;
+	if(n < 0){
+		if(n < DBL_MIN_10_EXP){
+			return 0.;
+		}
+		neg = 1;
+		n = -n;
+	}else if(n > DBL_MAX_10_EXP){
+		return HUGE_VAL;
+	}
+	if(n < (int)(sizeof(pows10)/sizeof(pows10[0])))
+		d = pows10[n];
+	else{
+		d = pows10[sizeof(pows10)/sizeof(pows10[0]) - 1];
+		for(;;){
+			n -= sizeof(pows10)/sizeof(pows10[0]) - 1;
+			if(n < (int)(sizeof(pows10)/sizeof(pows10[0]))){
+				d *= pows10[n];
+				break;
+			}
+			d *= pows10[sizeof(pows10)/sizeof(pows10[0]) - 1];
+		}
+	}
+	if(neg){
+		return 1./d;
+	}
+	return d;
+}
+
 static int
 xadd(char *a, int n, int v)
 {
@@ -27,7 +109,7 @@ xadd(char *a, int n, int v)
 		*b = '0';
 		v = 1;
 	}
-	*a = '1';	// overflow adding
+	*a = '1';	/* overflow adding */
 	return 1;
 }
 
@@ -46,7 +128,7 @@ xsub(char *a, int n, int v)
 		*b = '9';
 		v = 1;
 	}
-	*a = '9';	// underflow subtracting
+	*a = '9';	/* underflow subtracting */
 	return 1;
 }
 
@@ -291,22 +373,22 @@ found:
 	s2[d] = 0;
 }
 
-int
-_floatfmt(Fmt *fmt, double f)
+static int
+floatfmt(Fmt *fmt, double f)
 {
-	char s[FDIGIT+10];
+	char s[341];		/* precision+exponent+sign+'.'+null */
 
 	xdtoa(fmt, s, f);
 	fmt->flags &= FmtWidth|FmtLeft;
-	_fmtcpy(fmt, s, strlen(s), strlen(s));
+	__fmtcpy(fmt, s, strlen(s), strlen(s));
 	return 0;
 }
 
 int
-_efgfmt(Fmt *f)
+__efgfmt(Fmt *f)
 {
 	double d;
 
 	d = va_arg(f->args, double);
-	return _floatfmt(f, d);
+	return floatfmt(f, d);
 }