Nan and Infinity can be negative

Decimal point was missing for some exponential output
Only divide sign by 10 once per loop
Add a missing NUL terminator for one case
If there is no whole number portion, print a leading zero (e.g. 0.1 not .1)

1 files changed, 12 insertions, 6 deletions

diff --git a/src/lib/libc/stdlib/gcvt.c b/src/lib/libc/stdlib/gcvt.c
index 849af60304..87bd843307 100644
--- a/src/lib/libc/stdlib/gcvt.c
+++ b/src/lib/libc/stdlib/gcvt.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: gcvt.c,v 1.6 2005/08/08 08:05:36 espie Exp $  */
+/*      $OpenBSD: gcvt.c,v 1.7 2006/01/10 02:08:28 millert Exp $        */
 
 /*
  * Copyright (c) 2002, 2003 Todd C. Miller <Todd.Miller@courtesan.com>
@@ -40,7 +40,7 @@ gcvt(double value, int ndigit, char *buf)
         digits = __dtoa(value, 2, ndigit, &decpt, &sign, NULL);
         if (decpt == 9999) {
                 /* Infinity or NaN, assume buffer is at least ndigit long. */
-                strlcpy(buf, digits, ndigit + 1);
+                snprintf(buf, ndigit + 1, "%s%s", sign ? "-" : "", digits);
                 return (buf);
         }
 
@@ -49,13 +49,16 @@ gcvt(double value, int ndigit, char *buf)
                 *dst++ = '-';
 
         if (decpt < 0 || decpt > ndigit) {
-                /* exponential format */
+                /* exponential format (e.g. 1.2345e+13) */
                 if (--decpt < 0) {
                         sign = 1;
                         decpt = -decpt;
                 } else
                         sign = 0;
-                for (src = digits; *src != '\0'; )
+                src = digits;
+                *dst++ = *src++;
+                *dst++ = '.';           /* XXX - locale-specific */
+                while (*src != '\0')
                         *dst++ = *src++;
                 *dst++ = 'e';
                 if (sign)
@@ -69,7 +72,8 @@ gcvt(double value, int ndigit, char *buf)
                 } else {
                         /* XXX - optimize */
                         for (sign = decpt, i = 0; (sign /= 10) != 0; i++)
-                                sign /= 10;
+                                continue;
+                        dst[i + 1] = '\0';
                         while (decpt != 0) {
                                 dst[i--] = '0' + decpt % 10;
                                 decpt /= 10;
@@ -84,7 +88,9 @@ gcvt(double value, int ndigit, char *buf)
                                 *dst++ = '0';
                 }
                 if (*src != '\0') {
-                        *dst++ = '.';           /* XXX - locale-specific (LC_NUMERIC) */
+                        if (src == digits)
+                                *dst++ = '0';   /* zero before decimal point */
+                        *dst++ = '.';           /* XXX - locale-specific */
                         for (i = decpt; digits[i] != '\0'; i++) {
                                 *dst++ = digits[i];
                         }