Teach proj_strtod to understand corner cases 0 and 0. (#611)

1 files changed, 16 insertions, 8 deletions

diff --git a/src/proj_strtod.c b/src/proj_strtod.c
index aa2211f5..42b7691d 100644
--- a/src/proj_strtod.c
+++ b/src/proj_strtod.c
@@ -86,6 +86,7 @@ Thomas Knudsen, thokn@sdfe.dk, 2017-01-17/2017-09-18
 ***********************************************************************/
 
 
+#include <stdio.h> /* for strchr */
 #include <string.h> /* for strchr */
 #include <errno.h>
 #include <ctype.h>
@@ -141,10 +142,14 @@ double proj_strtod(const char *str, char **endptr) {
             return HUGE_VAL;
     }
 
-    /* skip prefixed zeros */
+    /* skip prefixed zeros before '.' */
     while ('0'==*p || '_'==*p)
         p++;
 
+    /* zero? */
+    if (0==*p || 0==strchr ("0123456789eE.", *p))
+        return 0;
+
     /* Now expect a (potentially zero-length) string of digits */
     while (isdigit(*p) || ('_'==*p)) {
         if ('_'==*p) {
@@ -171,8 +176,11 @@ double proj_strtod(const char *str, char **endptr) {
             }
 
         /* if the next character is nonnumeric, we have reached the end */
-        if (0==strchr ("0123456789eE+-", *p))
+        if (0==*p || 0==strchr ("0123456789eE+-", *p)) {
+            if (endptr)
+                *endptr = p;
             return integral_part;
+        }
 
         while (isdigit(*p) || '_'==*p) {
             /* Don't let pathologically long fractions destroy precision */
@@ -244,10 +252,10 @@ double proj_strtod(const char *str, char **endptr) {
     }
 
     if ((exponent < DBL_MIN_EXP) || (exponent > DBL_MAX_EXP)) {
-      errno = ERANGE;
-      if (endptr)
-          *endptr = p;
-      return HUGE_VAL;
+        errno = ERANGE;
+        if (endptr)
+            *endptr = p;
+        return HUGE_VAL;
     }
 
     /* on some platforms pow() is very slow - so don't call it if exponent==0 */
@@ -260,15 +268,15 @@ double proj_strtod(const char *str, char **endptr) {
 
     if (endptr)
         *endptr = p;
-
     return number;
 }
 
 double proj_atof(const char *str) {
-  return proj_strtod(str, (void *) 0);
+    return proj_strtod(str, (void *) 0);
 }
 
 #ifdef TEST
+#include <stdio.h>
 #include <string.h>
 
 int main (int argc, char **argv) {