Make ns[C]String::AppendFloat locale-independent. b=209569 r=jag sr=bzbarsky

git-svn-id: svn://10.0.0.236/trunk@144638 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/xpcom/string/obsolete/nsStr.cpp

@@ -45,6 +45,7 @@
 #include "nsStr.h"
 #include "bufferRoutines.h"
 #include <stdio.h>  //only used for printf
+#include "prdtoa.h"
 
 /******************************************************************************************
   MODULE NOTES:
@@ -1126,6 +1127,97 @@ nsStrPrivate::HashCode(const nsStr& aDest)
   }
 }
 
+/**
+ * This is a copy of |PR_cnvtf| with a bug fixed.  (The second argument
+ * of PR_dtoa is 2 rather than 1.)
+ */
+void 
+nsStrPrivate::cnvtf(char *buf, int bufsz, int prcsn, double fval)
+{
+  PRIntn decpt, sign, numdigits;
+  char *num, *nump;
+  char *bufp = buf;
+  char *endnum;
+
+  /* If anything fails, we store an empty string in 'buf' */
+  num = (char*)PR_MALLOC(bufsz);
+  if (num == NULL) {
+    buf[0] = '\0';
+    return;
+  }
+  if (PR_dtoa(fval, 2, prcsn, &decpt, &sign, &endnum, num, bufsz)
+      == PR_FAILURE) {
+    buf[0] = '\0';
+    goto done;
+  }
+  numdigits = endnum - num;
+  nump = num;
+
+  /*
+   * The NSPR code had a fancy way of checking that we weren't dealing
+   * with -0.0 or -NaN, but I'll just use < instead.
+   * XXX Should we check !isnan(fval) as well?  Is it portable?  We
+   * probably don't need to bother since NAN isn't portable.
+   */
+  if (sign && fval < 0.0f) {
+    *bufp++ = '-';
+  }
+
+  if (decpt == 9999) {
+    while ((*bufp++ = *nump++) != 0) {} /* nothing to execute */
+    goto done;
+  }
+
+  if (decpt > (prcsn+1) || decpt < -(prcsn-1) || decpt < -5) {
+    *bufp++ = *nump++;
+    if (numdigits != 1) {
+      *bufp++ = '.';
+    }
+
+    while (*nump != '\0') {
+      *bufp++ = *nump++;
+    }
+    *bufp++ = 'e';
+    PR_snprintf(bufp, bufsz - (bufp - buf), "%+d", decpt-1);
+  }
+  else if (decpt >= 0) {
+    if (decpt == 0) {
+      *bufp++ = '0';
+    }
+    else {
+      while (decpt--) {
+        if (*nump != '\0') {
+          *bufp++ = *nump++;
+        }
+        else {
+          *bufp++ = '0';
+        }
+      }
+    }
+    if (*nump != '\0') {
+      *bufp++ = '.';
+      while (*nump != '\0') {
+        *bufp++ = *nump++;
+      }
+    }
+    *bufp++ = '\0';
+  }
+  else if (decpt < 0) {
+    *bufp++ = '0';
+    *bufp++ = '.';
+    while (decpt++) {
+      *bufp++ = '0';
+    }
+
+    while (*nump != '\0') {
+      *bufp++ = *nump++;
+    }
+    *bufp++ = '\0';
+  }
+done:
+  PR_DELETE(num);
+}
+
 #ifdef NS_STR_STATS
 
 #include <ctype.h>