Initial import

external/json/g_fmt.c

@@ -0,0 +1,111 @@
+/****************************************************************
+ *
+ * The author of this software is David M. Gay.
+ *
+ * Copyright (c) 1991, 1996 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 AUTHOR NOR LUCENT MAKES ANY
+ * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
+ * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
+ *
+ ***************************************************************/
+
+/* g_fmt(buf,x) stores the closest decimal approximation to x in buf;
+ * it suffices to declare buf
+ *	char buf[32];
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+ extern char *dtoa(double, int, int, int *, int *, char **);
+ extern int g_fmt(char *, double, int);
+ extern void freedtoa(char*);
+#ifdef __cplusplus
+	}
+#endif
+
+int
+fpconv_g_fmt(char *b, double x, int precision)
+{
+	register int i, k;
+	register char *s;
+	int decpt, j, sign;
+	char *b0, *s0, *se;
+
+	b0 = b;
+#ifdef IGNORE_ZERO_SIGN
+	if (!x) {
+		*b++ = '0';
+		*b = 0;
+		goto done;
+		}
+#endif
+	s = s0 = dtoa(x, 2, precision, &decpt, &sign, &se);
+	if (sign)
+		*b++ = '-';
+	if (decpt == 9999) /* Infinity or Nan */ {
+		while((*b++ = *s++));
+		/* "b" is used to calculate the return length. Decrement to exclude the
+		 * Null terminator from the length */
+		b--;
+		goto done0;
+		}
+	if (decpt <= -4 || decpt > precision) {
+		*b++ = *s++;
+		if (*s) {
+			*b++ = '.';
+			while((*b = *s++))
+				b++;
+			}
+		*b++ = 'e';
+		/* sprintf(b, "%+.2d", decpt - 1); */
+		if (--decpt < 0) {
+			*b++ = '-';
+			decpt = -decpt;
+			}
+		else
+			*b++ = '+';
+		for(j = 2, k = 10; 10*k <= decpt; j++, k *= 10);
+		for(;;) {
+			i = decpt / k;
+			*b++ = i + '0';
+			if (--j <= 0)
+				break;
+			decpt -= i*k;
+			decpt *= 10;
+			}
+		*b = 0;
+		}
+	else if (decpt <= 0) {
+		*b++ = '0';
+		*b++ = '.';
+		for(; decpt < 0; decpt++)
+			*b++ = '0';
+		while((*b++ = *s++));
+		b--;
+		}
+	else {
+		while((*b = *s++)) {
+			b++;
+			if (--decpt == 0 && *s)
+				*b++ = '.';
+			}
+		for(; decpt > 0; decpt--)
+			*b++ = '0';
+		*b = 0;
+		}
+ done0:
+	freedtoa(s0);
+#ifdef IGNORE_ZERO_SIGN
+ done:
+#endif
+	return b - b0;
+	}