1 files changed, 104 insertions, 0 deletions

diff --git a/g_fmt.c b/g_fmt.c
new file mode 100644
index 0000000..543430a
--- /dev/null
+++ b/g_fmt.c
@@ -0,0 +1,104 @@
+/****************************************************************
+ *
+ * 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 char *g_fmt(char *, double);
+ extern void freedtoa(char*);
+#ifdef __cplusplus
+        }
+#endif
+
+ char *
+g_fmt(register char *b, double x)
+{
+        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, 0, 0, &decpt, &sign, &se);
+        if (sign)
+                *b++ = '-';
+        if (decpt == 9999) /* Infinity or Nan */ {
+                while(*b++ = *s++);
+                goto done0;
+                }
+        if (decpt <= -4 || decpt > se - s + 5) {
+                *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++ = '.';
+                for(; decpt < 0; decpt++)
+                        *b++ = '0';
+                while(*b++ = *s++);
+                }
+        else {
+                while(*b = *s++) {
+                        b++;
+                        if (--decpt == 0 && *s)
+                                *b++ = '.';
+                        }
+                for(; decpt > 0; decpt--)
+                        *b++ = '0';
+                *b = 0;
+                }
+ done0:
+        freedtoa(s0);
+ done:
+        return b0;
+        }