fp_toradix[_n]: revise and split up

src/bin/fp_toradix.c

@@ -9,77 +9,6 @@
  */
 #include <tfm.h>
 
-/**
- * a:		pointer to fp_int representing the input number
- * str:		output buffer
- * radix:	number of character to use for encoding of the number
- * maxlen:	maximum number of the buffer that can be used
- *
- * The radix value can be in the range 2 to 64. This function converts number
- * a into a string str. This function writes at most size bytes (including the
- * terminating null byte to str. It behaves like snprintf(3) in regard to this.
- *
- * Return: If invalid parameter are detected a negative value is returned. On
- * success the function returns the number of bytes that would be written if
- * the function had enough space. Thus a return value of maxlen or more means
- * that the function was not able store all characters and the output is
- * incomplete.
- */
-int fp_toradix_n(fp_int *a, char *str, int radix, unsigned int maxlen)
-{
-  int     digs;
-  fp_int  t;
-  fp_digit d;
-  char   *_s = str;
-  unsigned int wrote;
-
-  /* check range of the radix */
-  if (radix < 2 || radix > 64)
-    return -1;
-
-  /* quick check for zero */
-  if (fp_iszero(a) == 1) {
-    if (maxlen >= 2)
-       *str++ = '0';
-    if (maxlen >= 1)
-      *str = '\0';
-    return 1;
-  }
-
-  wrote = 0;
-
-  fp_init_copy(&t, a);
-
-  /* if it is negative output a - */
-  if (t.sign == FP_NEG) {
-    ++_s;
-    wrote++;
-    if (wrote < maxlen)
-      *str++ = '-';
-    t.sign = FP_ZPOS;
-  }
-
-  digs = 0;
-  while (fp_iszero (&t) == FP_NO) {
-    fp_div_d (&t, (fp_digit) radix, &t, &d);
-    wrote++;
-    if (wrote < maxlen)
-      *str++ = fp_s_rmap[d];
-    ++digs;
-  }
-
-  /* reverse the digits of the string.  In this case _s points
-   * to the first digit [exluding the sign] of the number]
-   */
-  if (wrote < maxlen)
-    fp_reverse ((unsigned char *)_s, digs);
-
-    /* append a NULL so the string is properly terminated */
-  if (maxlen >= 1)
-    *str = '\0';
-  return wrote;
-}
-
 /**
  * a:		pointer to fp_int representing the input number
  * str:		output buffer
@@ -94,10 +23,9 @@ int fp_toradix_n(fp_int *a, char *str, int radix, unsigned int maxlen)
  */
 int fp_toradix(fp_int *a, char *str, int radix)
 {
-  int ret;
-
-  ret = fp_toradix_n(a, str, radix, UINT_MAX);
-  if (ret < 0)
-    return FP_VAL;
-  return FP_OKAY;
+   return fp_toradix_n(a, str, radix, INT_MAX);
 }
+
+/* $Source$ */
+/* $Revision$ */
+/* $Date$ */

src/bin/fp_toradix_n.c

@@ -0,0 +1,85 @@
+/* TomsFastMath, a fast ISO C bignum library.
+ *
+ * This project is meant to fill in where LibTomMath
+ * falls short.  That is speed ;-)
+ *
+ * This project is public domain and free for all purposes.
+ *
+ * Tom St Denis, tomstdenis@gmail.com
+ */
+#include <tfm.h>
+
+/**
+ * a:		pointer to fp_int representing the input number
+ * str:		output buffer
+ * radix:	number of character to use for encoding of the number
+ * maxlen:	maximum number of the buffer that can be used
+ *
+ * The radix value can be in the range 2 to 64. This function converts number
+ * a into a string str. This function writes at most size bytes (including the
+ * terminating null byte to str. It behaves like snprintf(3) in regard to this.
+ *
+ * Return: If invalid parameter are detected a negative value is returned. On
+ * success the function returns the number of bytes that would be written if
+ * the function had enough space. Thus a return value of maxlen or more means
+ * that the function was not able store all characters and the output is
+ * incomplete.
+ */
+int fp_toradix_n(fp_int *a, char *str, int radix, int maxlen)
+{
+   int digs;
+   fp_int t;
+   fp_digit d;
+   char *_s = str;
+
+   /* check range of the radix */
+   if (maxlen < 2 || radix < 2 || radix > 64)
+      return FP_VAL;
+
+   /* quick check for zero */
+   if (fp_iszero(a) == FP_YES) {
+      *str++ = '0';
+      *str = '\0';
+      return FP_OKAY;
+   }
+
+   fp_init_copy(&t, a);
+
+   /* if it is negative output a - */
+   if (t.sign == FP_NEG) {
+      /* we have to reverse our digits later... but not the - sign!! */
+      ++_s;
+
+      /* store the flag and mark the number as positive */
+      *str++ = '-';
+      t.sign = FP_ZPOS;
+
+      /* subtract a char */
+      --maxlen;
+   }
+
+   digs = 0;
+   while (fp_iszero (&t) == FP_NO) {
+      if (--maxlen < 1) {
+         /* no more room */
+         break;
+      }
+      fp_div_d(&t, (fp_digit) radix, &t, &d);
+      *str++ = fp_s_rmap[d];
+      ++digs;
+   }
+
+   /* reverse the digits of the string.  In this case _s points
+    * to the first digit [exluding the sign] of the number]
+    */
+   fp_reverse((unsigned char *) _s, digs);
+
+   /* append a NULL so the string is properly terminated */
+   *str = '\0';
+
+   return FP_OKAY;
+}
+
+/* $Source$ */
+/* $Revision$ */
+/* $Date$ */

src/headers/tfm.h

@@ -465,7 +465,7 @@ int fp_read_radix(fp_int *a, char *str, int radix);
 
 int fp_radix_size(fp_int *a, int radix, int *size);
 int fp_toradix(fp_int *a, char *str, int radix);
-int fp_toradix_n(fp_int * a, char *str, int radix, unsigned int maxlen);
+int fp_toradix_n(fp_int * a, char *str, int radix, int maxlen);
 
 
 /* VARIOUS LOW LEVEL STUFFS */