Fix fencepost bugs in binary radix writing.

diff --git a/mptext.c b/mptext.c
index 565322d..40e1764 100644 (file)
--- a/mptext.c
+++ b/mptext.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: mptext.c,v 1.14 2002/10/09 00:33:44 mdw Exp $
+ * $Id: mptext.c,v 1.15 2002/10/15 19:18:15 mdw Exp $
  *
  * Textual representation of multiprecision numbers
  *
@@ -30,6 +30,9 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: mptext.c,v $
+ * Revision 1.15  2002/10/15 19:18:15  mdw
+ * Fix fencepost bugs in binary radix writing.
+ *
  * Revision 1.14  2002/10/09 00:33:44  mdw
  * Allow `0o' and `0b' prefixes for octal and binary (from Haskell)
  *
@@ -629,11 +632,12 @@ static int binary(mp *m, int bit, int radix, const mptext_ops *ops, void *p)
   /* --- Work out where to start --- */
 
   n = mp_bits(m);
-  n += bit - (n % bit);
+  if (n % bit)
+    n += bit - (n % bit);
   b = n % MPW_BITS;
   n /= MPW_BITS;
-  
-  if (n > MP_LEN(m)) {
+
+  if (n >= MP_LEN(m)) {
     n--;
     b += MPW_BITS;
   }
@@ -704,6 +708,9 @@ int mp_write(mp *m, int radix, const mptext_ops *ops, void *p)
 {
   int rc;
 
+  if (MP_EQ(m, MP_ZERO))
+    return (ops->put("0", 1, p));
+
   /* --- Set various things up --- */
 
   m = MP_COPY(m);

diff --git a/tests/mptext b/tests/mptext
index c6f7a8b..db6ed83 100644 (file)
--- a/tests/mptext
+++ b/tests/mptext
@@ -1,6 +1,6 @@
 # Test vectors for MP textual I/O
 #
-# $Id: mptext,v 1.9 2002/10/09 00:34:57 mdw Exp $
+# $Id: mptext,v 1.10 2002/10/15 19:18:15 mdw Exp $
 
 mptext-ascii {
   # --- Perfectly valid things ---
@@ -49,6 +49,7 @@ mptext-ascii {
 
   # --- Word-boundary tests for binary-radix translation ---
 
+  0 0                                  16 0;
   8 1234567012                         8 1234567012;
   8 12345670123                                8 12345670123;
   8 123456701234                       8 123456701234;
@@ -57,6 +58,8 @@ mptext-ascii {
   16 12345678                          16 12345678;
   16 123456789                         16 123456789;
 
+  10 -4009356060                       16 -eef9eb1c;
+
   # --- Bugs ---
 
   16 84d192cd06ae59691897fa409da6198d5269325d