completly new implementation for printf string upper bounds calculation.

Tue Oct 12 12:16:12 1999  Tim Janik  <timj@gtk.org>

        * gmessages.c (g_printf_string_upper_bound): completly new implementation
        for printf string upper bounds calculation.
        we handle all glibc 2.1 format specifiers now, except for positional
        parameters (%nn$...) and wide char strings, plus some obscure upper
        case variants of the standard conversions. this fixes a lot of
        bugs in the old code, i.e.
        - NULL format strings
        - floats with exponents >+24
        - %G
        - precision specifications in general
        - negative field widths
        - %p for SIZEOF_VOID_P > 4 platforms
        we now issue warnigns in places where the old code would have
        caused buffer overruns anyways. warnings are suppressed when invoked
        from glogv(), to avoid infinite recursions if someone passes a log
        message that comes with really obscure format specifications.

Tue Oct 12 11:49:00 1999  Tim Janik  <timj@gtk.org>

        * gstrfuncs.c: nuked old g_printf_string_upper_bound() version.

Tue Oct 12 03:34:40 1999  Tim Janik  <timj@gtk.org>

        * glib.h: added GFloatIEEE754 and GDoubleIEEE754 unions to access sign,
        mantissa and exponent of IEEE floats and doubles (required by the new
        version of g_printf_string_upper_bound). the unions are endian specific,
        we handle G_LITTLE_ENDIAN and G_BIG_ENDIAN as of currently. ieee floats
        and doubles are supported (used for storage) by at least intel, ppc and
        sparc, reference:
        http://twister.ou.edu/workshop.docs/common-tools/numerical_comp_guide/ncg_math.doc.html

Mon Oct 11 18:01:49 1999  Tim Janik  <timj@gtk.org>

        * configure.in: added additional checks to figure sizes of size_t,
        ptrdiff_t and intmax_t (required by g_printf_string_upper_bound).

1 files changed, 68 insertions, 0 deletions

diff --git a/glib.h b/glib.h
index 4300fd3e0..64670120b 100644
--- a/glib.h
+++ b/glib.h
@@ -690,6 +690,8 @@ typedef struct _GCache		GCache;
 typedef struct _GCompletion	GCompletion;
 typedef	struct _GData		GData;
 typedef struct _GDebugKey	GDebugKey;
+typedef union  _GDoubleIEEE754	GDoubleIEEE754;
+typedef union  _GFloatIEEE754	GFloatIEEE754;
 typedef struct _GHashTable	GHashTable;
 typedef struct _GHook		GHook;
 typedef struct _GHookList	GHookList;
@@ -870,6 +872,72 @@ struct _GTuples
 };
 
 
+/* IEEE Standard 754 Single Precision Storage Format (gfloat):
+ *
+ *        31 30           23 22            0
+ * +--------+---------------+---------------+
+ * | s 1bit | e[30:23] 8bit | f[22:0] 23bit |
+ * +--------+---------------+---------------+
+ * B0------------------->B1------->B2-->B3-->
+ *
+ * IEEE Standard 754 Double Precision Storage Format (gdouble):
+ *
+ *        63 62            52 51            32   31            0
+ * +--------+----------------+----------------+ +---------------+
+ * | s 1bit | e[62:52] 11bit | f[51:32] 20bit | | f[31:0] 32bit |
+ * +--------+----------------+----------------+ +---------------+
+ * B0--------------->B1---------->B2--->B3---->  B4->B5->B6->B7->
+ */
+/* subtract from biased_exponent to form base2 exponent (normal numbers) */
+#define G_IEEE754_FLOAT_BIAS	(127)
+#define G_IEEE754_DOUBLE_BIAS	(1023)
+/* multiply with base2 exponent to get base10 exponent (nomal numbers) */
+#define G_LOG_2_BASE_10		(0.30102999566398119521)
+#if G_BYTE_ORDER == G_LITTLE_ENDIAN
+union _GFloatIEEE754
+{
+  gfloat v_float;
+  struct {
+    guint mantissa : 23;
+    guint biased_exponent : 8;
+    guint sign : 1;
+  } mpn;
+};
+union _GDoubleIEEE754
+{
+  gdouble v_double;
+  struct {
+    guint mantissa_low : 32;
+    guint mantissa_high : 20;
+    guint biased_exponent : 11;
+    guint sign : 1;
+  } mpn;
+};
+#elif G_BYTE_ORDER == G_BIG_ENDIAN
+union _GFloatIEEE754
+{
+  gfloat v_float;
+  struct {
+    guint sign : 1;
+    guint biased_exponent : 8;
+    guint mantissa : 23;
+  } mpn;
+};
+union _GDoubleIEEE754
+{
+  gdouble v_double;
+  struct {
+    guint sign : 1;
+    guint biased_exponent : 11;
+    guint mantissa_high : 20;
+    guint mantissa_low : 32;
+  } mpn;
+};
+#else /* !G_LITTLE_ENDIAN && !G_BIG_ENDIAN */
+#error unknown ENDIAN type
+#endif /* !G_LITTLE_ENDIAN && !G_BIG_ENDIAN */
+
+
 /* Doubly linked lists
  */
 void   g_list_push_allocator    (GAllocator     *allocator);