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Message-ID: <44A303DE.9080209@duigou.org>
Date: Wed, 28 Jun 2006 15:34:06 -0700
From: Mike Duigou <apr-dev@duigou.org>
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To: dev@apr.apache.org
Subject: Re: apr_uint8_t and apr_int8_t?
References: <44A1C6AF.6010601@duigou.org> <44A1C831.8060907@rowe-clan.net>
 <44A2B0B3.2000608@duigou.org> <44A2D544.3040301@rowe-clan.net>
In-Reply-To: <44A2D544.3040301@rowe-clan.net>
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A patch to add apr_uint8_t and apr_int8_t to apr.h is attached. It also 
ensures that CHAR_BIT is 8 bits (it normally is) and that short_value 
and long_value are defined.

Mike

William A. Rowe, Jr. wrote:
> I can definitely see your point.  Although it's not the highest priority,
> we would certainly consider a patch to effect this behavior.
> 
> Yours,
> 
> Bill
> 
> Mike Duigou wrote:
>> I'm motivated to ask to this for wire protocols which are defined with 
>> specific bit sizes. char and unsigned char are not defined to be 
>> *exactly* 8 bits and are apparently not 8 bits in some esoteric 
>> environments.
>>
>> The C standard 5.2.4.2.1 requires that char and unsigned char be *at 
>> least* 8 bits but does not fix a value. So assuming that UCHAR_MAX is 
>> 255 is just as unwise as assuming that UINT_MAX is 65535 or 4294967295.
>>
>> This request is also partially for completeness with the other bit 
>> sized scalar typedefs.
>>
>> Mike
>>
>> William A. Rowe, Jr. wrote:
>>> Can you give us any example where signed char, unsigned char don't
>>> fit the bill?
>>>
>>> Bill
>>>
>>> Mike Duigou wrote:
>>>> Hi!
>>>>
>>>> Would it be possible to add definitions for apr_uint8_t and 
>>>> apr_int8_t to apr.h? This appears to have been previously requested 
>>>> in 2001 
>>>> (http://mail-archives.apache.org/mod_mbox/apr-dev/200105.mbox/%3CJLEGKKNELMHCJPNMOKHOGELPDOAA.striker@samba-tng.org%3E) 
>>>> but I don't see any response indicating why the change was never made.
>>>>
>>>> Mike
>>>>
>>>> .
>>>>
>>>
>>>
>>>
>>
>>
>>
> 
> 


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Index: include/apr.h.in
===================================================================
--- include/apr.h.in	(revision 417882)
+++ include/apr.h.in	(working copy)
@@ -254,8 +254,11 @@
 
 /* Typedefs that APR needs. */
 
-typedef  unsigned char           apr_byte_t;
+typedef  unsigned @byte_value@   apr_byte_t;
 
+typedef  @byte_value@            apr_int8_t;
+typedef  unsigned @byte_value@   apr_uint8_t;
+
 typedef  @short_value@           apr_int16_t;
 typedef  unsigned @short_value@  apr_uint16_t;
                                                
Index: configure.in
===================================================================
--- configure.in	(revision 417882)
+++ configure.in	(working copy)
@@ -1098,6 +1098,21 @@
 fi
 
 dnl ----------------------------- Checks for standard typedefs
+echo "${nl}Checking for Standard Typedefs..."
+
+dnl Check that CHAR_BIT is an octect (8-bits) in length.
+AC_DEFUN([AC_C_CHAR_BIT_OCTET],
+[AC_CACHE_CHECK([if CHAR_BIT is octet on this platform], ac_cv_decl_char_bit_octet,
+[AC_EGREP_CPP(octet,
+[#ifdef HAVE_LIMITS_H
+#include <limits.h>
+#endif
+#if CHAR_BIT == 8
+octet
+#endif], ac_cv_decl_char_bit_octet=yes, ac_cv_decl_char_bit_octet=no)
+])
+])
+
 AC_TYPE_OFF_T
 AC_TYPE_PID_T
 AC_TYPE_SIZE_T
@@ -1119,18 +1134,34 @@
 fi
 
 dnl Checks for integer size
+AC_C_CHAR_BIT_OCTET
 AC_CHECK_SIZEOF(char, 1)
 AC_CHECK_SIZEOF(int, 4)
 AC_CHECK_SIZEOF(long, 4)
 AC_CHECK_SIZEOF(short, 2)
 AC_CHECK_SIZEOF(long long, 8)
 
+if test "$ac_cv_decl_char_bit_octet" = "yes"; then
+    byte_value=char
+else
+    # no known value for 8 bit type
+    AC_ERROR([could not detect a 8-bit integer type])
+fi
+
 if test "$ac_cv_sizeof_short" = "2"; then
     short_value=short
+else
+    # no known value for 16 bit type
+    AC_ERROR([could not detect a 16-bit integer type])
 fi
+
 if test "$ac_cv_sizeof_int" = "4"; then
     int_value=int
+else
+    # no known value for 32 bit type
+    AC_ERROR([could not detect a 32-bit integer type])
 fi
+
 # Now we need to find what apr_int64_t (sizeof == 8) will be.
 # The first match is our preference.
 if test "$ac_cv_sizeof_int" = "8"; then
@@ -1360,6 +1391,7 @@
 esac
 
 AC_SUBST(voidp_size)
+AC_SUBST(byte_value)
 AC_SUBST(short_value)
 AC_SUBST(int_value)
 AC_SUBST(long_value)

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