ICU-4497 u_init() is not necessary any more for thread safety, and loads the converter alias table instead of the Unicode properties files (whose data is now hardcoded)

X-SVN-Rev: 17541

icu4c/source/common/uinit.c

@@ -20,6 +20,7 @@
 #include "ustr_imp.h"
 #include "unormimp.h"
 #include "ucln_cmn.h"
+#include "ucnv_io.h"
 #include "umutex.h"
 #include "ucln.h"
 #include "cmemory.h"
@@ -93,6 +94,23 @@ u_init(UErrorCode *status) {
         return;
     }
 
+#if 1
+    /*
+     * 2005-may-02
+     *
+     * ICU4C 3.4 (jitterbug 4497) hardcodes the data for Unicode character
+     * properties for APIs that want to be fast.
+     * Therefore, we need not load them here nor check for errors.
+     * Instead, we load the converter alias table to see if any ICU data
+     * is available.
+     * Users should really open the service objects they need and check
+     * for errors there, to make sure that the actual items they need are
+     * available.
+     */
+#if !UCONFIG_NO_CONVERSION
+    ucnv_io_countStandards(status);
+#endif
+#else
     /* Do any required init for services that don't have open operations
      * and use "only" the double-check initialization method for performance
      * reasons (avoiding a mutex lock even for _checking_ whether the
@@ -109,6 +127,7 @@ u_init(UErrorCode *status) {
 #if !UCONFIG_NO_NORMALIZATION
     /*  Normalization  */
     unorm_haveData(status);
+#endif
 #endif
     gICUInitialized = TRUE;    /* TODO:  don't set if U_FAILURE? */
     umtx_unlock(&gICUInitMutex);

icu4c/source/common/unicode/uclean.h

@@ -1,7 +1,7 @@
 /*
 ******************************************************************************
 *                                                                            *
-* Copyright (C) 2001-2004, International Business Machines                   *
+* Copyright (C) 2001-2005, International Business Machines                   *
 *                Corporation and others. All Rights Reserved.                *
 *                                                                            *
 ******************************************************************************
@@ -20,7 +20,20 @@
 #include "unicode/utypes.h"
 
 /**
- *  Initialize ICU.  This function loads and initializes data items
+ *  Initialize ICU. The description further below applies to ICU 2.6 to ICU 3.4.
+ *  Starting with ICU 3.4, u_init() needs not be called any more for
+ *  ensuring thread safety, but it can give an indication for whether ICU
+ *  can load its data. In ICU 3.4, it will try to load the converter alias table
+ *  (cnvalias.icu) and give an error code if that fails.
+ *  This may change in the future.
+ *  <p>
+ *  For ensuring the availability of necessary data, an application should
+ *  open the service objects (converters, collators, etc.) that it will use
+ *  and check for error codes there.
+ *  <p>
+ *  Documentation for ICU 2.6 to ICU 3.4:
+ *  <p>
+ *  This function loads and initializes data items
  *  that are required internally by various ICU functions.  Use of this explicit
  *  initialization is required in multi-threaded applications; in 
  *  single threaded apps, use is optional, but incurs little additional