From 932759f00a750bb9c488d22265394f15612f39b1 Mon Sep 17 00:00:00 2001
From: George Rhoten <grhoten@users.noreply.github.com>
Date: Sat, 30 Sep 2006 22:35:25 +0000
Subject: [PATCH] ICU-5426 Make it easier to change the size of the converter
 hash table depending on the platform.

X-SVN-Rev: 20464
---
 icu4c/source/common/ucnv_bld.c | 14 +++++++++++++-
 icu4c/source/common/ucnv_io.c  |  4 ++--
 icu4c/source/common/ucnv_io.h  |  5 ++---
 icu4c/source/common/uinit.c    |  2 +-
 4 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/icu4c/source/common/ucnv_bld.c b/icu4c/source/common/ucnv_bld.c
index 62e1609f08..b4bf90174f 100644
--- a/icu4c/source/common/ucnv_bld.c
+++ b/icu4c/source/common/ucnv_bld.c
@@ -363,6 +363,15 @@ getAlgorithmicTypeFromName(const char *realName)
     return NULL;
 }
 
+/*
+* Based on the number of known converters, this determines how many times larger
+* the shared data hash table should be. When on small platforms, or just a couple
+* of converters are used, this number should be 2. When memory is plentiful, or
+* when ucnv_countAvailable is ever used, this should be 4.
+* Larger numbers reduce the number of hash collisions, but use more memory.
+*/
+#define UCNV_CACHE_LOAD_FACTOR 4
+
 /* Puts the shared data in the static hashtable SHARED_DATA_HASHTABLE */
 /*   Will always be called with the cnvCacheMutex alrady being held   */
 /*     by the calling function.                                       */
@@ -379,7 +388,7 @@ ucnv_shareConverterData(UConverterSharedData * data)
     if (SHARED_DATA_HASHTABLE == NULL)
     {
         SHARED_DATA_HASHTABLE = uhash_openSize(uhash_hashChars, uhash_compareChars, NULL,
-                            ucnv_io_countTotalAliases(&err),
+                            ucnv_io_countKnownConverters(&err)*UCNV_CACHE_LOAD_FACTOR,
                             &err);
         ucln_common_registerCleanup(UCLN_COMMON_UCNV, ucnv_cleanup);
 
@@ -1040,6 +1049,9 @@ static UBool haveAvailableConverterList(UErrorCode *pErrorCode) {
             return FALSE;
         }
 
+        /* Open the default converter to make sure that it has first dibs in the hash table. */
+        ucnv_close(ucnv_createConverter(&tempConverter, NULL, &localStatus));
+
         localConverterCount = 0;
 
         for (idx = 0; idx < allConverterCount; idx++) {
diff --git a/icu4c/source/common/ucnv_io.c b/icu4c/source/common/ucnv_io.c
index 4e570e55d9..8af52ce987 100644
--- a/icu4c/source/common/ucnv_io.c
+++ b/icu4c/source/common/ucnv_io.c
@@ -1069,9 +1069,9 @@ ucnv_openAllNames(UErrorCode *pErrorCode) {
 }
 
 U_CFUNC uint16_t
-ucnv_io_countTotalAliases(UErrorCode *pErrorCode) {
+ucnv_io_countKnownConverters(UErrorCode *pErrorCode) {
     if (haveAliasData(pErrorCode)) {
-        return (uint16_t)gMainTable.aliasListSize;
+        return (uint16_t)gMainTable.converterListSize;
     }
     return 0;
 }
diff --git a/icu4c/source/common/ucnv_io.h b/icu4c/source/common/ucnv_io.h
index 91bc6e5916..060ffd0595 100644
--- a/icu4c/source/common/ucnv_io.h
+++ b/icu4c/source/common/ucnv_io.h
@@ -95,13 +95,12 @@ U_CFUNC const char *
 ucnv_io_getConverterName(const char *alias, UBool *containsOption, UErrorCode *pErrorCode);
 
 /**
- * Return the number of all aliases and converter names.
- * This is helpful if you need a number for creating an alias table.
+ * Return the number of all known converter names (no aliases).
  * @param pErrorCode The error code
  * @return the number of all aliases
  */
 U_CFUNC uint16_t
-ucnv_io_countTotalAliases(UErrorCode *pErrorCode);
+ucnv_io_countKnownConverters(UErrorCode *pErrorCode);
 
 /**
  * Swap an ICU converter alias table. See implementation for details.
diff --git a/icu4c/source/common/uinit.c b/icu4c/source/common/uinit.c
index a70e51d0e6..56b686b365 100644
--- a/icu4c/source/common/uinit.c
+++ b/icu4c/source/common/uinit.c
@@ -85,7 +85,7 @@ u_init(UErrorCode *status) {
      * available.
      */
 #if !UCONFIG_NO_CONVERSION
-    ucnv_io_countTotalAliases(status);
+    ucnv_io_countKnownConverters(status);
 #endif
 #else
     /* Do any required init for services that don't have open operations