From d4ebc2590dfa535ec700d950eb8c4c03359fdb2b Mon Sep 17 00:00:00 2001
From: Syn Wee Quek <swquek@svn.icu-project.org>
Date: Fri, 9 Mar 2001 18:25:30 +0000
Subject: [PATCH] ICU-861 Updated previous iterator for Thai collation.

X-SVN-Rev: 3996
---
 icu4c/source/i18n/ucol_imp.h   | 13 ++++++++++---
 icu4c/source/i18n/ucoleitr.cpp | 27 ++++++++++++++++++---------
 2 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/icu4c/source/i18n/ucol_imp.h b/icu4c/source/i18n/ucol_imp.h
index e7b41521a2..e620e5a8de 100644
--- a/icu4c/source/i18n/ucol_imp.h
+++ b/icu4c/source/i18n/ucol_imp.h
@@ -277,9 +277,16 @@ struct incrementalContext {
       if (ch <= 0xFF) {                                                      \
         (order) = (coll)->latinOneMapping[ch];                               \
       }                                                                      \
-      else {                                                                 \
-        (order) = ucmp32_get((coll)->mapping, ch);                           \
-      }                                                                      \
+      else                                                                   \
+        if ((data).isThai && UCOL_ISTHAIBASECONSONANT(ch) &&                 \
+               ((data).pos) != (data).string &&                              \
+               ((data).pos) != (data).writableBuffer &&                      \
+               UCOL_ISTHAIPREVOWEL(*((data).pos -1))) {                      \
+          result = UCOL_THAI;                                                \
+        }                                                                    \
+        else {                                                               \
+          (result) = ucmp32_get((coll)->mapping, ch);                        \
+        }                                                                    \
       if ((order) >= UCOL_NOT_FOUND) {                                       \
         (order) = getSpecialPrevCE((coll), (order), &(data), (length),       \
                                                              (status));      \
diff --git a/icu4c/source/i18n/ucoleitr.cpp b/icu4c/source/i18n/ucoleitr.cpp
index 86477afff5..ac2bf14923 100644
--- a/icu4c/source/i18n/ucoleitr.cpp
+++ b/icu4c/source/i18n/ucoleitr.cpp
@@ -105,10 +105,8 @@ ucol_next(UCollationElements *elems,
   }
 
   elems->reset_ = FALSE;
-  
-  UCOL_GETNEXTCE(result, elems->collator_, elems->iteratordata_, status);
 
-#ifdef UCOL_DEBUG
+#ifdef _DEBUG
   if ((elems->iteratordata_).CEpos > (elems->iteratordata_).toReturn) 
     {                       
       result = *((elems->iteratordata_).toReturn++);                                      
@@ -135,6 +133,8 @@ ucol_next(UCollationElements *elems,
       } 
       else
         (result) = UCOL_NO_MORE_CES;
+#else
+      UCOL_GETNEXTCE(result, elems->collator_, elems->iteratordata_, status);
 #endif
   
   if (result == UCOL_NO_MORE_CES) {
@@ -160,10 +160,7 @@ ucol_previous(UCollationElements *elems,
 
     elems->reset_ = FALSE;
 
-    UCOL_GETPREVCE(result, elems->collator_, elems->iteratordata_, 
-                   elems->length_, status);
-
-#ifdef UCOL_DEBUG
+#ifdef _DEBUG
     const UCollator   *coll  = elems->collator_;
           collIterate *data  = &(elems->iteratordata_);
           int32_t     length = elems->length_;
@@ -186,8 +183,17 @@ ucol_previous(UCollationElements *elems,
         UChar ch = *(data->pos);
         if (ch <= 0xFF)                                                
           (result) = (coll)->latinOneMapping[ch];                                                                                       
-        else
-          (result) = ucmp32_get((coll)->mapping, ch);                           
+        else {
+          if (data->isThai && UCOL_ISTHAIBASECONSONANT(ch) && 
+                (data->pos) != data->string &&
+                (data->pos) != data->writableBuffer &&
+                UCOL_ISTHAIPREVOWEL(*(data->pos -1))) {
+            result = UCOL_THAI;                     
+         }
+          else {
+            (result) = ucmp32_get((coll)->mapping, ch);
+         }
+        }
                                                                        
         if ((result) >= UCOL_NOT_FOUND) 
         {
@@ -197,6 +203,9 @@ ucol_previous(UCollationElements *elems,
         }                                                                      
       }                                                                        
     } 
+#else
+    UCOL_GETPREVCE(result, elems->collator_, elems->iteratordata_, 
+                   elems->length_, status);
 #endif
     
     if (result == UCOL_NO_MORE_CES) {