ICU-124 charset detector, work in progress.

X-SVN-Rev: 17648

icu4c/source/common/unicode/utext.h

@@ -54,6 +54,24 @@
  *   (which would need to be passed in) became invalid during the operation.
  *   Same for copy().
  *
+ * - Single text iterator only.  Because UText owns the buffer for non-UTF-16 sources, there
+ *   can only be a single UTextIterator on a UText.  A second iterator could cause buffer
+ *   contents to be moved, while info about what's in the buffer in the first iterator would
+ *   not be updated.  
+ *
+ *     - Add some kind of failure status to construction of UTextIterator, to prevent
+ *       two from existing?  Seems hostile to developers.
+ *     - Make UText.clone() be shallow.  Don't clone the text, do clone the buffer so that
+ *       a second UTextIterator can be instantiated.   Developer hostile, again.
+ *     - Move the buffer from the UText to the UTextIterator.
+ *         - developer-friendly.
+ *         - NOP (good performance) on utf-16  strings.  (all can share a buffer)
+ *         - Extra allocation for buffer on utf-8, codepage data, etc.
+ *     - Use buffer in UText if available, otherwise allocate another
+ *         Complicated implementation.
+ *         Threading model?
+ *       
+ *
  * @see UText
  */
 
@@ -204,12 +222,10 @@ enum {
 /**
  * Function type declaration for UText.clone().
  *
- * clone this UText.  The cloned copy will refer to the same input text, and
- *    have the same current position as the original UText.  Subsequent iteration
- *    on the source and the copy UTexts operate independently of each other.
- *
- *   UText.clone() does not clone the underlying text itself.  Only the UText
- *   wrapper, including the interation position, is cloned.
+ * clone this UText.  
+ * Text providers are not required to support clone.
+ * Applications must be prepared for the possibility that clone is not supported.
+ * TODO:  should we just drop clone altogether?
  *
  * @return a pointer to the newly created copy of the UTex object.
  *         May return NULL if the object cannot be cloned.
@@ -514,7 +530,7 @@ U_NAMESPACE_BEGIN
  *
  *  UTextIterator    is the class used to access the text data that is
  *                   behind a UText object.  Services that receive text in the
- *                   form of a UText will instanitate one or more UTextIterators
+ *                   form of a UText will instanitate a UTextIterator
  *                   for this purpose.
  *
  *                   @draft ICU 3.4

icu4c/source/common/utext.cpp

@@ -451,6 +451,7 @@ utext_openUTF8(const uint8_t *s, int32_t length, UErrorCode *pErrorCode) {
     if(length>=0) {
         t8->length=length;
     } else {
+        // TODO:  really undesirable to do this scan upfront.
         t8->length=(int32_t)uprv_strlen((const char *)s);
     }
     return t8;

icu4c/source/test/intltest/utxttest.cpp

@@ -195,6 +195,29 @@ void UTextTest::TestAccess(UText *ut, int cpCount, m *cpMap) {
         }
     }
 
+    //
+    // moveIndex(int32_t delta);
+    //
+    uti.setIndex(0);
+    for (i=2; i<cpCount; i+=2) {
+        uti.moveIndex(2);
+        index = uti.getIndex();
+        expectedIndex = cpMap[i].nativeIdx;
+        TEST_ASSERT(expectedIndex == index);
+    }
+
+    i = cpMap[cpCount-1].nativeIdx;
+    uti.setIndex(i);
+    for (i=cpCount-1; i>=0; i-=3) {
+        index = uti.getIndex();
+        expectedIndex = cpMap[i].nativeIdx;
+        TEST_ASSERT(expectedIndex == index);
+        uti.moveIndex(-3);
+    }
+
+
+
+
 }