Check in the pristine copy of ICU 4.6...

icu46/source/common/unicode/ucnv_cb.h

+/*
+**********************************************************************
+*   Copyright (C) 2000-2004, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+**********************************************************************
+ *  ucnv_cb.h:
+ *  External APIs for the ICU's codeset conversion library
+ *  Helena Shih
+ * 
+ * Modification History:
+ *
+ *   Date        Name        Description
+ */
+
+/**
+ * \file 
+ * \brief C UConverter functions to aid the writers of callbacks
+ *
+ * <h2> Callback API for UConverter </h2>
+ * 
+ * These functions are provided here for the convenience of the callback
+ * writer. If you are just looking for callback functions to use, please
+ * see ucnv_err.h.  DO NOT call these functions directly when you are 
+ * working with converters, unless your code has been called as a callback
+ * via ucnv_setFromUCallback or ucnv_setToUCallback !!
+ * 
+ * A note about error codes and overflow.  Unlike other ICU functions,
+ * these functions do not expect the error status to be U_ZERO_ERROR.
+ * Callbacks must be much more careful about their error codes.
+ * The error codes used here are in/out parameters, which should be passed
+ * back in the callback's error parameter.
+ * 
+ * For example, if you call ucnv_cbfromUWriteBytes to write data out 
+ * to the output codepage, it may return U_BUFFER_OVERFLOW_ERROR if 
+ * the data did not fit in the target. But this isn't a failing error, 
+ * in fact, ucnv_cbfromUWriteBytes may be called AGAIN with the error
+ * status still U_BUFFER_OVERFLOW_ERROR to attempt to write further bytes,
+ * which will also go into the internal overflow buffers.
+ * 
+ * Concerning offsets, the 'offset' parameters here are relative to the start
+ * of SOURCE.  For example, Suppose the string "ABCD" was being converted 
+ * from Unicode into a codepage which doesn't have a mapping for 'B'.
+ * 'A' will be written out correctly, but
+ * The FromU Callback will be called on an unassigned character for 'B'.
+ * At this point, this is the state of the world:
+ *    Target:    A [..]     [points after A]
+ *    Source:  A B [C] D    [points to C - B has been consumed]
+ *             0 1  2  3 
+ *    codePoint = "B"       [the unassigned codepoint] 
+ * 
+ * Now, suppose a callback wants to write the substitution character '?' to
+ * the target. It calls ucnv_cbFromUWriteBytes() to write the ?. 
+ * It should pass ZERO as the offset, because the offset as far as the 
+ * callback is concerned is relative to the SOURCE pointer [which points 
+ * before 'C'.]  If the callback goes into the args and consumes 'C' also,
+ * it would call FromUWriteBytes with an offset of 1 (and advance the source
+ * pointer).
+ *
+ */
+
+#ifndef UCNV_CB_H
+#define UCNV_CB_H
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_CONVERSION
+
+#include "unicode/ucnv.h"
+#include "unicode/ucnv_err.h"
+
+/**
+ * ONLY used by FromU callback functions.
+ * Writes out the specified byte output bytes to the target byte buffer or to converter internal buffers.
+ *
+ * @param args callback fromUnicode arguments
+ * @param source source bytes to write
+ * @param length length of bytes to write
+ * @param offsetIndex the relative offset index from callback.
+ * @param err error status. If <TT>U_BUFFER_OVERFLOW</TT> is returned, then U_BUFFER_OVERFLOW <STRONG>must</STRONG> 
+ * be returned to the user, because it means that not all data could be written into the target buffer, and some is 
+ * in the converter error buffer.
+ * @see ucnv_cbFromUWriteSub
+ * @stable ICU 2.0
+ */
+U_STABLE void U_EXPORT2
+ucnv_cbFromUWriteBytes (UConverterFromUnicodeArgs *args,
+                        const char* source,
+                        int32_t length,
+                        int32_t offsetIndex,
+                        UErrorCode * err);
+
+/**
+ * ONLY used by FromU callback functions.  
+ * This function will write out the correct substitution character sequence 
+ * to the target.
+ *
+ * @param args callback fromUnicode arguments
+ * @param offsetIndex the relative offset index from the current source pointer to be used
+ * @param err error status. If <TT>U_BUFFER_OVERFLOW</TT> is returned, then U_BUFFER_OVERFLOW <STRONG>must</STRONG> 
+ * be returned to the user, because it means that not all data could be written into the target buffer, and some is 
+ * in the converter error buffer.
+ * @see ucnv_cbFromUWriteBytes
+ * @stable ICU 2.0
+ */
+U_STABLE void U_EXPORT2 
+ucnv_cbFromUWriteSub (UConverterFromUnicodeArgs *args,
+                      int32_t offsetIndex,
+                      UErrorCode * err);
+
+/**
+ * ONLY used by fromU callback functions.  
+ * This function will write out the error character(s) to the target UChar buffer.
+ *
+ * @param args callback fromUnicode arguments
+ * @param source pointer to pointer to first UChar to write [on exit: 1 after last UChar processed]
+ * @param sourceLimit pointer after last UChar to write
+ * @param offsetIndex the relative offset index from callback which will be set
+ * @param err error status <TT>U_BUFFER_OVERFLOW</TT>
+ * @see ucnv_cbToUWriteSub
+ * @stable ICU 2.0
+ */
+U_STABLE void U_EXPORT2 ucnv_cbFromUWriteUChars(UConverterFromUnicodeArgs *args,
+                             const UChar** source,
+                             const UChar*  sourceLimit,
+                             int32_t offsetIndex,
+                             UErrorCode * err);
+
+/**
+ * ONLY used by ToU callback functions.
+ *  This function will write out the specified characters to the target 
+ * UChar buffer.
+ *
+ * @param args callback toUnicode arguments
+ * @param source source string to write
+ * @param length the length of source string
+ * @param offsetIndex the relative offset index which will be written.
+ * @param err error status <TT>U_BUFFER_OVERFLOW</TT>
+ * @see ucnv_cbToUWriteSub
+ * @stable ICU 2.0
+ */
+U_STABLE void U_EXPORT2 ucnv_cbToUWriteUChars (UConverterToUnicodeArgs *args,
+                                             const UChar* source,
+                                             int32_t length,
+                                             int32_t offsetIndex,
+                                             UErrorCode * err);
+
+/**
+ * ONLY used by ToU  callback functions.  
+ * This function will write out the Unicode substitution character (U+FFFD).
+ *
+ * @param args callback fromUnicode arguments
+ * @param offsetIndex the relative offset index from callback.
+ * @param err error status <TT>U_BUFFER_OVERFLOW</TT>
+ * @see ucnv_cbToUWriteUChars
+ * @stable ICU 2.0
+ */
+U_STABLE void U_EXPORT2 ucnv_cbToUWriteSub (UConverterToUnicodeArgs *args,
+                       int32_t offsetIndex,
+                       UErrorCode * err);
+#endif
+
+#endif