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