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Diffstat (limited to 'intl/icu/source/common/unicode/ucnv_cb.h')
| -rw-r--r-- | intl/icu/source/common/unicode/ucnv_cb.h | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/intl/icu/source/common/unicode/ucnv_cb.h b/intl/icu/source/common/unicode/ucnv_cb.h new file mode 100644 index 000000000..7104c7245 --- /dev/null +++ b/intl/icu/source/common/unicode/ucnv_cb.h @@ -0,0 +1,164 @@ +// Copyright (C) 2016 and later: Unicode, Inc. and others. +// License & terms of use: http://www.unicode.org/copyright.html +/* +********************************************************************** +* 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 |