+ * Specify whether block separators must be allocated level zero,
+ * so that successive paragraphs will progress from left to right.
+ * This function must be called before <code>ubidi_setPara()</code>.
+ * Paragraph separators (B) may appear in the text. Setting them to level zero
+ * means that all paragraph separators (including one possibly appearing
+ * in the last text position) are kept in the reordered text after the text
+ * that they follow in the source text.
+ * When this feature is not enabled, a paragraph separator at the last
+ * position of the text before reordering will go to the first position
+ * of the reordered text when the paragraph level is odd.
+ *
+ * @param pBiDi is a <code>UBiDi</code> object.
+ *
+ * @param orderParagraphsLTR specifies whether paragraph separators (B) must
+ * receive level 0, so that successive paragraphs progress from left to right.
+ *
+ * @see ubidi_setPara
+ * @stable ICU 3.4
+ */
+U_STABLE void U_EXPORT2
+ubidi_orderParagraphsLTR(UBiDi *pBiDi, UBool orderParagraphsLTR);
+
+/**
+ * Is this Bidi object set to allocate level 0 to block separators so that
+ * successive paragraphs progress from left to right?
+ *
+ * @param pBiDi is a <code>UBiDi</code> object.
+ * @return TRUE if the Bidi object is set to allocate level 0 to block
+ * separators.
+ *
+ * @see ubidi_orderParagraphsLTR
+ * @stable ICU 3.4
+ */
+U_STABLE UBool U_EXPORT2
+ubidi_isOrderParagraphsLTR(UBiDi *pBiDi);
+
+/**
+ * <code>UBiDiReorderingMode</code> values indicate which variant of the Bidi
+ * algorithm to use.
+ *
+ * @see ubidi_setReorderingMode
+ * @stable ICU 3.6
+ */
+typedef enum UBiDiReorderingMode {
+ /** Regular Logical to Visual Bidi algorithm according to Unicode.
+ * This is a 0 value.
+ * @stable ICU 3.6 */
+ UBIDI_REORDER_DEFAULT = 0,
+ /** Logical to Visual algorithm which handles numbers in a way which
+ * mimicks the behavior of Windows XP.
+ * @stable ICU 3.6 */
+ UBIDI_REORDER_NUMBERS_SPECIAL,
+ /** Logical to Visual algorithm grouping numbers with adjacent R characters
+ * (reversible algorithm).
+ * @stable ICU 3.6 */
+ UBIDI_REORDER_GROUP_NUMBERS_WITH_R,
+ /** Reorder runs only to transform a Logical LTR string to the Logical RTL
+ * string with the same display, or vice-versa.<br>
+ * If this mode is set together with option
+ * <code>#UBIDI_OPTION_INSERT_MARKS</code>, some Bidi controls in the source
+ * text may be removed and other controls may be added to produce the
+ * minimum combination which has the required display.
+ * @stable ICU 3.6 */
+ UBIDI_REORDER_RUNS_ONLY,
+ /** Visual to Logical algorithm which handles numbers like L
+ * (same algorithm as selected by <code>ubidi_setInverse(TRUE)</code>.
+ * @see ubidi_setInverse
+ * @stable ICU 3.6 */
+ UBIDI_REORDER_INVERSE_NUMBERS_AS_L,
+ /** Visual to Logical algorithm equivalent to the regular Logical to Visual
+ * algorithm.
+ * @stable ICU 3.6 */
+ UBIDI_REORDER_INVERSE_LIKE_DIRECT,
+ /** Inverse Bidi (Visual to Logical) algorithm for the
+ * <code>UBIDI_REORDER_NUMBERS_SPECIAL</code> Bidi algorithm.
+ * @stable ICU 3.6 */
+ UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL,
+ /** Number of values for reordering mode.
+ * @stable ICU 3.6 */
+ UBIDI_REORDER_COUNT
+} UBiDiReorderingMode;
+
+/**
+ * Modify the operation of the Bidi algorithm such that it implements some
+ * variant to the basic Bidi algorithm or approximates an "inverse Bidi"
+ * algorithm, depending on different values of the "reordering mode".
+ * This function must be called before <code>ubidi_setPara()</code>, and stays
+ * in effect until called again with a different argument.
+ *
+ * <p>The normal operation of the Bidi algorithm as described
+ * in the Unicode Standard Annex #9 is to take text stored in logical
+ * (keyboard, typing) order and to determine how to reorder it for visual
+ * rendering.</p>
+ *
+ * <p>With the reordering mode set to a value other than
+ * <code>#UBIDI_REORDER_DEFAULT</code>, this function changes the behavior of
+ * some of the subsequent functions in a way such that they implement an
+ * inverse Bidi algorithm or some other algorithm variants.</p>
+ *
+ * <p>Some legacy systems store text in visual order, and for operations
+ * with standard, Unicode-based algorithms, the text needs to be transformed
+ * into logical order. This is effectively the inverse algorithm of the
+ * described Bidi algorithm. Note that there is no standard algorithm for
+ * this "inverse Bidi", so a number of variants are implemented here.</p>
+ *
+ * <p>In other cases, it may be desirable to emulate some variant of the
+ * Logical to Visual algorithm (e.g. one used in MS Windows), or perform a
+ * Logical to Logical transformation.</p>
+ *
+ * <ul>
+ * <li>When the reordering mode is set to <code>#UBIDI_REORDER_DEFAULT</code>,
+ * the standard Bidi Logical to Visual algorithm is applied.</li>
+ *
+ * <li>When the reordering mode is set to
+ * <code>#UBIDI_REORDER_NUMBERS_SPECIAL</code>,
+ * the algorithm used to perform Bidi transformations when calling
+ * <code>ubidi_setPara</code> should approximate the algorithm used in
+ * Microsoft Windows XP rather than strictly conform to the Unicode Bidi
+ * algorithm.
+ * <br>
+ * The differences between the basic algorithm and the algorithm addressed
+ * by this option are as follows:
+ * <ul>
+ * <li>Within text at an even embedding level, the sequence "123AB"
+ * (where AB represent R or AL letters) is transformed to "123BA" by the
+ * Unicode algorithm and to "BA123" by the Windows algorithm.</li>
+ * <li>Arabic-Indic numbers (AN) are handled by the Windows algorithm just
+ * like regular numbers (EN).</li>
+ * </ul></li>
+ *
+ * <li>When the reordering mode is set to
+ * <code>#UBIDI_REORDER_GROUP_NUMBERS_WITH_R</code>,
+ * numbers located between LTR text and RTL text are associated with the RTL
+ * text. For instance, an LTR paragraph with content "abc 123 DEF" (where
+ * upper case letters represent RTL characters) will be transformed to
+ * "abc FED 123" (and not "abc 123 FED"), "DEF 123 abc" will be transformed
+ * to "123 FED abc" and "123 FED abc" will be transformed to "DEF 123 abc".
+ * This makes the algorithm reversible and makes it useful when round trip
+ * (from visual to logical and back to visual) must be achieved without
+ * adding LRM characters. However, this is a variation from the standard
+ * Unicode Bidi algorithm.<br>
+ * The source text should not contain Bidi control characters other than LRM
+ * or RLM.</li>
+ *
+ * <li>When the reordering mode is set to
+ * <code>#UBIDI_REORDER_RUNS_ONLY</code>,
+ * a "Logical to Logical" transformation must be performed:
+ * <ul>
+ * <li>If the default text level of the source text (argument <code>paraLevel</code>
+ * in <code>ubidi_setPara</code>) is even, the source text will be handled as
+ * LTR logical text and will be transformed to the RTL logical text which has
+ * the same LTR visual display.</li>
+ * <li>If the default level of the source text is odd, the source text
+ * will be handled as RTL logical text and will be transformed to the
+ * LTR logical text which has the same LTR visual display.</li>
+ * </ul>
+ * This mode may be needed when logical text which is basically Arabic or
+ * Hebrew, with possible included numbers or phrases in English, has to be
+ * displayed as if it had an even embedding level (this can happen if the
+ * displaying application treats all text as if it was basically LTR).
+ * <br>
+ * This mode may also be needed in the reverse case, when logical text which is
+ * basically English, with possible included phrases in Arabic or Hebrew, has to
+ * be displayed as if it had an odd embedding level.
+ * <br>
+ * Both cases could be handled by adding LRE or RLE at the head of the text,
+ * if the display subsystem supports these formatting controls. If it does not,
+ * the problem may be handled by transforming the source text in this mode
+ * before displaying it, so that it will be displayed properly.<br>
+ * The source text should not contain Bidi control characters other than LRM
+ * or RLM.</li>
+ *
+ * <li>When the reordering mode is set to
+ * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>, an "inverse Bidi" algorithm
+ * is applied.
+ * Runs of text with numeric characters will be treated like LTR letters and
+ * may need to be surrounded with LRM characters when they are written in
+ * reordered sequence (the option <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> can
+ * be used with function <code>ubidi_writeReordered</code> to this end. This
+ * mode is equivalent to calling <code>ubidi_setInverse()</code> with
+ * argument <code>isInverse</code> set to <code>TRUE</code>.</li>
+ *
+ * <li>When the reordering mode is set to
+ * <code>#UBIDI_REORDER_INVERSE_LIKE_DIRECT</code>, the "direct" Logical to Visual
+ * Bidi algorithm is used as an approximation of an "inverse Bidi" algorithm.
+ * This mode is similar to mode <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>
+ * but is closer to the regular Bidi algorithm.
+ * <br>
+ * For example, an LTR paragraph with the content "FED 123 456 CBA" (where
+ * upper case represents RTL characters) will be transformed to
+ * "ABC 456 123 DEF", as opposed to "DEF 123 456 ABC"
+ * with mode <code>UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>.<br>
+ * When used in conjunction with option
+ * <code>#UBIDI_OPTION_INSERT_MARKS</code>, this mode generally
+ * adds Bidi marks to the output significantly more sparingly than mode
+ * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code> with option
+ * <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> in calls to
+ * <code>ubidi_writeReordered</code>.</li>
+ *
+ * <li>When the reordering mode is set to
+ * <code>#UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code>, the Logical to Visual
+ * Bidi algorithm used in Windows XP is used as an approximation of an "inverse Bidi" algorithm.
+ * <br>
+ * For example, an LTR paragraph with the content "abc FED123" (where
+ * upper case represents RTL characters) will be transformed to "abc 123DEF."</li>
+ * </ul>
+ *
+ * <p>In all the reordering modes specifying an "inverse Bidi" algorithm
+ * (i.e. those with a name starting with <code>UBIDI_REORDER_INVERSE</code>),
+ * output runs should be retrieved using
+ * <code>ubidi_getVisualRun()</code>, and the output text with
+ * <code>ubidi_writeReordered()</code>. The caller should keep in mind that in
+ * "inverse Bidi" modes the input is actually visually ordered text and
+ * reordered output returned by <code>ubidi_getVisualRun()</code> or
+ * <code>ubidi_writeReordered()</code> are actually runs or character string
+ * of logically ordered output.<br>
+ * For all the "inverse Bidi" modes, the source text should not contain
+ * Bidi control characters other than LRM or RLM.</p>
+ *
+ * <p>Note that option <code>#UBIDI_OUTPUT_REVERSE</code> of
+ * <code>ubidi_writeReordered</code> has no useful meaning and should not be
+ * used in conjunction with any value of the reordering mode specifying
+ * "inverse Bidi" or with value <code>UBIDI_REORDER_RUNS_ONLY</code>.
+ *
+ * @param pBiDi is a <code>UBiDi</code> object.
+ * @param reorderingMode specifies the required variant of the Bidi algorithm.
+ *
+ * @see UBiDiReorderingMode
+ * @see ubidi_setInverse
+ * @see ubidi_setPara
+ * @see ubidi_writeReordered
+ * @stable ICU 3.6
+ */
+U_STABLE void U_EXPORT2
+ubidi_setReorderingMode(UBiDi *pBiDi, UBiDiReorderingMode reorderingMode);
+
+/**
+ * What is the requested reordering mode for a given Bidi object?
+ *
+ * @param pBiDi is a <code>UBiDi</code> object.
+ * @return the current reordering mode of the Bidi object
+ * @see ubidi_setReorderingMode
+ * @stable ICU 3.6
+ */
+U_STABLE UBiDiReorderingMode U_EXPORT2
+ubidi_getReorderingMode(UBiDi *pBiDi);
+
+/**
+ * <code>UBiDiReorderingOption</code> values indicate which options are
+ * specified to affect the Bidi algorithm.
+ *
+ * @see ubidi_setReorderingOptions
+ * @stable ICU 3.6
+ */
+typedef enum UBiDiReorderingOption {
+ /**
+ * option value for <code>ubidi_setReorderingOptions</code>:
+ * disable all the options which can be set with this function
+ * @see ubidi_setReorderingOptions
+ * @stable ICU 3.6
+ */
+ UBIDI_OPTION_DEFAULT = 0,
+
+ /**
+ * option bit for <code>ubidi_setReorderingOptions</code>:
+ * insert Bidi marks (LRM or RLM) when needed to ensure correct result of
+ * a reordering to a Logical order
+ *
+ * <p>This option must be set or reset before calling
+ * <code>ubidi_setPara</code>.</p>
+ *
+ * <p>This option is significant only with reordering modes which generate
+ * a result with Logical order, specifically:</p>
+ * <ul>
+ * <li><code>#UBIDI_REORDER_RUNS_ONLY</code></li>
+ * <li><code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code></li>
+ * <li><code>#UBIDI_REORDER_INVERSE_LIKE_DIRECT</code></li>
+ * <li><code>#UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL</code></li>
+ * </ul>
+ *
+ * <p>If this option is set in conjunction with reordering mode
+ * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code> or with calling
+ * <code>ubidi_setInverse(TRUE)</code>, it implies
+ * option <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code>
+ * in calls to function <code>ubidi_writeReordered()</code>.</p>
+ *
+ * <p>For other reordering modes, a minimum number of LRM or RLM characters
+ * will be added to the source text after reordering it so as to ensure
+ * round trip, i.e. when applying the inverse reordering mode on the
+ * resulting logical text with removal of Bidi marks
+ * (option <code>#UBIDI_OPTION_REMOVE_CONTROLS</code> set before calling
+ * <code>ubidi_setPara()</code> or option <code>#UBIDI_REMOVE_BIDI_CONTROLS</code>
+ * in <code>ubidi_writeReordered</code>), the result will be identical to the
+ * source text in the first transformation.
+ *
+ * <p>This option will be ignored if specified together with option
+ * <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>. It inhibits option
+ * <code>UBIDI_REMOVE_BIDI_CONTROLS</code> in calls to function
+ * <code>ubidi_writeReordered()</code> and it implies option
+ * <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> in calls to function
+ * <code>ubidi_writeReordered()</code> if the reordering mode is
+ * <code>#UBIDI_REORDER_INVERSE_NUMBERS_AS_L</code>.</p>
+ *
+ * @see ubidi_setReorderingMode
+ * @see ubidi_setReorderingOptions
+ * @stable ICU 3.6
+ */
+ UBIDI_OPTION_INSERT_MARKS = 1,
+
+ /**
+ * option bit for <code>ubidi_setReorderingOptions</code>:
+ * remove Bidi control characters
+ *
+ * <p>This option must be set or reset before calling
+ * <code>ubidi_setPara</code>.</p>
+ *
+ * <p>This option nullifies option <code>#UBIDI_OPTION_INSERT_MARKS</code>.
+ * It inhibits option <code>#UBIDI_INSERT_LRM_FOR_NUMERIC</code> in calls
+ * to function <code>ubidi_writeReordered()</code> and it implies option
+ * <code>#UBIDI_REMOVE_BIDI_CONTROLS</code> in calls to that function.</p>
+ *
+ * @see ubidi_setReorderingMode
+ * @see ubidi_setReorderingOptions
+ * @stable ICU 3.6
+ */
+ UBIDI_OPTION_REMOVE_CONTROLS = 2,
+
+ /**
+ * option bit for <code>ubidi_setReorderingOptions</code>:
+ * process the output as part of a stream to be continued
+ *
+ * <p>This option must be set or reset before calling
+ * <code>ubidi_setPara</code>.</p>
+ *
+ * <p>This option specifies that the caller is interested in processing large
+ * text object in parts.
+ * The results of the successive calls are expected to be concatenated by the
+ * caller. Only the call for the last part will have this option bit off.</p>
+ *
+ * <p>When this option bit is on, <code>ubidi_setPara()</code> may process
+ * less than the full source text in order to truncate the text at a meaningful
+ * boundary. The caller should call <code>ubidi_getProcessedLength()</code>
+ * immediately after calling <code>ubidi_setPara()</code> in order to
+ * determine how much of the source text has been processed.
+ * Source text beyond that length should be resubmitted in following calls to
+ * <code>ubidi_setPara</code>. The processed length may be less than
+ * the length of the source text if a character preceding the last character of
+ * the source text constitutes a reasonable boundary (like a block separator)
+ * for text to be continued.<br>
+ * If the last character of the source text constitutes a reasonable
+ * boundary, the whole text will be processed at once.<br>
+ * If nowhere in the source text there exists
+ * such a reasonable boundary, the processed length will be zero.<br>
+ * The caller should check for such an occurrence and do one of the following:
+ * <ul><li>submit a larger amount of text with a better chance to include
+ * a reasonable boundary.</li>
+ * <li>resubmit the same text after turning off option
+ * <code>UBIDI_OPTION_STREAMING</code>.</li></ul>
+ * In all cases, this option should be turned off before processing the last
+ * part of the text.</p>
+ *
+ * <p>When the <code>UBIDI_OPTION_STREAMING</code> option is used,
+ * it is recommended to call <code>ubidi_orderParagraphsLTR()</code> with
+ * argument <code>orderParagraphsLTR</code> set to <code>TRUE</code> before
+ * calling <code>ubidi_setPara</code> so that later paragraphs may be
+ * concatenated to previous paragraphs on the right.</p>
+ *
+ * @see ubidi_setReorderingMode
+ * @see ubidi_setReorderingOptions
+ * @see ubidi_getProcessedLength
+ * @see ubidi_orderParagraphsLTR
+ * @stable ICU 3.6
+ */
+ UBIDI_OPTION_STREAMING = 4
+} UBiDiReorderingOption;
+
+/**
+ * Specify which of the reordering options
+ * should be applied during Bidi transformations.
+ *
+ * @param pBiDi is a <code>UBiDi</code> object.
+ * @param reorderingOptions is a combination of zero or more of the following
+ * options:
+ * <code>#UBIDI_OPTION_DEFAULT</code>, <code>#UBIDI_OPTION_INSERT_MARKS</code>,
+ * <code>#UBIDI_OPTION_REMOVE_CONTROLS</code>, <code>#UBIDI_OPTION_STREAMING</code>.
+ *
+ * @see ubidi_getReorderingOptions
+ * @stable ICU 3.6
+ */
+U_STABLE void U_EXPORT2
+ubidi_setReorderingOptions(UBiDi *pBiDi, uint32_t reorderingOptions);
+
+/**
+ * What are the reordering options applied to a given Bidi object?
+ *
+ * @param pBiDi is a <code>UBiDi</code> object.
+ * @return the current reordering options of the Bidi object
+ * @see ubidi_setReorderingOptions
+ * @stable ICU 3.6
+ */
+U_STABLE uint32_t U_EXPORT2
+ubidi_getReorderingOptions(UBiDi *pBiDi);
+
+/**
+ * Set the context before a call to ubidi_setPara().<p>
+ *
+ * ubidi_setPara() computes the left-right directionality for a given piece
+ * of text which is supplied as one of its arguments. Sometimes this piece
+ * of text (the "main text") should be considered in context, because text
+ * appearing before ("prologue") and/or after ("epilogue") the main text
+ * may affect the result of this computation.<p>
+ *
+ * This function specifies the prologue and/or the epilogue for the next
+ * call to ubidi_setPara(). The characters specified as prologue and
+ * epilogue should not be modified by the calling program until the call
+ * to ubidi_setPara() has returned. If successive calls to ubidi_setPara()
+ * all need specification of a context, ubidi_setContext() must be called
+ * before each call to ubidi_setPara(). In other words, a context is not
+ * "remembered" after the following successful call to ubidi_setPara().<p>
+ *
+ * If a call to ubidi_setPara() specifies UBIDI_DEFAULT_LTR or
+ * UBIDI_DEFAULT_RTL as paraLevel and is preceded by a call to
+ * ubidi_setContext() which specifies a prologue, the paragraph level will
+ * be computed taking in consideration the text in the prologue.<p>
+ *
+ * When ubidi_setPara() is called without a previous call to
+ * ubidi_setContext, the main text is handled as if preceded and followed
+ * by strong directional characters at the current paragraph level.
+ * Calling ubidi_setContext() with specification of a prologue will change
+ * this behavior by handling the main text as if preceded by the last
+ * strong character appearing in the prologue, if any.
+ * Calling ubidi_setContext() with specification of an epilogue will change
+ * the behavior of ubidi_setPara() by handling the main text as if followed
+ * by the first strong character or digit appearing in the epilogue, if any.<p>
+ *
+ * Note 1: if <code>ubidi_setContext</code> is called repeatedly without
+ * calling <code>ubidi_setPara</code>, the earlier calls have no effect,
+ * only the last call will be remembered for the next call to
+ * <code>ubidi_setPara</code>.<p>
+ *
+ * Note 2: calling <code>ubidi_setContext(pBiDi, NULL, 0, NULL, 0, &errorCode)</code>
+ * cancels any previous setting of non-empty prologue or epilogue.
+ * The next call to <code>ubidi_setPara()</code> will process no
+ * prologue or epilogue.<p>
+ *
+ * Note 3: users must be aware that even after setting the context
+ * before a call to ubidi_setPara() to perform e.g. a logical to visual
+ * transformation, the resulting string may not be identical to what it
+ * would have been if all the text, including prologue and epilogue, had
+ * been processed together.<br>
+ * Example (upper case letters represent RTL characters):<br>
+ * prologue = "<code>abc DE</code>"<br>
+ * epilogue = none<br>
+ * main text = "<code>FGH xyz</code>"<br>
+ * paraLevel = UBIDI_LTR<br>
+ * display without prologue = "<code>HGF xyz</code>"
+ * ("HGF" is adjacent to "xyz")<br>
+ * display with prologue = "<code>abc HGFED xyz</code>"
+ * ("HGF" is not adjacent to "xyz")<br>
+ *
+ * @param pBiDi is a paragraph <code>UBiDi</code> object.
+ *
+ * @param prologue is a pointer to the text which precedes the text that
+ * will be specified in a coming call to ubidi_setPara().
+ * If there is no prologue to consider, then <code>proLength</code>
+ * must be zero and this pointer can be NULL.
+ *
+ * @param proLength is the length of the prologue; if <code>proLength==-1</code>
+ * then the prologue must be zero-terminated.
+ * Otherwise proLength must be >= 0. If <code>proLength==0</code>, it means
+ * that there is no prologue to consider.
+ *
+ * @param epilogue is a pointer to the text which follows the text that
+ * will be specified in a coming call to ubidi_setPara().
+ * If there is no epilogue to consider, then <code>epiLength</code>
+ * must be zero and this pointer can be NULL.
+ *
+ * @param epiLength is the length of the epilogue; if <code>epiLength==-1</code>
+ * then the epilogue must be zero-terminated.
+ * Otherwise epiLength must be >= 0. If <code>epiLength==0</code>, it means
+ * that there is no epilogue to consider.
+ *
+ * @param pErrorCode must be a valid pointer to an error code value.
+ *
+ * @see ubidi_setPara
+ * @stable ICU 4.8
+ */
+U_STABLE void U_EXPORT2
+ubidi_setContext(UBiDi *pBiDi,
+ const UChar *prologue, int32_t proLength,
+ const UChar *epilogue, int32_t epiLength,
+ UErrorCode *pErrorCode);
+
+/**
+ * Perform the Unicode Bidi algorithm. It is defined in the
projects / apple / icu.git / blobdiff