1293 lines
44 KiB
C
1293 lines
44 KiB
C
/*
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*******************************************************************************
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* *
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* COPYRIGHT: *
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* (C) Copyright International Business Machines Corporation, 1999 *
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* Licensed Material - Program-Property of IBM - All Rights Reserved. *
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* US Government Users Restricted Rights - Use, duplication, or disclosure *
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* restricted by GSA ADP Schedule Contract with IBM Corp. *
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* *
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*******************************************************************************
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* file name: ubidi.c
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* encoding: US-ASCII
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* tab size: 8 (not used)
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* indentation:4
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*
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* created on: 1999jul27
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* created by: Markus W. Scherer
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*/
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/* set import/export definitions */
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#ifndef U_COMMON_IMPLEMENTATION
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# define U_COMMON_IMPLEMENTATION
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#endif
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#include "cmemory.h"
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#include "unicode/utypes.h"
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#include "unicode/ustring.h"
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#include "unicode/uchar.h"
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#include "unicode/ubidi.h"
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#include "ubidiimp.h"
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/*
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* General implementation notes:
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*
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* Throughout the implementation, there are comments like (W2) that refer to
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* rules of the BiDi algorithm in its version 5, in this example to the second
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* rule of the resolution of weak types.
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*
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* For handling surrogate pairs, where two UChar's form one "abstract" (or UTF-32)
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* character according to UTF-16, the second UChar gets the directional property of
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* the entire character assigned, while the first one gets a BN, a boundary
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* neutral, type, which is ignored by most of the algorithm according to
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* rule (X9) and the implementation suggestions of the BiDi algorithm.
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*
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* Later, adjustWSLevels() will set the level for each BN to that of the
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* following character (UChar), which results in surrogate pairs getting the
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* same level on each of their surrogates.
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*
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* In a UTF-8 implementation, the same thing could be done: the last byte of
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* a multi-byte sequence would get the "real" property, while all previous
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* bytes of that sequence would get BN.
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*
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* It is not possible to assign all those parts of a character the same real
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* property because this would fail in the resolution of weak types with rules
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* that look at immediately surrounding types.
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*
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* As a related topic, this implementation does not remove Boundary Neutral
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* types from the input, but ignores them whereever this is relevant.
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* For example, the loop for the resolution of the weak types reads
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* types until it finds a non-BN.
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* Also, explicit embedding codes are neither changed into BN nor removed.
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* They are only treated the same way real BNs are.
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* As stated before, adjustWSLevels() takes care of them at the end.
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* For the purpose of conformance, the levels of all these codes
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* do not matter.
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*
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* Note that this implementation never modifies the dirProps
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* after the initial setup.
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*
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*
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* In this implementation, the resolution of weak types (Wn),
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* neutrals (Nn), and the assignment of the resolved level (In)
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* are all done in one single loop, in resolveImplicitLevels().
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* Changes of dirProp values are done on the fly, without writing
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* them back to the dirProps array.
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*
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*
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* This implementation contains code that allows to bypass steps of the
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* algorithm that are not needed on the specific paragraph
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* in order to speed up the most common cases considerably,
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* like text that is entirely LTR, or RTL text without numbers.
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*
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* Most of this is done by setting a bit for each directional property
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* in a flags variable and later checking for whether there are
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* any LTR characters or any RTL characters, or both, whether
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* there are any explicit embedding codes, etc.
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*
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* If the (Xn) steps are performed, then the flags are re-evaluated,
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* because they will then not contain the embedding codes any more
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* and will be adjusted for override codes, so that subsequently
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* more bypassing may be possible than what the initial flags suggested.
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*
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* If the text is not mixed-directional, then the
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* algorithm steps for the weak type resolution are not performed,
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* and all levels are set to the paragraph level.
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*
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* If there are no explicit embedding codes, then the (Xn) steps
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* are not performed.
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*
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* If embedding levels are supplied as a parameter, then all
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* explicit embedding codes are ignored, and the (Xn) steps
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* are not performed.
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*
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* White Space types could get the level of the run they belong to,
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* and are checked with a test of (flags&MASK_EMBEDDING) to
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* consider if the paragraph direction should be considered in
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* the flags variable.
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*
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* If there are no White Space types in the paragraph, then
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* (L1) is not necessary in adjustWSLevels().
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*/
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/* prototypes --------------------------------------------------------------- */
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static void
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getDirProps(UBiDi *pBiDi, const UChar *text);
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static UBiDiDirection
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resolveExplicitLevels(UBiDi *pBiDi);
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static UBiDiDirection
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checkExplicitLevels(UBiDi *pBiDi, UErrorCode *pErrorCode);
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static UBiDiDirection
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directionFromFlags(Flags flags);
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static void
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resolveImplicitLevels(UBiDi *pBiDi,
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UTextOffset start, UTextOffset limit,
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DirProp sor, DirProp eor);
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static void
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adjustWSLevels(UBiDi *pBiDi);
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/* UBiDi object management -------------------------------------------------- */
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U_CAPI UBiDi * U_EXPORT2
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ubidi_open(void)
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{
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UErrorCode errorCode=U_ZERO_ERROR;
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return ubidi_openSized(0, 0, &errorCode);
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}
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U_CAPI UBiDi * U_EXPORT2
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ubidi_openSized(UTextOffset maxLength, UTextOffset maxRunCount, UErrorCode *pErrorCode) {
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UBiDi *pBiDi;
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/* check the argument values */
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if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
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return NULL;
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} else if(maxLength<0 || maxRunCount<0) {
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*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
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return NULL; /* invalid arguments */
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}
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/* allocate memory for the object */
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pBiDi=(UBiDi *)uprv_malloc(sizeof(UBiDi));
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if(pBiDi==NULL) {
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*pErrorCode=U_MEMORY_ALLOCATION_ERROR;
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return NULL;
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}
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/* reset the object, all pointers NULL, all flags FALSE, all sizes 0 */
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uprv_memset(pBiDi, 0, sizeof(UBiDi));
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/* allocate memory for arrays as requested */
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if(maxLength>0) {
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if( !getInitialDirPropsMemory(pBiDi, maxLength) ||
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!getInitialLevelsMemory(pBiDi, maxLength)
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) {
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*pErrorCode=U_MEMORY_ALLOCATION_ERROR;
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}
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} else {
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pBiDi->mayAllocateText=TRUE;
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}
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if(maxRunCount>0) {
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if(maxRunCount==1) {
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/* use simpleRuns[] */
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pBiDi->runsSize=sizeof(Run);
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} else if(!getInitialRunsMemory(pBiDi, maxRunCount)) {
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*pErrorCode=U_MEMORY_ALLOCATION_ERROR;
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}
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} else {
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pBiDi->mayAllocateRuns=TRUE;
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}
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if(U_SUCCESS(*pErrorCode)) {
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return pBiDi;
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} else {
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ubidi_close(pBiDi);
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return NULL;
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}
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}
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/*
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* We are allowed to allocate memory if memory==NULL or
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* mayAllocate==TRUE for each array that we need.
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* We also try to grow and shrink memory as needed if we
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* allocate it.
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*
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* Assume sizeNeeded>0.
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* If *pMemory!=NULL, then assume *pSize>0.
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*
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* ### this realloc() may unnecessarily copy the old data,
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* which we know we don't need any more;
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* is this the best way to do this??
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*/
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extern bool_t
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getMemory(void **pMemory, UTextOffset *pSize, bool_t mayAllocate, UTextOffset sizeNeeded) {
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/* check for existing memory */
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if(*pMemory==NULL) {
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/* we need to allocate memory */
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if(mayAllocate && (*pMemory=uprv_malloc(sizeNeeded))!=NULL) {
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*pSize=sizeNeeded;
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return TRUE;
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} else {
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return FALSE;
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}
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} else {
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/* there is some memory, is it enough or too much? */
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if(sizeNeeded>*pSize && !mayAllocate) {
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/* not enough memory, and we must not allocate */
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return FALSE;
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} else if(sizeNeeded!=*pSize && mayAllocate) {
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/* we may try to grow or shrink */
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void *memory;
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if((memory=uprv_realloc(*pMemory, sizeNeeded))!=NULL) {
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*pMemory=memory;
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*pSize=sizeNeeded;
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return TRUE;
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} else {
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/* we failed to grow */
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return FALSE;
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}
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} else {
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/* we have at least enough memory and must not allocate */
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return TRUE;
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}
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}
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}
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U_CAPI void U_EXPORT2
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ubidi_close(UBiDi *pBiDi) {
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if(pBiDi!=NULL) {
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if(pBiDi->dirPropsMemory!=NULL) {
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uprv_free(pBiDi->dirPropsMemory);
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}
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if(pBiDi->levelsMemory!=NULL) {
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uprv_free(pBiDi->levelsMemory);
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}
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if(pBiDi->runsMemory!=NULL) {
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uprv_free(pBiDi->runsMemory);
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}
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uprv_free(pBiDi);
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}
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}
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/* ubidi_setPara ------------------------------------------------------------ */
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U_CAPI void U_EXPORT2
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ubidi_setPara(UBiDi *pBiDi, const UChar *text, UTextOffset length,
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UBiDiLevel paraLevel, UBiDiLevel *embeddingLevels,
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UErrorCode *pErrorCode) {
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UBiDiDirection direction;
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/* check the argument values */
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if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
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return;
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} else if(pBiDi==NULL || text==NULL ||
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(UBIDI_MAX_EXPLICIT_LEVEL<paraLevel) && !IS_DEFAULT_LEVEL(paraLevel) ||
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length<-1
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) {
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*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
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return;
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}
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if(length==-1) {
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length=u_strlen(text);
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}
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/* initialize the UBiDi structure */
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pBiDi->length=length;
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pBiDi->paraLevel=paraLevel;
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pBiDi->direction=UBIDI_LTR;
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pBiDi->trailingWSStart=length; /* the levels[] will reflect the WS run */
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pBiDi->dirProps=NULL;
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pBiDi->levels=NULL;
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pBiDi->runs=NULL;
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if(length==0) {
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/*
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* For an empty paragraph, create a UBiDi object with the paraLevel and
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* the flags and the direction set but without allocating zero-length arrays.
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* There is nothing more to do.
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*/
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if(IS_DEFAULT_LEVEL(paraLevel)) {
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pBiDi->paraLevel&=1;
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}
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if(paraLevel&1) {
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pBiDi->flags=DIRPROP_FLAG(R);
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pBiDi->direction=UBIDI_RTL;
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} else {
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pBiDi->flags=DIRPROP_FLAG(L);
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pBiDi->direction=UBIDI_LTR;
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}
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pBiDi->runCount=0;
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return;
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}
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pBiDi->runCount=-1;
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/*
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* Get the directional properties,
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* the flags bit-set, and
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* determine the partagraph level if necessary.
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*/
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if(getDirPropsMemory(pBiDi, length)) {
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pBiDi->dirProps=pBiDi->dirPropsMemory;
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getDirProps(pBiDi, text);
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} else {
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*pErrorCode=U_MEMORY_ALLOCATION_ERROR;
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return;
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}
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/* are explicit levels specified? */
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if(embeddingLevels==NULL) {
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/* no: determine explicit levels according to the (Xn) rules */\
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if(getLevelsMemory(pBiDi, length)) {
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pBiDi->levels=pBiDi->levelsMemory;
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direction=resolveExplicitLevels(pBiDi);
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} else {
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*pErrorCode=U_MEMORY_ALLOCATION_ERROR;
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return;
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}
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} else {
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/* set BN for all explicit codes, check that all levels are paraLevel..UBIDI_MAX_EXPLICIT_LEVEL */
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pBiDi->levels=embeddingLevels;
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direction=checkExplicitLevels(pBiDi, pErrorCode);
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if(U_FAILURE(*pErrorCode)) {
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return;
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}
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}
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/*
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* The steps after (X9) in the UBiDi algorithm are performed only if
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* the paragraph text has mixed directionality!
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*/
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switch(direction) {
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case UBIDI_LTR:
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/* make sure paraLevel is even */
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pBiDi->paraLevel=(pBiDi->paraLevel+1)&~1;
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/* all levels are implicitly at paraLevel (important for ubidi_getLevels()) */
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pBiDi->trailingWSStart=0;
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break;
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case UBIDI_RTL:
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/* make sure paraLevel is odd */
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pBiDi->paraLevel|=1;
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/* all levels are implicitly at paraLevel (important for ubidi_getLevels()) */
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pBiDi->trailingWSStart=0;
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break;
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default:
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/*
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* If there are no external levels specified and there
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* are no significant explicit level codes in the text,
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* then we can treat the entire paragraph as one run.
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* Otherwise, we need to perform the following rules on runs of
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* the text with the same embedding levels. (X10)
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* "Significant" explicit level codes are ones that actually
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* affect non-BN characters.
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* Examples for "insignificant" ones are empty embeddings
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* LRE-PDF, LRE-RLE-PDF-PDF, etc.
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*/
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if(embeddingLevels==NULL && !(pBiDi->flags&DIRPROP_FLAG_MULTI_RUNS)) {
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resolveImplicitLevels(pBiDi, 0, length,
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GET_LR_FROM_LEVEL(pBiDi->paraLevel),
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GET_LR_FROM_LEVEL(pBiDi->paraLevel));
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} else {
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/* sor, eor: start and end types of same-level-run */
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UBiDiLevel *levels=pBiDi->levels;
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UTextOffset start, limit=0;
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UBiDiLevel level, nextLevel;
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DirProp sor, eor;
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/* determine the first sor and set eor to it because of the loop body (sor=eor there) */
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level=pBiDi->paraLevel;
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nextLevel=levels[0];
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if(level<nextLevel) {
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eor=GET_LR_FROM_LEVEL(nextLevel);
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} else {
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eor=GET_LR_FROM_LEVEL(level);
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}
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do {
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/* determine start and limit of the run (end points just behind the run) */
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/* the values for this run's start are the same as for the previous run's end */
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sor=eor;
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start=limit;
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level=nextLevel;
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/* search for the limit of this run */
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while(++limit<length && levels[limit]==level) {}
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/* get the correct level of the next run */
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if(limit<length) {
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nextLevel=levels[limit];
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} else {
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nextLevel=pBiDi->paraLevel;
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}
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/* determine eor from max(level, nextLevel); sor is last run's eor */
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if((level&~UBIDI_LEVEL_OVERRIDE)<(nextLevel&~UBIDI_LEVEL_OVERRIDE)) {
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eor=GET_LR_FROM_LEVEL(nextLevel);
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} else {
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eor=GET_LR_FROM_LEVEL(level);
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}
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/* if the run consists of overridden directional types, then there
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are no implicit types to be resolved */
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if(!(level&UBIDI_LEVEL_OVERRIDE)) {
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resolveImplicitLevels(pBiDi, start, limit, sor, eor);
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}
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} while(limit<length);
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}
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/* reset the embedding levels for some non-graphic characters (L1), (X9) */
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adjustWSLevels(pBiDi);
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break;
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}
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pBiDi->direction=direction;
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}
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/* perform (P2)..(P3) ------------------------------------------------------- */
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/*
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* Get the directional properties for the text,
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* calculate the flags bit-set, and
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* determine the partagraph level if necessary.
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*/
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static void
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getDirProps(UBiDi *pBiDi, const UChar *text) {
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DirProp *dirProps=pBiDi->dirPropsMemory; /* pBiDi->dirProps is const */
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UTextOffset i=0, length=pBiDi->length;
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Flags flags=0; /* collect all directionalities in the text */
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UChar uchar;
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DirProp dirProp;
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if(IS_DEFAULT_LEVEL(pBiDi->paraLevel)) {
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/* determine the paragraph level (P2..P3) */
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for(;;) {
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uchar=text[i];
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if(!IS_FIRST_SURROGATE(uchar) || i+1==length || !IS_SECOND_SURROGATE(text[i+1])) {
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/* not a surrogate pair */
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flags|=DIRPROP_FLAG(dirProps[i]=dirProp=u_charDirection(uchar));
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} else {
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/* a surrogate pair */
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dirProps[i++]=BN; /* first surrogate in the pair gets the BN type */
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flags|=DIRPROP_FLAG(dirProps[i]=dirProp=u_charDirection(GET_UTF_32(uchar, text[i])))|DIRPROP_FLAG(BN);
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}
|
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++i;
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if(dirProp==L) {
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pBiDi->paraLevel=0;
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break;
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} else if(dirProp==R || dirProp==AL) {
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pBiDi->paraLevel=1;
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break;
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} else if(i==length) {
|
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/*
|
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* see comment in ubidi.h:
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* the DEFAULT_XXX values are designed so that
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* their bit 0 alone yields the intended default
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*/
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pBiDi->paraLevel&=1;
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break;
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}
|
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}
|
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}
|
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|
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/* get the rest of the directional properties and the flags bits */
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while(i<length) {
|
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uchar=text[i];
|
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if(!IS_FIRST_SURROGATE(uchar) || i+1==length || !IS_SECOND_SURROGATE(text[i+1])) {
|
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/* not a surrogate pair */
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flags|=DIRPROP_FLAG(dirProps[i]=u_charDirection(uchar));
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} else {
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/* a surrogate pair */
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dirProps[i++]=BN; /* second surrogate in the pair gets the BN type */
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flags|=DIRPROP_FLAG(dirProps[i]=u_charDirection(GET_UTF_32(uchar, text[i])))|DIRPROP_FLAG(BN);
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}
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++i;
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}
|
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if(flags&MASK_EMBEDDING) {
|
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flags|=DIRPROP_FLAG_LR(pBiDi->paraLevel);
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}
|
|
|
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pBiDi->flags=flags;
|
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}
|
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|
|
/* perform (X1)..(X9) ------------------------------------------------------- */
|
|
|
|
/*
|
|
* Resolve the explicit levels as specified by explicit embedding codes.
|
|
* Recalculate the flags to have them reflect the real properties
|
|
* after taking the explicit embeddings into account.
|
|
*
|
|
* The BiDi algorithm is designed to result in the same behavior whether embedding
|
|
* levels are externally specified (from "styled text", supposedly the preferred
|
|
* method) or set by explicit embedding codes (LRx, RLx, PDF) in the plain text.
|
|
* That is why (X9) instructs to remove all explicit codes (and BN).
|
|
* However, in a real implementation, this removal of these codes and their index
|
|
* positions in the plain text is undesirable since it would result in
|
|
* reallocated, reindexed text.
|
|
* Instead, this implementation leaves the codes in there and just ignores them
|
|
* in the subsequent processing.
|
|
* In order to get the same reordering behavior, positions with a BN or an
|
|
* explicit embedding code just get the same level assigned as the last "real"
|
|
* character.
|
|
*
|
|
* Some implementations, not this one, then overwrite some of these
|
|
* directionality properties at "real" same-level-run boundaries by
|
|
* L or R codes so that the resolution of weak types can be performed on the
|
|
* entire paragraph at once instead of having to parse it once more and
|
|
* perform that resolution on same-level-runs.
|
|
* This limits the scope of the implicit rules in effectively
|
|
* the same way as the run limits.
|
|
*
|
|
* Instead, this implementation does not modify these codes.
|
|
* On one hand, the paragraph has to be scanned for same-level-runs, but
|
|
* on the other hand, this saves another loop to reset these codes,
|
|
* or saves making and modifying a copy of dirProps[].
|
|
*
|
|
*
|
|
* Note that (Pn) and (Xn) changed significantly from version 4 of the BiDi algorithm.
|
|
*
|
|
*
|
|
* Handling the stack of explicit levels (Xn):
|
|
*
|
|
* With the BiDi stack of explicit levels,
|
|
* as pushed with each LRE, RLE, LRO, and RLO and popped with each PDF,
|
|
* the explicit level must never exceed UBIDI_MAX_EXPLICIT_LEVEL==61.
|
|
*
|
|
* In order to have a correct push-pop semantics even in the case of overflows,
|
|
* there are two overflow counters:
|
|
* - countOver60 is incremented with each LRx at level 60
|
|
* - from level 60, one RLx increases the level to 61
|
|
* - countOver61 is incremented with each LRx and RLx at level 61
|
|
*
|
|
* Popping levels with PDF must work in the opposite order so that level 61
|
|
* is correct at the correct point. Underflows (too many PDFs) must be checked.
|
|
*
|
|
* This implementation assumes that UBIDI_MAX_EXPLICIT_LEVEL is odd.
|
|
*/
|
|
|
|
static UBiDiDirection
|
|
resolveExplicitLevels(UBiDi *pBiDi) {
|
|
const DirProp *dirProps=pBiDi->dirProps;
|
|
UBiDiLevel *levels=pBiDi->levels;
|
|
|
|
UTextOffset i=0, length=pBiDi->length;
|
|
Flags flags=pBiDi->flags; /* collect all directionalities in the text */
|
|
DirProp dirProp;
|
|
UBiDiLevel level=pBiDi->paraLevel;
|
|
|
|
UBiDiDirection direction;
|
|
|
|
/* determine if the text is mixed-directional or single-directional */
|
|
direction=directionFromFlags(flags);
|
|
|
|
/* we may not need to resolve any explicit levels */
|
|
if(direction!=UBIDI_MIXED) {
|
|
/* not mixed directionality: levels don't matter - trailingWSStart will be 0 */
|
|
} else if(!(flags&MASK_EXPLICIT)) {
|
|
/* mixed, but all characters are at the same embedding level */
|
|
/* set all levels to the paragraph level */
|
|
for(i=0; i<length; ++i) {
|
|
levels[i]=level;
|
|
}
|
|
} else {
|
|
/* continue to perform (Xn) */
|
|
|
|
/* (X1) level is set for all codes, embeddingLevel keeps track of the push/pop operations */
|
|
/* both variables may carry the UBIDI_LEVEL_OVERRIDE flag to indicate the override status */
|
|
UBiDiLevel embeddingLevel=level, newLevel, stackTop=0;
|
|
|
|
UBiDiLevel stack[UBIDI_MAX_EXPLICIT_LEVEL]; /* we never push anything >=UBIDI_MAX_EXPLICIT_LEVEL */
|
|
uint32_t countOver60=0, countOver61=0; /* count overflows of explicit levels */
|
|
|
|
/* recalculate the flags */
|
|
flags=0;
|
|
|
|
/* since we assume that this is a single paragraph, we ignore (X8) */
|
|
for(i=0; i<length; ++i) {
|
|
dirProp=dirProps[i];
|
|
switch(dirProp) {
|
|
case LRE:
|
|
case LRO:
|
|
/* (X3, X5) */
|
|
newLevel=(embeddingLevel+2)&~(UBIDI_LEVEL_OVERRIDE|1); /* least greater even level */
|
|
if(newLevel<=UBIDI_MAX_EXPLICIT_LEVEL) {
|
|
stack[stackTop]=embeddingLevel;
|
|
++stackTop;
|
|
embeddingLevel=newLevel;
|
|
if(dirProp==LRO) {
|
|
embeddingLevel|=UBIDI_LEVEL_OVERRIDE;
|
|
} else {
|
|
embeddingLevel&=~UBIDI_LEVEL_OVERRIDE;
|
|
}
|
|
} else if((embeddingLevel&~UBIDI_LEVEL_OVERRIDE)==UBIDI_MAX_EXPLICIT_LEVEL) {
|
|
++countOver61;
|
|
} else /* (embeddingLevel&~UBIDI_LEVEL_OVERRIDE)==UBIDI_MAX_EXPLICIT_LEVEL-1 */ {
|
|
++countOver60;
|
|
}
|
|
flags|=DIRPROP_FLAG(BN);
|
|
break;
|
|
case RLE:
|
|
case RLO:
|
|
/* (X2, X4) */
|
|
newLevel=((embeddingLevel&~UBIDI_LEVEL_OVERRIDE)+1)|1; /* least greater odd level */
|
|
if(newLevel<=UBIDI_MAX_EXPLICIT_LEVEL) {
|
|
stack[stackTop]=embeddingLevel;
|
|
++stackTop;
|
|
embeddingLevel=newLevel;
|
|
if(dirProp==RLO) {
|
|
embeddingLevel|=UBIDI_LEVEL_OVERRIDE;
|
|
} else {
|
|
embeddingLevel&=~UBIDI_LEVEL_OVERRIDE;
|
|
}
|
|
} else {
|
|
++countOver61;
|
|
}
|
|
flags|=DIRPROP_FLAG(BN);
|
|
break;
|
|
case PDF:
|
|
/* (X7) */
|
|
/* handle all the overflow cases first */
|
|
if(countOver61>0) {
|
|
--countOver61;
|
|
} else if(countOver60>0 && (embeddingLevel&~UBIDI_LEVEL_OVERRIDE)!=UBIDI_MAX_EXPLICIT_LEVEL) {
|
|
/* handle LRx overflows from level 60 */
|
|
--countOver60;
|
|
} else if(stackTop>0) {
|
|
/* this is the pop operation; it also pops level 61 while countOver60>0 */
|
|
--stackTop;
|
|
embeddingLevel=stack[stackTop];
|
|
/* } else { (underflow) */
|
|
}
|
|
flags|=DIRPROP_FLAG(BN);
|
|
break;
|
|
case B:
|
|
/*
|
|
* We do not really expect to see a paragraph separator (B),
|
|
* but we should do something reasonable with it,
|
|
* especially at the end of the text.
|
|
*/
|
|
stackTop=0;
|
|
countOver60=countOver61=0;
|
|
embeddingLevel=level=pBiDi->paraLevel;
|
|
flags|=DIRPROP_FLAG(B);
|
|
break;
|
|
case BN:
|
|
/* BN, LRE, RLE, and PDF are supposed to be removed (X9) */
|
|
/* they will get their levels set correctly in adjustWSLevels() */
|
|
flags|=DIRPROP_FLAG(BN);
|
|
break;
|
|
default:
|
|
/* all other types get the "real" level */
|
|
if(level!=embeddingLevel) {
|
|
level=embeddingLevel;
|
|
if(level&UBIDI_LEVEL_OVERRIDE) {
|
|
flags|=DIRPROP_FLAG_O(level)|DIRPROP_FLAG_MULTI_RUNS;
|
|
} else {
|
|
flags|=DIRPROP_FLAG_E(level)|DIRPROP_FLAG_MULTI_RUNS;
|
|
}
|
|
}
|
|
if(!(level&UBIDI_LEVEL_OVERRIDE)) {
|
|
flags|=DIRPROP_FLAG(dirProp);
|
|
}
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* We need to set reasonable levels even on BN codes and
|
|
* explicit codes because we will later look at same-level runs (X10).
|
|
*/
|
|
levels[i]=level;
|
|
}
|
|
if(flags&MASK_EMBEDDING) {
|
|
flags|=DIRPROP_FLAG_LR(pBiDi->paraLevel);
|
|
}
|
|
|
|
/* subsequently, ignore the explicit codes and BN (X9) */
|
|
|
|
/* again, determine if the text is mixed-directional or single-directional */
|
|
pBiDi->flags=flags;
|
|
direction=directionFromFlags(flags);
|
|
}
|
|
return direction;
|
|
}
|
|
|
|
/*
|
|
* Use a pre-specified embedding levels array:
|
|
*
|
|
* Adjust the directional properties for overrides (->LEVEL_OVERRIDE),
|
|
* ignore all explicit codes (X9),
|
|
* and check all the preset levels.
|
|
*
|
|
* Recalculate the flags to have them reflect the real properties
|
|
* after taking the explicit embeddings into account.
|
|
*/
|
|
static UBiDiDirection
|
|
checkExplicitLevels(UBiDi *pBiDi, UErrorCode *pErrorCode) {
|
|
const DirProp *dirProps=pBiDi->dirProps;
|
|
UBiDiLevel *levels=pBiDi->levels;
|
|
|
|
UTextOffset i, length=pBiDi->length;
|
|
Flags flags=0; /* collect all directionalities in the text */
|
|
UBiDiLevel level, paraLevel=pBiDi->paraLevel;
|
|
|
|
for(i=0; i<length; ++i) {
|
|
level=levels[i];
|
|
if(level&UBIDI_LEVEL_OVERRIDE) {
|
|
/* keep the override flag in levels[i] but adjust the flags */
|
|
level&=~UBIDI_LEVEL_OVERRIDE; /* make the range check below simpler */
|
|
flags|=DIRPROP_FLAG_O(level);
|
|
} else {
|
|
/* set the flags */
|
|
flags|=DIRPROP_FLAG_E(level)|DIRPROP_FLAG(dirProps[i]);
|
|
}
|
|
if(level<paraLevel || UBIDI_MAX_EXPLICIT_LEVEL<level) {
|
|
/* level out of bounds */
|
|
*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
|
|
return UBIDI_LTR;
|
|
}
|
|
}
|
|
if(flags&MASK_EMBEDDING) {
|
|
flags|=DIRPROP_FLAG_LR(pBiDi->paraLevel);
|
|
}
|
|
|
|
/* determine if the text is mixed-directional or single-directional */
|
|
pBiDi->flags=flags;
|
|
return directionFromFlags(flags);
|
|
}
|
|
|
|
/* determine if the text is mixed-directional or single-directional */
|
|
static UBiDiDirection
|
|
directionFromFlags(Flags flags) {
|
|
/* if the text contains AN and neutrals, then some neutrals may become RTL */
|
|
if(!(flags&MASK_RTL || flags&DIRPROP_FLAG(AN) && flags&MASK_POSSIBLE_N)) {
|
|
return UBIDI_LTR;
|
|
} else if(!(flags&MASK_LTR)) {
|
|
return UBIDI_RTL;
|
|
} else {
|
|
return UBIDI_MIXED;
|
|
}
|
|
}
|
|
|
|
/* perform rules (Wn), (Nn), and (In) on a run of the text ------------------ */
|
|
|
|
/*
|
|
* This implementation of the (Wn) rules applies all rules in one pass.
|
|
* In order to do so, it needs a look-ahead of typically 1 character
|
|
* (except for W5: sequences of ET) and keeps track of changes
|
|
* in a rule Wp that affect a later Wq (p<q).
|
|
*
|
|
* historyOfEN is a variable-saver: it contains 4 boolean states;
|
|
* a bit in it set to 1 means:
|
|
* bit 0: the current code is an EN after W2
|
|
* bit 1: the current code is an EN after W4
|
|
* bit 2: the previous code was an EN after W2
|
|
* bit 3: the previous code was an EN after W4
|
|
* In other words, b0..1 have transitions of EN in the current iteration,
|
|
* while b2..3 have the transitions of EN in the previous iteration.
|
|
* A simple historyOfEN<<=2 suffices for the propagation.
|
|
*
|
|
* The (Nn) and (In) rules are also performed in that same single loop,
|
|
* but effectively one iteration behind for white space.
|
|
*
|
|
* Since all implicit rules are performed in one step, it is not necessary
|
|
* to actually store the intermediate directional properties in dirProps[].
|
|
*/
|
|
|
|
#define EN_SHIFT 2
|
|
#define EN_AFTER_W2 1
|
|
#define EN_AFTER_W4 2
|
|
#define EN_ALL 3
|
|
#define PREV_EN_AFTER_W2 4
|
|
#define PREV_EN_AFTER_W4 8
|
|
|
|
static void
|
|
resolveImplicitLevels(UBiDi *pBiDi,
|
|
UTextOffset start, UTextOffset limit,
|
|
DirProp sor, DirProp eor) {
|
|
const DirProp *dirProps=pBiDi->dirProps;
|
|
UBiDiLevel *levels=pBiDi->levels;
|
|
|
|
UTextOffset i, next, neutralStart=-1;
|
|
DirProp prevDirProp, dirProp, nextDirProp, lastStrong, beforeNeutral;
|
|
uint8_t historyOfEN;
|
|
|
|
/* initialize: current at sor, next at start (it is start<limit) */
|
|
next=start;
|
|
dirProp=lastStrong=sor;
|
|
nextDirProp=dirProps[next];
|
|
historyOfEN=0;
|
|
|
|
/*
|
|
* In all steps of this implementation, BN and explicit embedding codes
|
|
* must be treated as if they didn't exist (X9).
|
|
* They will get levels set before a non-neutral character, and remain
|
|
* undefined before a neutral one, but adjustWSLevels() will take care
|
|
* of all of them.
|
|
*/
|
|
while(DIRPROP_FLAG(nextDirProp)&MASK_BN_EXPLICIT) {
|
|
if(++next<limit) {
|
|
nextDirProp=dirProps[next];
|
|
} else {
|
|
nextDirProp=eor;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Note: at the end of this file, there is a prototype
|
|
* of a version of this function that uses a statetable
|
|
* at the core of this state machine.
|
|
* If you make changes to this state machine,
|
|
* please update that prototype as well.
|
|
*/
|
|
|
|
/* loop for entire run */
|
|
while(next<limit) {
|
|
/* advance */
|
|
prevDirProp=dirProp;
|
|
dirProp=nextDirProp;
|
|
i=next;
|
|
do {
|
|
if(++next<limit) {
|
|
nextDirProp=dirProps[next];
|
|
} else {
|
|
nextDirProp=eor;
|
|
break;
|
|
}
|
|
} while(DIRPROP_FLAG(nextDirProp)&MASK_BN_EXPLICIT);
|
|
historyOfEN<<=EN_SHIFT;
|
|
|
|
/* (W1..W7) */
|
|
switch(dirProp) {
|
|
case L:
|
|
lastStrong=L;
|
|
break;
|
|
case R:
|
|
lastStrong=R;
|
|
break;
|
|
case AL:
|
|
/* (W3) */
|
|
lastStrong=AL;
|
|
dirProp=R;
|
|
break;
|
|
case EN:
|
|
/* we have to set historyOfEN correctly */
|
|
if(lastStrong==AL) {
|
|
/* (W2) */
|
|
dirProp=AN;
|
|
} else {
|
|
if(lastStrong==L) {
|
|
/* (W7) */
|
|
dirProp=L;
|
|
}
|
|
/* this EN stays after (W2) and (W4) - at least before (W7) */
|
|
historyOfEN|=EN_ALL;
|
|
}
|
|
break;
|
|
case ES:
|
|
if( historyOfEN&PREV_EN_AFTER_W2 && /* previous was EN before (W4) */
|
|
nextDirProp==EN && lastStrong!=AL /* next is EN and (W2) won't make it AN */
|
|
) {
|
|
/* (W4) */
|
|
if(lastStrong!=L) {
|
|
dirProp=EN;
|
|
} else {
|
|
/* (W7) */
|
|
dirProp=L;
|
|
}
|
|
historyOfEN|=EN_AFTER_W4;
|
|
} else {
|
|
/* (W6) */
|
|
dirProp=ON;
|
|
}
|
|
break;
|
|
case CS:
|
|
if( historyOfEN&PREV_EN_AFTER_W2 && /* previous was EN before (W4) */
|
|
nextDirProp==EN && lastStrong!=AL /* next is EN and (W2) won't make it AN */
|
|
) {
|
|
/* (W4) */
|
|
if(lastStrong!=L) {
|
|
dirProp=EN;
|
|
} else {
|
|
/* (W7) */
|
|
dirProp=L;
|
|
}
|
|
historyOfEN|=EN_AFTER_W4;
|
|
} else if(prevDirProp==AN && /* previous was AN */
|
|
(nextDirProp==AN || /* next is AN */
|
|
nextDirProp==EN && lastStrong==AL) /* or (W2) will make it one */
|
|
) {
|
|
/* (W4) */
|
|
dirProp=AN;
|
|
} else {
|
|
/* (W6) */
|
|
dirProp=ON;
|
|
}
|
|
break;
|
|
case ET:
|
|
/* get sequence of ET; advance only next, not current, previous or historyOfEN */
|
|
while(next<limit && DIRPROP_FLAG(nextDirProp)&MASK_ET_NSM_BN /* (W1), (X9) */) {
|
|
if(++next<limit) {
|
|
nextDirProp=dirProps[next];
|
|
} else {
|
|
nextDirProp=eor;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if( historyOfEN&PREV_EN_AFTER_W4 || /* previous was EN before (W5) */
|
|
nextDirProp==EN && lastStrong!=AL /* next is EN and (W2) won't make it AN */
|
|
) {
|
|
/* (W5) */
|
|
if(lastStrong!=L) {
|
|
dirProp=EN;
|
|
} else {
|
|
/* (W7) */
|
|
dirProp=L;
|
|
}
|
|
} else {
|
|
/* (W6) */
|
|
dirProp=ON;
|
|
}
|
|
|
|
/* apply the result of (W1), (W5)..(W7) to the entire sequence of ET */
|
|
break;
|
|
case NSM:
|
|
/* (W1) */
|
|
dirProp=prevDirProp;
|
|
/* set historyOfEN back to prevDirProp's historyOfEN */
|
|
historyOfEN>>=EN_SHIFT;
|
|
/*
|
|
* Technically, this should be done before the switch() in the form
|
|
* if(nextDirProp==NSM) {
|
|
* dirProps[next]=nextDirProp=dirProp;
|
|
* }
|
|
*
|
|
* - effectively one iteration ahead.
|
|
* However, whether the next dirProp is NSM or is equal to the current dirProp
|
|
* does not change the outcome of any condition in (W2)..(W7).
|
|
*/
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
/* here, it is always [prev,this,next]dirProp!=BN; it may be next>i+1 */
|
|
|
|
/* perform (Nn) - here, only L, R, EN, AN, and neutrals are left */
|
|
/* this is one iteration late for the neutrals */
|
|
if(DIRPROP_FLAG(dirProp)&MASK_N) {
|
|
if(neutralStart<0) {
|
|
/* start of a sequence of neutrals */
|
|
neutralStart=i;
|
|
beforeNeutral=prevDirProp;
|
|
}
|
|
} else /* not a neutral, can be only one of { L, R, EN, AN } */ {
|
|
/*
|
|
* Note that all levels[] values are still the same at this
|
|
* point because this function is called for an entire
|
|
* same-level run.
|
|
* Therefore, we need to read only one actual level.
|
|
*/
|
|
UBiDiLevel level=levels[i];
|
|
|
|
if(neutralStart>=0) {
|
|
UBiDiLevel final;
|
|
/* end of a sequence of neutrals (dirProp is "afterNeutral") */
|
|
if(beforeNeutral==L) {
|
|
if(dirProp==L) {
|
|
final=0; /* make all neutrals L (N1) */
|
|
} else {
|
|
final=level; /* make all neutrals "e" (N2) */
|
|
}
|
|
} else /* beforeNeutral is one of { R, EN, AN } */ {
|
|
if(dirProp==L) {
|
|
final=level; /* make all neutrals "e" (N2) */
|
|
} else {
|
|
final=1; /* make all neutrals R (N1) */
|
|
}
|
|
}
|
|
/* perform (In) on the sequence of neutrals */
|
|
if((level^final)&1) {
|
|
/* do something only if we need to _change_ the level */
|
|
do {
|
|
++levels[neutralStart];
|
|
} while(++neutralStart<i);
|
|
}
|
|
neutralStart=-1;
|
|
}
|
|
|
|
/* perform (In) on the non-neutral character */
|
|
/*
|
|
* in the cases of (W5), processing a sequence of ET,
|
|
* and of (X9), skipping BN,
|
|
* there may be multiple characters from i to <next
|
|
* that all get (virtually) the same dirProp and (really) the same level
|
|
*/
|
|
if(dirProp==L) {
|
|
if(level&1) {
|
|
++level;
|
|
} else {
|
|
i=next; /* we keep the levels */
|
|
}
|
|
} else if(dirProp==R) {
|
|
if(!(level&1)) {
|
|
++level;
|
|
} else {
|
|
i=next; /* we keep the levels */
|
|
}
|
|
} else /* EN or AN */ {
|
|
level=(level+2)&~1; /* least greater even level */
|
|
}
|
|
|
|
/* apply the new level to the sequence, if necessary */
|
|
while(i<next) {
|
|
levels[i++]=level;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* perform (Nn) - here,
|
|
the character after the the neutrals is eor, which is either L or R */
|
|
/* this is one iteration late for the neutrals */
|
|
if(neutralStart>=0) {
|
|
/*
|
|
* Note that all levels[] values are still the same at this
|
|
* point because this function is called for an entire
|
|
* same-level run.
|
|
* Therefore, we need to read only one actual level.
|
|
*/
|
|
UBiDiLevel level=levels[neutralStart], final;
|
|
|
|
/* end of a sequence of neutrals (eor is "afterNeutral") */
|
|
if(beforeNeutral==L) {
|
|
if(eor==L) {
|
|
final=0; /* make all neutrals L (N1) */
|
|
} else {
|
|
final=level; /* make all neutrals "e" (N2) */
|
|
}
|
|
} else /* beforeNeutral is one of { R, EN, AN } */ {
|
|
if(eor==L) {
|
|
final=level; /* make all neutrals "e" (N2) */
|
|
} else {
|
|
final=1; /* make all neutrals R (N1) */
|
|
}
|
|
}
|
|
/* perform (In) on the sequence of neutrals */
|
|
if((level^final)&1) {
|
|
/* do something only if we need to _change_ the level */
|
|
do {
|
|
++levels[neutralStart];
|
|
} while(++neutralStart<limit);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* perform (L1) and (X9) ---------------------------------------------------- */
|
|
|
|
/*
|
|
* Reset the embedding levels for some non-graphic characters (L1).
|
|
* This function also sets appropriate levels for BN, and
|
|
* explicit embedding types that are supposed to have been removed
|
|
* from the paragraph in (X9).
|
|
*/
|
|
static void
|
|
adjustWSLevels(UBiDi *pBiDi) {
|
|
const DirProp *dirProps=pBiDi->dirProps;
|
|
UBiDiLevel *levels=pBiDi->levels;
|
|
UTextOffset i;
|
|
|
|
if(pBiDi->flags&MASK_WS) {
|
|
UBiDiLevel paraLevel=pBiDi->paraLevel;
|
|
Flags flag;
|
|
|
|
i=pBiDi->trailingWSStart;
|
|
while(i>0) {
|
|
/* reset a sequence of WS/BN before eop and B/S to the paragraph paraLevel */
|
|
while(i>0 && DIRPROP_FLAG(dirProps[--i])&MASK_WS) {
|
|
levels[i]=paraLevel;
|
|
}
|
|
|
|
/* reset BN to the next character's paraLevel until B/S, which restarts above loop */
|
|
/* here, i+1 is guaranteed to be <length */
|
|
while(i>0) {
|
|
flag=DIRPROP_FLAG(dirProps[--i]);
|
|
if(flag&MASK_BN_EXPLICIT) {
|
|
levels[i]=levels[i+1];
|
|
} else if(flag&MASK_B_S) {
|
|
levels[i]=paraLevel;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* now remove the UBIDI_LEVEL_OVERRIDE flags, if any */
|
|
/* (a separate loop can be optimized more easily by a compiler) */
|
|
if(pBiDi->flags&MASK_OVERRIDE) {
|
|
for(i=pBiDi->trailingWSStart; i>0;) {
|
|
levels[--i]&=~UBIDI_LEVEL_OVERRIDE;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* -------------------------------------------------------------------------- */
|
|
|
|
U_CAPI UBiDiDirection U_EXPORT2
|
|
ubidi_getDirection(const UBiDi *pBiDi) {
|
|
if(pBiDi!=NULL) {
|
|
return pBiDi->direction;
|
|
} else {
|
|
return UBIDI_LTR;
|
|
}
|
|
}
|
|
|
|
U_CAPI UTextOffset U_EXPORT2
|
|
ubidi_getLength(const UBiDi *pBiDi) {
|
|
if(pBiDi!=NULL) {
|
|
return pBiDi->length;
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
U_CAPI UBiDiLevel U_EXPORT2
|
|
ubidi_getParaLevel(const UBiDi *pBiDi) {
|
|
if(pBiDi!=NULL) {
|
|
return pBiDi->paraLevel;
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/* statetable prototype ----------------------------------------------------- */
|
|
|
|
/*
|
|
* This is here for possible future
|
|
* performance work and is not compiled right now.
|
|
*/
|
|
|
|
#if 0
|
|
/*
|
|
* This is a piece of code that could be part of ubidi.c/resolveImplicitLevels().
|
|
* It replaces in the (Wn) state machine the switch()-if()-cascade with
|
|
* just a few if()s and a state table.
|
|
*/
|
|
|
|
/* use the state table only for the following dirProp's */
|
|
#define MASK_W_TABLE (FLAG(L)|FLAG(R)|FLAG(AL)|FLAG(EN)|FLAG(ES)|FLAG(CS)|FLAG(ET)|FLAG(AN))
|
|
|
|
/*
|
|
* inputs:
|
|
*
|
|
* 0..1 historyOfEN - 2b
|
|
* 2 prevDirProp==AN - 1b
|
|
* 3..4 lastStrong, one of { L, R, AL, none } - 2b
|
|
* 5..7 dirProp, one of { L, R, AL, EN, ES, CS, ET, AN } - 3b
|
|
* 8..9 nextDirProp, one of { EN, AN, other }
|
|
*
|
|
* total: 10b=1024 states
|
|
*/
|
|
enum { _L, _R, _AL, _EN, _ES, _CS, _ET, _AN, _OTHER }; /* lastStrong, dirProp */
|
|
enum { __EN, __AN, __OTHER }; /* nextDirProp */
|
|
|
|
#define LAST_STRONG_SHIFT 3
|
|
#define DIR_PROP_SHIFT 5
|
|
#define NEXT_DIR_PROP_SHIFT 8
|
|
|
|
/* masks after shifting */
|
|
#define LAST_STRONG_MASK 3
|
|
#define DIR_PROP_MASK 7
|
|
#define STATE_MASK 0x1f
|
|
|
|
/* convert dirProp into _dirProp (above enum) */
|
|
static DirProp inputDirProp[dirPropCount]={ _X<<DIR_PROP_SHIFT, ... };
|
|
|
|
/* convert dirProp into __dirProp (above enum) */
|
|
static DirProp inputNextDirProp[dirPropCount]={ __X<<NEXT_DIR_PROP_SHIFT, ... };
|
|
|
|
/*
|
|
* outputs:
|
|
*
|
|
* dirProp, one of { L, R, EN, AN, ON } - 3b
|
|
*
|
|
* 0..1 historyOfEN - 2b
|
|
* 2 prevDirProp==AN - 1b
|
|
* 3..4 lastStrong, one of { L, R, AL, none } - 2b
|
|
* 5..7 new dirProp, one of { L, R, EN, AN, ON }
|
|
*
|
|
* total: 8 bits=1 byte per state
|
|
*/
|
|
enum { ___L, ___R, ___EN, ___AN, ___ON, ___count };
|
|
|
|
/* convert ___dirProp into dirProp (above enum) */
|
|
static DirProp outputDirProp[___count]={ X, ... };
|
|
|
|
/* state table */
|
|
static uint8_t wnTable[1024]={ /* calculate with switch()-if()-cascade */ };
|
|
|
|
static void
|
|
resolveImplicitLevels(BiDi *pBiDi,
|
|
Index start, Index end,
|
|
DirProp sor, DirProp eor) {
|
|
/* new variable */
|
|
uint8_t state;
|
|
|
|
/* remove variable lastStrong */
|
|
|
|
/* set initial state (set lastStrong, the rest is 0) */
|
|
state= sor==L ? 0 : _R<<LAST_STRONG_SHIFT;
|
|
|
|
while(next<limit) {
|
|
/* advance */
|
|
prevDirProp=dirProp;
|
|
dirProp=nextDirProp;
|
|
i=next;
|
|
do {
|
|
if(++next<limit) {
|
|
nextDirProp=dirProps[next];
|
|
} else {
|
|
nextDirProp=eor;
|
|
break;
|
|
}
|
|
} while(FLAG(nextDirProp)&MASK_BN_EXPLICIT);
|
|
|
|
/* (W1..W7) */
|
|
/* ### This may be more efficient with a switch(dirProp). */
|
|
if(FLAG(dirProp)&MASK_W_TABLE) {
|
|
state=wnTable[
|
|
((int)state)|
|
|
inputDirProp[dirProp]|
|
|
inputNextDirProp[nextDirProp]
|
|
];
|
|
dirProp=outputDirProp[state>>DIR_PROP_SHIFT];
|
|
state&=STATE_MASK;
|
|
} else if(dirProp==ET) {
|
|
/* get sequence of ET; advance only next, not current, previous or historyOfEN */
|
|
while(next<limit && FLAG(nextDirProp)&MASK_ET_NSM_BN /* (W1), (X9) */) {
|
|
if(++next<limit) {
|
|
nextDirProp=dirProps[next];
|
|
} else {
|
|
nextDirProp=eor;
|
|
break;
|
|
}
|
|
}
|
|
|
|
state=wnTable[
|
|
((int)state)|
|
|
_ET<<DIR_PROP_SHIFT|
|
|
inputNextDirProp[nextDirProp]
|
|
];
|
|
dirProp=outputDirProp[state>>DIR_PROP_SHIFT];
|
|
state&=STATE_MASK;
|
|
|
|
/* apply the result of (W1), (W5)..(W7) to the entire sequence of ET */
|
|
} else if(dirProp==NSM) {
|
|
/* (W1) */
|
|
dirProp=prevDirProp;
|
|
/* keep prevDirProp's EN and AN states! */
|
|
} else /* other */ {
|
|
/* set EN and AN states to 0 */
|
|
state&=LAST_STRONG_MASK<<LAST_STRONG_SHIFT;
|
|
}
|
|
|
|
/* perform (Nn) and (In) as usual */
|
|
}
|
|
/* perform (Nn) and (In) as usual */
|
|
}
|
|
#endif
|