tdf#163105 Consolidated duplicated kashida justification code

The kashida candidate position selection logic was copied-and-pasted
from Writer into Edit Engine. This change consolidates the shared code
into a library. This change also adds some minimal characteristic tests,
which previously did not exist.

Change-Id: I2bfbfa79858347803474b754566436f3e74d1a54
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/173883
Reviewed-by: Jonathan Clark <jonathan@libreoffice.org>
Tested-by: Jenkins

1 files changed, 8 insertions, 261 deletions

diff --git a/sw/source/core/text/porlay.cxx b/sw/source/core/text/porlay.cxx
index 923d5286c458..8574f6d31d12 100644
--- a/sw/source/core/text/porlay.cxx
+++ b/sw/source/core/text/porlay.cxx
@@ -79,124 +79,12 @@
 #include <unicode/ubidi.h>
 #include <i18nutil/scripttypedetector.hxx>
 #include <i18nutil/unicode.hxx>
+#include <i18nutil/kashida.hxx>
 #include <unotxdoc.hxx>
 
 using namespace ::com::sun::star;
 using namespace i18n::ScriptType;
 
-/*
-   https://www.khtt.net/en/page/1821/the-big-kashida-secret
-
-   the rules of priorities that govern the addition of kashidas in Arabic text
-   made ... for ... Explorer 5.5 browser.
-
-   The kashida justification is based on a connection priority scheme that
-   decides where kashidas are put automatically.
-
-   This is how the software decides on kashida-inserting priorities:
-   1. First it looks for characters with the highest priority in each word,
-   which means kashida-extensions will only been used in one position in each
-   word. Not more.
-   2. The kashida will be connected to the character with the highest priority.
-   3. If kashida connection opportunities are found with an equal level of
-   priority in one word, the kashida will be placed towards the end of the
-   word.
-
-   The priority list of characters and the positioning is as follows:
-   1. after a kashida that is manually placed in the text by the user,
-   2. after a Seen or Sad (initial and medial form),
-   3. before the final form of Taa Marbutah, Haa, Dal,
-   4. before the final form of Alef, Tah Lam, Kaf and Gaf,
-   5. before the preceding medial Baa of Ra, Ya and Alef Maqsurah,
-   6. before the final form of Waw, Ain, Qaf and Fa,
-   7. before the final form of other characters that can be connected.
-*/
-
-#define IS_JOINING_GROUP(c, g) ( u_getIntPropertyValue( (c), UCHAR_JOINING_GROUP ) == U_JG_##g )
-#define isAinChar(c)        IS_JOINING_GROUP((c), AIN)
-#define isAlefChar(c)       IS_JOINING_GROUP((c), ALEF)
-#define isDalChar(c)        IS_JOINING_GROUP((c), DAL)
-#define isFehChar(c)       (IS_JOINING_GROUP((c), FEH) || IS_JOINING_GROUP((c), AFRICAN_FEH))
-#define isGafChar(c)        IS_JOINING_GROUP((c), GAF)
-#define isHehChar(c)        IS_JOINING_GROUP((c), HEH)
-#define isKafChar(c)        IS_JOINING_GROUP((c), KAF)
-#define isLamChar(c)        IS_JOINING_GROUP((c), LAM)
-#define isQafChar(c)       (IS_JOINING_GROUP((c), QAF) || IS_JOINING_GROUP((c), AFRICAN_QAF))
-#define isRehChar(c)        IS_JOINING_GROUP((c), REH)
-#define isTahChar(c)        IS_JOINING_GROUP((c), TAH)
-#define isTehMarbutaChar(c) IS_JOINING_GROUP((c), TEH_MARBUTA)
-#define isWawChar(c)        IS_JOINING_GROUP((c), WAW)
-#define isSeenOrSadChar(c)  (IS_JOINING_GROUP((c), SAD) || IS_JOINING_GROUP((c), SEEN))
-
-// Beh and characters that behave like Beh in medial form.
-static bool isBehChar(sal_Unicode cCh)
-{
-    bool bRet = false;
-    switch (u_getIntPropertyValue(cCh, UCHAR_JOINING_GROUP))
-    {
-    case U_JG_BEH:
-    case U_JG_NOON:
-    case U_JG_AFRICAN_NOON:
-    case U_JG_NYA:
-    case U_JG_YEH:
-    case U_JG_FARSI_YEH:
-    case U_JG_BURUSHASKI_YEH_BARREE:
-        bRet = true;
-        break;
-    default:
-        bRet = false;
-        break;
-    }
-
-    return bRet;
-}
-
-// Yeh and characters that behave like Yeh in final form.
-static bool isYehChar(sal_Unicode cCh)
-{
-    bool bRet = false;
-    switch (u_getIntPropertyValue(cCh, UCHAR_JOINING_GROUP))
-    {
-    case U_JG_YEH:
-    case U_JG_FARSI_YEH:
-    case U_JG_YEH_BARREE:
-    case U_JG_BURUSHASKI_YEH_BARREE:
-    case U_JG_YEH_WITH_TAIL:
-        bRet = true;
-        break;
-    default:
-        bRet = false;
-        break;
-    }
-
-    return bRet;
-}
-
-static bool isTransparentChar ( sal_Unicode cCh )
-{
-    return u_getIntPropertyValue( cCh, UCHAR_JOINING_TYPE ) == U_JT_TRANSPARENT;
-}
-
-// Checks if cCh + cNectCh builds a ligature (used for Kashidas)
-static bool lcl_IsLigature( sal_Unicode cCh, sal_Unicode cNextCh )
-{
-            // Lam + Alef
-    return ( isLamChar ( cCh ) && isAlefChar ( cNextCh ));
-}
-
-// Checks if cCh is connectable to cPrevCh (used for Kashidas)
-static bool lcl_ConnectToPrev( sal_Unicode cCh, sal_Unicode cPrevCh )
-{
-    const int32_t nJoiningType = u_getIntPropertyValue( cPrevCh, UCHAR_JOINING_TYPE );
-    bool bRet = nJoiningType != U_JT_RIGHT_JOINING && nJoiningType != U_JT_NON_JOINING;
-
-    // check for ligatures cPrevChar + cChar
-    if( bRet )
-        bRet = !lcl_IsLigature( cPrevCh, cCh );
-
-    return bRet;
-}
-
 static  bool lcl_HasStrongLTR ( std::u16string_view rText, sal_Int32 nStart, sal_Int32 nEnd )
  {
      for( sal_Int32 nCharIdx = nStart; nCharIdx < nEnd; ++nCharIdx )
@@ -1618,157 +1506,16 @@ void SwScriptInfo::InitScriptInfo(const SwTextNode& rNode,
             while ( aScanner.NextWord() )
             {
                 const OUString& rWord = aScanner.GetWord();
+                auto stKashidaPos = i18nutil::GetWordKashidaPosition(rWord);
 
-                sal_Int32 nIdx = 0, nPrevIdx = 0;
-                sal_Int32 nKashidaPos = -1;
-                sal_Unicode cCh, cPrevCh = 0;
-
-                int nPriorityLevel = 7;    // 0..6 = level found
-                                           // 7 not found
-
-                sal_Int32 nWordLen = rWord.getLength();
-
-                // ignore trailing vowel chars
-                while( nWordLen && isTransparentChar( rWord[ nWordLen - 1 ] ))
-                    --nWordLen;
-
-                while (nIdx < nWordLen)
+                if (stKashidaPos.has_value())
                 {
-                    cCh = rWord[ nIdx ];
-
-                    // 1. Priority:
-                    // after user inserted kashida
-                    if ( 0x640 == cCh )
-                    {
-                        nKashidaPos = aScanner.GetBegin() + nIdx;
-                        nPriorityLevel = 0;
-                    }
-
-                    // 2. Priority:
-                    // after a Seen or Sad
-                    if (nPriorityLevel >= 1 && nIdx < nWordLen - 1)
-                    {
-                        if( isSeenOrSadChar( cCh )
-                         && (rWord[ nIdx+1 ] != 0x200C) ) // #i98410#: prevent ZWNJ expansion
-                        {
-                            nKashidaPos  = aScanner.GetBegin() + nIdx;
-                            nPriorityLevel = 1;
-                        }
-                    }
-
-                    // 3. Priority:
-                    // before final form of Teh Marbuta, Heh, Dal
-                    if ( nPriorityLevel >= 2 && nIdx > 0 )
-                    {
-                        if ( isTehMarbutaChar ( cCh ) || // Teh Marbuta (right joining)
-                             isDalChar ( cCh ) ||        // Dal (right joining) final form may appear in the middle of word
-                             ( isHehChar ( cCh ) && nIdx == nWordLen - 1))  // Heh (dual joining) only at end of word
-                        {
-
-                            SAL_WARN_IF( 0 == cPrevCh, "sw.core", "No previous character" );
-                            // check if character is connectable to previous character,
-                            if ( lcl_ConnectToPrev( cCh, cPrevCh ) )
-                            {
-                                nKashidaPos = aScanner.GetBegin() + nPrevIdx;
-                                nPriorityLevel = 2;
-                            }
-                        }
-                    }
-
-                    // 4. Priority:
-                    // before final form of Alef, Tah, Lam, Kaf or Gaf
-                    if ( nPriorityLevel >= 3 && nIdx > 0 )
-                    {
-                        if ( isAlefChar ( cCh ) ||   // Alef (right joining) final form may appear in the middle of word
-                             (( isLamChar ( cCh ) || // Lam,
-                              isTahChar ( cCh )   || // Tah,
-                              isKafChar ( cCh )   || // Kaf (all dual joining)
-                              isGafChar ( cCh ) )
-                              && nIdx == nWordLen - 1))  // only at end of word
-                        {
-                            SAL_WARN_IF( 0 == cPrevCh, "sw.core", "No previous character" );
-                            // check if character is connectable to previous character,
-                            if ( lcl_ConnectToPrev( cCh, cPrevCh ) )
-                            {
-                                nKashidaPos = aScanner.GetBegin() + nPrevIdx;
-                                nPriorityLevel = 3;
-                            }
-                        }
-                    }
-
-                    // 5. Priority:
-                    // before medial Beh-like
-                    if ( nPriorityLevel >= 4 && nIdx > 0 && nIdx < nWordLen - 1 )
-                    {
-                        if ( isBehChar ( cCh ) )
-                        {
-                            // check if next character is Reh or Yeh-like
-                            sal_Unicode cNextCh = rWord[ nIdx + 1 ];
-                            if ( isRehChar ( cNextCh ) || isYehChar ( cNextCh ))
-                            {
-                                SAL_WARN_IF( 0 == cPrevCh, "sw.core", "No previous character" );
-                                // check if character is connectable to previous character,
-                                if ( lcl_ConnectToPrev( cCh, cPrevCh ) )
-                                {
-                                    nKashidaPos = aScanner.GetBegin() + nPrevIdx;
-                                    nPriorityLevel = 4;
-                                }
-                            }
-                        }
+                    // Only populate kashida positions for the invalidated tail
+                    TextFrameIndex nNewKashidaPos{aScanner.GetBegin() + stKashidaPos->nIndex};
+                    if(nNewKashidaPos >= nLastKashida) {
+                        m_Kashida.insert(m_Kashida.begin() + nCntKash, nNewKashidaPos);
+                        nCntKash++;
                     }
-
-                    // 6. Priority:
-                    // before the final form of Waw, Ain, Qaf and Feh
-                    if ( nPriorityLevel >= 5 && nIdx > 0 )
-                    {
-                        if ( isWawChar ( cCh )   || // Wav (right joining)
-                                                    // final form may appear in the middle of word
-                             (( isAinChar ( cCh ) ||  // Ain (dual joining)
-                                isQafChar ( cCh ) ||  // Qaf (dual joining)
-                                isFehChar ( cCh ) )   // Feh (dual joining)
-                                && nIdx == nWordLen - 1))  // only at end of word
-                        {
-                            SAL_WARN_IF( 0 == cPrevCh, "sw.core", "No previous character" );
-                            // check if character is connectable to previous character,
-                            if ( lcl_ConnectToPrev( cCh, cPrevCh ) )
-                            {
-                                nKashidaPos = aScanner.GetBegin() + nPrevIdx;
-                                nPriorityLevel = 5;
-                            }
-                        }
-                    }
-
-                    // other connecting possibilities
-                    if ( nPriorityLevel >= 6 && nIdx > 0 )
-                    {
-                        // Reh, Zain
-                        if ( isRehChar ( cCh ) )
-                        {
-                            SAL_WARN_IF( 0 == cPrevCh, "sw.core", "No previous character" );
-                            // check if character is connectable to previous character,
-                            if ( lcl_ConnectToPrev( cCh, cPrevCh ) )
-                            {
-                                nKashidaPos = aScanner.GetBegin() + nPrevIdx;
-                                nPriorityLevel = 6;
-                            }
-                        }
-                    }
-
-                    // Do not consider vowel marks when checking if a character
-                    // can be connected to previous character.
-                    if ( !isTransparentChar ( cCh) )
-                    {
-                        cPrevCh = cCh;
-                        nPrevIdx = nIdx;
-                    }
-
-                    ++nIdx;
-                } // end of current word
-
-                if ( -1 != nKashidaPos )
-                {
-                    m_Kashida.insert(m_Kashida.begin() + nCntKash, TextFrameIndex(nKashidaPos));
-                    nCntKash++;
                 }
             } // end of kashida search
         }