tdf#94810: fix reverse offset mapping

With simple transliteration, TextSearch::searchForward used to use
whole string to perform the search, then started to create substring
to search. But it left the precautions from
commit c00601dab0f5533b152cd63cec0a89bfec1ba95f by Eike Rathke:
searching for $ may actually return a result set pointing behind the
search string which it does with the ICU regex engine.
The precaution made it to skip reverse mapping if index was 0.

Commit 9aae521b451269007f03527c83645b8b935eb419 by Michael Stahl
didn't consider the case when nStop is 0, and startPos > 0. Then it
tried to get offset[-1].

Anyway, using value of startPos in those conditions seems illogical.

Removed those precautions (and made assertions for that).
Fixed handling zero indexes.

Reviewed-on: https://gerrit.libreoffice.org/19840
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>
(cherry picked from commit 4cf1d290bab29e18e1312b63ff862f5102e00387)

remove comment that makes no sense, tdf#94810 follow-up

nStart should not become <0, not even when searching for $ end.

(cherry picked from commit 67ab2ce3c6fed2ceaacaad890a7d8683ce0397a7)

similar to searchForward() use the correct offsets, tdf#94810 related

(cherry picked from commit ce91f3c1292f3e9b84157acf10b67ad9ca16719d)

Change-Id: I2066abc51fff7fb7323bc7f6198bdea06439d4f3
79586471f1a7908372fa3ee044a6f66499b1790f
cb5a45acaad9029e0998594de8b3dc2e9211866e
Reviewed-on: https://gerrit.libreoffice.org/20136
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Mike Kaganski <mikekaganski@hotmail.com>

2 files changed, 23 insertions, 6 deletions

diff --git a/i18npool/qa/cppunit/test_textsearch.cxx b/i18npool/qa/cppunit/test_textsearch.cxx
index db2d4022250e..3c99f632fd38 100644
--- a/i18npool/qa/cppunit/test_textsearch.cxx
+++ b/i18npool/qa/cppunit/test_textsearch.cxx
@@ -24,6 +24,7 @@
 #include <com/sun/star/util/SearchOptions.hpp>
 #include <com/sun/star/util/SearchAlgorithms.hpp>
 #include <com/sun/star/util/XTextSearch.hpp>
+#include <com/sun/star/i18n/Transliteration.hpp>
 #include <unotest/bootstrapfixturebase.hxx>
 
 #include <unicode/regex.h>
@@ -123,6 +124,16 @@ void TestTextSearch::testSearches()
     CPPUNIT_ASSERT( aRes.subRegExpressions > 0 );
     CPPUNIT_ASSERT( aRes.startOffset[0] == bStartRes );
     CPPUNIT_ASSERT( aRes.endOffset[0] == bEndRes );
+
+    aOptions.transliterateFlags = ::css::i18n::TransliterationModules::TransliterationModules_IGNORE_CASE
+                                | ::css::i18n::TransliterationModules::TransliterationModules_IGNORE_WIDTH;
+    aOptions.searchString = "([^ ]*)[ ]*([^ ]*)";
+    m_xSearch->setOptions(aOptions);
+    aRes = m_xSearch->searchForward("11 22 33", 2, 7);
+    CPPUNIT_ASSERT(aRes.subRegExpressions == 3);
+    CPPUNIT_ASSERT((aRes.startOffset[0] == 2) && (aRes.endOffset[0] == 5));
+    CPPUNIT_ASSERT((aRes.startOffset[1] == 2) && (aRes.endOffset[1] == 2));
+    CPPUNIT_ASSERT((aRes.startOffset[2] == 3) && (aRes.endOffset[2] == 5));
 }
 
 void TestTextSearch::setUp()
diff --git a/i18npool/source/search/textsearch.cxx b/i18npool/source/search/textsearch.cxx
index b8005fb66ecf..472d509691f4 100644
--- a/i18npool/source/search/textsearch.cxx
+++ b/i18npool/source/search/textsearch.cxx
@@ -301,15 +301,18 @@ SearchResult TextSearch::searchForward( const OUString& searchStr, sal_Int32 sta
             for ( sal_Int32 k = 0; k < nGroups; k++ )
             {
                 const sal_Int32 nStart = sres.startOffset[k] - nExtraOffset;
-                if (startPos > 0 || nStart > 0)
-                    sres.startOffset[k] = (nStart < nOffsets ? offset[nStart] : (offset[nOffsets - 1] + 1));
+                assert(nStart >= 0);
+                sres.startOffset[k] = (nStart < nOffsets ? offset[nStart] : (offset[nOffsets - 1] + 1));
                 // JP 20.6.2001: end is ever exclusive and then don't return
                 //               the position of the next character - return the
                 //               next position behind the last found character!
                 //               "a b c" find "b" must return 2,3 and not 2,4!!!
                 const sal_Int32 nStop = sres.endOffset[k] - nExtraOffset;
-                if (startPos > 0 || nStop > 0)
+                assert(nStop >= 0);
+                if (nStop > 0)
                     sres.endOffset[k] = offset[(nStop <= nOffsets ? nStop : nOffsets) - 1] + 1;
+                else
+                    sres.endOffset[k] = offset[0];
             }
         }
     }
@@ -401,15 +404,18 @@ SearchResult TextSearch::searchBackward( const OUString& searchStr, sal_Int32 st
             for ( sal_Int32 k = 0; k < nGroups; k++ )
             {
                 const sal_Int32 nStart = sres.startOffset[k];
-                if (endPos > 0 || nStart > 0)
+                assert(nStart >= 0);
+                if (nStart > 0)
                     sres.startOffset[k] = offset[(nStart <= nOffsets ? nStart : nOffsets) - 1] + 1;
+                else
+                    sres.startOffset[k] = offset[0];
                 // JP 20.6.2001: end is ever exclusive and then don't return
                 //               the position of the next character - return the
                 //               next position behind the last found character!
                 //               "a b c" find "b" must return 2,3 and not 2,4!!!
                 const sal_Int32 nStop = sres.endOffset[k];
-                if (endPos > 0 || nStop > 0)
-                    sres.endOffset[k] = (nStop < nOffsets ? offset[nStop] : (offset[nOffsets - 1] + 1));
+                assert(nStop >= 0);
+                sres.endOffset[k] = (nStop < nOffsets ? offset[nStop] : (offset[nOffsets - 1] + 1));
             }
         }
     }