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authorHerbert Dürr <hdu@apache.org>2014-03-27 16:07:37 +0000
committerCaolán McNamara <caolanm@redhat.com>2014-03-28 11:12:58 +0000
commit67688d3118b1a361d5dbdaa78e918815c163d75c (patch)
tree871f8fa43ea62a7946f6a666a088d688ef8715da
parentf6bcdc5ae6da9cb9b13bdc3551bef917d8b0362d (diff)
Related: #i124516# handle bad surrogate pairs gracefully on Windows
When running into invalid Unicode surrogate pairs the text layout code on Windows ran into massive problems like crashes. This change detects the situation of an invalid surrogate pair and falls back to treat it as a simple character instead of requesting a complex glyph fallback. (cherry picked from commit 913f1fc4b1362f6e91595af5ae10c4cba79fd355) Change-Id: I2988f4b64061d0a5df211f6f0f04b1f235fcd6a5
-rw-r--r--vcl/win/source/gdi/winlayout.cxx17
1 files changed, 12 insertions, 5 deletions
diff --git a/vcl/win/source/gdi/winlayout.cxx b/vcl/win/source/gdi/winlayout.cxx
index a3aca6d5c4e4..f47456bf286d 100644
--- a/vcl/win/source/gdi/winlayout.cxx
+++ b/vcl/win/source/gdi/winlayout.cxx
@@ -386,12 +386,19 @@ bool SimpleWinLayout::LayoutText( ImplLayoutArgs& rArgs )
bool bSurrogate = ((nCharCode >= 0xD800) && (nCharCode <= 0xDFFF));
if( bSurrogate )
{
- if( nCharCode >= 0xDC00 ) // this part of a surrogate pair was already processed
+ // ignore high surrogates, they were already processed with their low surrogates
+ if( nCharCode >= 0xDC00 )
continue;
- nCharCode = 0x10000 + ((pCodes[0] - 0xD800) << 10) + (pCodes[1] - 0xDC00);
- }
+ // check the second half of the surrogate pair
+ bSurrogate &= (0xDC00 <= pCodes[1]) && (pCodes[1] <= 0xDFFF);
+ // calculate the UTF-32 code of valid surrogate pairs
+ if( bSurrogate )
+ nCharCode = 0x10000 + ((pCodes[0] - 0xD800) << 10) + (pCodes[1] - 0xDC00);
+ else // or fall back to a replacement character
+ nCharCode = '?';
+ }
- // get the advance width for the current UCS-4 code point
+ // get the advance width for the current UTF-32 code point
int nGlyphWidth = mrWinFontEntry.GetCachedGlyphWidth( nCharCode );
if( nGlyphWidth == -1 )
{
@@ -409,7 +416,7 @@ bool SimpleWinLayout::LayoutText( ImplLayoutArgs& rArgs )
mpGlyphAdvances[ i ] = nGlyphWidth;
mnWidth += nGlyphWidth;
- // remaining codes of surrogate pair get a zero width
+ // the second half of surrogate pair gets a zero width
if( bSurrogate && ((i+1) < mnGlyphCount) )
mpGlyphAdvances[ i+1 ] = 0;