mirror of https://github.com/freetype/freetype
Update 2 files
- /src/base/ftcalc.c - /include/freetype/internal/ftcalc.h
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@ -509,8 +509,8 @@ FT_BEGIN_HEADER
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* @note:
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* This function is not very fast.
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*/
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FT_BASE( FT_Int32 )
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FT_SqrtFixed( FT_Int32 x );
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FT_BASE( FT_UInt32 )
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FT_SqrtFixed( FT_UInt32 x );
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#endif /* 0 */
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@ -917,36 +917,29 @@
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/* documentation is in ftcalc.h */
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FT_BASE_DEF( FT_Int32 )
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FT_SqrtFixed( FT_Int32 x )
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/* Algorithm and code by Christophe Meessen (1993). */
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FT_BASE_DEF( FT_UInt32 )
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FT_SqrtFixed( FT_UInt32 r )
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{
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FT_UInt32 root, rem_hi, rem_lo, test_div;
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FT_Int count;
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FT_UInt32 t, q, b;
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root = 0;
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q = 0;
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if ( x > 0 )
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b = 0x40000000;
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while ( b > 0x40 )
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{
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rem_hi = 0;
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rem_lo = (FT_UInt32)x;
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count = 24;
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do
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t = q + b;
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if ( r >= t )
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{
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rem_hi = ( rem_hi << 2 ) | ( rem_lo >> 30 );
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rem_lo <<= 2;
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root <<= 1;
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test_div = ( root << 1 ) + 1;
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if ( rem_hi >= test_div )
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{
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rem_hi -= test_div;
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root += 1;
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}
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} while ( --count );
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r -= t;
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q = t + b; /* equivalent to q += 2*b */
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}
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r <<= 1;
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b >>= 1;
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}
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return (FT_Int32)root;
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return q >> 8;
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}
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#endif /* 0 */
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