1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/os/textandloc/fontservices/textshaperplugin/IcuSource/layout/LookupTables.cpp	Fri Jun 15 03:10:57 2012 +0200
     1.3 @@ -0,0 +1,85 @@
     1.4 +/*
     1.5 + *
     1.6 + * (C) Copyright IBM Corp. 1998-2004 - All Rights Reserved
     1.7 + *
     1.8 + */
     1.9 +
    1.10 +#include "LETypes.h"
    1.11 +#include "LayoutTables.h"
    1.12 +#include "LookupTables.h"
    1.13 +#include "LESwaps.h"
    1.14 +
    1.15 +U_NAMESPACE_BEGIN
    1.16 +
    1.17 +/*
    1.18 +    These are the rolled-up versions of the uniform binary search.
    1.19 +    Someday, if we need more performance, we can un-roll them.
    1.20 +    
    1.21 +    Note: I put these in the base class, so they only have to
    1.22 +    be written once. Since the base class doesn't define the
    1.23 +    segment table, these routines assume that it's right after
    1.24 +    the binary search header.
    1.25 +
    1.26 +    Another way to do this is to put each of these routines in one
    1.27 +    of the derived classes, and implement it in the others by casting
    1.28 +    the "this" pointer to the type that has the implementation.
    1.29 +*/ 
    1.30 +const LookupSegment *BinarySearchLookupTable::lookupSegment(const LookupSegment *segments, LEGlyphID glyph) const
    1.31 +{
    1.32 +    le_int16  unity = SWAPW(unitSize);
    1.33 +    le_int16  probe = SWAPW(searchRange);
    1.34 +    le_int16  extra = SWAPW(rangeShift);
    1.35 +    TTGlyphID ttGlyph = (TTGlyphID) LE_GET_GLYPH(glyph);
    1.36 +    const LookupSegment *entry = segments;
    1.37 +    const LookupSegment *trial = (const LookupSegment *) ((char *) entry + extra);
    1.38 +
    1.39 +    if (SWAPW(trial->lastGlyph) <= ttGlyph) {
    1.40 +        entry = trial;
    1.41 +    }
    1.42 +
    1.43 +    while (probe > unity) {
    1.44 +        probe >>= 1;
    1.45 +        trial = (const LookupSegment *) ((char *) entry + probe);
    1.46 +
    1.47 +        if (SWAPW(trial->lastGlyph) <= ttGlyph) {
    1.48 +            entry = trial;
    1.49 +        }
    1.50 +    }
    1.51 +
    1.52 +    if (SWAPW(entry->firstGlyph) <= ttGlyph) {
    1.53 +        return entry;
    1.54 +    }
    1.55 +
    1.56 +    return NULL;
    1.57 +}
    1.58 +
    1.59 +const LookupSingle *BinarySearchLookupTable::lookupSingle(const LookupSingle *entries, LEGlyphID glyph) const
    1.60 +{
    1.61 +    le_int16  unity = SWAPW(unitSize);
    1.62 +    le_int16  probe = SWAPW(searchRange);
    1.63 +    le_int16  extra = SWAPW(rangeShift);
    1.64 +    TTGlyphID ttGlyph = (TTGlyphID) LE_GET_GLYPH(glyph);
    1.65 +    const LookupSingle *entry = entries;
    1.66 +    const LookupSingle *trial = (const LookupSingle *) ((char *) entry + extra);
    1.67 +
    1.68 +    if (SWAPW(trial->glyph) <= ttGlyph) {
    1.69 +        entry = trial;
    1.70 +    }
    1.71 +
    1.72 +    while (probe > unity) {
    1.73 +        probe >>= 1;
    1.74 +        trial = (const LookupSingle *) ((char *) entry + probe);
    1.75 +
    1.76 +        if (SWAPW(trial->glyph) <= ttGlyph) {
    1.77 +            entry = trial;
    1.78 +        }
    1.79 +    }
    1.80 +
    1.81 +    if (SWAPW(entry->glyph) == ttGlyph) {
    1.82 +        return entry;
    1.83 +    }
    1.84 +
    1.85 +    return NULL;
    1.86 +}
    1.87 +
    1.88 +U_NAMESPACE_END