[PATCH 3/5] usp10: Simplify the chaining context table assignments in GPOS_apply_ChainContextPos().

[Aric Stewart]

Signed-off-by: Aric Stewart <aric at codeweavers.com>

On 4/5/17 3:21 AM, Henri Verbeet wrote:
> And avoid some endian conversions in the process.
> 
> Signed-off-by: Henri Verbeet <hverbeet at codeweavers.com>
> ---
>  dlls/usp10/opentype.c | 35 ++++++++++++++++-------------------
>  1 file changed, 16 insertions(+), 19 deletions(-)
> 
> diff --git a/dlls/usp10/opentype.c b/dlls/usp10/opentype.c
> index fd8fe91..b5ee5d1 100644
> --- a/dlls/usp10/opentype.c
> +++ b/dlls/usp10/opentype.c
> @@ -2226,57 +2226,54 @@ static unsigned int GPOS_apply_ChainContextPos(const ScriptCache *script_cache,
>          }
>          else if (GET_BE_WORD(backtrack->PosFormat) == 3)
>          {
> +            WORD backtrack_count, input_count, lookahead_count;
>              int k;
> -            int indexGlyphs;
>              const GPOS_ChainContextPosFormat3_2 *input;
>              const GPOS_ChainContextPosFormat3_3 *lookahead;
>              const GPOS_ChainContextPosFormat3_4 *positioning;
>  
>              TRACE("  subtype 3 (Coverage-based Chaining Context Glyph Positioning)\n");
>  
> -            for (k = 0; k < GET_BE_WORD(backtrack->BacktrackGlyphCount); ++k)
> +            backtrack_count = GET_BE_WORD(backtrack->BacktrackGlyphCount);
> +            input = (const GPOS_ChainContextPosFormat3_2 *)&backtrack->Coverage[backtrack_count];
> +            input_count = GET_BE_WORD(input->InputGlyphCount);
> +            lookahead = (const GPOS_ChainContextPosFormat3_3 *)&input->Coverage[input_count];
> +            lookahead_count = GET_BE_WORD(lookahead->LookaheadGlyphCount);
> +            positioning = (const GPOS_ChainContextPosFormat3_4 *)&lookahead->Coverage[lookahead_count];
> +
> +            for (k = 0; k < backtrack_count; ++k)
>              {
>                  offset = GET_BE_WORD(backtrack->Coverage[k]);
>                  if (GSUB_is_glyph_covered((const BYTE *)backtrack + offset,
>                          glyphs[glyph_index + (dirBacktrack * (k + 1))]) == -1)
>                      break;
>              }
> -            if (k != GET_BE_WORD(backtrack->BacktrackGlyphCount))
> +            if (k != backtrack_count)
>                  continue;
>              TRACE("Matched Backtrack\n");
>  
> -            input = (const GPOS_ChainContextPosFormat3_2 *)((BYTE *)backtrack +
> -                    FIELD_OFFSET(GPOS_ChainContextPosFormat3_1, Coverage[GET_BE_WORD(backtrack->BacktrackGlyphCount)]));
> -
> -            indexGlyphs = GET_BE_WORD(input->InputGlyphCount);
> -            for (k = 0; k < indexGlyphs; k++)
> +            for (k = 0; k < input_count; ++k)
>              {
>                  offset = GET_BE_WORD(input->Coverage[k]);
>                  if (GSUB_is_glyph_covered((const BYTE *)backtrack + offset,
>                          glyphs[glyph_index + (write_dir * k)]) == -1)
>                      break;
>              }
> -            if (k != indexGlyphs)
> +            if (k != input_count)
>                  continue;
>              TRACE("Matched IndexGlyphs\n");
>  
> -            lookahead = (const GPOS_ChainContextPosFormat3_3 *)((BYTE *)input +
> -                    FIELD_OFFSET(GPOS_ChainContextPosFormat3_2, Coverage[GET_BE_WORD(input->InputGlyphCount)]));
> -
> -            for (k = 0; k < GET_BE_WORD(lookahead->LookaheadGlyphCount); ++k)
> +            for (k = 0; k < lookahead_count; ++k)
>              {
>                  offset = GET_BE_WORD(lookahead->Coverage[k]);
>                  if (GSUB_is_glyph_covered((const BYTE *)backtrack + offset,
> -                        glyphs[glyph_index + (dirLookahead * (indexGlyphs + k))]) == -1)
> +                        glyphs[glyph_index + (dirLookahead * (input_count + k))]) == -1)
>                      break;
>              }
> -            if (k != GET_BE_WORD(lookahead->LookaheadGlyphCount))
> +            if (k != lookahead_count)
>                  continue;
>              TRACE("Matched LookAhead\n");
>  
> -            positioning = (const GPOS_ChainContextPosFormat3_4 *)((BYTE *)lookahead +
> -                    FIELD_OFFSET(GPOS_ChainContextPosFormat3_3, Coverage[GET_BE_WORD(lookahead->LookaheadGlyphCount)]));
> -
>              if (GET_BE_WORD(positioning->PosCount))
>              {
>                  for (k = 0; k < GET_BE_WORD(positioning->PosCount); ++k)
> @@ -2288,7 +2285,7 @@ static unsigned int GPOS_apply_ChainContextPos(const ScriptCache *script_cache,
>                      GPOS_apply_lookup(script_cache, otm, logfont, analysis, advance, lookup, lookupIndex,
>                              glyphs, glyph_index + SequenceIndex, glyph_count, goffset);
>                  }
> -                return indexGlyphs + GET_BE_WORD(lookahead->LookaheadGlyphCount);
> +                return input_count + lookahead_count;
>              }
>              else return 1;
>          }
>