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[subset] Refactor composite glyf iteration code into an Iterator outside of the accelerator.

This commit is contained in:
Garret Rieger 2018-02-16 16:56:15 -07:00 committed by Behdad Esfahbod
parent dc6d67df13
commit 49544eb860
2 changed files with 60 additions and 56 deletions
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110
src/hb-ot-glyf-table.hh
View File

@ -133,6 +133,58 @@ struct glyf
return size;
}
struct Iterator
{
const char *glyph_start;
const char *glyph_end;
const CompositeGlyphHeader *current;
inline bool move_to_next ()
{
if (current->flags & CompositeGlyphHeader::MORE_COMPONENTS)
{
const CompositeGlyphHeader *possible =
&StructAfter<CompositeGlyphHeader, CompositeGlyphHeader> (*current);
if (!in_range (possible))
return false;
current = possible;
return true;
}
return false;
}
inline bool in_range (const CompositeGlyphHeader *composite) const
{
return (const char *) composite >= glyph_start
&& ((const char *) composite + CompositeGlyphHeader::min_size) <= glyph_end
&& ((const char *) composite + composite->get_size()) <= glyph_end;
}
};
static inline bool get_iterator (const char * glyph_data,
unsigned int length,
CompositeGlyphHeader::Iterator *iterator /* OUT */)
{
if (length < GlyphHeader::static_size)
return false; /* Empty glyph; zero extents. */
const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (glyph_data, 0);
if (glyph_header.numberOfContours < 0)
{
const CompositeGlyphHeader *possible =
&StructAfter<CompositeGlyphHeader, GlyphHeader> (glyph_header);
iterator->glyph_start = glyph_data;
iterator->glyph_end = (const char *) glyph_data + length;
if (!iterator->in_range (possible))
return false;
iterator->current = possible;
return true;
}
return false;
}
DEFINE_SIZE_MIN (4);
};
@ -166,69 +218,21 @@ struct glyf
hb_blob_destroy (glyf_blob);
}
inline bool in_table (const char *offset, unsigned int len) const
{
return (offset - (const char *) glyf_table + len) <= glyf_len;
}
inline bool in_table (const CompositeGlyphHeader *header) const
{
return in_table ((const char *) header, CompositeGlyphHeader::min_size)
&& in_table ((const char *) header, header->get_size());
}
inline bool in_glyph (const CompositeGlyphHeader *header,
unsigned int start_offset,
unsigned int end_offset) const
{
do
{
unsigned int offset_in_glyf = (const char *) header - (const char*) glyf_table;
if (offset_in_glyf < start_offset
|| offset_in_glyf + header->get_size() > end_offset)
return false;
} while (next_composite (&header));
return true;
}
/*
* Returns true if the referenced glyph is a valid glyph and a composite glyph.
* If true is returned a pointer to the composite glyph will be written into
* composite.
*/
inline bool get_composite (hb_codepoint_t glyph, const CompositeGlyphHeader ** composite /* OUT */) const
inline bool get_composite (hb_codepoint_t glyph,
CompositeGlyphHeader::Iterator *composite /* OUT */) const
{
unsigned int start_offset, end_offset;
if (!get_offsets (glyph, &start_offset, &end_offset))
return false; /* glyph not found */
if (end_offset - start_offset < GlyphHeader::static_size)
return false; /* Empty glyph; zero extents. */
const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (glyf_table, start_offset);
if (glyph_header.numberOfContours < 0) {
const CompositeGlyphHeader *possible = &StructAfter<CompositeGlyphHeader, GlyphHeader> (glyph_header);
if (!in_table (possible)
|| !in_glyph (possible, start_offset, end_offset))
return false;
*composite = possible;
return true;
}
return false;
}
inline bool next_composite (const CompositeGlyphHeader ** next /* IN/OUT */) const
{
if ((*next)->flags & CompositeGlyphHeader::MORE_COMPONENTS)
{
const CompositeGlyphHeader *possible = &StructAfter<CompositeGlyphHeader, CompositeGlyphHeader> (**next);
if (!in_table (possible))
return false;
*next = possible;
return true;
}
return false;
return CompositeGlyphHeader::get_iterator ((const char*) this->glyf_table + start_offset,
end_offset - start_offset,
composite);
}
inline bool get_offsets (hb_codepoint_t glyph,

6
src/hb-subset-plan.cc
View File

@ -106,13 +106,13 @@ _add_gid_and_children (const OT::glyf::accelerator_t &glyf,
hb_set_add (gids_to_retain, gid);
const OT::glyf::CompositeGlyphHeader *composite;
OT::glyf::CompositeGlyphHeader::Iterator composite;
if (glyf.get_composite (gid, &composite))
{
do
{
_add_gid_and_children (glyf, (hb_codepoint_t) composite->glyphIndex, gids_to_retain);
} while (glyf.next_composite (&composite));
_add_gid_and_children (glyf, (hb_codepoint_t) composite.current->glyphIndex, gids_to_retain);
} while (composite.move_to_next());
}
}