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Avoid div-by-zero, validate upem

This commit is contained in:
Behdad Esfahbod 2010-10-01 19:09:23 -04:00
parent 7f97d2cd90
commit ac0c1663fa
2 changed files with 10 additions and 3 deletions
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7
src/hb-ot-head-private.hh
View File

@ -42,12 +42,19 @@ struct head
{ {
static const hb_tag_t Tag = HB_OT_TAG_head; static const hb_tag_t Tag = HB_OT_TAG_head;
inline unsigned int get_upem (void) const {
unsigned int upem = unitsPerEm;
/* If no valid head table found, assume 1000, which matches typicaly Type1 usage. */
return 16 <= upem && upem <= 16384 ? upem : 1000;
}
inline bool sanitize (hb_sanitize_context_t *c) { inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE (); TRACE_SANITIZE ();
/* Shall we check for magicNumber here? Who cares? */ /* Shall we check for magicNumber here? Who cares? */
return c->check_struct (this) && likely (version.major == 1); return c->check_struct (this) && likely (version.major == 1);
} }
private:
FixedVersion version; /* Version of the head table--currently FixedVersion version; /* Version of the head table--currently
* 0x00010000 for version 1.0. */ * 0x00010000 for version 1.0. */
FixedVersion fontRevision; /* Set by font manufacturer. */ FixedVersion fontRevision; /* Set by font manufacturer. */

6
src/hb-ot-layout-private.hh
View File

@ -77,9 +77,9 @@ struct hb_ot_layout_context_t
} info; } info;
/* Convert from font-space to user-space */ /* Convert from font-space to user-space */
/* XXX div-by-zero / speed up */ /* XXX speed up */
inline hb_position_t scale_x (int16_t v) { return (int64_t) this->font->x_scale * v / this->face->head_table->unitsPerEm; } inline hb_position_t scale_x (int16_t v) { return (int64_t) this->font->x_scale * v / this->face->head_table->get_upem (); }
inline hb_position_t scale_y (int16_t v) { return (int64_t) this->font->y_scale * v / this->face->head_table->unitsPerEm; } inline hb_position_t scale_y (int16_t v) { return (int64_t) this->font->y_scale * v / this->face->head_table->get_upem (); }
}; };