[OTLayout] Fix 'size' featureParams implementation
Looks at alternate location now.
This commit is contained in:
Behdad Esfahbod
parent
e77b442574
commit
efe252e600
@ -261,7 +261,71 @@ struct FeatureParamsSize
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{
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inline bool sanitize (hb_sanitize_context_t *c) {
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TRACE_SANITIZE (this);
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return TRACE_RETURN (c->check_struct (this));
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if (unlikely (!c->check_struct (this))) return TRACE_RETURN (false);
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/* This subtable has some "history", if you will. Some earlier versions of
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* Adobe tools calculated the offset of the FeatureParams sutable from the
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* beginning of the FeatureList table! Now, that is dealt with in the
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* Feature implementation. But we still need to be able to tell junk from
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* real data. Note: We don't check that the nameID actually exists.
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*
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* Read Roberts wrote on 9/15/06 on opentype-list@indx.co.uk :
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*
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* Yes, it is correct that a new version of the AFDKO (version 2.0) will be
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* coming out soon, and that the makeotf program will build a font with a
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* 'size' feature that is correct by the specification.
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*
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* The specification for this feature tag is in the "OpenType Layout Tag
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* Registry". You can see a copy of this at:
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* http://partners.adobe.com/public/developer/opentype/index_tag8.html#size
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*
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* Here is one set of rules to determine if the 'size' feature is built
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* correctly, or as by the older versions of MakeOTF. You may be able to do
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* better.
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*
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* Assume that the offset to the size feature is according to specification,
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* and make the following value checks. If it fails, assume the the size
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* feature is calculated as versions of MakeOTF before the AFDKO 2.0 built it.
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* If this fails, reject the 'size' feature. The older makeOTF's calculated the
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* offset from the beginning of the FeatureList table, rather than from the
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* beginning of the 'size' Feature table.
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*
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* If "design size" == 0:
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* fails check
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*
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* Else if ("subfamily identifier" == 0 and
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* "range start" == 0 and
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* "range end" == 0 and
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* "range start" == 0 and
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* "menu name ID" == 0)
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* passes check: this is the format used when there is a design size
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* specified, but there is no recommended size range.
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*
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* Else if ("design size" < "range start" or
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* "design size" > "range end" or
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* "range end" <= "range start" or
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* "menu name ID" < 256 or
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* "menu name ID" > 32767 or
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* menu name ID is not a name ID which is actually in the name table)
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* fails test
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* Else
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* passes test.
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*/
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if (!designSize)
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return TRACE_RETURN (false);
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else if (subfamilyID == 0 &&
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subfamilyNameID == 0 &&
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rangeStart == 0 &&
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rangeEnd == 0)
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return TRACE_RETURN (true);
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else if (designSize < rangeStart ||
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designSize > rangeEnd ||
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subfamilyNameID < 256 ||
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subfamilyNameID > 32767)
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return TRACE_RETURN (false);
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else
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return TRACE_RETURN (true);
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}
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USHORT designSize; /* Represents the design size in 720/inch
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@ -343,9 +407,7 @@ struct FeatureParamsCharacterVariants
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return TRACE_RETURN (c->check_struct (this) &&
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characters.sanitize (c));
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}
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/* TODO: This is made private since we don't have the facilities in
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* FeatureParams to correctly sanitize this. */
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private:
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USHORT format; /* Format number is set to 0. */
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USHORT featUILableNameID; /* The ‘name’ table name ID that
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* specifies a string (or strings,
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@ -380,24 +442,25 @@ struct FeatureParamsCharacterVariants
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struct FeatureParams
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{
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/* Note:
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*
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* FeatureParams structures unfortunately don't have a generic length argument,
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* so their length depends on the feature name / requested use. We don't have
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* that information at sanitize time. As such, we sanitize for the longest
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* subtable possible. This may nuke a possibly valid subtable if it's unfortunate
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* enough to happen at the very end of the GSUB/GPOS table. But that's very
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* unlikely (I hope!).
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*
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* When we fully implement FeatureParamsCharacterVariants, we should fix this
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* shortcoming...
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*/
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inline bool sanitize (hb_sanitize_context_t *c) {
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inline bool sanitize (hb_sanitize_context_t *c, hb_tag_t tag) {
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TRACE_SANITIZE (this);
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return TRACE_RETURN (c->check_struct (this));
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if (tag == HB_TAG ('s','i','z','e'))
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return TRACE_RETURN (u.size.sanitize (c));
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if ((tag & 0xFFFF0000) == HB_TAG ('s','s','\0','\0')) /* ssXX */
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return TRACE_RETURN (u.stylisticSet.sanitize (c));
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if ((tag & 0xFFFF0000) == HB_TAG ('c','v','\0','\0')) /* cvXX */
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return TRACE_RETURN (u.characterVariants.sanitize (c));
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return TRACE_RETURN (true);
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}
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inline const FeatureParamsSize& get_size_params (hb_tag_t tag) const
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{
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if (tag == HB_TAG ('s','i','z','e'))
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return u.size;
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return Null(FeatureParamsSize);
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}
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private:
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union {
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FeatureParamsSize size;
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FeatureParamsStylisticSet stylisticSet;
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@ -426,26 +489,36 @@ struct Feature
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if (unlikely (!(c->check_struct (this) && lookupIndex.sanitize (c))))
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return TRACE_RETURN (false);
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/* Some earlier versions of Adobe tools calculated the offset of the
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* FeatureParams subtable from the beginning of the FeatureList table!
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*
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* If sanitizing "failed" for the FeatureParams subtable, try it with the
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* alternative location. We would know sanitize "failed" if old value
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* of the offset was non-zero, but it's zeroed now.
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*/
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Offset orig_offset = featureParams;
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if (likely (featureParams.sanitize (c, this)))
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if (unlikely (!featureParams.sanitize (c, this, closure ? closure->tag : HB_TAG_NONE)))
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return TRACE_RETURN (false);
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if (likely (!orig_offset))
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return TRACE_RETURN (true);
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/* Some earlier versions of Adobe tools calculated the offset of the
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* FeatureParams sutable from the beginning of the FeatureList table!
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* Try that instead... */
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if (closure && closure->list_base)
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if (featureParams == 0 && closure && closure->list_base && closure->list_base < this)
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{
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Offset new_offset;
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new_offset.set (orig_offset - ((char *) this - (char *) closure->list_base));
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/* Check that it did not overflow. */
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if (new_offset != (orig_offset - ((char *) this - (char *) closure->list_base)))
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return TRACE_RETURN (false);
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unsigned int new_offset_int = (unsigned int) orig_offset -
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((char *) this - (char *) closure->list_base);
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return TRACE_RETURN (featureParams.try_set (c, new_offset) &&
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featureParams.sanitize (c, this));
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Offset new_offset;
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/* Check that it did not overflow. */
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new_offset.set (new_offset_int);
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if (new_offset == new_offset_int &&
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featureParams.try_set (c, new_offset) &&
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!featureParams.sanitize (c, this, closure ? closure->tag : HB_TAG_NONE))
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return TRACE_RETURN (false);
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}
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return TRACE_RETURN (false);
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return TRACE_RETURN (true);
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}
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OffsetTo<FeatureParams>
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@ -647,104 +647,39 @@ hb_ot_layout_get_size_params (hb_face_t *face,
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unsigned int *range_start, /* OUT. May be NULL */
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unsigned int *range_end /* OUT. May be NULL */)
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{
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bool ret = false;
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const OT::GPOS &gpos = _get_gpos (face);
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const hb_tag_t tag = HB_TAG ('s','i','z','e');
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unsigned int num_features = gpos.get_feature_count ();
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for (unsigned int i = 0; i < num_features; i++)
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{
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if (HB_TAG ('s','i','z','e') == gpos.get_feature_tag (i))
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if (tag == gpos.get_feature_tag (i))
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{
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const OT::Feature &f = gpos.get_feature (i);
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const OT::FeatureParamsSize ¶ms = f.get_feature_params ().u.size;
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const OT::FeatureParamsSize ¶ms = f.get_feature_params ().get_size_params (tag);
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/* This subtable has some "history", if you will. Some earlier versions of
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* Adobe tools calculated the offset of the FeatureParams sutable from the
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* beginning of the FeatureList table! Now, we don't check for that possibility,
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* but we want to at least detect junk data and reject it.
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*
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* Read Roberts wrote on 9/15/06 on opentype-list@indx.co.uk :
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*
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* Yes, it is correct that a new version of the AFDKO (version 2.0) will be
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* coming out soon, and that the makeotf program will build a font with a
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* 'size' feature that is correct by the specification.
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*
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* The specification for this feature tag is in the "OpenType Layout Tag
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* Registry". You can see a copy of this at:
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* http://partners.adobe.com/public/developer/opentype/index_tag8.html#size
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*
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* Here is one set of rules to determine if the 'size' feature is built
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* correctly, or as by the older versions of MakeOTF. You may be able to do
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* better.
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*
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* Assume that the offset to the size feature is according to specification,
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* and make the following value checks. If it fails, assume the the size
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* feature is calculated as versions of MakeOTF before the AFDKO 2.0 built it.
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* If this fails, reject the 'size' feature. The older makeOTF's calculated the
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* offset from the beginning of the FeatureList table, rather than from the
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* beginning of the 'size' Feature table.
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*
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* If "design size" == 0:
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* fails check
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*
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* Else if ("subfamily identifier" == 0 and
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* "range start" == 0 and
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* "range end" == 0 and
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* "range start" == 0 and
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* "menu name ID" == 0)
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* passes check: this is the format used when there is a design size
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* specified, but there is no recommended size range.
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*
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* Else if ("design size" < "range start" or
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* "design size" > "range end" or
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* "range end" <= "range start" or
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* "menu name ID" < 256 or
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* "menu name ID" > 32767 or
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* menu name ID is not a name ID which is actually in the name table)
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* fails test
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* Else
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* passes test.
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*/
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if (!params.designSize)
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ret = false;
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else if (params.subfamilyID == 0 &&
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params.subfamilyNameID == 0 &&
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params.rangeStart == 0 &&
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params.rangeEnd == 0)
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ret = true;
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else if (params.designSize < params.rangeStart ||
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params.designSize > params.rangeEnd ||
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params.subfamilyNameID < 256 ||
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params.subfamilyNameID > 32767)
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ret = false;
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else
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ret = true;
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#define PARAM(a, A) if (a) *a = params.A
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if (ret)
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if (params.designSize)
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{
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#define PARAM(a, A) if (a) *a = params.A
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PARAM (design_size, designSize);
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PARAM (subfamily_id, subfamilyID);
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PARAM (subfamily_name_id, subfamilyNameID);
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PARAM (range_start, rangeStart);
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PARAM (range_end, rangeEnd);
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break;
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}
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#undef PARAM
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return true;
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}
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}
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}
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#define PARAM(a, A) if (a) *a = 0
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if (!ret)
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{
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PARAM (design_size, designSize);
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PARAM (subfamily_id, subfamilyID);
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PARAM (subfamily_name_id, subfamilyNameID);
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PARAM (range_start, rangeStart);
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PARAM (range_end, rangeEnd);
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}
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PARAM (design_size, designSize);
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PARAM (subfamily_id, subfamilyID);
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PARAM (subfamily_name_id, subfamilyNameID);
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PARAM (range_start, rangeStart);
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PARAM (range_end, rangeEnd);
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#undef PARAM
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return ret;
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return false;
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}
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