start to plumb ttcIndex into fonthost. For now just add to SkFontStream and its callers.

trunk/src/core/SkFontStream.cpp

Index: trunk/src/core/SkFontStream.cpp
===================================================================
--- trunk/src/core/SkFontStream.cpp	(revision 7997)
+++ trunk/src/core/SkFontStream.cpp	(working copy)
@@ -43,7 +43,9 @@
 
     On an error, return 0 for number of tables, and ignore offsetToDir
  */
-static int count_tables(SkStream* stream, size_t* offsetToDir = NULL) {
+static int count_tables(SkStream* stream, int ttcIndex, size_t* offsetToDir) {

[bungeman-skia, 2013/03/05 22:07:33]

ttcIndex may well be perfectly well served by an int, but why not unsigned?
You're already casting it to unsigned below anyway, asserting below, and
obviously it can't reasonably be negative.

+    SkASSERT(ttcIndex >= 0);
+
     SkSharedTTHeader shared;
     if (stream->read(&shared, sizeof(shared)) != sizeof(shared)) {
         return 0;
@@ -55,11 +57,20 @@
     // if we're really a collection, the first 4-bytes will be 'ttcf'
     uint32_t tag = SkEndian_SwapBE32(shared.fCollection.fTag);
     if (SkSetFourByteTag('t', 't', 'c', 'f') == tag) {
-        if (shared.fCollection.fNumOffsets == 0) {
+        unsigned count = SkEndian_SwapBE32(shared.fCollection.fNumOffsets);
+        if ((unsigned)ttcIndex >= count) {
             return 0;
         }
-        // this is the offset to the first local SkSFNTHeader
-        offset = SkEndian_SwapBE32(shared.fCollection.fOffset0);
+        
+        if (ttcIndex > 0) { // need to read more of the shared header
+            stream->rewind();
+            size_t amount = sizeof(shared) + ttcIndex * sizeof(uint32_t);
+            if (stream->read(&shared, amount) != amount) {
+                return 0;
+            }
+        }
+        // this is the offset to the local SkSFNTHeader
+        offset = SkEndian_SwapBE32((&shared.fCollection.fOffset0)[ttcIndex]);
         stream->rewind();
         if (stream->skip(offset) != offset) {
             return 0;
@@ -88,11 +99,11 @@
 
         fDir will be automatically freed when this object is destroyed
      */
-    bool init(SkStream* stream) {
+    bool init(SkStream* stream, int ttcIndex) {
         stream->rewind();
 
         size_t offsetToDir;
-        fCount = count_tables(stream, &offsetToDir);
+        fCount = count_tables(stream, ttcIndex, &offsetToDir);
         if (0 == fCount) {
             return false;
         }
@@ -113,9 +124,27 @@
 
 ///////////////////////////////////////////////////////////////////////////////
 
-int SkFontStream::GetTableTags(SkStream* stream, SkFontTableTag tags[]) {
+int SkFontStream::CountTTCEntries(SkStream* stream) {
+    stream->rewind();
+
+    SkSharedTTHeader shared;
+    if (stream->read(&shared, sizeof(shared)) != sizeof(shared)) {
+        return -1;
+    }
+
+    // if we're really a collection, the first 4-bytes will be 'ttcf'
+    uint32_t tag = SkEndian_SwapBE32(shared.fCollection.fTag);
+    if (SkSetFourByteTag('t', 't', 'c', 'f') == tag) {
+        return SkEndian_SwapBE32(shared.fCollection.fNumOffsets);
+    } else {
+        return 0;

[bungeman-skia, 2013/03/05 22:07:33]

The doc says return 0 for sfnt, but this returns 0 for everything > ~20 bytes?
Just return 0 for "Doesn't look like a TTC"?

+    }        
+}
+
+int SkFontStream::GetTableTags(SkStream* stream, int ttcIndex,
+                               SkFontTableTag tags[]) {
     SfntHeader  header;
-    if (!header.init(stream)) {
+    if (!header.init(stream, ttcIndex)) {
         return 0;
     }
 
@@ -127,10 +156,11 @@
     return header.fCount;
 }
 
-size_t SkFontStream::GetTableData(SkStream* stream, SkFontTableTag tag,
+size_t SkFontStream::GetTableData(SkStream* stream, int ttcIndex,
+                                  SkFontTableTag tag,
                                   size_t offset, size_t length, void* data) {
     SfntHeader  header;
-    if (!header.init(stream)) {
+    if (!header.init(stream, ttcIndex)) {
         return 0;
     }