From a927294790fb8b1f3c57dcc93f0cb67d0cd9b68f Mon Sep 17 00:00:00 2001
From: Patrick Walton <pcwalton@mimiga.net>
Date: Fri, 27 Jan 2017 13:01:21 -0800
Subject: [PATCH] Add rudimentary support for TTC

---
 examples/lorem-ipsum.rs |  3 +++
 src/otf/cmap.rs         | 32 ++++++++++++++++++++------------
 src/otf/mod.rs          | 38 +++++++++++++++++++++++++++++++++++---
 3 files changed, 58 insertions(+), 15 deletions(-)

diff --git a/examples/lorem-ipsum.rs b/examples/lorem-ipsum.rs
index 5d6d850e..03b866d6 100644
--- a/examples/lorem-ipsum.rs
+++ b/examples/lorem-ipsum.rs
@@ -1,6 +1,9 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
+#![feature(alloc_system)]
+
+extern crate alloc_system;
 extern crate compute_shader;
 extern crate euclid;
 extern crate gl;
diff --git a/src/otf/cmap.rs b/src/otf/cmap.rs
index 9ed484c2..8ee8c1d3 100644
--- a/src/otf/cmap.rs
+++ b/src/otf/cmap.rs
@@ -52,20 +52,28 @@ impl<'a> CmapTable<'a> {
 
         // Check platform ID and encoding.
         // TODO(pcwalton): Handle more.
-        // TODO(pcwalton): Search for one that we can handle.
-        let platform_id = try!(cmap_reader.read_u16::<BigEndian>().map_err(drop));
-        let encoding_id = try!(cmap_reader.read_u16::<BigEndian>().map_err(drop));
-        match (platform_id, encoding_id) {
-            (PLATFORM_ID_UNICODE, _) |
-            (PLATFORM_ID_MICROSOFT, MICROSOFT_ENCODING_ID_UNICODE_BMP) |
-            (PLATFORM_ID_MICROSOFT, MICROSOFT_ENCODING_ID_UNICODE_UCS4) => {}
-            _ => return Err(())
+        let mut table_found = false;
+        for _ in 0..num_tables {
+            let platform_id = try!(cmap_reader.read_u16::<BigEndian>().map_err(drop));
+            let encoding_id = try!(cmap_reader.read_u16::<BigEndian>().map_err(drop));
+            let offset = try!(cmap_reader.read_u32::<BigEndian>().map_err(drop));
+            match (platform_id, encoding_id) {
+                (PLATFORM_ID_UNICODE, _) |
+                (PLATFORM_ID_MICROSOFT, MICROSOFT_ENCODING_ID_UNICODE_BMP) |
+                (PLATFORM_ID_MICROSOFT, MICROSOFT_ENCODING_ID_UNICODE_UCS4) => {
+                    // Move to the mapping table.
+                    cmap_reader = self.table.bytes;
+                    try!(cmap_reader.jump(offset as usize));
+                    table_found = true;
+                    break
+                }
+                _ => {}
+            }
         }
 
-        // Move to the mapping table.
-        let offset = try!(cmap_reader.read_u32::<BigEndian>().map_err(drop));
-        cmap_reader = self.table.bytes;
-        try!(cmap_reader.jump(offset as usize));
+        if !table_found {
+            return Err(())
+        }
 
         // Check the mapping table format.
         let format = try!(cmap_reader.read_u16::<BigEndian>().map_err(drop));
diff --git a/src/otf/mod.rs b/src/otf/mod.rs
index 73a7834c..8d8198cb 100644
--- a/src/otf/mod.rs
+++ b/src/otf/mod.rs
@@ -50,6 +50,15 @@ const LOCA: u32 = ((b'l' as u32) << 24) |
                   ((b'o' as u32) << 16) |
                   ((b'c' as u32) << 8)  |
                    (b'a' as u32);
+const TTCF: u32 = ((b't' as u32) << 24) |
+                  ((b't' as u32) << 16) |
+                  ((b'c' as u32) << 8)  |
+                   (b'f' as u32);
+
+static SFNT_VERSIONS: [u32; 2] = [
+    0x10000,
+    ((b't' as u32) << 24) | ((b'r' as u32) << 16) | ((b'u' as u32) << 8) | (b'e' as u32),
+];
 
 pub struct Font<'a> {
     pub bytes: &'a [u8],
@@ -71,10 +80,33 @@ pub struct FontTable<'a> {
 impl<'a> Font<'a> {
     #[inline]
     pub fn new<'b>(bytes: &'b [u8]) -> Result<Font<'b>, ()> {
-        // Read the tables we care about.
+        // Check magic number.
         let mut reader = bytes;
-        let sfnt_version = try!(reader.read_u32::<BigEndian>().map_err(drop));
-        if sfnt_version != 0x10000 {
+        let mut magic_number = try!(reader.read_u32::<BigEndian>().map_err(drop));
+        if magic_number == TTCF {
+            // This is a font collection. Read the first font.
+            //
+            // TODO(pcwalton): Provide a mechanism to read others.
+            let major_version = try!(reader.read_u16::<BigEndian>().map_err(drop));
+            let minor_version = try!(reader.read_u16::<BigEndian>().map_err(drop));
+            if (major_version != 1 && major_version != 2) || minor_version != 0 {
+                return Err(())
+            }
+
+            let num_fonts = try!(reader.read_u32::<BigEndian>().map_err(drop));
+            if num_fonts == 0 {
+                return Err(())
+            }
+
+            let table_offset = try!(reader.read_u32::<BigEndian>().map_err(drop));
+            reader = bytes;
+            try!(reader.jump(table_offset as usize));
+
+            magic_number = try!(reader.read_u32::<BigEndian>().map_err(drop));
+        }
+
+        // Check version.
+        if !SFNT_VERSIONS.contains(&magic_number) {
             return Err(())
         }