[sfntdiff] Support diff'ing different font formats

Fixes #626

c/sfntdiff/source/Dmain.c

@@ -100,7 +100,7 @@ IntN main(IntN argc, Byte8 *argv[]) {
 
     volatile IntX i = 0;
     IntN argi;
-    Card32 value, value2;
+    Card32 value;
     Byte8 *filename1;
     Byte8 *filename2;
     IntN name1isDir, name2isDir;
@@ -152,12 +152,6 @@ IntN main(IntN argc, Byte8 *argv[]) {
 
         /* See if we can recognize the file type */
         value = fileSniff(1);
-        value2 = fileSniff(2);
-        if (value != value2) {
-            fileClose(1);
-            fileClose(2);
-            fatal("file1 [%s] is not the same type as file2 [%s]\n", filename1, filename2);
-        }
 
         switch (value) {
             case bits_:
@@ -212,12 +206,6 @@ IntN main(IntN argc, Byte8 *argv[]) {
 
             /* See if we can recognize the file type */
             value = fileSniff(1);
-            value2 = fileSniff(2);
-            if (value != value2) {
-                fileClose(1);
-                fileClose(2);
-                fatal("file1 [%s] is not the same type as file2 [%s]\n", fil1, fil2);
-            }
 
             switch (value) {
                 case bits_:
@@ -270,12 +258,6 @@ IntN main(IntN argc, Byte8 *argv[]) {
 
         /* See if we can recognize the file type */
         value = fileSniff(1);
-        value2 = fileSniff(2);
-        if (value != value2) {
-            fileClose(1);
-            fileClose(2);
-            fatal("file1 [%s] is not the same type as file2 [%s]\n", filename1, fil2);
-        }
 
         switch (value) {
             case bits_:

tests/sfntdiff_data/expected_output/bug626.txt

@@ -0,0 +1,8 @@
+Thu Mar 14 02:59:39 2019
+sfntdiff (2.21217) (-d 0)  files:
+< SourceSerifPro-It.otf
+> SourceSerifPro-It.ttf
+'sfnt' differs.
+'head' differs.
+'maxp' differs.
+'post' differs.

tests/sfntdiff_test.py

@@ -8,6 +8,7 @@
 from test_utils import get_expected_path
 
 TOOL = 'sfntdiff'
+CMD = ['-t', TOOL]
 
 
 # -----
@@ -41,7 +42,13 @@ def test_exit_unknown_option(arg):
 def test_diff(args, txt_filename):
     if args:
         args.insert(0, '-o')
-    actual_path = runner(
-        ['-t', TOOL, '-s', '-f', 'regular.otf', 'bold.otf'] + args)
+    actual_path = runner(CMD + ['-s', '-f', 'regular.otf', 'bold.otf'] + args)
     expected_path = get_expected_path(txt_filename)
     assert differ([expected_path, actual_path, '-l', '1-4'])
+
+
+def test_diff_otf_vs_ttf_bug626():
+    actual_path = runner(CMD + ['-s', '-f', 'SourceSerifPro-It.otf',
+                                            'SourceSerifPro-It.ttf'])
+    expected_path = get_expected_path('bug626.txt')
+    assert differ([expected_path, actual_path, '-l', '1-4'])