initial commit.

git-svn-id: http://ots.googlecode.com/svn/trunk@2 a4e77c2c-9104-11de-800e-5b313e0d2bf3

8 files changed, 950 insertions, 0 deletions

diff --git a/test/README b/test/README
new file mode 100644
index 0000000..c31f7ce
--- /dev/null
+++ b/test/README
@@ -0,0 +1,243 @@
+------------------------------------------------------------------------------
+ot-sanitise - TTF/OTF font transcoder
+
+Description:
+  ot-sanitise is a program which validates and transcodes a truetype or
+  opentype font file using the OTS library:
+
+      transcoded_font = ValidateAndTranscode(original_font);
+      if (validation_error)
+        PrintErrorAndExit;
+      OutputToStdout(transcoded_font);
+
+Usage:
+  $ ./ot-sanitise ttf_or_otf_file > transcoded_file
+
+Example:
+  $ ./ot-sanitise sample.otf > transcoded_sample.otf
+  $ ./ot-sanitise malformed.ttf > transcoded_malformed.ttf
+  WARNING at ots/src/ots.cc:158: bad range shift
+  ERROR at ots/src/ots.cc:199 (bool<unnamed>::do_ots_process(ots::OpenTypeFile*, ots::OTSStream*, const uint8_t*, size_t))
+  Failed to sanitise file!
+  $
+
+------------------------------------------------------------------------------
+idempotent - TTF/OTF font transcoder (for OTS debugging)
+
+Description:
+  idempotent is a program which validates and transcodes a truetype or opentype
+  font file using OTS. This tool transcodes the original font twice and then
+  verifies that the two transcoded fonts are identical:
+
+      t1 = ValidateAndTranscode(original_font);
+      if (validation_error)
+        PrintErrorAndExit;
+      t2 = ValidateAndTranscode(t1);
+      if (validation_error)
+        PrintErrorAndExit;
+      if (t1 != t2)
+        PrintErrorAndExit;
+
+  This tool is basically for OTS developers.
+
+Usage:
+  $ ./idempotent ttf_or_otf_file
+
+Example:
+  $ ./idempotent sample.otf
+  $ ./idempotent malformed.ttf
+  WARNING at ots/src/ots.cc:158: bad range shift
+  ERROR at ots/src/ots.cc:199 (bool<unnamed>::do_ots_process(ots::OpenTypeFile*, ots::OTSStream*, const uint8_t*, size_t))
+  Failed to sanitise file!
+  $
+
+------------------------------------------------------------------------------
+validator_checker - font validation checker
+
+Description:
+  validator_checker is a program which is intended to validate malformed fonts.
+  If the program detects that the font is invalid, it prints "OK" and returns
+  with 0 (success). If it coulndn't detect any errors, the program then opens
+  the transcoded font and renders some characters using FreeType2:
+
+      transcoded_font = ValidateAndTranscode(malicious_font);
+      if (validation_error)
+        Print("OK");
+      OpenAndRenderSomeCharacters(transcoded_font);  # may cause SIGSEGV
+      Print("OK");
+
+  If SEGV doesn't raise inside FreeType2 library, the program prints "OK" and
+  returns with 0 as well. You should run this tool under the catchsegv or
+  valgrind command so that you can easily verify that all transformed fonts
+  don't crash the library (see the example below).
+
+Usage:
+  $ catchsegv ./validator_checker malicous_ttf_or_otf_file
+
+Example:
+  $ for f in malformed/*.ttf ; do catchsegv ./validator-checker "$f" ; done
+  OK: the malicious font was filtered: malformed/1.ttf
+  OK: the malicious font was filtered: malformed/2.ttf
+  OK: FreeType2 didn't crash: malformed/3.ttf
+  OK: the malicious font was filtered: malformed/4.ttf
+  $
+
+------------------------------------------------------------------------------
+perf - performance checker
+
+Description:
+  perf is a program which validates and transcodes a truetype or opentype font
+  file N times using OTS, then prints the elapsed time:
+
+      for (N times)
+        ValidateAndTranscode(original_font);
+      Print(elapsed_time_in_us / N);
+
+Usage:
+  $ ./perf ttf_or_otf_file
+
+Example:
+  $ ./perf sample.ttf 
+  903 [us] sample.ttf (139332 bytes, 154 [byte/us])
+  $ ./perf sample-bold.otf
+  291 [us] sample-bold.otf (150652 bytes, 517 [byte/us])
+
+------------------------------------------------------------------------------
+side-by-side - font quality checker
+
+Description:
+  side-by-side is a program which renders some characters (ASCII, Latin-1, CJK)
+  using both original font and transcoded font and checks that the two rendering
+  results are exactly equal.
+
+  The following Unicode characters are used during the test:
+    0x0020 - 0x007E  // Basic Latin
+    0x00A1 - 0x017F  // Latin-1
+    0x1100 - 0x11FF  // Hangul
+    0x3040 - 0x309F  // Japanese HIRAGANA letters
+    0x3130 - 0x318F  // Hangul
+    0x4E00 - 0x4F00  // CJK Kanji/Hanja
+    0xAC00 - 0xAD00  // Hangul
+
+  This tool uses FreeType2 library.
+  Note: This tool doesn't check kerning (GPOS/kern) nor font substitution
+  (GSUB). These should be tested in Layout tests if necessary.
+
+Usage:
+  $ ./side-by-side ttf_or_otf_file
+
+Example:
+  $ ./side-by-side linux/kochi-gothic.ttf  # no problem
+  $ ./side-by-side free/kredit1.ttf        # this is known issue of OTS.
+  bitmap metrics doesn't match! (14, 57), (37, 45)
+  EXPECTED:
+                
+    +#######*.  
+   +##########+ 
+  .###+.#.   .#.
+  *#*   #     #*
+  ##.   #     ##
+  ##    #     ##
+  ##    #     ##
+  ##    #.    ##
+  ##.   #.   .##
+  ##.   #.   .##
+  *#+   *+   +#*
+  *#+   *+   +#*
+  *#+   *+   +#*
+  *#+   *+   +#*
+  *#+   *+   *#*
+  *#+   ++   *#+
+  +#*   +*   *#+
+  +#*   +*   *#+
+  +#*   +*   *#+
+  +#*   +*   ##.
+  +#*   +*   ##.
+  .##   .#   ## 
+  .##   .#   ## 
+  .##   .#   ## 
+   ##    #   ## 
+   ##    #   ## 
+   ##    #  .## 
+   ##    #  .## 
+   ##   .#+ +#* 
+   ##  +######* 
+   ##.+#######* 
+   *##########* 
+   +##########+ 
+    #########*  
+    .########   
+      +####+    
+                
+                
+                
+                
+                
+                
+    .*######*   
+   +##*.*#####  
+  .##+.#+    +# 
+  *#* ##      #+
+  ##*###      ##
+  ######      ##
+  ##+.##+    +##
+  ##  ##########
+  ##  +#########
+  ##   +########
+  *#. .########*
+  .#* #########.
+   +##########+ 
+    +*######*   
+  
+  ACTUAL:
+
+    .*##*+                             
+   +##+.##*.                           
+  .#* .##.+#*                          
+  *#  ###   *#+                        
+  #*######+  .*#+                      
+  #########*.  +#*.                    
+  ###########*   +#*                   
+  *############+   *#+                 
+  +##############.  .##.               
+   *##############*   +#*              
+    +###############+   *#+            
+      *###############+  .*#+          
+       .###############*.  +#*.        
+         +###############*   +#*       
+           *###############+   *#+     
+            .*###############+  .*#+   
+              +###############*.  +#*  
+                +###############*   ** 
+                  *###############+  #+
+                   .###############* ##
+                     +############+  ##
+                       +########*   .##
+                        .######.   +###
+                       +#####+   .*#..#
+                     +#####*    *###..#
+                    *#####.   +#######*
+                  +#####+   .*########.
+                +#####*    +#########* 
+               *#####.   +##########+  
+             +#####+    *#########*.   
+           .#####*    +##########+     
+          *#####.   +##########*       
+        +#####+    *#########*.        
+      .#####*    +##########+          
+     *#####+   +##########*            
+   .#*++#+    *#########*.             
+  .#+  ##   +##########+               
+  ****###+.##########*                 
+  ##################.                  
+  ###+  *#########+                    
+  ##   +########*                      
+  *#+ *########.                       
+   ##.#######+                         
+   +#######*                           
+     *###*.                            
+  
+  
+  Glyph mismatch! (file: free/kredit1.ttf, U+0021, 100pt)!
+  $
+------------------------------------------------------------------------------
diff --git a/test/SConstruct b/test/SConstruct
new file mode 100644
index 0000000..4e688d3
--- /dev/null
+++ b/test/SConstruct
@@ -0,0 +1,43 @@
+# Build script for Linux
+#
+# Usage:
+#   $ cd ots/test/
+#   $ scons -c         # clean
+#   $ scons            # build
+#
+
+# Since the validator-checker tool might handle malicious font files, all hardening options for recent g++/ld are enabled just in case.
+# See http://wiki.debian.org/Hardening for details.
+env = Environment(CCFLAGS = ['-O2', '-I../include', '-I/usr/include/freetype2', '-ggdb', '-Wall', '-W', '-Wno-unused-parameter', '-fPIE', '-fstack-protector', '-D_FORTIFY_SOURCE=2', '-DOTS_DEBUG'], LINKFLAGS = ['-ggdb', '-Wl,-z,relro', '-Wl,-z,now', '-pie'])
+# TODO(yusukes): better to use pkg-config freetype2 --cflags
+ 
+env.Library('../src/libots.a',
+            ['../src/cff.cc',
+	    '../src/cmap.cc',
+	    '../src/cvt.cc',
+	    '../src/fpgm.cc',
+	    '../src/gasp.cc',
+	    '../src/glyf.cc',
+	    '../src/hdmx.cc',
+	    '../src/head.cc',
+	    '../src/hhea.cc',
+	    '../src/hmtx.cc',
+	    '../src/loca.cc',
+	    '../src/ltsh.cc',
+	    '../src/maxp.cc',
+	    '../src/name.cc',
+	    '../src/os2.cc',
+	    '../src/ots.cc',
+	    '../src/post.cc',
+	    '../src/prep.cc',
+	    '../src/vdmx.cc',
+	    '../src/vorg.cc'
+            ])
+ 
+env.Program('../test/ot-sanitise.cc', LIBS = ['ots'], LIBPATH='../src')
+env.Program('../test/idempotent.cc', LIBS = ['ots'], LIBPATH='../src')
+env.Program('../test/perf.cc', LIBS = ['ots'], LIBPATH='../src')
+
+# TODO(yusukes): better to use pkg-config freetype2 --libs
+env.Program('../test/side-by-side.cc', LIBS = ['ots', 'freetype', 'z', 'm'], LIBPATH = '../src')
+env.Program('../test/validator-checker.cc', LIBS = ['ots', 'freetype', 'z', 'm'], LIBPATH = '../src')
diff --git a/test/file-stream.h b/test/file-stream.h
new file mode 100644
index 0000000..58f85e1
--- /dev/null
+++ b/test/file-stream.h
@@ -0,0 +1,39 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef OTS_FILE_STREAM_H_
+#define OTS_FILE_STREAM_H_
+
+#include "opentype-sanitiser.h"
+
+namespace ots {
+
+class FILEStream : public OTSStream {
+ public:
+  explicit FILEStream(FILE *stream)
+      : file_(stream) {
+  }
+
+  ~FILEStream() {
+  }
+
+  bool WriteRaw(const void *data, size_t length) {
+    return fwrite(data, length, 1, file_) == 1;
+  }
+
+  bool Seek(off_t position) {
+    return fseek(file_, position, SEEK_SET) == 0;
+  }
+
+  off_t Tell() const {
+    return ftell(file_);
+  }
+
+ private:
+  FILE * const file_;
+};
+
+}  // namespace ots
+
+#endif  // OTS_FILE_STREAM_H_
diff --git a/test/idempotent.cc b/test/idempotent.cc
new file mode 100644
index 0000000..7f33a47
--- /dev/null
+++ b/test/idempotent.cc
@@ -0,0 +1,94 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+
+#include "opentype-sanitiser.h"
+#include "ots-memory-stream.h"
+
+namespace {
+
+int Usage(const char *argv0) {
+  std::fprintf(stderr, "Usage: %s <ttf file>\n", argv0);
+  return 1;
+}
+
+}  // namespace
+
+int main(int argc, char **argv) {
+  if (argc != 2) return Usage(argv[0]);
+
+  const int fd = ::open(argv[1], O_RDONLY);
+  if (fd < 0) {
+    ::perror("open");
+    return 1;
+  }
+
+  struct stat st;
+  ::fstat(fd, &st);
+
+  uint8_t *data = new uint8_t[st.st_size];
+  if (::read(fd, data, st.st_size) != st.st_size) {
+    ::close(fd);
+    std::fprintf(stderr, "Failed to read file!\n");
+    return 1;
+  }
+  ::close(fd);
+
+  // A transcoded font is usually smaller than an original font.
+  // However, it can be slightly bigger than the original one due to
+  // name table replacement and/or padding for glyf table.
+  static const size_t kPadLen = 20 * 1024;
+  uint8_t *result = new uint8_t[st.st_size + kPadLen];
+  ots::MemoryStream output(result, st.st_size + kPadLen);
+
+  bool r = ots::Process(&output, data, st.st_size);
+  if (!r) {
+    std::fprintf(stderr, "Failed to sanitise file!\n");
+    return 1;
+  }
+  const size_t result_len = output.Tell();
+  free(data);
+
+  uint8_t *result2 = new uint8_t[result_len];
+  ots::MemoryStream output2(result2, result_len);
+  r = ots::Process(&output2, result, result_len);
+  if (!r) {
+    std::fprintf(stderr, "Failed to sanitise previous output!\n");
+    return 1;
+  }
+  const size_t result2_len = output2.Tell();
+
+  bool dump_results = false;
+  if (result2_len != result_len) {
+    std::fprintf(stderr, "Outputs differ in length\n");
+    dump_results = true;
+  } else if (std::memcmp(result2, result, result_len)) {
+    std::fprintf(stderr, "Outputs differ in content\n");
+    dump_results = true;
+  }
+
+  if (dump_results) {
+    std::fprintf(stderr, "Dumping results to out1.tff and out2.tff\n");
+    int fd1 = ::open("out1.ttf", O_WRONLY | O_CREAT | O_TRUNC, 0600);
+    int fd2 = ::open("out2.ttf", O_WRONLY | O_CREAT | O_TRUNC, 0600);
+    if (fd1 < 0 || fd2 < 0) {
+      ::perror("opening output file");
+      return 1;
+    }
+    if ((::write(fd1, result, result_len) < 0) ||
+        (::write(fd2, result2, result2_len) < 0)) {
+      ::perror("writing output file");
+      return 1;
+    }
+  }
+
+  return 0;
+}
diff --git a/test/ot-sanitise.cc b/test/ot-sanitise.cc
new file mode 100644
index 0000000..313a6bc
--- /dev/null
+++ b/test/ot-sanitise.cc
@@ -0,0 +1,54 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// A very simple driver program while sanitises the file given as argv[1] and
+// writes the sanitised version to stdout.
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <cstdio>
+#include <cstdlib>
+
+#include "file-stream.h"
+#include "opentype-sanitiser.h"
+
+namespace {
+
+int Usage(const char *argv0) {
+  std::fprintf(stderr, "Usage: %s ttf_file > dest_ttf_file\n", argv0);
+  return 1;
+}
+
+}  // namespace
+
+int main(int argc, char **argv) {
+  if (argc != 2) return Usage(argv[0]);
+  if (::isatty(1)) return Usage(argv[0]);
+
+  const int fd = ::open(argv[1], O_RDONLY);
+  if (fd < 0) {
+    ::perror("open");
+    return 1;
+  }
+
+  struct stat st;
+  ::fstat(fd, &st);
+
+  uint8_t *data = new uint8_t[st.st_size];
+  if (::read(fd, data, st.st_size) != st.st_size) {
+    ::perror("read");
+    return 1;
+  }
+  ::close(fd);
+
+  ots::FILEStream output(stdout);
+  const bool result = ots::Process(&output, data, st.st_size);
+
+  if (!result) {
+    std::fprintf(stderr, "Failed to sanitise file!\n");
+  }
+  return !result;
+}
diff --git a/test/perf.cc b/test/perf.cc
new file mode 100644
index 0000000..34fe931
--- /dev/null
+++ b/test/perf.cc
@@ -0,0 +1,79 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/time.h>  // for timersub macro.
+#include <unistd.h>
+#include <time.h>
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+
+#include "opentype-sanitiser.h"
+#include "ots-memory-stream.h"
+
+namespace {
+
+int Usage(const char *argv0) {
+  std::fprintf(stderr, "Usage: %s <ttf file>\n", argv0);
+  return 1;
+}
+
+}  // namespace
+
+int main(int argc, char **argv) {
+  ots::DisableDebugOutput();  // turn off ERROR and WARNING outputs.
+
+  if (argc != 2) return Usage(argv[0]);
+
+  const int fd = ::open(argv[1], O_RDONLY);
+  if (fd < 0) {
+    ::perror("open");
+    return 1;
+  }
+
+  struct stat st;
+  ::fstat(fd, &st);
+
+  uint8_t *data = new uint8_t[st.st_size];
+  if (::read(fd, data, st.st_size) != st.st_size) {
+    std::fprintf(stderr, "Failed to read file!\n");
+    return 1;
+  }
+
+  // A transcoded font is usually smaller than an original font.
+  // However, it can be slightly bigger than the original one due to
+  // name table replacement and/or padding for glyf table.
+  static const size_t kPadLen = 20 * 1024;
+  uint8_t *result = new uint8_t[st.st_size + kPadLen];
+
+  int num_repeat = 250;
+  if (st.st_size < 1024 * 1024) {
+    num_repeat = 2500;
+  }
+  if (st.st_size < 1024 * 100) {
+    num_repeat = 5000;
+  }
+
+  struct timeval start, end, elapsed;
+  ::gettimeofday(&start, 0);
+  for (int i = 0; i < num_repeat; ++i) {
+    ots::MemoryStream output(result, st.st_size + kPadLen);
+    bool r = ots::Process(&output, data, st.st_size);
+    if (!r) {
+      std::fprintf(stderr, "Failed to sanitise file!\n");
+      return 1;
+    }
+  }
+  ::gettimeofday(&end, 0);
+  timersub(&end, &start, &elapsed);
+
+  uint64_t us = ((elapsed.tv_sec * 1000 * 1000) + elapsed.tv_usec) / num_repeat;
+  std::fprintf(stderr, "%lu [us] %s (%lu bytes, %lu [byte/us])\n",
+               us, argv[1], st.st_size, (us ? st.st_size / us : 0));
+
+  return 0;
+}
diff --git a/test/side-by-side.cc b/test/side-by-side.cc
new file mode 100644
index 0000000..1b5ff90
--- /dev/null
+++ b/test/side-by-side.cc
@@ -0,0 +1,281 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <fcntl.h>
+#include <freetype/ftoutln.h>
+#include <ft2build.h>
+#include FT_FREETYPE_H
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+
+#include "opentype-sanitiser.h"
+#include "ots-memory-stream.h"
+
+namespace {
+
+void DumpBitmap(const FT_Bitmap *bitmap) {
+  for (int i = 0; i < bitmap->rows * bitmap->width; ++i) {
+    if (bitmap->buffer[i] > 192) {
+      std::fprintf(stderr, "#");
+    } else if (bitmap->buffer[i] > 128) {
+      std::fprintf(stderr, "*");
+    } else if (bitmap->buffer[i] > 64) {
+      std::fprintf(stderr, "+");
+    } else if (bitmap->buffer[i] > 32) {
+      std::fprintf(stderr, ".");
+    } else {
+      std::fprintf(stderr, " ");
+    }
+
+    if ((i + 1) % bitmap->width == 0) {
+      std::fprintf(stderr, "\n");
+    }
+  }
+}
+
+int CompareBitmaps(const FT_Bitmap *orig, const FT_Bitmap *trans) {
+  int ret = 0;
+
+  if (orig->width == trans->width &&
+      orig->rows == trans->rows) {
+    for (int i = 0; i < orig->rows * orig->width; ++i) {
+      if (orig->buffer[i] != trans->buffer[i]) {
+        std::fprintf(stderr, "bitmap data doesn't match!\n");
+        ret = 1;
+        break;
+      }
+    }
+  } else {
+    std::fprintf(stderr, "bitmap metrics doesn't match! (%d, %d), (%d, %d)\n",
+                 orig->width, orig->rows, trans->width, trans->rows);
+    ret = 1;
+  }
+
+  if (ret) {
+    std::fprintf(stderr, "EXPECTED:\n");
+    DumpBitmap(orig);
+    std::fprintf(stderr, "\nACTUAL:\n");
+    DumpBitmap(trans);
+    std::fprintf(stderr, "\n\n");
+  }
+
+  delete[] orig->buffer;
+  delete[] trans->buffer;
+  return ret;
+}
+
+int GetBitmap(FT_Library library, FT_Outline *outline, FT_Bitmap *bitmap) {
+  FT_BBox bbox;
+  FT_Outline_Get_CBox(outline, &bbox);
+
+  bbox.xMin &= ~63;
+  bbox.yMin &= ~63;
+  bbox.xMax = (bbox.xMax + 63) & ~63;
+  bbox.yMax = (bbox.yMax + 63) & ~63;
+  FT_Outline_Translate(outline, -bbox.xMin, -bbox.yMin);
+
+  const int w = (bbox.xMax - bbox.xMin) >> 6;
+  const int h = (bbox.yMax - bbox.yMin) >> 6;
+
+  if (w == 0 || h == 0) {
+    return -1;  // white space
+  }
+  if (w < 0 || h < 0) {
+    std::fprintf(stderr, "bad width/height\n");
+    return 1;  // error
+  }
+
+  uint8_t *buf = new uint8_t[w * h];
+  std::memset(buf, 0x0, w * h);
+
+  bitmap->width = w;
+  bitmap->rows = h;
+  bitmap->pitch = w;
+  bitmap->buffer = buf;
+  bitmap->pixel_mode = FT_PIXEL_MODE_GRAY;
+  bitmap->num_grays = 256;
+  if (FT_Outline_Get_Bitmap(library, outline, bitmap)) {
+    std::fprintf(stderr, "can't get outline\n");
+    delete[] buf;
+    return 1;  // error.
+  }
+
+  return 0;
+}
+
+int LoadChar(FT_Face face, bool use_bitmap, int pt, FT_ULong c) {
+  static const int kDpi = 72;
+
+  FT_Matrix matrix;
+  matrix.xx = matrix.yy = 1 << 16;
+  matrix.xy = matrix.yx = 0 << 16;
+
+  FT_Int32 flags = FT_LOAD_DEFAULT | FT_LOAD_TARGET_NORMAL;
+  if (!use_bitmap) {
+    // Since the transcoder drops embedded bitmaps from the transcoded one,
+    // we have to use FT_LOAD_NO_BITMAP flag for the original face.
+    flags |= FT_LOAD_NO_BITMAP;
+  }
+
+  FT_Error error = FT_Set_Char_Size(face, pt * (1 << 6), 0, kDpi, 0);
+  if (error) {
+    std::fprintf(stderr, "Failed to set the char size!\n");
+    return 1;
+  }
+
+  FT_Set_Transform(face, &matrix, 0);
+
+  error = FT_Load_Char(face, c, flags);
+  if (error) return -1;  // no such glyf in the font.
+
+  if (face->glyph->format != FT_GLYPH_FORMAT_OUTLINE) {
+    std::fprintf(stderr, "bad format\n");
+    return 1;
+  }
+
+  return 0;
+}
+
+int LoadCharThenCompare(FT_Library library,
+                        FT_Face orig_face, FT_Face trans_face,
+                        int pt, FT_ULong c) {
+  FT_Bitmap orig_bitmap, trans_bitmap;
+
+  // Load original bitmap.
+  int ret = LoadChar(orig_face, false, pt, c);
+  if (ret) return ret;  // 1: error, -1: no such glyph
+
+  FT_Outline *outline = &orig_face->glyph->outline;
+  ret = GetBitmap(library, outline, &orig_bitmap);
+  if (ret) return ret;  // white space?
+
+  // Load transformed bitmap.
+  ret = LoadChar(trans_face, true, pt, c);
+  if (ret == -1) {
+    std::fprintf(stderr, "the glyph is not found on the transcoded font\n");
+  }
+  if (ret) return 1;  // -1 should be treated as error.
+  outline = &trans_face->glyph->outline;
+  ret = GetBitmap(library, outline, &trans_bitmap);
+  if (ret) return ret;  // white space?
+
+  return CompareBitmaps(&orig_bitmap, &trans_bitmap);
+}
+
+int SideBySide(FT_Library library, const char *file_name,
+               uint8_t *orig_font, size_t orig_len,
+               uint8_t *trans_font, size_t trans_len) {
+  FT_Face orig_face;
+  FT_Error error
+      = FT_New_Memory_Face(library, orig_font, orig_len, 0, &orig_face);
+  if (error) {
+    std::fprintf(stderr, "Failed to open the original font: %s!\n", file_name);
+    return 1;
+  }
+
+  FT_Face trans_face;
+  error = FT_New_Memory_Face(library, trans_font, trans_len, 0, &trans_face);
+  if (error) {
+    std::fprintf(stderr, "Failed to open the transcoded font: %s!\n",
+                 file_name);
+    return 1;
+  }
+
+  static const int kPts[] = {100, 20, 18, 16, 12, 10, 8};  // pt
+  static const size_t kPtsLen = sizeof(kPts) / sizeof(kPts[0]);
+
+  static const int kUnicodeRanges[] = {
+    0x0020, 0x007E,  // Basic Latin (ASCII)
+    0x00A1, 0x017F,  // Latin-1
+    0x1100, 0x11FF,  // Hangul
+    0x3040, 0x309F,  // Japanese HIRAGANA letters
+    0x3130, 0x318F,  // Hangul
+    0x4E00, 0x4F00,  // CJK Kanji/Hanja
+    0xAC00, 0xAD00,  // Hangul
+  };
+  static const size_t kUnicodeRangesLen
+      = sizeof(kUnicodeRanges) / sizeof(kUnicodeRanges[0]);
+
+  for (size_t i = 0; i < kPtsLen; ++i) {
+    for (size_t j = 0; j < kUnicodeRangesLen; j += 2) {
+      for (int k = 0; k <= kUnicodeRanges[j + 1] - kUnicodeRanges[j]; ++k) {
+        int ret = LoadCharThenCompare(library, orig_face, trans_face,
+                                      kPts[i],
+                                      kUnicodeRanges[j] + k);
+        if (ret > 0) {
+          std::fprintf(stderr, "Glyph mismatch! (file: %s, U+%04x, %dpt)!\n",
+                       file_name, kUnicodeRanges[j] + k, kPts[i]);
+          return 1;
+        }
+      }
+    }
+  }
+
+  return 0;
+}
+
+}  // namespace
+
+int main(int argc, char **argv) {
+  ots::DisableDebugOutput();  // turn off ERROR and WARNING outputs.
+
+  if (argc != 2) {
+    std::fprintf(stderr, "Usage: %s ttf_or_otf_filename\n", argv[0]);
+    return 1;
+  }
+
+  // load the font to memory.
+  const int fd = ::open(argv[1], O_RDONLY);
+  if (fd < 0) {
+    ::perror("open");
+    return 1;
+  }
+
+  struct stat st;
+  ::fstat(fd, &st);
+  const off_t orig_len = st.st_size;
+
+  uint8_t *orig_font = new uint8_t[orig_len];
+  if (::read(fd, orig_font, orig_len) != orig_len) {
+    std::fprintf(stderr, "Failed to read file!\n");
+    return 1;
+  }
+  ::close(fd);
+
+  // check if FreeType2 can open the original font.
+  FT_Library library;
+  FT_Error error = FT_Init_FreeType(&library);
+  if (error) {
+    std::fprintf(stderr, "Failed to initialize FreeType2!\n");
+    return 1;
+  }
+  FT_Face dummy;
+  error = FT_New_Memory_Face(library, orig_font, orig_len, 0, &dummy);
+  if (error) {
+    std::fprintf(stderr, "Failed to open the original font with FT2! %s\n",
+                 argv[1]);
+    return 1;
+  }
+
+  // transcode the original font.
+  static const size_t kPadLen = 20 * 1024;
+  uint8_t *trans_font = new uint8_t[orig_len + kPadLen];
+  ots::MemoryStream output(trans_font, orig_len + kPadLen);
+
+  bool result = ots::Process(&output, orig_font, orig_len);
+  if (!result) {
+    std::fprintf(stderr, "Failed to sanitise file! %s\n", argv[1]);
+    return 1;
+  }
+  const size_t trans_len = output.Tell();
+
+  // perform side-by-side tests.
+  return SideBySide(library, argv[1],
+                    orig_font, orig_len,
+                    trans_font, trans_len);
+}
diff --git a/test/validator-checker.cc b/test/validator-checker.cc
new file mode 100644
index 0000000..66c2b75
--- /dev/null
+++ b/test/validator-checker.cc
@@ -0,0 +1,117 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <fcntl.h>
+#include <ft2build.h>
+#include FT_FREETYPE_H
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+
+#include "opentype-sanitiser.h"
+#include "ots-memory-stream.h"
+
+namespace {
+
+void LoadChar(FT_Face face, int pt, FT_ULong c) {
+  FT_Matrix matrix;
+  matrix.xx = matrix.yy = 1 << 16;
+  matrix.xy = matrix.yx = 0 << 16;
+
+  FT_Set_Char_Size(face, pt * (1 << 6), 0, 72, 0);
+  FT_Set_Transform(face, &matrix, 0);
+  FT_Load_Char(face, c, FT_LOAD_RENDER);
+}
+
+int OpenAndLoadChars(FT_Library library, const char *file_name,
+                     uint8_t *trans_font, size_t trans_len) {
+  FT_Face trans_face;
+  FT_Error error
+      = FT_New_Memory_Face(library, trans_font, trans_len, 0, &trans_face);
+  if (error) {
+    std::fprintf(stderr,
+                 "OK: FreeType2 couldn't open the transcoded font: %s\n",
+                 file_name);
+    return 0;
+  }
+
+  static const int kPts[] = {100, 20, 18, 16, 12, 10, 8};  // pt
+  static const size_t kPtsLen = sizeof(kPts) / sizeof(kPts[0]);
+
+  static const int kUnicodeRanges[] = {
+    0x0020, 0x007E,  // Basic Latin (ASCII)
+    0x00A1, 0x017F,  // Latin-1
+    0x1100, 0x11FF,  // Hangul
+    0x3040, 0x309F,  // Japanese HIRAGANA letters
+    0x3130, 0x318F,  // Hangul
+    0x4E00, 0x4F00,  // CJK Kanji/Hanja
+    0xAC00, 0xAD00,  // Hangul
+  };
+  static const size_t kUnicodeRangesLen
+      = sizeof(kUnicodeRanges) / sizeof(kUnicodeRanges[0]);
+
+  for (size_t i = 0; i < kPtsLen; ++i) {
+    for (size_t j = 0; j < kUnicodeRangesLen; j += 2) {
+      for (int k = 0; k <= kUnicodeRanges[j + 1] - kUnicodeRanges[j]; ++k) {
+        LoadChar(trans_face, kPts[i], kUnicodeRanges[j] + k);
+      }
+    }
+  }
+
+  std::fprintf(stderr, "OK: FreeType2 didn't crash: %s\n", file_name);
+  return 0;
+}
+
+}  // namespace
+
+int main(int argc, char **argv) {
+  ots::DisableDebugOutput();  // turn off ERROR and WARNING outputs.
+
+  if (argc != 2) {
+    std::fprintf(stderr, "Usage: %s ttf_or_otf_filename\n", argv[0]);
+    return 1;
+  }
+
+  // load the font to memory.
+  const int fd = ::open(argv[1], O_RDONLY);
+  if (fd < 0) {
+    ::perror("open");
+    return 1;
+  }
+
+  struct stat st;
+  ::fstat(fd, &st);
+  const off_t orig_len = st.st_size;
+
+  uint8_t *orig_font = new uint8_t[orig_len];
+  if (::read(fd, orig_font, orig_len) != orig_len) {
+    std::fprintf(stderr, "Failed to read file!\n");
+    return 1;
+  }
+  ::close(fd);
+
+  // transcode the malicious font.
+  static const size_t kBigPadLen = 1024 * 1024;  // 1MB
+  uint8_t *trans_font = new uint8_t[orig_len + kBigPadLen];
+  ots::MemoryStream output(trans_font, orig_len + kBigPadLen);
+
+  bool result = ots::Process(&output, orig_font, orig_len);
+  if (!result) {
+    std::fprintf(stderr, "OK: the malicious font was filtered: %s\n", argv[1]);
+    return 0;
+  }
+  const size_t trans_len = output.Tell();
+
+  FT_Library library;
+  FT_Error error = FT_Init_FreeType(&library);
+  if (error) {
+    std::fprintf(stderr, "Failed to initialize FreeType2!\n");
+    return 1;
+  }
+
+  return OpenAndLoadChars(library, argv[1], trans_font, trans_len);
+}