1 files changed, 110 insertions, 0 deletions
diff --git a/gfx/ots/src/cff_charstring.h b/gfx/ots/src/cff_charstring.h
new file mode 100644
index 0000000000..b407db564f
--- /dev/null
+++ b/gfx/ots/src/cff_charstring.h
@@ -0,0 +1,110 @@
+// Copyright (c) 2010-2017 The OTS 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_CFF_TYPE2_CHARSTRING_H_
+#define OTS_CFF_TYPE2_CHARSTRING_H_
+
+#include "cff.h"
+#include "ots.h"
+
+#include <map>
+#include <vector>
+
+namespace ots {
+
+const size_t kMaxCFF1ArgumentStack = 48;
+const size_t kMaxCFF2ArgumentStack = 513;
+
+// Validates all charstrings in |char_strings_index|. Charstring is a small
+// language for font hinting defined in Adobe Technical Note #5177.
+// http://www.adobe.com/devnet/font/pdfs/5177.Type2.pdf
+//
+// The validation will fail if one of the following conditions is met:
+//  1. The code uses more than the max argument stack size (48 for CFF1; 513 for CFF2)
+//  2. The code uses deeply nested subroutine calls (more than 10 levels.)
+//  3. The code passes invalid number of operands to an operator.
+//  4. The code calls an undefined global or local subroutine.
+//  5. The code uses one of the following operators that are unlikely used in
+//     an ordinary fonts, and could be dangerous: random, put, get, index, roll.
+//
+// Arguments:
+//  cff: parent OpenTypeCFF reference
+//  global_subrs_index: Global subroutines which could be called by a charstring
+//                      in |char_strings_index|.
+//  cff_table: A buffer which contains actual byte code of charstring, global
+//             subroutines and local subroutines.
+bool ValidateCFFCharStrings(
+    OpenTypeCFF& cff,
+    const CFFIndex &global_subrs_index,
+    Buffer *cff_table);
+
+// The list of Operators. See Appendix. A in Adobe Technical Note #5177.
+// and https://docs.microsoft.com/en-us/typography/opentype/spec/cff2charstr
+enum CharStringOperator {
+  kHStem = 1,
+  kVStem = 3,
+  kVMoveTo = 4,
+  kRLineTo = 5,
+  kHLineTo = 6,
+  kVLineTo = 7,
+  kRRCurveTo = 8,
+  kCallSubr = 10,
+  kReturn = 11,
+  kEndChar = 14,
+  kVSIndex = 15,
+  kBlend = 16,
+  kHStemHm = 18,
+  kHintMask = 19,
+  kCntrMask = 20,
+  kRMoveTo = 21,
+  kHMoveTo = 22,
+  kVStemHm = 23,
+  kRCurveLine = 24,
+  kRLineCurve = 25,
+  kVVCurveTo = 26,
+  kHHCurveTo = 27,
+  kCallGSubr = 29,
+  kVHCurveTo = 30,
+  kHVCurveTo = 31,
+  kDotSection = 12 << 8,
+  kAnd = (12 << 8) + 3,
+  kOr = (12 << 8) + 4,
+  kNot = (12 << 8) + 5,
+  kAbs = (12 << 8) + 9,
+  kAdd = (12 << 8) + 10,
+  kSub = (12 << 8) + 11,
+  kDiv = (12 << 8) + 12,
+  kNeg = (12 << 8) + 14,
+  kEq = (12 << 8) + 15,
+  kDrop = (12 << 8) + 18,
+  kPut = (12 << 8) + 20,
+  kGet = (12 << 8) + 21,
+  kIfElse = (12 << 8) + 22,
+  kRandom = (12 << 8) + 23,
+  kMul = (12 << 8) + 24,
+  kSqrt = (12 << 8) + 26,
+  kDup = (12 << 8) + 27,
+  kExch = (12 << 8) + 28,
+  kIndex = (12 << 8) + 29,
+  kRoll = (12 << 8) + 30,
+  kHFlex = (12 << 8) + 34,
+  kFlex = (12 << 8) + 35,
+  kHFlex1 = (12 << 8) + 36,
+  kFlex1 = (12 << 8) + 37,
+  // Operators that are undocumented will be rejected.
+};
+
+struct CharStringContext {
+  bool endchar_seen = false;
+  bool width_seen = false;
+  size_t num_stems = 0;
+  bool cff2 = false;
+  bool blend_seen = false;
+  bool vsindex_seen = false;
+  int32_t vsindex = 0;
+};
+
+}  // namespace ots
+
+#endif  // OTS_CFF_TYPE2_CHARSTRING_H_