Addressed Tavis's comments in http://codereview.chromium.org/3023041/....

src/cff_type2_charstring.h

 // Copyright (c) 2010 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_CFF_TYPE2_CHARSTRING_H_
 #define OTS_CFF_TYPE2_CHARSTRING_H_
 
 #include "cff.h"
 #include "ots.h"
 
@@ skipping 24 matching lines @@
 //  cff_table: A buffer which contains actual byte code of charstring, global
 //             subroutines and local subroutines.
 bool ValidateType2CharStringIndex(
     const CFFIndex &char_strings_index,
     const CFFIndex &global_subrs_index,
     const std::map<uint16_t, uint8_t> &fd_select,
     const std::vector<CFFIndex *> &local_subrs_per_font,
     const CFFIndex *local_subrs,
     Buffer *cff_table);
 
+// The list of Operators. See Appendix. A in Adobe Technical Note #5177.
+enum Type2CharStringOperator {
+  kHStem = 1,
+  kVStem = 3,
+  kVMoveTo = 4,
+  kRLineTo = 5,
+  kHLineTo = 6,
+  kVLineTo = 7,
+  kRRCurveTo = 8,
+  kCallSubr = 10,
+  kReturn = 11,
+  kEndChar = 14,
+  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,
+  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 obsoleted or undocumented, such as 'blend', will be
+  // rejected.
+};
+
 }  // namespace ots
 
 #endif  // OTS_CFF_TYPE2_CHARSTRING_H_