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// 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_
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