1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
// 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"
#include <map>
#include <vector>
namespace ots {
// 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 48 values of argument stack.
// 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:
// global_subrs_index: Global subroutines which could be called by a charstring
// in |char_strings_index|.
// fd_select: A map from glyph # to font #.
// local_subrs_per_font: A list of Local Subrs associated with FDArrays. Can be
// empty.
// local_subrs: A Local Subrs associated with Top DICT. Can be NULL.
// cff_table: A buffer which contains actual byte code of charstring, global
// subroutines and local subroutines.
bool ValidateType2CharStringIndex(
Font *font,
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,
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, such as 'blend', will be rejected.
};
} // namespace ots
#endif // OTS_CFF_TYPE2_CHARSTRING_H_
|
