1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.fontbox.cff;
18
19 import java.io.IOException;
20 import java.util.ArrayList;
21 import java.util.List;
22
23 /**
24 * This class represents a converter for a mapping into a Type2-sequence.
25 * @author Villu Ruusmann
26 * @version $Revision: 1.0 $
27 */
28 public class Type2CharStringParser
29 {
30
31 private DataInput input = null;
32 private int hstemCount = 0;
33 private int vstemCount = 0;
34 private List<Object> sequence = null;
35
36 /**
37 * The given byte array will be parsed and converted to a Type2 sequence.
38 * @param bytes the given mapping as byte array
39 * @return the Type2 sequence
40 * @throws IOException if an error occurs during reading
41 */
42 public List<Object> parse(byte[] bytes) throws IOException
43 {
44 input = new DataInput(bytes);
45
46 hstemCount = 0;
47 vstemCount = 0;
48
49 sequence = new ArrayList<Object>();
50
51 while (input.hasRemaining())
52 {
53 int b0 = input.readUnsignedByte();
54
55 if (b0 >= 0 && b0 <= 27)
56 {
57 sequence.add(readCommand(b0));
58 }
59 else if (b0 == 28)
60 {
61 sequence.add(readNumber(b0));
62 }
63 else if (b0 >= 29 && b0 <= 31)
64 {
65 sequence.add(readCommand(b0));
66 }
67 else if (b0 >= 32 && b0 <= 255)
68 {
69 sequence.add(readNumber(b0));
70 }
71 else
72 {
73 throw new IllegalArgumentException();
74 }
75 }
76
77 return sequence;
78 }
79
80 private CharStringCommand readCommand(int b0) throws IOException
81 {
82
83 if (b0 == 1 || b0 == 18)
84 {
85 hstemCount += peekNumbers().size() / 2;
86 }
87 else if (b0 == 3 || b0 == 19 || b0 == 20 || b0 == 23)
88 {
89 vstemCount += peekNumbers().size() / 2;
90 } // End if
91
92 if (b0 == 12)
93 {
94 int b1 = input.readUnsignedByte();
95
96 return new CharStringCommand(b0, b1);
97 }
98 else if (b0 == 19 || b0 == 20)
99 {
100 int[] value = new int[1 + getMaskLength()];
101 value[0] = b0;
102
103 for (int i = 1; i < value.length; i++)
104 {
105 value[i] = input.readUnsignedByte();
106 }
107
108 return new CharStringCommand(value);
109 }
110
111 return new CharStringCommand(b0);
112 }
113
114 private Integer readNumber(int b0) throws IOException
115 {
116
117 if (b0 == 28)
118 {
119 int b1 = input.readUnsignedByte();
120 int b2 = input.readUnsignedByte();
121
122 return Integer.valueOf((short) (b1 << 8 | b2));
123 }
124 else if (b0 >= 32 && b0 <= 246)
125 {
126 return Integer.valueOf(b0 - 139);
127 }
128 else if (b0 >= 247 && b0 <= 250)
129 {
130 int b1 = input.readUnsignedByte();
131
132 return Integer.valueOf((b0 - 247) * 256 + b1 + 108);
133 }
134 else if (b0 >= 251 && b0 <= 254)
135 {
136 int b1 = input.readUnsignedByte();
137
138 return Integer.valueOf(-(b0 - 251) * 256 - b1 - 108);
139 }
140 else if (b0 == 255)
141 {
142 int b1 = input.readUnsignedByte();
143 int b2 = input.readUnsignedByte();
144 int b3 = input.readUnsignedByte();
145 int b4 = input.readUnsignedByte();
146
147 // The lower bytes are representing the digits after
148 // the decimal point and aren't needed in this context
149 return Integer.valueOf((short)(b1 << 8 | b2));
150 }
151 else
152 {
153 throw new IllegalArgumentException();
154 }
155 }
156
157 private int getMaskLength()
158 {
159 int length = 1;
160
161 int hintCount = hstemCount + vstemCount;
162 while ((hintCount -= 8) > 0)
163 {
164 length++;
165 }
166
167 return length;
168 }
169
170 private List<Number> peekNumbers()
171 {
172 List<Number> numbers = new ArrayList<Number>();
173
174 for (int i = sequence.size() - 1; i > -1; i--)
175 {
176 Object object = sequence.get(i);
177
178 if (object instanceof Number)
179 {
180 Number number = (Number) object;
181
182 numbers.add(0, number);
183
184 continue;
185 }
186
187 return numbers;
188 }
189
190 return numbers;
191 }
192 }