|
1
31 package org.pdfbox.filter;
32
33 import java.io.ByteArrayInputStream  ;
34 import java.io.ByteArrayOutputStream ;
35 import java.io.IOException ;
36 import java.io.InputStream ;
37 import java.io.OutputStream ;
38 import java.util.zip.DeflaterOutputStream ;
39 import java.util.zip.InflaterInputStream ;
40
41 import org.pdfbox.cos.COSDictionary;
42
43
50 public class FlateFilter implements Filter
51 {
52 private static final int BUFFER_SIZE = 2048;
53
54
67
68 public void decode(InputStream compressedData, OutputStream result, COSDictionary options) throws IOException
69 {
70 COSDictionary dict = (COSDictionary) options.getDictionaryObject("DecodeParms");
71 int predictor = -1;
72 int colors = -1;
73 int bitsPerPixel = -1;
74 int columns = -1;
75 InflaterInputStream decompressor = null;
76 ByteArrayInputStream bais = null;
77 ByteArrayOutputStream baos = null;
78 if (dict!=null)
79 {
80 predictor = dict.getInt("Predictor");
81 colors = dict.getInt("Colors");
82 bitsPerPixel = options.getInt("BitsPerComponent");
83 columns = dict.getInt("Columns");
84 }
85
86 try
87 {
88 decompressor = new InflaterInputStream (compressedData);
90 byte[] buffer = new byte[BUFFER_SIZE];
91 int amountRead;
92
93 if (predictor==-1 || predictor == 1 && predictor == 10)
95 {
96 while ((amountRead = decompressor.read(buffer, 0, BUFFER_SIZE)) != -1)
98 {
99 result.write(buffer, 0, amountRead);
100 }
101 }
102 else
103 {
104 if (colors==-1 || bitsPerPixel==-1 || columns==-1)
105 {
106 throw new IOException ("Could not read all parameters to decode image");
107 }
108
109 baos = new ByteArrayOutputStream ();
110 while ((amountRead = decompressor.read(buffer, 0, BUFFER_SIZE)) != -1)
111 {
112 baos.write(buffer, 0, amountRead);
113 }
114 baos.flush();
115
116 bais = new ByteArrayInputStream (baos.toByteArray());
118 baos.close();
119 baos = null;
120
121 byte[] decodedData = decodePredictor(predictor, colors, bitsPerPixel, columns, bais);
122 bais.close();
123 bais = new ByteArrayInputStream (decodedData);
124
125 while ((amountRead = bais.read(buffer)) != -1)
127 {
128 result.write(buffer, 0, amountRead);
129 }
130 bais.close();
131 bais = null;
132 }
133
134
135 result.flush();
136 }
137 finally
138 {
139 if (decompressor != null)
140 {
141 decompressor.close();
142 }
143 if (bais != null)
144 {
145 bais.close();
146 }
147 if (baos != null)
148 {
149 baos.close();
150 }
151 }
152 }
153
154 private byte[] decodePredictor(int predictor, int colors, int bitsPerComponent, int columns, InputStream data)
155 throws IOException
156 {
157 ByteArrayOutputStream baos = new ByteArrayOutputStream ();
158 byte[] buffer = new byte[2048];
159
160 if (predictor == 1 || predictor == 10)
161 {
162 int i = 0;
164 while ((i = data.read(buffer)) != -1)
165 {
166 baos.write(buffer, 0, i);
167 }
168 }
169 else
170 {
171 int bpp = (colors * bitsPerComponent + 7) / 8;
173 int rowlength = (columns * colors * bitsPerComponent + 7) / 8 + bpp;
174 byte[] actline = new byte[rowlength];
175 byte[] lastline = new byte[rowlength]; boolean done = false;
179 int linepredictor = predictor;
180
181 while (!done)
182 {
183 if (predictor == 15)
184 {
185 linepredictor = data.read(); if (linepredictor == -1)
187 {
188 done = true; break;
190 }
191 else
192 {
193 linepredictor += 10; }
195 }
198
199 int i = 0;
201 int offset = bpp;
202 while (offset < rowlength && ((i = data.read(actline, offset, rowlength - offset)) != -1))
203 {
204 offset += i;
205 }
206
207 switch (linepredictor)
209 {
210 case 2:
214 throw new IOException ("TIFF-Predictor not supported");
215 case 11: for (int p = bpp; p < rowlength; p++)
217 {
218 int sub = actline[p] & 0xff;
219 int left = actline[p - bpp] & 0xff;
220 actline[p] = (byte) (sub + left);
221 }
222 break;
223 case 12: for (int p = bpp; p < rowlength; p++)
225 {
226 int up = actline[p] & 0xff;
227 int prior = lastline[p] & 0xff;
228 actline[p] = (byte) (up + prior);
229 }
230 break;
231 case 13: for (int p = bpp; p < rowlength; p++)
233 {
234 int avg = actline[p] & 0xff;
235 int left = actline[p - bpp] & 0xff;
236 int up = lastline[p] & 0xff;
237 actline[p] = (byte) (avg + ((left + up) / 2));
238 }
239 break;
240 case 14: for (int p = bpp; p < rowlength; p++)
242 {
243 int paeth = actline[p] & 0xff;
244 int a = actline[p - bpp] & 0xff; int b = lastline[p] & 0xff; int c = lastline[p - bpp] & 0xff; int value = a + b - c;
248 int absa = Math.abs(value - a);
249 int absb = Math.abs(value - b);
250 int absc = Math.abs(value - c);
251
252 if (absa <= absb && absa <= absc)
253 {
254 actline[p] = (byte) (paeth + absa);
255 }
256 else if (absb <= absc)
257 {
258 actline[p] += (byte) (paeth + absb);
259 }
260 else
261 {
262 actline[p] += (byte) (paeth + absc);
263 }
264 }
265 break;
266 default:
267 break;
268 }
269
270 lastline = actline;
271 baos.write(actline, bpp, actline.length - bpp);
272 }
273 }
274
275 return baos.toByteArray();
276 }
277
278
291 public void encode(InputStream rawData, OutputStream result, COSDictionary options) throws IOException
292 {
293 DeflaterOutputStream out = new DeflaterOutputStream (result);
294 byte[] buffer = new byte[BUFFER_SIZE];
295 int amountRead = 0;
296 while ((amountRead = rawData.read(buffer, 0, BUFFER_SIZE)) != -1)
297 {
298 out.write(buffer, 0, amountRead);
299 }
300 out.close();
301 result.flush();
302 }
303 } |
Popular Tags |
Java API By Example, From Geeks To Geeks.