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record length in chars and mark/reset reader to produce overlaps

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This commit is contained in:
millmanorama 2017-01-04 15:50:28 +01:00
parent d8ec4290f2
commit 151742c21b
1 changed files with 34 additions and 25 deletions
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59
KeywordSearch/src/org/sleuthkit/autopsy/keywordsearch/Ingester.java
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@ -19,6 +19,7 @@
package org.sleuthkit.autopsy.keywordsearch;
import com.google.common.base.Utf8;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
@ -156,14 +157,14 @@ class Ingester {
Map<String, String> fields = getContentFields(source);
//Get a stream and a reader for that stream
try (final InputStream stream = extractor.getInputStream(source);
Reader reader = extractor.getReader(stream, source);) {
Reader reader = new BufferedReader(extractor.getReader(stream, source));) {
Chunker chunker = new Chunker(reader);
for (StringBuilder chunk : chunker) {
for (Chunk chunk : chunker) {
String chunkId = Server.getChunkIdString(sourceID, numChunks + 1);
fields.put(Server.Schema.ID.toString(), chunkId);
fields.put(Server.Schema.CHUNK_SIZE.toString(), String.valueOf(chunk.length()));
fields.put(Server.Schema.CHUNK_SIZE.toString(), String.valueOf(chunk.getLength()));
try {
//add the chunk text to Solr index
indexChunk(chunk.toString(), sourceName, fields);
@ -377,14 +378,13 @@ class Ingester {
* Encapsulates the content chunking algorithm in implementation of the Iterator
* interface.
*/
class Chunker implements Iterator<StringBuilder>, Iterable<StringBuilder> {
private static final int INITIAL_CHUNK_SIZE = 30 * 1024; //bytes
class Chunker implements Iterator<Chunk>, Iterable<Chunk> {
private static final int MAX_CHUNK_SIZE = 32766; //bytes
private static final int INITIAL_BASE_CHUNK_SIZE = 30 * 1024; //bytes
private static final int MAXIMUM_BASE_CHUNK_SIZE = 31 * 1024; //bytes
private static final int WHITE_SPACE_BUFFER_SIZE = 900; //bytes
private static final int MAX_WINDOW_SIZE = 1024; //bytes
private static final int SINGLE_READ_CHARS = 1024;
private static final int SINGLE_READ_CHARS = 512;
private int windowSizeBytes = 0;
private int chunkSizeBytes = 0; // the size in bytes of the base chunk (so far)
private int charsRead = 0; // number of chars read in the most recent read operation
private boolean whitespace = false;
@ -392,6 +392,7 @@ class Chunker implements Iterator<StringBuilder>, Iterable<StringBuilder> {
private StringBuilder chunk;
private boolean endOfContent = false;
private final Reader reader;
private int chunkSizeChars;
/**
* Create a Chunker that will chunk the content of the given Reader.
@ -403,7 +404,7 @@ class Chunker implements Iterator<StringBuilder>, Iterable<StringBuilder> {
}
@Override
public Iterator<StringBuilder> iterator() {
public Iterator<Chunk> iterator() {
return this;
}
@ -442,14 +443,19 @@ class Chunker implements Iterator<StringBuilder>, Iterable<StringBuilder> {
@Override
public StringBuilder next() {
public Chunk next() {
if (hasNext()) {
try {
reader.reset();
} catch (IOException ex) {
throw new RuntimeException("IOException while attempting to reset chunk reader.", ex);
}
chunk = new StringBuilder();
tempChunkBuf = new char[SINGLE_READ_CHARS];
chunkSizeBytes = 0;
windowSizeBytes = 0;
//read chars up to initial chunk size
while (chunkSizeBytes < INITIAL_CHUNK_SIZE && endOfContent == false) {
while (chunkSizeBytes < INITIAL_BASE_CHUNK_SIZE && endOfContent == false) {
try {
charsRead = reader.read(tempChunkBuf, 0, SINGLE_READ_CHARS);
} catch (IOException ex) {
@ -471,23 +477,23 @@ class Chunker implements Iterator<StringBuilder>, Iterable<StringBuilder> {
throw new RuntimeException("IOException while attempting to read chunk to white space.", ex);
}
}
return sanitizeToUTF8(chunk);
return new Chunk(sanitizeToUTF8(chunk), chunkSizeChars);
} else {
throw new NoSuchElementException("There are no more chunks.");
}
}
private boolean readWindow() throws IOException {
tempChunkBuf = new char[MAX_WINDOW_SIZE];
tempChunkBuf = new char[SINGLE_READ_CHARS];
charsRead = 0;
while (windowSizeBytes < MAX_WINDOW_SIZE) {
while (chunkSizeBytes < MAX_CHUNK_SIZE - WHITE_SPACE_BUFFER_SIZE) {
charsRead = reader.read(tempChunkBuf, 0, SINGLE_READ_CHARS);
if (-1 == charsRead) {
//this is the last chunk
return true;
} else {
String windowSegment = new String(tempChunkBuf, 0, charsRead);
windowSizeBytes += Utf8.encodedLength(windowSegment);
chunkSizeBytes += Utf8.encodedLength(windowSegment);
chunk.append(windowSegment);
}
}
@ -499,7 +505,7 @@ class Chunker implements Iterator<StringBuilder>, Iterable<StringBuilder> {
whitespace = false;
//if we haven't reached the end of the file,
//try to read char-by-char until whitespace to not break words
while ((chunkSizeBytes < INITIAL_CHUNK_SIZE + WHITE_SPACE_BUFFER_SIZE)
while ((chunkSizeBytes < MAXIMUM_BASE_CHUNK_SIZE)
&& (false == whitespace)) {
charsRead = reader.read(tempChunkBuf, 0, 1);
@ -511,8 +517,10 @@ class Chunker implements Iterator<StringBuilder>, Iterable<StringBuilder> {
String chunkSegment = new String(tempChunkBuf, 0, 1);
chunkSizeBytes += Utf8.encodedLength(chunkSegment);
chunk.append(chunkSegment);
chunkSizeChars = chunkSegment.length();
}
}
reader.mark(1024);
return readWindow();
}
@ -522,7 +530,7 @@ class Chunker implements Iterator<StringBuilder>, Iterable<StringBuilder> {
whitespace = false;
//if we haven't reached the end of the file,
//try to read char-by-char until whitespace to not break words
while ((windowSizeBytes < MAX_WINDOW_SIZE)
while ((chunkSizeBytes < MAX_CHUNK_SIZE)
&& (false == whitespace)) {
charsRead = reader.read(tempChunkBuf, 0, 1);
if (-1 == charsRead) {
@ -531,7 +539,7 @@ class Chunker implements Iterator<StringBuilder>, Iterable<StringBuilder> {
} else {
whitespace = Character.isWhitespace(tempChunkBuf[0]);
String windowSegment = new String(tempChunkBuf, 0, 1);
windowSizeBytes += Utf8.encodedLength(windowSegment);
chunkSizeBytes += Utf8.encodedLength(windowSegment);
chunk.append(windowSegment);
}
}
@ -544,16 +552,17 @@ class Chunk {
private final StringBuilder sb;
private final int chunksize;
Chunk(StringBuilder sb, int chunksize) {
Chunk(StringBuilder sb, int chunkLength) {
this.sb = sb;
this.chunksize = chunksize;
this.chunksize = chunkLength;
}
StringBuilder getText() {
return sb;
@Override
public String toString() {
return sb.toString();
}
int getSize() {
int getLength() {
return chunksize;
}
}