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InputStream does not need support mark/reset #7

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InputStream does not need support mark/reset #7

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79 changes: 33 additions & 46 deletions src/main/java/org/bitlet/wetorrent/bencode/Bencode.java
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Expand Up @@ -40,10 +40,7 @@ public class Bencode {
* This creates and parse a bencoded InputStream
*/
public Bencode(InputStream is) throws IOException {
if (!is.markSupported()) {
throw new IOException("is.markSupported should be true");
}
rootElement = parse(is);
rootElement = parse(readHead(is), is);
}

/**
Expand Down Expand Up @@ -100,16 +97,18 @@ private void print(Object object, OutputStream os) throws IOException {
}
}

private Object parse(InputStream is) throws IOException {
is.mark(0);
int readChar = is.read();
switch (readChar) {
private int readHead(InputStream is) throws IOException {
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We can avoid this method and just call is.read in every place instead of readHead(is).

return is.read();
}

private Object parse(int head, InputStream tail) throws IOException {
switch (head) {
case 'i':
return parseInteger(is);
return parseInteger(readHead(tail), tail);
case 'l':
return parseList(is);
return parseList(readHead(tail), tail);
case 'd':
return parseDictionary(is);
return parseDictionary(readHead(tail), tail);
case '0':
case '1':
case '2':
Expand All @@ -120,8 +119,7 @@ private Object parse(InputStream is) throws IOException {
case '7':
case '8':
case '9':
is.reset();
return parseByteString(is);
return parseByteString(head, tail);
default:
throw new IOException("Problem parsing bencoded file");
}
Expand All @@ -135,75 +133,64 @@ public void setRootElement(Object rootElement) {
this.rootElement = rootElement;
}

private Long parseInteger(InputStream is) throws IOException {

int readChar = is.read();
private Long parseInteger(int head, InputStream tail) throws IOException {
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Why does this need the head parameter?


StringBuffer buff = new StringBuffer();
do {
if (readChar < 0) {
if (head < 0) {
throw new IOException("Unexpected EOF found");
}
buff.append((char) readChar);
readChar = is.read();
} while (readChar != 'e');
buff.append((char) head);
head = readHead(tail);
} while (head != 'e');

// System.out.println("Loaded int: " + buff);
return Long.parseLong(buff.toString());
}

private List<Object> parseList(InputStream is) throws IOException {
private List<Object> parseList(int head, InputStream tail) throws IOException {

List<Object> list = new LinkedList<Object>();
is.mark(0);
int readChar = is.read();
while (readChar != 'e') {
if (readChar < 0) {
while (head != 'e') {
if (head < 0) {
throw new IOException("Unexpected EOF found");
}
is.reset();
list.add(parse(is));
is.mark(0);
readChar = is.read();
list.add(parse(head, tail));
head = readHead(tail);
}

return list;
}

private SortedMap parseDictionary(InputStream is) throws IOException {
private SortedMap parseDictionary(int head, InputStream tail) throws IOException {
SortedMap<ByteBuffer, Object> map = new TreeMap<ByteBuffer, Object>(new DictionaryComparator());
is.mark(0);
int readChar = is.read();
while (readChar != 'e') {
if (readChar < 0) {
while (head != 'e') {
if (head < 0) {
throw new IOException("Unexpected EOF found");
}
is.reset();
map.put(parseByteString(is), parse(is));
is.mark(0);
readChar = is.read();
ByteBuffer key = parseByteString(head, tail);
map.put(key, parse(readHead(tail), tail));
head = readHead(tail);
}

return map;
}

private ByteBuffer parseByteString(InputStream is) throws IOException {

int readChar = is.read();
private ByteBuffer parseByteString(int head, InputStream tail) throws IOException {

StringBuffer buff = new StringBuffer();
do {
if (readChar < 0) {
if (head < 0) {
throw new IOException("Unexpected EOF found");
}
buff.append((char) readChar);
readChar = is.read();
} while (readChar != ':');
buff.append((char) head);
head = readHead(tail);
} while (head != ':');
Integer length = Integer.parseInt(buff.toString());

byte[] byteString = new byte[length];
for (int i = 0; i < byteString.length; i++) {
byteString[i] = (byte) is.read();
byteString[i] = (byte) readHead(tail);
// System.out.println("Loaded string: " + new String(byteString));
}
return ByteBuffer.wrap(byteString);
Expand Down