com.upokecenter.mail.transforms.BoundaryCheckerTransform Maven / Gradle / Ivy
package com.upokecenter.mail.transforms;
/*
Written by Peter O. in 2014.
Any copyright is dedicated to the Public Domain.
http://creativecommons.org/publicdomain/zero/1.0/
If you like this, you should donate to Peter O.
at: http://upokecenter.dreamhosters.com/articles/donate-now-2/
*/
import java.util.*;
import com.upokecenter.util.*;
import com.upokecenter.mail.*;
public final class BoundaryCheckerTransform implements IByteReader {
private IByteReader input;
private boolean ungetting;
private int lastByte;
private byte[] buffer;
private int bufferIndex;
private int bufferCount;
private boolean started;
private boolean readingHeaders;
private boolean hasNewBodyPart;
private boolean endOfStream;
private ArrayList boundaries;
private void ResizeBuffer(int size) {
this.buffer = (this.buffer == null) ? ((new byte[size + 10])) : this.buffer;
if (size > this.buffer.length) {
byte[] newbuffer = new byte[size + 10];
System.arraycopy(this.buffer, 0, newbuffer, 0, this.buffer.length);
this.buffer = newbuffer;
}
this.bufferCount = size;
this.bufferIndex = 0;
}
public BoundaryCheckerTransform (IByteReader stream) {
this.input = stream;
this.boundaries = new ArrayList();
this.started = true;
}
public void PushBoundary(String boundary) {
this.boundaries.add(boundary);
}
public int read() {
if (this.bufferIndex < this.bufferCount) {
int ret = this.buffer[this.bufferIndex];
++this.bufferIndex;
if (this.bufferIndex == this.bufferCount) {
this.bufferCount = 0;
this.bufferIndex = 0;
}
ret &= 0xff;
return ret;
}
if (this.hasNewBodyPart || this.endOfStream) {
return -1;
}
int c = this.lastByte = this.ungetting ? this.lastByte :
this.input.read();
this.ungetting = false;
if (this.readingHeaders) {
return c;
}
if (c < 0) {
this.started = false;
return c;
}
if (c == '-' && this.started) {
// Check for a boundary
this.started = false;
c = this.lastByte = this.ungetting ? this.lastByte :
this.input.read();
this.ungetting = false;
if (c == '-') {
// Possible boundary candidate
return this.CheckBoundaries(false);
}
this.ungetting = true;
return '-';
}
this.started = false;
if (c == 0x0d) {
c = this.lastByte = this.ungetting ? this.lastByte :
this.input.read();
this.ungetting = false;
if (c == 0x0a) {
// Line break was read
c = this.lastByte = this.ungetting ? this.lastByte :
this.input.read();
this.ungetting = false;
if (c == -1) {
this.ResizeBuffer(1);
this.buffer[0] = 0x0a;
return 0x0d;
}
if (c == 0x0d) {
// Unget the CR, in case the next line is a boundary line
this.ungetting = true;
this.ResizeBuffer(1);
this.buffer[0] = 0x0a;
return 0x0d;
}
if (c != '-') {
this.ResizeBuffer(2);
this.buffer[0] = 0x0a;
this.buffer[1] = (byte)c;
return 0x0d;
}
c = this.lastByte = this.ungetting ? this.lastByte :
this.input.read();
this.ungetting = false;
if (c == -1) {
this.ResizeBuffer(2);
this.buffer[0] = 0x0a;
this.buffer[1] = (byte)'-';
return 0x0d;
}
if (c == 0x0d) {
// Unget the CR, in case the next line is a boundary line
this.ungetting = true;
this.ResizeBuffer(2);
this.buffer[0] = 0x0a;
this.buffer[1] = (byte)'-';
return 0x0d;
}
if (c != '-') {
this.ResizeBuffer(3);
this.buffer[0] = 0x0a;
this.buffer[1] = (byte)'-';
this.buffer[2] = (byte)c;
return 0x0d;
}
// Possible boundary candidate
return this.CheckBoundaries(true);
}
this.ungetting = true;
return 0x0d;
}
return c;
}
private int CheckBoundaries(boolean includeCrLf) {
// Reached here when the "--" of a possible
// boundary delimiter is read. We need to
// check boundaries here in order to find out
// whether to emit the CRLF before the "--".
boolean done = false;
while (!done) {
done = true;
int bufferStart = 0;
if (includeCrLf) {
this.ResizeBuffer(3);
bufferStart = 3;
// store LF, '-', and '-' in the buffer in case
// the boundary check fails, in which case
// this method will return CR
this.buffer[0] = 0x0a;
this.buffer[1] = (byte)'-';
this.buffer[2] = (byte)'-';
} else {
bufferStart = 1;
this.ResizeBuffer(1);
this.buffer[0] = (byte)'-';
}
// Check up to 72 bytes (the maximum size
// of a boundary plus 2 bytes for the closing
// hyphens)
int c;
int bytesRead = 0;
for (int i = 0; i < 72; ++i) {
c = this.lastByte = this.ungetting ? this.lastByte :
this.input.read(); this.ungetting = false;
if (c < 0 || c >= 0x80 || c == 0x0d) {
this.ungetting = true;
break;
}
// Console.Write("" + ((char)c));
++bytesRead;
this.ResizeBuffer(bytesRead + bufferStart);
this.buffer[bytesRead + bufferStart - 1] = (byte)c;
}
// System.out.println("::" + bytesRead);
// NOTE: All boundary strings are assumed to
// have only ASCII characters (with values
// less than 128). Check boundaries from
// top to bottom in the stack.
String matchingBoundary = null;
int matchingIndex = -1;
for (int i = this.boundaries.size() - 1; i >= 0; --i) {
String boundary = this.boundaries.get(i);
if (!((boundary) == null || (boundary).length() == 0) && boundary.length() <= bytesRead) {
boolean match = true;
for (int j = 0; j < boundary.length(); ++j) {
match &= (boundary.charAt(j) & 0xff) == (int)(this.buffer[j + bufferStart] &
0xff);
}
if (match) {
matchingBoundary = boundary;
matchingIndex = i;
break;
}
}
}
if (matchingBoundary != null) {
boolean closingDelim = false;
// Pop the stack until the matching body part
// is on top
while (this.boundaries.size() > matchingIndex + 1) {
this.boundaries.remove(matchingIndex + 1);
}
// Boundary line found
if (matchingBoundary.length() + 1 < bytesRead) {
closingDelim |= this.buffer[matchingBoundary.length() +
bufferStart] == '-' && this.buffer[matchingBoundary.length() + 1 +
bufferStart] == '-';
}
// Clear the buffer, the boundary line
// isn't part of any body data
this.bufferCount = 0;
this.bufferIndex = 0;
if (closingDelim) {
// Pop this entry, it's the top of the stack
this.boundaries.remove(this.boundaries.size() - 1);
if (this.boundaries.size() == 0) {
// There's nothing else significant
// after this boundary,
// so return now
this.hasNewBodyPart = false;
this.endOfStream = true;
this.bufferCount = 0;
return -1;
}
// Read to end of line. Since this is the last body
// part, the rest of the data before the next boundary
// is insignificant
while (true) {
c = this.lastByte = this.ungetting ? this.lastByte :
this.input.read();
this.ungetting = false;
if (c == -1) {
// The body higher up didn't end yet
throw new MessageDataException("Premature end of message");
}
if (c == 0x0d) {
c = this.lastByte = this.ungetting ? this.lastByte :
this.input.read();
this.ungetting = false;
if (c == -1) {
// The body higher up didn't end yet
throw new MessageDataException("Premature end of message");
}
if (c == 0x0a) {
// Start of new body part
c = this.lastByte = this.ungetting ? this.lastByte :
this.input.read();
this.ungetting = false;
if (c == -1) {
throw new MessageDataException("Premature end of message");
}
if (c == 0x0d) {
// Unget the CR, in case the next line is a boundary line
this.ungetting = true;
continue;
}
if (c != '-') {
// Not a boundary delimiter
continue;
}
c = this.lastByte = this.ungetting ? this.lastByte :
this.input.read();
this.ungetting = false;
if (c == -1) {
throw new MessageDataException("Premature end of message");
}
if (c == 0x0d) {
// Unget the CR, in case the next line is a boundary line
this.ungetting = true;
continue;
}
if (c != '-') {
// Not a boundary delimiter
continue;
}
// Found the next boundary delimiter
done = false;
break;
}
this.ungetting = true;
}
}
if (!done) {
// Recheck the next line for a boundary delimiter
continue;
}
} else {
// Read to end of line (including CRLF; the
// next line will start the headers of the
// next body part).
while (true) {
c = this.lastByte = this.ungetting ? this.lastByte :
this.input.read();
this.ungetting = false;
if (c == -1) {
throw new MessageDataException("Premature end of message");
}
if (c == 0x0d) {
c = this.lastByte = this.ungetting ? this.lastByte :
this.input.read();
this.ungetting = false;
if (c == -1) {
throw new MessageDataException("Premature end of message");
}
if (c == 0x0a) {
// Start of new body part
this.hasNewBodyPart = true;
this.bufferCount = 0;
return -1;
}
this.ungetting = true;
}
}
}
}
// Not a boundary, return CR (the
// ReadByte method will then return LF,
// the hyphens, and the other bytes
// already read)
return includeCrLf ? 0x0d : '-';
}
// Not a boundary, return CR (the
// ReadByte method will then return LF,
// the hyphens, and the other bytes
// already read)
return includeCrLf ? 0x0d : '-';
}
public int BoundaryCount() {
return this.boundaries.size();
}
public void StartBodyPartHeaders() {
this.readingHeaders = true;
this.hasNewBodyPart = false;
}
public void EndBodyPartHeaders() {
this.readingHeaders = false;
this.hasNewBodyPart = false;
this.started = true; // in case a boundary delimiter immediately starts
}
/**
* Gets a value indicating whether a new body part was detected.
* @return True if a new body part was detected; otherwise, false.
*/
public final boolean getHasNewBodyPart() {
return this.hasNewBodyPart;
}
}
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