public SpdyHeaderBlockJZlibEncoder(
SpdyVersion version, int compressionLevel, int windowBits, int memLevel) {
super(version);
if (compressionLevel < 0 || compressionLevel > 9) {
throw new IllegalArgumentException(
"compressionLevel: " + compressionLevel + " (expected: 0-9)");
}
if (windowBits < 9 || windowBits > 15) {
throw new IllegalArgumentException("windowBits: " + windowBits + " (expected: 9-15)");
}
if (memLevel < 1 || memLevel > 9) {
throw new IllegalArgumentException("memLevel: " + memLevel + " (expected: 1-9)");
}
int resultCode = z.deflateInit(compressionLevel, windowBits, memLevel, JZlib.W_ZLIB);
if (resultCode != JZlib.Z_OK) {
throw new CompressionException(
"failed to initialize an SPDY header block deflater: " + resultCode);
} else {
resultCode = z.deflateSetDictionary(SPDY_DICT, SPDY_DICT.length);
if (resultCode != JZlib.Z_OK) {
throw new CompressionException("failed to set the SPDY dictionary: " + resultCode);
}
}
}
private void setInput(ByteBuf decompressed) {
byte[] in = new byte[decompressed.readableBytes()];
decompressed.readBytes(in);
z.next_in = in;
z.next_in_index = 0;
z.avail_in = in.length;
}
@Override
public void end() {
if (finished) {
return;
}
finished = true;
z.deflateEnd();
z.next_in = null;
z.next_out = null;
}
private void encode(ByteBuf compressed) {
try {
byte[] out = new byte[(int) Math.ceil(z.next_in.length * 1.001) + 12];
z.next_out = out;
z.next_out_index = 0;
z.avail_out = out.length;
int resultCode = z.deflate(JZlib.Z_SYNC_FLUSH);
if (resultCode != JZlib.Z_OK) {
throw new CompressionException("compression failure: " + resultCode);
}
if (z.next_out_index != 0) {
compressed.writeBytes(out, 0, z.next_out_index);
}
} finally {
// Deference the external references explicitly to tell the VM that
// the allocated byte arrays are temporary so that the call stack
// can be utilized.
// I'm not sure if the modern VMs do this optimization though.
z.next_in = null;
z.next_out = null;
}
}