/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2000-2013. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* %CopyrightEnd%
*/
package com.ericsson.otp.erlang;
// import java.io.OutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.text.DecimalFormat;
import java.util.zip.Deflater;
/**
* Provides a stream for encoding Erlang terms to external format, for transmission or
* storage.
*
* <p>
* Note that this class is not synchronized, if you need synchronization you must provide
* it yourself.
*
*/
public class OtpOutputStream extends ByteArrayOutputStream {
/** The default initial size of the stream. * */
public static final int defaultInitialSize = 2048;
/**
* The default increment used when growing the stream (increment at least this much).
* *
*/
public static final int defaultIncrement = 2048;
// static formats, used to encode floats and doubles
@SuppressWarnings("unused")
private static final DecimalFormat eform = new DecimalFormat("e+00;e-00");
@SuppressWarnings("unused")
private static final BigDecimal ten = new BigDecimal(10.0);
@SuppressWarnings("unused")
private static final BigDecimal one = new BigDecimal(1.0);
private int fixedSize = Integer.MAX_VALUE;
/**
* Create a stream with the default initial size (2048 bytes).
*/
public OtpOutputStream() {
this(defaultInitialSize);
}
/**
* Create a stream with the specified initial size.
*/
public OtpOutputStream(final int size) {
super(size);
}
/**
* Create a stream containing the encoded version of the given Erlang term.
*/
public OtpOutputStream(final OtpErlangObject o) {
this();
write_any(o);
}
// package scope
/*
* Get the contents of the output stream as an input stream instead. This is used
* internally in {@link OtpCconnection} for tracing outgoing packages.
*
* @param offset where in the output stream to read data from when creating the input
* stream. The offset is necessary because header contents start 5 bytes into the
* header buffer, whereas payload contents start at the beginning
*
* @return an input stream containing the same raw data.
*/
OtpInputStream getOtpInputStream(final int offset) {
return new OtpInputStream(super.buf, offset, super.count - offset, 0);
}
/**
* Get the current position in the stream.
*
* @return the current position in the stream.
*/
public int getPos() {
return super.count;
}
/**
* Trims the capacity of this <tt>OtpOutputStream</tt> instance to be the buffer's
* current size. An application can use this operation to minimize the storage of an
* <tt>OtpOutputStream</tt> instance.
*/
public void trimToSize() {
resize(super.count);
}
private void resize(final int size) {
if (size < super.buf.length) {
final byte[] tmp = new byte[size];
System.arraycopy(super.buf, 0, tmp, 0, size);
super.buf = tmp;
} else if (size > super.buf.length) {
ensureCapacity(size);
}
}
/**
* Increases the capacity of this <tt>OtpOutputStream</tt> instance, if necessary, to
* ensure that it can hold at least the number of elements specified by the minimum
* capacity argument.
*
* @param minCapacity
* the desired minimum capacity
*/
public void ensureCapacity(final int minCapacity) {
if (minCapacity > fixedSize) {
throw new IllegalArgumentException("Trying to increase fixed-size buffer");
}
final int oldCapacity = super.buf.length;
if (minCapacity > oldCapacity) {
int newCapacity = oldCapacity * 3 / 2 + 1;
if (newCapacity < oldCapacity + defaultIncrement) {
newCapacity = oldCapacity + defaultIncrement;
}
if (newCapacity < minCapacity) {
newCapacity = minCapacity;
}
newCapacity = Math.min(fixedSize, newCapacity);
// minCapacity is usually close to size, so this is a win:
final byte[] tmp = new byte[newCapacity];
System.arraycopy(super.buf, 0, tmp, 0, super.count);
super.buf = tmp;
}
}
/**
* Write one byte to the stream.
*
* @param b
* the byte to write.
*
*/
public void write(final byte b) {
ensureCapacity(super.count + 1);
super.buf[super.count++] = b;
}
/*
* (non-Javadoc)
*
* @see java.io.ByteArrayOutputStream#write(byte[])
*/
@Override
public void write(final byte[] abuf) {
// don't assume that super.write(byte[]) calls write(buf, 0, buf.length)
write(abuf, 0, abuf.length);
}
/*
* (non-Javadoc)
*
* @see java.io.ByteArrayOutputStream#write(int)
*/
@Override
public synchronized void write(final int b) {
ensureCapacity(super.count + 1);
super.buf[super.count] = (byte) b;
count += 1;
}
/*
* (non-Javadoc)
*
* @see java.io.ByteArrayOutputStream#write(byte[], int, int)
*/
@Override
public synchronized void write(final byte[] b, final int off, final int len) {
if (off < 0 || off > b.length || len < 0 || off + len - b.length > 0) {
throw new IndexOutOfBoundsException();
}
ensureCapacity(super.count + len);
System.arraycopy(b, off, super.buf, super.count, len);
super.count += len;
}
@Override
public synchronized void writeTo(final OutputStream out) throws IOException {
super.writeTo(out);
}
public synchronized void writeToAndFlush(final OutputStream out) throws IOException {
super.writeTo(out);
out.flush();
}
/**
* Write the low byte of a value to the stream.
*
* @param n
* the value to use.
*
*/
public void write1(final long n) {
write((byte) (n & 0xff));
}
/**
* Write an array of bytes to the stream.
*
* @param bytes
* the array of bytes to write.
*
*/
public void writeN(final byte[] bytes) {
write(bytes);
}
/**
* Get the current capacity of the stream. As bytes are added the capacity of the
* stream is increased automatically, however this method returns the current size.
*
* @return the size of the internal buffer used by the stream.
*/
public int length() {
return super.buf.length;
}
/**
* Get the number of bytes in the stream.
*
* @return the number of bytes in the stream.
*
* @deprecated As of Jinterface 1.4, replaced by super.size().
* @see #size()
*/
@Deprecated
public int count() {
return count;
}
/**
* Write the low two bytes of a value to the stream in big endian order.
*
* @param n
* the value to use.
*/
public void write2BE(final long n) {
write((byte) ((n & 0xff00) >> 8));
write((byte) (n & 0xff));
}
/**
* Write the low four bytes of a value to the stream in big endian order.
*
* @param n
* the value to use.
*/
public void write4BE(final long n) {
write((byte) ((n & 0xff000000) >> 24));
write((byte) ((n & 0xff0000) >> 16));
write((byte) ((n & 0xff00) >> 8));
write((byte) (n & 0xff));
}
/**
* Write the low eight (all) bytes of a value to the stream in big endian order.
*
* @param n
* the value to use.
*/
public void write8BE(final long n) {
write((byte) (n >> 56 & 0xff));
write((byte) (n >> 48 & 0xff));
write((byte) (n >> 40 & 0xff));
write((byte) (n >> 32 & 0xff));
write((byte) (n >> 24 & 0xff));
write((byte) (n >> 16 & 0xff));
write((byte) (n >> 8 & 0xff));
write((byte) (n & 0xff));
}
/**
* Write any number of bytes in little endian format.
*
* @param n
* the value to use.
* @param b
* the number of bytes to write from the little end.
*/
public void writeLE(final long n, final int b) {
long v = n;
for (int i = 0; i < b; i++) {
write((byte) (v & 0xff));
v >>= 8;
}
}
/**
* Write the low two bytes of a value to the stream in little endian order.
*
* @param n
* the value to use.
*/
public void write2LE(final long n) {
write((byte) (n & 0xff));
write((byte) ((n & 0xff00) >> 8));
}
/**
* Write the low four bytes of a value to the stream in little endian order.
*
* @param n
* the value to use.
*/
public void write4LE(final long n) {
write((byte) (n & 0xff));
write((byte) ((n & 0xff00) >> 8));
write((byte) ((n & 0xff0000) >> 16));
write((byte) ((n & 0xff000000) >> 24));
}
/**
* Write the low eight bytes of a value to the stream in little endian order.
*
* @param n
* the value to use.
*/
public void write8LE(final long n) {
write((byte) (n & 0xff));
write((byte) (n >> 8 & 0xff));
write((byte) (n >> 16 & 0xff));
write((byte) (n >> 24 & 0xff));
write((byte) (n >> 32 & 0xff));
write((byte) (n >> 40 & 0xff));
write((byte) (n >> 48 & 0xff));
write((byte) (n >> 56 & 0xff));
}
/**
* Write the low four bytes of a value to the stream in bif endian order, at the
* specified position. If the position specified is beyond the end of the stream, this
* method will have no effect.
*
* Normally this method should be used in conjunction with {@link #size() size()},
* when is is necessary to insert data into the stream before it is known what the
* actual value should be. For example:
*
* <pre>
* int pos = s.size();
* s.write4BE(0); // make space for length data,
* // but final value is not yet known
* [ ...more write statements...]
* // later... when we know the length value
* s.poke4BE(pos, length);
* </pre>
*
*
* @param offset
* the position in the stream.
* @param n
* the value to use.
*/
public void poke4BE(final int offset, final long n) {
if (offset < super.count) {
buf[offset + 0] = (byte) ((n & 0xff000000) >> 24);
buf[offset + 1] = (byte) ((n & 0xff0000) >> 16);
buf[offset + 2] = (byte) ((n & 0xff00) >> 8);
buf[offset + 3] = (byte) (n & 0xff);
}
}
/**
* Write a string to the stream as an Erlang atom.
*
* @param atom
* the string to write.
*/
public void write_atom(final String atom) {
String enc_atom;
byte[] bytes;
boolean isLatin1 = true;
if (atom.codePointCount(0, atom.length()) <= OtpExternal.maxAtomLength) {
enc_atom = atom;
} else {
/*
* Throwing an exception would be better I think, but truncation seems to be
* the way it has been done in other parts of OTP...
*/
enc_atom = new String(OtpErlangString.stringToCodePoints(atom), 0,
OtpExternal.maxAtomLength);
}
for (int offset = 0; offset < enc_atom.length();) {
final int cp = enc_atom.codePointAt(offset);
if ((cp & ~0xFF) != 0) {
isLatin1 = false;
break;
}
offset += Character.charCount(cp);
}
try {
if (isLatin1) {
bytes = enc_atom.getBytes("ISO-8859-1");
write1(OtpExternal.atomTag);
write2BE(bytes.length);
} else {
bytes = enc_atom.getBytes("UTF-8");
final int length = bytes.length;
if (length < 256) {
write1(OtpExternal.smallAtomUtf8Tag);
write1(length);
} else {
write1(OtpExternal.atomUtf8Tag);
write2BE(length);
}
}
writeN(bytes);
} catch (final java.io.UnsupportedEncodingException e) {
/*
* Sigh, why didn't the API designer add an OtpErlangEncodeException to these
* encoding functions?!? Instead of changing the API we write an invalid atom
* and let it fail for whoever trying to decode this... Sigh, again...
*/
write1(OtpExternal.smallAtomUtf8Tag);
write1(2);
write2BE(0xffff); /* Invalid UTF-8 */
}
}
/**
* Write an array of bytes to the stream as an Erlang binary.
*
* @param bin
* the array of bytes to write.
*/
public void write_binary(final byte[] bin) {
write1(OtpExternal.binTag);
write4BE(bin.length);
writeN(bin);
}
/**
* Write an array of bytes to the stream as an Erlang bitstr.
*
* @param bin
* the array of bytes to write.
* @param pad_bits
* the number of zero pad bits at the low end of the last byte
*/
public void write_bitstr(final byte[] bin, final int pad_bits) {
if (pad_bits == 0) {
write_binary(bin);
return;
}
write1(OtpExternal.bitBinTag);
write4BE(bin.length);
write1(8 - pad_bits);
writeN(bin);
}
/**
* Write a boolean value to the stream as the Erlang atom 'true' or 'false'.
*
* @param b
* the boolean value to write.
*/
public void write_boolean(final boolean b) {
write_atom(String.valueOf(b));
}
/**
* Write a single byte to the stream as an Erlang integer. The byte is really an IDL
* 'octet', that is, unsigned.
*
* @param b
* the byte to use.
*/
public void write_byte(final byte b) {
this.write_long(b & 0xffL, true);
}
/**
* Write a character to the stream as an Erlang integer. The character may be a 16 bit
* character, kind of IDL 'wchar'. It is up to the Erlang side to take care of souch,
* if they should be used.
*
* @param c
* the character to use.
*/
public void write_char(final char c) {
this.write_long(c & 0xffffL, true);
}
/**
* Write a double value to the stream.
*
* @param d
* the double to use.
*/
public void write_double(final double d) {
write1(OtpExternal.newFloatTag);
write8BE(Double.doubleToLongBits(d));
}
/**
* Write a float value to the stream.
*
* @param f
* the float to use.
*/
public void write_float(final float f) {
write_double(f);
}
public void write_big_integer(final BigInteger v) {
if (v.bitLength() < 64) {
this.write_long(v.longValue(), true);
return;
}
final int signum = v.signum();
BigInteger val = v;
if (signum < 0) {
val = val.negate();
}
final byte[] magnitude = val.toByteArray();
final int n = magnitude.length;
// Reverse the array to make it little endian.
for (int i = 0, j = n; i < j--; i++) {
// Swap [i] with [j]
final byte b = magnitude[i];
magnitude[i] = magnitude[j];
magnitude[j] = b;
}
if ((n & 0xFF) == n) {
write1(OtpExternal.smallBigTag);
write1(n); // length
} else {
write1(OtpExternal.largeBigTag);
write4BE(n); // length
}
write1(signum < 0 ? 1 : 0); // sign
// Write the array
writeN(magnitude);
}
void write_long(final long v, final boolean unsigned) {
/*
* If v<0 and unsigned==true the value
* java.lang.Long.MAX_VALUE-java.lang.Long.MIN_VALUE+1+v is written, i.e v is
* regarded as unsigned two's complement.
*/
if ((v & 0xffL) == v) {
// will fit in one byte
write1(OtpExternal.smallIntTag);
write1(v);
} else {
// note that v != 0L
if (v < 0 && unsigned || v < OtpExternal.erlMin || v > OtpExternal.erlMax) {
// some kind of bignum
final long abs = unsigned ? v : v < 0 ? -v : v;
final int sign = unsigned ? 0 : v < 0 ? 1 : 0;
int n;
long mask;
for (mask = 0xFFFFffffL, n = 4; (abs & mask) != abs; n++, mask = mask << 8
| 0xffL) {
// count nonzero bytes
}
write1(OtpExternal.smallBigTag);
write1(n); // length
write1(sign); // sign
writeLE(abs, n); // value. obs! little endian
} else {
write1(OtpExternal.intTag);
write4BE(v);
}
}
}
/**
* Write a long to the stream.
*
* @param l
* the long to use.
*/
public void write_long(final long l) {
this.write_long(l, false);
}
/**
* Write a positive long to the stream. The long is interpreted as a two's complement
* unsigned long even if it is negative.
*
* @param ul
* the long to use.
*/
public void write_ulong(final long ul) {
this.write_long(ul, true);
}
/**
* Write an integer to the stream.
*
* @param i
* the integer to use.
*/
public void write_int(final int i) {
this.write_long(i, false);
}
/**
* Write a positive integer to the stream. The integer is interpreted as a two's
* complement unsigned integer even if it is negative.
*
* @param ui
* the integer to use.
*/
public void write_uint(final int ui) {
this.write_long(ui & 0xFFFFffffL, true);
}
/**
* Write a short to the stream.
*
* @param s
* the short to use.
*/
public void write_short(final short s) {
this.write_long(s, false);
}
/**
* Write a positive short to the stream. The short is interpreted as a two's
* complement unsigned short even if it is negative.
*
* @param us
* the short to use.
*/
public void write_ushort(final short us) {
this.write_long(us & 0xffffL, true);
}
/**
* Write an Erlang list header to the stream. After calling this method, you must
* write 'arity' elements to the stream followed by nil, or it will not be possible to
* decode it later.
*
* @param arity
* the number of elements in the list.
*/
public void write_list_head(final int arity) {
if (arity == 0) {
write_nil();
} else {
write1(OtpExternal.listTag);
write4BE(arity);
}
}
/**
* Write an empty Erlang list to the stream.
*/
public void write_nil() {
write1(OtpExternal.nilTag);
}
/**
* Write an Erlang tuple header to the stream. After calling this method, you must
* write 'arity' elements to the stream or it will not be possible to decode it later.
*
* @param arity
* the number of elements in the tuple.
*/
public void write_tuple_head(final int arity) {
if (arity < 0xff) {
write1(OtpExternal.smallTupleTag);
write1(arity);
} else {
write1(OtpExternal.largeTupleTag);
write4BE(arity);
}
}
/**
* Write an Erlang PID to the stream.
*
* @param node
* the nodename.
*
* @param id
* an arbitrary number. Only the low order 15 bits will be used.
*
* @param serial
* another arbitrary number. Only the low order 13 bits will be used.
*
* @param creation
* yet another arbitrary number. Only the low order 2 bits will be used.
*
*/
public void write_pid(final String node, final int id, final int serial,
final int creation) {
write1(OtpExternal.pidTag);
write_atom(node);
write4BE(id & 0x7fff); // 15 bits
write4BE(serial & 0x1fff); // 13 bits
write1(creation & 0x3); // 2 bits
}
/**
* Write an Erlang port to the stream.
*
* @param node
* the nodename.
*
* @param id
* an arbitrary number. Only the low order 28 bits will be used.
*
* @param creation
* another arbitrary number. Only the low order 2 bits will be used.
*
*/
public void write_port(final String node, final int id, final int creation) {
write1(OtpExternal.portTag);
write_atom(node);
write4BE(id & 0xfffffff); // 28 bits
write1(creation & 0x3); // 2 bits
}
/**
* Write an old style Erlang ref to the stream.
*
* @param node
* the nodename.
*
* @param id
* an arbitrary number. Only the low order 18 bits will be used.
*
* @param creation
* another arbitrary number. Only the low order 2 bits will be used.
*
*/
public void write_ref(final String node, final int id, final int creation) {
write1(OtpExternal.refTag);
write_atom(node);
write4BE(id & 0x3ffff); // 18 bits
write1(creation & 0x3); // 2 bits
}
/**
* Write a new style (R6 and later) Erlang ref to the stream.
*
* @param node
* the nodename.
*
* @param ids
* an array of arbitrary numbers. Only the low order 18 bits of the first
* number will be used. If the array contains only one number, an old style
* ref will be written instead. At most three numbers will be read from the
* array.
*
* @param creation
* another arbitrary number. Only the low order 2 bits will be used.
*
*/
public void write_ref(final String node, final int[] ids, final int creation) {
int arity = ids.length;
if (arity > 3) {
arity = 3; // max 3 words in ref
}
if (arity == 1) {
// use old method
this.write_ref(node, ids[0], creation);
} else {
// r6 ref
write1(OtpExternal.newRefTag);
// how many id values
write2BE(arity);
write_atom(node);
// note: creation BEFORE id in r6 ref
write1(creation & 0x3); // 2 bits
// first int gets truncated to 18 bits
write4BE(ids[0] & 0x3ffff);
// remaining ones are left as is
for (int i = 1; i < arity; i++) {
write4BE(ids[i]);
}
}
}
/**
* Write a string to the stream.
*
* @param s
* the string to write.
*/
public void write_string(final String s) {
final int len = s.length();
switch (len) {
case 0:
write_nil();
break;
default:
if (len <= 65535 && is8bitString(s)) { // 8-bit string
try {
final byte[] bytebuf = s.getBytes("ISO-8859-1");
write1(OtpExternal.stringTag);
write2BE(len);
writeN(bytebuf);
} catch (final UnsupportedEncodingException e) {
write_nil(); // it should never ever get here...
}
} else { // unicode or longer, must code as list
final int[] codePoints = OtpErlangString.stringToCodePoints(s);
write_list_head(codePoints.length);
for (final int codePoint : codePoints) {
write_int(codePoint);
}
write_nil();
}
}
}
private boolean is8bitString(final String s) {
for (int i = 0; i < s.length(); ++i) {
final char c = s.charAt(i);
if (c < 0 || c > 255) {
return false;
}
}
return true;
}
/**
* Write an arbitrary Erlang term to the stream in compressed format.
*
* @param o
* the Erlang term to write.
*/
public void write_compressed(final OtpErlangObject o) {
write_compressed(o, Deflater.DEFAULT_COMPRESSION);
}
/**
* Write an arbitrary Erlang term to the stream in compressed format.
*
* @param o
* the Erlang term to write.
* @param level
* the compression level (<tt>0..9</tt>)
*/
public void write_compressed(final OtpErlangObject o, final int level) {
@SuppressWarnings("resource")
final OtpOutputStream oos = new OtpOutputStream(o);
/*
* similar to erts_term_to_binary() in external.c: We don't want to compress if
* compression actually increases the size. Since compression uses 5 extra bytes
* (COMPRESSED tag + size), don't compress if the original term is smaller.
*/
if (oos.size() < 5) {
// fast path for small terms
try {
oos.writeToAndFlush(this);
// if the term is written as a compressed term, the output
// stream is closed, so we do this here, too
close();
} catch (final IOException e) {
throw new java.lang.IllegalArgumentException(
"Intermediate stream failed for Erlang object " + o);
}
} else {
final int startCount = super.count;
// we need destCount bytes for an uncompressed term
// -> if compression uses more, use the uncompressed term!
final int destCount = startCount + oos.size();
fixedSize = destCount;
final Deflater def = new Deflater(level);
@SuppressWarnings("resource")
final java.util.zip.DeflaterOutputStream dos = new java.util.zip.DeflaterOutputStream(
this, def);
try {
write1(OtpExternal.compressedTag);
write4BE(oos.size());
oos.writeTo(dos);
} catch (final IllegalArgumentException e) {
/*
* Discard further un-compressed data (if not called, there may be memory
* leaks).
*
* After calling java.util.zip.Deflater.end(), the deflater should not be
* used anymore, not even the close() method of dos. Calling dos.close()
* before def.end() is prevented since an unfinished DeflaterOutputStream
* will try to deflate its unprocessed data to the (fixed) byte array
* which is prevented by ensureCapacity() and would also unnecessarily
* process further data that is discarded anyway.
*
* Since we are re-using the byte array of this object below, we must not
* call close() in e.g. a finally block either (with or without a call to
* def.end()).
*/
def.end();
// could not make the value smaller than originally
// -> reset to starting count, write uncompressed
super.count = startCount;
try {
oos.writeTo(this);
// if the term is written as a compressed term, the output
// stream is closed, so we do this here, too
close();
} catch (final IOException e2) {
throw new java.lang.IllegalArgumentException(
"Intermediate stream failed for Erlang object " + o);
}
} catch (final IOException e) {
throw new java.lang.IllegalArgumentException(
"Intermediate stream failed for Erlang object " + o);
} finally {
fixedSize = Integer.MAX_VALUE;
try {
dos.close(); // note: closes this, too!
} catch (final IOException e) {
// ignore
}
}
}
}
/**
* Write an arbitrary Erlang term to the stream.
*
* @param o
* the Erlang term to write.
*/
public void write_any(final OtpErlangObject o) {
// calls one of the above functions, depending on o
o.encode(this);
}
public void write_fun(final OtpErlangPid pid, final String module,
final long old_index, final int arity, final byte[] md5, final long index,
final long uniq, final OtpErlangObject[] freeVars) {
if (arity == -1) {
write1(OtpExternal.funTag);
write4BE(freeVars.length);
pid.encode(this);
write_atom(module);
write_long(index);
write_long(uniq);
for (final OtpErlangObject fv : freeVars) {
fv.encode(this);
}
} else {
write1(OtpExternal.newFunTag);
final int saveSizePos = getPos();
write4BE(0); // this is where we patch in the size
write1(arity);
writeN(md5);
write4BE(index);
write4BE(freeVars.length);
write_atom(module);
write_long(old_index);
write_long(uniq);
pid.encode(this);
for (final OtpErlangObject fv : freeVars) {
fv.encode(this);
}
poke4BE(saveSizePos, getPos() - saveSizePos);
}
}
public void write_external_fun(final String module, final String function,
final int arity) {
write1(OtpExternal.externalFunTag);
write_atom(module);
write_atom(function);
write_long(arity);
}
public void write_map_head(final int arity) {
write1(OtpExternal.mapTag);
write4BE(arity);
}
}