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The ProximaX IPFS Java API is a Java library for interacting IPFS server.
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package io.ipfs.api.cbor;
import static io.ipfs.api.cbor.CborConstants.*;
import static io.ipfs.api.cbor.CborType.getName;
import static io.ipfs.api.cbor.CborType.valueOf;
/*
* JACOB - CBOR implementation in Java.
*
* (C) Copyright - 2013 - J.W. Janssen
*/
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
/**
* Provides a decoder capable of handling CBOR encoded data from a {@link InputStream}.
*/
public class CborDecoder {
protected final PushbackInputStream m_is;
/**
* Creates a new {@link CborDecoder} instance.
*
* @param is the actual input stream to read the CBOR-encoded data from, cannot be null.
*/
public CborDecoder(InputStream is) {
if (is == null) {
throw new IllegalArgumentException("InputStream cannot be null!");
}
m_is = (is instanceof PushbackInputStream) ? (PushbackInputStream) is : new PushbackInputStream(is);
}
private static void fail(String msg, Object... args) throws IOException {
throw new IOException(msg + args);
}
private static String lengthToString(int len) {
return (len < 0) ? "no payload" : (len == ONE_BYTE) ? "one byte" : (len == TWO_BYTES) ? "two bytes"
: (len == FOUR_BYTES) ? "four bytes" : (len == EIGHT_BYTES) ? "eight bytes" : "(unknown)";
}
/**
* Peeks in the input stream for the upcoming type.
*
* @return the upcoming type in the stream, or null in case of an end-of-stream.
* @throws IOException in case of I/O problems reading the CBOR-type from the underlying input stream.
*/
public CborType peekType() throws IOException {
int p = m_is.read();
if (p < 0) {
// EOF, nothing to peek at...
return null;
}
m_is.unread(p);
return valueOf(p);
}
/**
* Prolog to reading an array value in CBOR format.
*
* @return the number of elements in the array to read, or -1 in case of infinite-length arrays.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public long readArrayLength() throws IOException {
return readMajorTypeWithSize(TYPE_ARRAY);
}
/**
* Reads a boolean value in CBOR format.
*
* @return the read boolean.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public boolean readBoolean() throws IOException {
int b = readMajorType(TYPE_FLOAT_SIMPLE);
if (b != FALSE && b != TRUE) {
fail("Unexpected boolean value: %d!", b);
}
return b == TRUE;
}
/**
* Reads a "break"/stop value in CBOR format.
*
* @return always null.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public Object readBreak() throws IOException {
readMajorTypeExact(TYPE_FLOAT_SIMPLE, BREAK);
return null;
}
/**
* Reads a byte string value in CBOR format.
*
* @return the read byte string, never null. In case the encoded string has a length of 0, an empty string is returned.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public byte[] readByteString() throws IOException {
long len = readMajorTypeWithSize(TYPE_BYTE_STRING);
if (len < 0) {
fail("Infinite-length byte strings not supported!");
}
if (len > Integer.MAX_VALUE) {
fail("String length too long!");
}
return readFully(new byte[(int) len]);
}
/**
* Prolog to reading a byte string value in CBOR format.
*
* @return the number of bytes in the string to read, or -1 in case of infinite-length strings.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public long readByteStringLength() throws IOException {
return readMajorTypeWithSize(TYPE_BYTE_STRING);
}
/**
* Reads a double-precision float value in CBOR format.
*
* @return the read double value, values from {@link Float#MIN_VALUE} to {@link Float#MAX_VALUE} are supported.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public double readDouble() throws IOException {
readMajorTypeExact(TYPE_FLOAT_SIMPLE, DOUBLE_PRECISION_FLOAT);
return Double.longBitsToDouble(readUInt64());
}
/**
* Reads a single-precision float value in CBOR format.
*
* @return the read float value, values from {@link Float#MIN_VALUE} to {@link Float#MAX_VALUE} are supported.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public float readFloat() throws IOException {
readMajorTypeExact(TYPE_FLOAT_SIMPLE, SINGLE_PRECISION_FLOAT);
return Float.intBitsToFloat((int) readUInt32());
}
/**
* Reads a half-precision float value in CBOR format.
*
* @return the read half-precision float value, values from {@link Float#MIN_VALUE} to {@link Float#MAX_VALUE} are supported.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public double readHalfPrecisionFloat() throws IOException {
readMajorTypeExact(TYPE_FLOAT_SIMPLE, HALF_PRECISION_FLOAT);
int half = readUInt16();
int exp = (half >> 10) & 0x1f;
int mant = half & 0x3ff;
double val;
if (exp == 0) {
val = mant * Math.pow(2, -24);
} else if (exp != 31) {
val = (mant + 1024) * Math.pow(2, exp - 25);
} else if (mant != 0) {
val = Double.NaN;
} else {
val = Double.POSITIVE_INFINITY;
}
return ((half & 0x8000) == 0) ? val : -val;
}
/**
* Reads a signed or unsigned integer value in CBOR format.
*
* @return the read integer value, values from {@link Long#MIN_VALUE} to {@link Long#MAX_VALUE} are supported.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public long readInt() throws IOException {
int ib = m_is.read();
// in case of negative integers, extends the sign to all bits; otherwise zero...
long ui = expectIntegerType(ib);
// in case of negative integers does a ones complement
return ui ^ readUInt(ib & 0x1f, false /* breakAllowed */);
}
/**
* Reads a signed or unsigned 16-bit integer value in CBOR format.
*
* @return the small integer value, values from [-65536..65535] are supported.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying output stream.
*/
public int readInt16() throws IOException {
int ib = m_is.read();
// in case of negative integers, extends the sign to all bits; otherwise zero...
long ui = expectIntegerType(ib);
// in case of negative integers does a ones complement
return (int) (ui ^ readUIntExact(TWO_BYTES, ib & 0x1f));
}
/**
* Reads a signed or unsigned 32-bit integer value in CBOR format.
*
* @return the small integer value, values in the range [-4294967296..4294967295] are supported.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying output stream.
*/
public long readInt32() throws IOException {
int ib = m_is.read();
// in case of negative integers, extends the sign to all bits; otherwise zero...
long ui = expectIntegerType(ib);
// in case of negative integers does a ones complement
return ui ^ readUIntExact(FOUR_BYTES, ib & 0x1f);
}
/**
* Reads a signed or unsigned 64-bit integer value in CBOR format.
*
* @return the small integer value, values from {@link Long#MIN_VALUE} to {@link Long#MAX_VALUE} are supported.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying output stream.
*/
public long readInt64() throws IOException {
int ib = m_is.read();
// in case of negative integers, extends the sign to all bits; otherwise zero...
long ui = expectIntegerType(ib);
// in case of negative integers does a ones complement
return ui ^ readUIntExact(EIGHT_BYTES, ib & 0x1f);
}
/**
* Reads a signed or unsigned 8-bit integer value in CBOR format.
*
* @return the small integer value, values in the range [-256..255] are supported.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying output stream.
*/
public int readInt8() throws IOException {
int ib = m_is.read();
// in case of negative integers, extends the sign to all bits; otherwise zero...
long ui = expectIntegerType(ib);
// in case of negative integers does a ones complement
return (int) (ui ^ readUIntExact(ONE_BYTE, ib & 0x1f));
}
/**
* Prolog to reading a map of key-value pairs in CBOR format.
*
* @return the number of entries in the map, >= 0.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public long readMapLength() throws IOException {
return readMajorTypeWithSize(TYPE_MAP);
}
/**
* Reads a null-value in CBOR format.
*
* @return always null.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public Object readNull() throws IOException {
readMajorTypeExact(TYPE_FLOAT_SIMPLE, NULL);
return null;
}
/**
* Reads a single byte value in CBOR format.
*
* @return the read byte value.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public byte readSimpleValue() throws IOException {
readMajorTypeExact(TYPE_FLOAT_SIMPLE, ONE_BYTE);
return (byte) readUInt8();
}
/**
* Reads a signed or unsigned small (<= 23) integer value in CBOR format.
*
* @return the small integer value, values in the range [-24..23] are supported.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying output stream.
*/
public int readSmallInt() throws IOException {
int ib = m_is.read();
// in case of negative integers, extends the sign to all bits; otherwise zero...
long ui = expectIntegerType(ib);
// in case of negative integers does a ones complement
return (int) (ui ^ readUIntExact(-1, ib & 0x1f));
}
/**
* Reads a semantic tag value in CBOR format.
*
* @return the read tag value.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public long readTag() throws IOException {
return readUInt(readMajorType(TYPE_TAG), false /* breakAllowed */);
}
/**
* Reads an UTF-8 encoded string value in CBOR format.
*
* @return the read UTF-8 encoded string, never null. In case the encoded string has a length of 0, an empty string is returned.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public String readTextString() throws IOException {
long len = readMajorTypeWithSize(TYPE_TEXT_STRING);
if (len < 0) {
fail("Infinite-length text strings not supported!");
}
if (len > Integer.MAX_VALUE) {
fail("String length too long!");
}
return new String(readFully(new byte[(int) len]), "UTF-8");
}
/**
* Prolog to reading an UTF-8 encoded string value in CBOR format.
*
* @return the length of the string to read, or -1 in case of infinite-length strings.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public long readTextStringLength() throws IOException {
return readMajorTypeWithSize(TYPE_TEXT_STRING);
}
/**
* Reads an undefined value in CBOR format.
*
* @return always null.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
public Object readUndefined() throws IOException {
readMajorTypeExact(TYPE_FLOAT_SIMPLE, UNDEFINED);
return null;
}
/**
* Reads the next major type from the underlying input stream, and verifies whether it matches the given expectation.
*
* @param ib the expected major type
* @return either -1 if the major type was an signed integer, or 0 otherwise.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
protected long expectIntegerType(int ib) throws IOException {
int majorType = ((ib & 0xFF) >>> 5);
if ((majorType != TYPE_UNSIGNED_INTEGER) && (majorType != TYPE_NEGATIVE_INTEGER)) {
fail("Unexpected type: %s, expected type %s or %s!", getName(majorType), getName(TYPE_UNSIGNED_INTEGER),
getName(TYPE_NEGATIVE_INTEGER));
}
return -majorType;
}
/**
* Reads the next major type from the underlying input stream, and verifies whether it matches the given expectation.
*
* @param majorType the expected major type, cannot be null (unchecked).
* @return the read subtype, or payload, of the read major type.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
protected int readMajorType(int majorType) throws IOException {
int ib = m_is.read();
if (majorType != ((ib >>> 5) & 0x07)) {
fail("Unexpected type: %s, expected: %s!", getName(ib), getName(majorType));
}
return ib & 0x1F;
}
/**
* Reads the next major type from the underlying input stream, and verifies whether it matches the given expectations.
*
* @param majorType the expected major type, cannot be null (unchecked);
* @param subtype the expected subtype.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
protected void readMajorTypeExact(int majorType, int subtype) throws IOException {
int st = readMajorType(majorType);
if ((st ^ subtype) != 0) {
fail("Unexpected subtype: %d, expected: %d!", st, subtype);
}
}
/**
* Reads the next major type from the underlying input stream, verifies whether it matches the given expectation, and decodes the payload into a size.
*
* @param majorType the expected major type, cannot be null (unchecked).
* @return the number of succeeding bytes, >= 0, or -1 if an infinite-length type is read.
* @throws IOException in case of I/O problems reading the CBOR-encoded value from the underlying input stream.
*/
protected long readMajorTypeWithSize(int majorType) throws IOException {
return readUInt(readMajorType(majorType), true /* breakAllowed */);
}
/**
* Reads an unsigned integer with a given length-indicator.
*
* @param length the length indicator to use;
* @return the read unsigned integer, as long value.
* @throws IOException in case of I/O problems reading the unsigned integer from the underlying input stream.
*/
protected long readUInt(int length, boolean breakAllowed) throws IOException {
long result = -1;
if (length < ONE_BYTE) {
result = length;
} else if (length == ONE_BYTE) {
result = readUInt8();
} else if (length == TWO_BYTES) {
result = readUInt16();
} else if (length == FOUR_BYTES) {
result = readUInt32();
} else if (length == EIGHT_BYTES) {
result = readUInt64();
} else if (breakAllowed && length == BREAK) {
return -1;
}
if (result < 0) {
fail("Not well-formed CBOR integer found, invalid length: %d!", result);
}
return result;
}
/**
* Reads an unsigned 16-bit integer value
*
* @return value the read value, values from {@link Long#MIN_VALUE} to {@link Long#MAX_VALUE} are supported.
* @throws IOException in case of I/O problems writing the CBOR-encoded value to the underlying output stream.
*/
protected int readUInt16() throws IOException {
byte[] buf = readFully(new byte[2]);
return (buf[0] & 0xFF) << 8 | (buf[1] & 0xFF);
}
/**
* Reads an unsigned 32-bit integer value
*
* @return value the read value, values from {@link Long#MIN_VALUE} to {@link Long#MAX_VALUE} are supported.
* @throws IOException in case of I/O problems writing the CBOR-encoded value to the underlying output stream.
*/
protected long readUInt32() throws IOException {
byte[] buf = readFully(new byte[4]);
return ((buf[0] & 0xFF) << 24 | (buf[1] & 0xFF) << 16 | (buf[2] & 0xFF) << 8 | (buf[3] & 0xFF)) & 0xffffffffL;
}
/**
* Reads an unsigned 64-bit integer value
*
* @return value the read value, values from {@link Long#MIN_VALUE} to {@link Long#MAX_VALUE} are supported.
* @throws IOException in case of I/O problems writing the CBOR-encoded value to the underlying output stream.
*/
protected long readUInt64() throws IOException {
byte[] buf = readFully(new byte[8]);
return (buf[0] & 0xFFL) << 56 | (buf[1] & 0xFFL) << 48 | (buf[2] & 0xFFL) << 40 | (buf[3] & 0xFFL) << 32 | //
(buf[4] & 0xFFL) << 24 | (buf[5] & 0xFFL) << 16 | (buf[6] & 0xFFL) << 8 | (buf[7] & 0xFFL);
}
/**
* Reads an unsigned 8-bit integer value
*
* @return value the read value, values from {@link Long#MIN_VALUE} to {@link Long#MAX_VALUE} are supported.
* @throws IOException in case of I/O problems writing the CBOR-encoded value to the underlying output stream.
*/
protected int readUInt8() throws IOException {
return m_is.read() & 0xff;
}
/**
* Reads an unsigned integer with a given length-indicator.
*
* @param length the length indicator to use;
* @return the read unsigned integer, as long value.
* @throws IOException in case of I/O problems reading the unsigned integer from the underlying input stream.
*/
protected long readUIntExact(int expectedLength, int length) throws IOException {
if (((expectedLength == -1) && (length >= ONE_BYTE)) || ((expectedLength >= 0) && (length != expectedLength))) {
fail("Unexpected payload/length! Expected %s, but got %s.", lengthToString(expectedLength),
lengthToString(length));
}
return readUInt(length, false /* breakAllowed */);
}
private byte[] readFully(byte[] buf) throws IOException {
int len = buf.length;
int n = 0, off = 0;
while (n < len) {
int count = m_is.read(buf, off + n, len - n);
if (count < 0) {
throw new EOFException();
}
n += count;
}
return buf;
}
}