public abstract class CodedInputStream
Reads and decodes protocol message fields.
This class contains two kinds of methods: methods that read specific protocol message
constructs and field types (e.g. #readTag() and #readInt32()) and methods that
read low-level values (e.g. #readRawVarint32() and #readRawBytes). If you are
reading encoded protocol messages, you should use the former methods, but if you are reading some
other format of your own design, use the latter.
Static Methods
public static int decodeZigZag32(int n)
Decode a ZigZag-encoded 32-bit value. ZigZag encodes signed integers into values that can be
efficiently encoded with varint. (Otherwise, negative values must be sign-extended to 64 bits
to be varint encoded, thus always taking 10 bytes on the wire.)
| Parameter |
|---|
| Name | Description |
n | int
An unsigned 32-bit integer, stored in a signed int because Java has no explicit
unsigned support.
|
| Returns |
|---|
| Type | Description |
int | A signed 32-bit integer.
|
public static long decodeZigZag64(long n)
Decode a ZigZag-encoded 64-bit value. ZigZag encodes signed integers into values that can be
efficiently encoded with varint. (Otherwise, negative values must be sign-extended to 64 bits
to be varint encoded, thus always taking 10 bytes on the wire.)
| Parameter |
|---|
| Name | Description |
n | long
An unsigned 64-bit integer, stored in a signed int because Java has no explicit
unsigned support.
|
| Returns |
|---|
| Type | Description |
long | A signed 64-bit integer.
|
public static CodedInputStream newInstance(byte[] buf)
Create a new CodedInputStream wrapping the given byte array.
| Parameter |
|---|
| Name | Description |
buf | byte[]
|
public static CodedInputStream newInstance(byte[] buf, int off, int len)
Create a new CodedInputStream wrapping the given byte array slice.
public static CodedInputStream newInstance(InputStream input)
Create a new CodedInputStream wrapping the given InputStream.
public static CodedInputStream newInstance(InputStream input, int bufferSize)
Create a new CodedInputStream wrapping the given InputStream, with a specified buffer size.
public static CodedInputStream newInstance(Iterable<ByteBuffer> input)
Create a new CodedInputStream wrapping the given Iterable .
public static CodedInputStream newInstance(ByteBuffer buf)
Create a new CodedInputStream wrapping the given ByteBuffer. The data starting from the
ByteBuffer's current position to its limit will be read. The returned CodedInputStream may or
may not share the underlying data in the ByteBuffer, therefore the ByteBuffer cannot be changed
while the CodedInputStream is in use. Note that the ByteBuffer's position won't be changed by
this function. Concurrent calls with the same ByteBuffer object are safe if no other thread is
trying to alter the ByteBuffer's status.
public static int readRawVarint32(int firstByte, InputStream input)
Like #readRawVarint32(InputStream), but expects that the caller has already read one
byte. This allows the caller to determine if EOF has been reached before attempting to read.
| Returns |
|---|
| Type | Description |
int | |
Methods
public abstract T <T>readGroup(int fieldNumber, Parser<T> parser, ExtensionRegistryLite extensionRegistry)
Read a group field value from the stream.
public abstract T <T>readMessage(Parser<T> parser, ExtensionRegistryLite extensionRegistry)
Read an embedded message field value from the stream.
public abstract void checkLastTagWas(int value)
Verifies that the last call to readTag() returned the given tag value. This is used to verify
that a nested group ended with the correct end tag.
| Parameter |
|---|
| Name | Description |
value | int
|
public void checkRecursionLimit()
public abstract void enableAliasing(boolean enabled)
Enables ByteString aliasing of the underlying buffer, trading off on buffer pinning for
data copies. Only valid for buffer-backed streams.
| Parameter |
|---|
| Name | Description |
enabled | boolean
|
public abstract int getBytesUntilLimit()
Returns the number of bytes to be read before the current limit. If no limit is set, returns
-1.
| Returns |
|---|
| Type | Description |
int | |
public abstract int getLastTag()
| Returns |
|---|
| Type | Description |
int | |
public abstract int getTotalBytesRead()
The total bytes read up to the current position. Calling #resetSizeCounter() resets
this value to zero.
| Returns |
|---|
| Type | Description |
int | |
public abstract boolean isAtEnd()
Returns true if the stream has reached the end of the input. This is the case if either the end
of the underlying input source has been reached or if the stream has reached a limit created
using #pushLimit(int). This function may get blocked when using StreamDecoder as it
invokes StreamDecoder#tryRefillBuffer(int) in this function which will try to read
bytes from input.
public abstract void popLimit(int oldLimit)
Discards the current limit, returning to the previous limit.
| Parameter |
|---|
| Name | Description |
oldLimit | int
The old limit, as returned by pushLimit.
|
public abstract int pushLimit(int byteLimit)
Sets currentLimit to (current position) + byteLimit. This is called when
descending into a length-delimited embedded message.
Note that pushLimit() does NOT affect how many bytes the CodedInputStream
reads from an underlying InputStream when refreshing its buffer. If you need to prevent
reading past a certain point in the underlying InputStream (e.g. because you expect it
to contain more data after the end of the message which you need to handle differently) then
you must place a wrapper around your InputStream which limits the amount of data that
can be read from it.
| Parameter |
|---|
| Name | Description |
byteLimit | int
|
| Returns |
|---|
| Type | Description |
int | the old limit.
|
public abstract boolean readBool()
Read a bool field value from the stream.
public abstract byte[] readByteArray()
Read a bytes field value from the stream.
| Returns |
|---|
| Type | Description |
byte[] | |
public abstract ByteBuffer readByteBuffer()
Read a bytes field value from the stream.
public abstract ByteString readBytes()
Read a bytes field value from the stream.
public abstract double readDouble()
Read a double field value from the stream.
public abstract int readEnum()
Read an enum field value from the stream. Caller is responsible for converting the numeric
value to an actual enum.
| Returns |
|---|
| Type | Description |
int | |
public abstract int readFixed32()
Read a fixed32 field value from the stream.
| Returns |
|---|
| Type | Description |
int | |
public abstract long readFixed64()
Read a fixed64 field value from the stream.
| Returns |
|---|
| Type | Description |
long | |
public abstract float readFloat()
Read a float field value from the stream.
| Returns |
|---|
| Type | Description |
float | |
public abstract void readGroup(int fieldNumber, MessageLite.Builder builder, ExtensionRegistryLite extensionRegistry)
Read a group field value from the stream.
public abstract int readInt32()
Read an int32 field value from the stream.
| Returns |
|---|
| Type | Description |
int | |
public abstract long readInt64()
Read an int64 field value from the stream.
| Returns |
|---|
| Type | Description |
long | |
public abstract void readMessage(MessageLite.Builder builder, ExtensionRegistryLite extensionRegistry)
Read an embedded message field value from the stream.
public abstract byte readRawByte()
Read one byte from the input.
| Returns |
|---|
| Type | Description |
byte | |
| Exceptions |
|---|
| Type | Description |
IOException | The end of the stream or the current limit was reached.
|
public abstract byte[] readRawBytes(int size)
Read a fixed size of bytes from the input.
| Parameter |
|---|
| Name | Description |
size | int
|
| Returns |
|---|
| Type | Description |
byte[] | |
| Exceptions |
|---|
| Type | Description |
IOException | The end of the stream or the current limit was reached.
|
public abstract int readRawLittleEndian32()
Read a 32-bit little-endian integer from the stream.
| Returns |
|---|
| Type | Description |
int | |
public abstract long readRawLittleEndian64()
Read a 64-bit little-endian integer from the stream.
| Returns |
|---|
| Type | Description |
long | |
public abstract int readRawVarint32()
Read a raw Varint from the stream. If larger than 32 bits, discard the upper bits.
| Returns |
|---|
| Type | Description |
int | |
public abstract long readRawVarint64()
Read a raw Varint from the stream.
| Returns |
|---|
| Type | Description |
long | |
public abstract int readSFixed32()
Read an sfixed32 field value from the stream.
| Returns |
|---|
| Type | Description |
int | |
public abstract long readSFixed64()
Read an sfixed64 field value from the stream.
| Returns |
|---|
| Type | Description |
long | |
public abstract int readSInt32()
Read an sint32 field value from the stream.
| Returns |
|---|
| Type | Description |
int | |
public abstract long readSInt64()
Read an sint64 field value from the stream.
| Returns |
|---|
| Type | Description |
long | |
public abstract String readString()
Read a string field value from the stream. If the stream contains malformed UTF-8,
replace the offending bytes with the standard UTF-8 replacement character.
public abstract String readStringRequireUtf8()
public abstract int readTag()
Attempt to read a field tag, returning zero if we have reached EOF. Protocol message parsers
use this to read tags, since a protocol message may legally end wherever a tag occurs, and zero
is not a valid tag number.
| Returns |
|---|
| Type | Description |
int | |
public abstract int readUInt32()
Read a uint32 field value from the stream.
| Returns |
|---|
| Type | Description |
int | |
public abstract long readUInt64()
Read a uint64 field value from the stream.
| Returns |
|---|
| Type | Description |
long | |
public abstract void readUnknownGroup(int fieldNumber, MessageLite.Builder builder)
Deprecated. UnknownFieldSet.Builder now implements MessageLite.Builder, so you can just call
#readGroup.
Reads a group field value from the stream and merges it into the given UnknownFieldSet.
public abstract void resetSizeCounter()
public final int setRecursionLimit(int limit)
Set the maximum message recursion depth. In order to prevent malicious messages from causing
stack overflows, CodedInputStream limits how deeply messages may be nested. The default
limit is 100.
| Parameter |
|---|
| Name | Description |
limit | int
|
| Returns |
|---|
| Type | Description |
int | the old limit.
|
public final int setSizeLimit(int limit)
Only valid for InputStream-backed streams.
Set the maximum message size. In order to prevent malicious messages from exhausting memory
or causing integer overflows, CodedInputStream limits how large a message may be. The
default limit is Integer.MAX_VALUE. You should set this limit as small as you can
without harming your app's functionality. Note that size limits only apply when reading from an
InputStream, not when constructed around a raw byte array.
If you want to read several messages from a single CodedInputStream, you could call #resetSizeCounter() after each one to avoid hitting the size limit.
| Parameter |
|---|
| Name | Description |
limit | int
|
| Returns |
|---|
| Type | Description |
int | the old limit.
|
public abstract boolean skipField(int tag)
Reads and discards a single field, given its tag value.
| Parameter |
|---|
| Name | Description |
tag | int
|
| Returns |
|---|
| Type | Description |
boolean | false if the tag is an endgroup tag, in which case nothing is skipped.
Otherwise, returns true.
|
public abstract boolean skipField(int tag, CodedOutputStream output)
Deprecated. use UnknownFieldSet or UnknownFieldSetLite to skip to an output
stream.
Reads a single field and writes it to output in wire format, given its tag value.
| Returns |
|---|
| Type | Description |
boolean | false if the tag is an endgroup tag, in which case nothing is skipped.
Otherwise, returns true.
|
public abstract void skipMessage()
Reads and discards an entire message. This will read either until EOF or until an endgroup tag,
whichever comes first.
public abstract void skipMessage(CodedOutputStream output)
Reads an entire message and writes it to output in wire format. This will read either until EOF
or until an endgroup tag, whichever comes first.
public abstract void skipRawBytes(int size)
Reads and discards size bytes.
| Parameter |
|---|
| Name | Description |
size | int
|
| Exceptions |
|---|
| Type | Description |
IOException | The end of the stream or the current limit was reached.
|
