okio

Interface BufferedSource

All Superinterfaces:

AutoCloseable, Closeable, Source

All Known Implementing Classes:

Buffer

public interface BufferedSource
extends Source

A source that keeps a buffer internally so that callers can do small reads without a performance penalty. It also allows clients to read ahead, buffering as much as necessary before consuming input.

Method Summary

Modifier and Type	Method and Description
Buffer	buffer() Returns this source's internal buffer.
boolean	exhausted() Returns true if there are no more bytes in this source.
long	indexOf(byte b) Equivalent to indexOf(b, 0).
long	indexOf(byte b, long fromIndex) Returns the index of the first b in the buffer at or after fromIndex.
long	indexOf(byte b, long fromIndex, long toIndex) Returns the index of b if it is found in the range of fromIndex inclusive to toIndex exclusive.
long	indexOf(ByteString bytes) Equivalent to indexOf(bytes, 0).
long	indexOf(ByteString bytes, long fromIndex) Returns the index of the first match for bytes in the buffer at or after fromIndex.
long	indexOfElement(ByteString targetBytes) Equivalent to indexOfElement(targetBytes, 0).
long	indexOfElement(ByteString targetBytes, long fromIndex) Returns the first index in this buffer that is at or after fromIndex and that contains any of the bytes in targetBytes.
InputStream	inputStream() Returns an input stream that reads from this source.
boolean	rangeEquals(long offset, ByteString bytes) Returns true if the bytes at offset in this source equal bytes.
boolean	rangeEquals(long offset, ByteString bytes, int bytesOffset, int byteCount) Returns true if byteCount bytes at offset in this source equal bytes at bytesOffset.
int	read(byte[] sink) Removes up to sink.length bytes from this and copies them into sink.
int	read(byte[] sink, int offset, int byteCount) Removes up to byteCount bytes from this and copies them into sink at offset.
long	readAll(Sink sink) Removes all bytes from this and appends them to sink.
byte	readByte() Removes a byte from this source and returns it.
byte[]	readByteArray() Removes all bytes from this and returns them as a byte array.
byte[]	readByteArray(long byteCount) Removes byteCount bytes from this and returns them as a byte array.
ByteString	readByteString() Removes all bytes bytes from this and returns them as a byte string.
ByteString	readByteString(long byteCount) Removes byteCount bytes from this and returns them as a byte string.
long	readDecimalLong() Reads a long from this source in signed decimal form (i.e., as a string in base 10 with optional leading '-').
void	readFully(Buffer sink, long byteCount) Removes exactly byteCount bytes from this and appends them to sink.
void	readFully(byte[] sink) Removes exactly sink.length bytes from this and copies them into sink.
long	readHexadecimalUnsignedLong() Reads a long form this source in hexadecimal form (i.e., as a string in base 16).
int	readInt() Removes four bytes from this source and returns a big-endian int.
int	readIntLe() Removes four bytes from this source and returns a little-endian int.
long	readLong() Removes eight bytes from this source and returns a big-endian long.
long	readLongLe() Removes eight bytes from this source and returns a little-endian long.
short	readShort() Removes two bytes from this source and returns a big-endian short.
short	readShortLe() Removes two bytes from this source and returns a little-endian short.
String	readString(Charset charset) Removes all bytes from this, decodes them as charset, and returns the string.
String	readString(long byteCount, Charset charset) Removes byteCount bytes from this, decodes them as charset, and returns the string.
String	readUtf8() Removes all bytes from this, decodes them as UTF-8, and returns the string.
String	readUtf8(long byteCount) Removes byteCount bytes from this, decodes them as UTF-8, and returns the string.
int	readUtf8CodePoint() Removes and returns a single UTF-8 code point, reading between 1 and 4 bytes as necessary.
String	readUtf8Line() Removes and returns characters up to but not including the next line break.
String	readUtf8LineStrict() Removes and returns characters up to but not including the next line break.
String	readUtf8LineStrict(long limit) Like readUtf8LineStrict(), except this allows the caller to specify the longest allowed match.
boolean	request(long byteCount) Returns true when the buffer contains at least byteCount bytes, expanding it as necessary.
void	require(long byteCount) Returns when the buffer contains at least byteCount bytes.
int	select(Options options) Finds the first string in options that is a prefix of this buffer, consumes it from this buffer, and returns its index.
void	skip(long byteCount) Reads and discards byteCount bytes from this source.

Methods inherited from interface okio.Source

close, read, timeout

Method Detail

buffer

Buffer buffer()

Returns this source's internal buffer.

exhausted

boolean exhausted()
           throws IOException

Returns true if there are no more bytes in this source. This will block until there are bytes to read or the source is definitely exhausted.

Throws:

IOException

require

void require(long byteCount)
      throws IOException

Returns when the buffer contains at least byteCount bytes. Throws an EOFException if the source is exhausted before the required bytes can be read.

Throws:

IOException

request

boolean request(long byteCount)
         throws IOException

Returns true when the buffer contains at least byteCount bytes, expanding it as necessary. Returns false if the source is exhausted before the requested bytes can be read.

Throws:

IOException

readByte

byte readByte()
       throws IOException

Removes a byte from this source and returns it.

Throws:

IOException

readShort

short readShort()
         throws IOException

Removes two bytes from this source and returns a big-endian short.

   Buffer buffer = new Buffer()
       .writeByte(0x7f)
       .writeByte(0xff)
       .writeByte(0x00)
       .writeByte(0x0f);
   assertEquals(4, buffer.size());

   assertEquals(32767, buffer.readShort());
   assertEquals(2, buffer.size());

   assertEquals(15, buffer.readShort());
   assertEquals(0, buffer.size());
 

Throws:

IOException

readShortLe

short readShortLe()
           throws IOException

Removes two bytes from this source and returns a little-endian short.

   Buffer buffer = new Buffer()
       .writeByte(0xff)
       .writeByte(0x7f)
       .writeByte(0x0f)
       .writeByte(0x00);
   assertEquals(4, buffer.size());

   assertEquals(32767, buffer.readShortLe());
   assertEquals(2, buffer.size());

   assertEquals(15, buffer.readShortLe());
   assertEquals(0, buffer.size());
 

Throws:

IOException

readInt

int readInt()
     throws IOException

Removes four bytes from this source and returns a big-endian int.

   Buffer buffer = new Buffer()
       .writeByte(0x7f)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x0f);
   assertEquals(8, buffer.size());

   assertEquals(2147483647, buffer.readInt());
   assertEquals(4, buffer.size());

   assertEquals(15, buffer.readInt());
   assertEquals(0, buffer.size());
 

Throws:

IOException

readIntLe

int readIntLe()
       throws IOException

Removes four bytes from this source and returns a little-endian int.

   Buffer buffer = new Buffer()
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0x7f)
       .writeByte(0x0f)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x00);
   assertEquals(8, buffer.size());

   assertEquals(2147483647, buffer.readIntLe());
   assertEquals(4, buffer.size());

   assertEquals(15, buffer.readIntLe());
   assertEquals(0, buffer.size());
 

Throws:

IOException

readLong

long readLong()
       throws IOException

Removes eight bytes from this source and returns a big-endian long.

   Buffer buffer = new Buffer()
       .writeByte(0x7f)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x0f);
   assertEquals(16, buffer.size());

   assertEquals(9223372036854775807L, buffer.readLong());
   assertEquals(8, buffer.size());

   assertEquals(15, buffer.readLong());
   assertEquals(0, buffer.size());
 

Throws:

IOException

readLongLe

long readLongLe()
         throws IOException

Removes eight bytes from this source and returns a little-endian long.

   Buffer buffer = new Buffer()
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0xff)
       .writeByte(0x7f)
       .writeByte(0x0f)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x00)
       .writeByte(0x00);
   assertEquals(16, buffer.size());

   assertEquals(9223372036854775807L, buffer.readLongLe());
   assertEquals(8, buffer.size());

   assertEquals(15, buffer.readLongLe());
   assertEquals(0, buffer.size());
 

Throws:

IOException

readDecimalLong

long readDecimalLong()
              throws IOException

Reads a long from this source in signed decimal form (i.e., as a string in base 10 with optional leading '-'). This will iterate until a non-digit character is found.

   Buffer buffer = new Buffer()
       .writeUtf8("8675309 -123 00001");

   assertEquals(8675309L, buffer.readDecimalLong());
   assertEquals(' ', buffer.readByte());
   assertEquals(-123L, buffer.readDecimalLong());
   assertEquals(' ', buffer.readByte());
   assertEquals(1L, buffer.readDecimalLong());
 

Throws:

NumberFormatException - if the found digits do not fit into a long or a decimal number was not present.

IOException

readHexadecimalUnsignedLong

long readHexadecimalUnsignedLong()
                          throws IOException

Reads a long form this source in hexadecimal form (i.e., as a string in base 16). This will iterate until a non-hexadecimal character is found.

   Buffer buffer = new Buffer()
       .writeUtf8("ffff CAFEBABE 10");

   assertEquals(65535L, buffer.readHexadecimalUnsignedLong());
   assertEquals(' ', buffer.readByte());
   assertEquals(0xcafebabeL, buffer.readHexadecimalUnsignedLong());
   assertEquals(' ', buffer.readByte());
   assertEquals(0x10L, buffer.readHexadecimalUnsignedLong());
 

Throws:

NumberFormatException - if the found hexadecimal does not fit into a long or hexadecimal was not found.

IOException

skip

void skip(long byteCount)
   throws IOException

Reads and discards byteCount bytes from this source. Throws an EOFException if the source is exhausted before the requested bytes can be skipped.

Throws:

IOException

readByteString

ByteString readByteString()
                   throws IOException

Removes all bytes bytes from this and returns them as a byte string.

Throws:

IOException

readByteString

ByteString readByteString(long byteCount)
                   throws IOException

Removes byteCount bytes from this and returns them as a byte string.

Throws:

IOException

select

int select(Options options)
    throws IOException

Finds the first string in options that is a prefix of this buffer, consumes it from this buffer, and returns its index. If no byte string in options is a prefix of this buffer this returns -1 and no bytes are consumed.

This can be used as an alternative to readByteString() or even readUtf8() if the set of expected values is known in advance.

   Options FIELDS = Options.of(
       ByteString.encodeUtf8("depth="),
       ByteString.encodeUtf8("height="),
       ByteString.encodeUtf8("width="));

   Buffer buffer = new Buffer()
       .writeUtf8("width=640\n")
       .writeUtf8("height=480\n");

   assertEquals(2, buffer.select(FIELDS));
   assertEquals(640, buffer.readDecimalLong());
   assertEquals('\n', buffer.readByte());
   assertEquals(1, buffer.select(FIELDS));
   assertEquals(480, buffer.readDecimalLong());
   assertEquals('\n', buffer.readByte());
 

Throws:

IOException

readByteArray

byte[] readByteArray()
              throws IOException

Removes all bytes from this and returns them as a byte array.

Throws:

IOException

readByteArray

byte[] readByteArray(long byteCount)
              throws IOException

Removes byteCount bytes from this and returns them as a byte array.

Throws:

IOException

read

int read(byte[] sink)
  throws IOException

Removes up to sink.length bytes from this and copies them into sink. Returns the number of bytes read, or -1 if this source is exhausted.

Throws:

IOException

readFully

void readFully(byte[] sink)
        throws IOException

Removes exactly sink.length bytes from this and copies them into sink. Throws an EOFException if the requested number of bytes cannot be read.

Throws:

IOException

read

int read(byte[] sink,
         int offset,
         int byteCount)
  throws IOException

Removes up to byteCount bytes from this and copies them into sink at offset. Returns the number of bytes read, or -1 if this source is exhausted.

Throws:

IOException

readFully

void readFully(Buffer sink,
               long byteCount)
        throws IOException

Removes exactly byteCount bytes from this and appends them to sink. Throws an EOFException if the requested number of bytes cannot be read.

Throws:

IOException

readAll

long readAll(Sink sink)
      throws IOException

Removes all bytes from this and appends them to sink. Returns the total number of bytes written to sink which will be 0 if this is exhausted.

Throws:

IOException

readUtf8

String readUtf8()
         throws IOException

Removes all bytes from this, decodes them as UTF-8, and returns the string. Returns the empty string if this source is empty.

   Buffer buffer = new Buffer()
       .writeUtf8("Uh uh uh!")
       .writeByte(' ')
       .writeUtf8("You didn't say the magic word!");

   assertEquals("Uh uh uh! You didn't say the magic word!", buffer.readUtf8());
   assertEquals(0, buffer.size());

   assertEquals("", buffer.readUtf8());
   assertEquals(0, buffer.size());
 

Throws:

IOException

readUtf8

String readUtf8(long byteCount)
         throws IOException

Removes byteCount bytes from this, decodes them as UTF-8, and returns the string.

   Buffer buffer = new Buffer()
       .writeUtf8("Uh uh uh!")
       .writeByte(' ')
       .writeUtf8("You didn't say the magic word!");
   assertEquals(40, buffer.size());

   assertEquals("Uh uh uh! You ", buffer.readUtf8(14));
   assertEquals(26, buffer.size());

   assertEquals("didn't say the", buffer.readUtf8(14));
   assertEquals(12, buffer.size());

   assertEquals(" magic word!", buffer.readUtf8(12));
   assertEquals(0, buffer.size());
 

Throws:

IOException

readUtf8Line

@Nullable
String readUtf8Line()
                       throws IOException

Removes and returns characters up to but not including the next line break. A line break is either "\n" or "\r\n"; these characters are not included in the result.

   Buffer buffer = new Buffer()
       .writeUtf8("I'm a hacker!\n")
       .writeUtf8("That's what I said: you're a nerd.\n")
       .writeUtf8("I prefer to be called a hacker!\n");
   assertEquals(81, buffer.size());

   assertEquals("I'm a hacker!", buffer.readUtf8Line());
   assertEquals(67, buffer.size());

   assertEquals("That's what I said: you're a nerd.", buffer.readUtf8Line());
   assertEquals(32, buffer.size());

   assertEquals("I prefer to be called a hacker!", buffer.readUtf8Line());
   assertEquals(0, buffer.size());

   assertEquals(null, buffer.readUtf8Line());
   assertEquals(0, buffer.size());
 

On the end of the stream this method returns null, just like BufferedReader. If the source doesn't end with a line break then an implicit line break is assumed. Null is returned once the source is exhausted. Use this for human-generated data, where a trailing line break is optional.

Throws:

IOException

readUtf8LineStrict

String readUtf8LineStrict()
                   throws IOException

Removes and returns characters up to but not including the next line break. A line break is either "\n" or "\r\n"; these characters are not included in the result.

On the end of the stream this method throws. Every call must consume either '\r\n' or '\n'. If these characters are absent in the stream, an EOFException is thrown. Use this for machine-generated data where a missing line break implies truncated input.

Throws:

IOException

readUtf8LineStrict

String readUtf8LineStrict(long limit)
                   throws IOException

Like readUtf8LineStrict(), except this allows the caller to specify the longest allowed match. Use this to protect against streams that may not include "\n" or "\r\n".

The returned string will have at most limit UTF-8 bytes, and the maximum number of bytes scanned is limit + 2. If limit == 0 this will always throw an EOFException because no bytes will be scanned.

This method is safe. No bytes are discarded if the match fails, and the caller is free to try another match:

   Buffer buffer = new Buffer();
   buffer.writeUtf8("12345\r\n");

   // This will throw! There must be \r\n or \n at the limit or before it.
   buffer.readUtf8LineStrict(4);

   // No bytes have been consumed so the caller can retry.
   assertEquals("12345", buffer.readUtf8LineStrict(5));
 

Throws:

IOException

readUtf8CodePoint

int readUtf8CodePoint()
               throws IOException

Removes and returns a single UTF-8 code point, reading between 1 and 4 bytes as necessary.

If this source is exhausted before a complete code point can be read, this throws an EOFException and consumes no input.

If this source doesn't start with a properly-encoded UTF-8 code point, this method will remove 1 or more non-UTF-8 bytes and return the replacement character (U+FFFD). This covers encoding problems (the input is not properly-encoded UTF-8), characters out of range (beyond the 0x10ffff limit of Unicode), code points for UTF-16 surrogates (U+d800..U+dfff) and overlong encodings (such as 0xc080 for the NUL character in modified UTF-8).

Throws:

IOException

readString

String readString(Charset charset)
           throws IOException

Removes all bytes from this, decodes them as charset, and returns the string.

Throws:

IOException

readString

String readString(long byteCount,
                  Charset charset)
           throws IOException

Removes byteCount bytes from this, decodes them as charset, and returns the string.

Throws:

IOException

indexOf

long indexOf(byte b)
      throws IOException

Equivalent to indexOf(b, 0).

Throws:

IOException

indexOf

long indexOf(byte b,
             long fromIndex)
      throws IOException

Returns the index of the first b in the buffer at or after fromIndex. This expands the buffer as necessary until b is found. This reads an unbounded number of bytes into the buffer. Returns -1 if the stream is exhausted before the requested byte is found.

   Buffer buffer = new Buffer();
   buffer.writeUtf8("Don't move! He can't see us if we don't move.");

   byte m = 'm';
   assertEquals(6,  buffer.indexOf(m));
   assertEquals(40, buffer.indexOf(m, 12));
 

Throws:

IOException

indexOf

long indexOf(byte b,
             long fromIndex,
             long toIndex)
      throws IOException

Returns the index of b if it is found in the range of fromIndex inclusive to toIndex exclusive. If b isn't found, or if fromIndex == toIndex, then -1 is returned.

The scan terminates at either toIndex or the end of the buffer, whichever comes first. The maximum number of bytes scanned is toIndex-fromIndex.

Throws:

IOException

indexOf

long indexOf(ByteString bytes)
      throws IOException

Equivalent to indexOf(bytes, 0).

Throws:

IOException

indexOf

long indexOf(ByteString bytes,
             long fromIndex)
      throws IOException

Returns the index of the first match for bytes in the buffer at or after fromIndex. This expands the buffer as necessary until bytes is found. This reads an unbounded number of bytes into the buffer. Returns -1 if the stream is exhausted before the requested bytes are found.

   ByteString MOVE = ByteString.encodeUtf8("move");

   Buffer buffer = new Buffer();
   buffer.writeUtf8("Don't move! He can't see us if we don't move.");

   assertEquals(6,  buffer.indexOf(MOVE));
   assertEquals(40, buffer.indexOf(MOVE, 12));
 

Throws:

IOException

indexOfElement

long indexOfElement(ByteString targetBytes)
             throws IOException

Equivalent to indexOfElement(targetBytes, 0).

Throws:

IOException

indexOfElement

long indexOfElement(ByteString targetBytes,
                    long fromIndex)
             throws IOException

Returns the first index in this buffer that is at or after fromIndex and that contains any of the bytes in targetBytes. This expands the buffer as necessary until a target byte is found. This reads an unbounded number of bytes into the buffer. Returns -1 if the stream is exhausted before the requested byte is found.

   ByteString ANY_VOWEL = ByteString.encodeUtf8("AEOIUaeoiu");

   Buffer buffer = new Buffer();
   buffer.writeUtf8("Dr. Alan Grant");

   assertEquals(4,  buffer.indexOfElement(ANY_VOWEL));    // 'A' in 'Alan'.
   assertEquals(11, buffer.indexOfElement(ANY_VOWEL, 9)); // 'a' in 'Grant'.
 

Throws:

IOException

rangeEquals

boolean rangeEquals(long offset,
                    ByteString bytes)
             throws IOException

Returns true if the bytes at offset in this source equal bytes. This expands the buffer as necessary until a byte does not match, all bytes are matched, or if the stream is exhausted before enough bytes could determine a match.

   ByteString simonSays = ByteString.encodeUtf8("Simon says:");

   Buffer standOnOneLeg = new Buffer().writeUtf8("Simon says: Stand on one leg.");
   assertTrue(standOnOneLeg.rangeEquals(0, simonSays));

   Buffer payMeMoney = new Buffer().writeUtf8("Pay me $1,000,000.");
   assertFalse(payMeMoney.rangeEquals(0, simonSays));
 

Throws:

IOException

rangeEquals

boolean rangeEquals(long offset,
                    ByteString bytes,
                    int bytesOffset,
                    int byteCount)
             throws IOException

Returns true if byteCount bytes at offset in this source equal bytes at bytesOffset. This expands the buffer as necessary until a byte does not match, all bytes are matched, or if the stream is exhausted before enough bytes could determine a match.

Throws:

IOException

inputStream

InputStream inputStream()

Returns an input stream that reads from this source.