net.sf.farrago.type.runtime
Class BytePointer

java.lang.Object
  java.io.InputStream
      java.io.ByteArrayInputStream
          net.sf.farrago.type.runtime.BytePointer

All Implemented Interfaces:

Closeable, CharSequence, AssignableValue, DataValue

Direct Known Subclasses:

EncodedCharPointer

public class BytePointer
extends ByteArrayInputStream
implements AssignableValue, CharSequence

BytePointer is instantiated during execution to refer to a contiguous subset of a byte array. It exists to avoid the need to instantiate a new object for each variable-width value read.

NOTE: BytePointer is not declared to implement NullableValue, although it actually provides the necessary method implementations. Instead, the NullableValue interface is declared by generated subclasses representing nullable types. This allows the presence of the NullableValue interface to be used in runtime contexts where we need to determine nullability but have lost explicit type information during code generation.

Version:

$Id: //open/dev/farrago/src/net/sf/farrago/type/runtime/BytePointer.java#39 $

Author:

John V. Sichi

Field Summary

static String	CONCAT_METHOD_NAME
static byte[]	emptyBytes Read-only global for 0-length byte array
static String	ENFORCE_PRECISION_METHOD_NAME
static String	GET_BYTE_COUNT_METHOD_NAME
static String	INITCAP_METHOD_NAME
protected int	L1
static String	LOWER_METHOD_NAME
static String	OVERLAY_METHOD_NAME
protected byte[]	ownBytes An allocate-on-demand array used when a new value must be created.
static String	POSITION_METHOD_NAME
protected int	S1 two temp variables to store the substring pointers
static String	SET_POINTER_METHOD_NAME
static String	SUBSTRING_METHOD_NAME
static String	TRIM_METHOD_NAME
static String	UPPER_METHOD_NAME

Fields inherited from class java.io.ByteArrayInputStream

buf, count, mark, pos

Fields inherited from interface net.sf.farrago.type.runtime.AssignableValue

ASSIGNMENT_METHOD_NAME

Constructor Summary

BytePointer()
Creates a new BytePointer object.

Method Summary

protected void	allocateOwnBytes(int n)
protected void	allocateOwnBytesForPrecision(int n)
void	assignFrom(Object obj) Assigns value from an Object.
long	attemptFastAsciiByteToLong() Attempts to convert this pointer's contents from a single-byte-ASCII-encoded integer string into a long.
protected void	calcSubstringPointers(int S, int L, int LC, boolean useLength)
void	cast(boolean b, int precision)
void	cast(double d, int precision)
void	cast(EncodedSqlDecimal d, int precision)
void	cast(float f, int precision)
void	cast(long l, int precision)
private void	castDecimal(long l, int precision, int scale) Casts a decimal into a string.
private void	castNoChecking(double d, int precision, boolean isFloat)
char	charAt(int index)
int	compareBytes(BytePointer other) Implementation for Comparable.compareTo() which assumes non-null and does byte-for-byte comparison.
void	concat(BytePointer bp1, BytePointer bp2) Assigns this pointer to the result of concatenating two input strings.
protected void	copyFrom(BytePointer bp1)
void	enforceBytePrecision(int precision, boolean needPad, byte padByte) Pads or truncates this value according to the given precision.
protected void	finishOverlay(BytePointer bp1, BytePointer bp2, int starting)
int	getByteCount()
protected int	getByteCountForPrecision(int n)
protected byte[]	getBytesForString(String string) Gets the byte representation of a string.
protected String	getCharsetName()
Object	getNullableData()
void	initcap(BytePointer bp1) initcap the string.
boolean	isNull()
int	length()
void	lower(BytePointer bp1) lower the case for each character of the string
void	overlay(BytePointer bp1, BytePointer bp2, int starting, int length, boolean useLength) Assigns this value to the result of inserting bp2's value into bp1's value at a specified starting point, possibly deleting a prefix of the remainder of bp1 of a given length.
int	position(BytePointer bp1)
protected int	positionImpl(BytePointer bp1, int bytesPerChar)
protected void	setCharAt(int index, char c)
void	setNull(boolean isNull)
void	setPointer(byte[] buf, int pos, int end) Sets the pointer to reference a buffer.
CharSequence	subSequence(int start, int end)
void	substring(int starting, int length, boolean useLength) Reduces the value to a substring of the current value.
String	toString()
void	trim(int trimOrdinal, BytePointer bp1, BytePointer bp2)
void	upper(BytePointer bp1) upper the case for each character of the string
void	writeToBuffer(ByteBuffer byteBuffer) Writes the contents of this pointer to a ByteBuffer.
void	writeToBufferAbsolute(ByteBuffer byteBuffer, int offset) Writes the contents of this pointer to a ByteBuffer at a given offset without modifying the current position.

Methods inherited from class java.io.ByteArrayInputStream

available, close, mark, markSupported, read, read, reset, skip

Methods inherited from class java.io.InputStream

read

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

ENFORCE_PRECISION_METHOD_NAME

public static final String ENFORCE_PRECISION_METHOD_NAME

See Also:

Constant Field Values

SET_POINTER_METHOD_NAME

public static final String SET_POINTER_METHOD_NAME

See Also:

Constant Field Values

GET_BYTE_COUNT_METHOD_NAME

public static final String GET_BYTE_COUNT_METHOD_NAME

See Also:

Constant Field Values

SUBSTRING_METHOD_NAME

public static final String SUBSTRING_METHOD_NAME

See Also:

Constant Field Values

OVERLAY_METHOD_NAME

public static final String OVERLAY_METHOD_NAME

See Also:

Constant Field Values

INITCAP_METHOD_NAME

public static final String INITCAP_METHOD_NAME

See Also:

Constant Field Values

CONCAT_METHOD_NAME

public static final String CONCAT_METHOD_NAME

See Also:

Constant Field Values

UPPER_METHOD_NAME

public static final String UPPER_METHOD_NAME

See Also:

Constant Field Values

LOWER_METHOD_NAME

public static final String LOWER_METHOD_NAME

See Also:

Constant Field Values

TRIM_METHOD_NAME

public static final String TRIM_METHOD_NAME

See Also:

Constant Field Values

POSITION_METHOD_NAME

public static final String POSITION_METHOD_NAME

See Also:

Constant Field Values

emptyBytes

public static final byte[] emptyBytes

Read-only global for 0-length byte array

ownBytes

protected byte[] ownBytes

An allocate-on-demand array used when a new value must be created.

S1

protected int S1

two temp variables to store the substring pointers

L1

protected int L1

Constructor Detail

BytePointer

public BytePointer()

Creates a new BytePointer object.

Method Detail

setNull

public void setNull(boolean isNull)

isNull

public boolean isNull()

getNullableData

public Object getNullableData()

Specified by:

getNullableData in interface DataValue

Returns:

an Object representation of this value's data, or null if this value is null

setPointer

public void setPointer(byte[] buf,
                       int pos,
                       int end)

Sets the pointer to reference a buffer.

Parameters:

buf - the buffer to point into

pos - position in buffer to point at

end - buffer position at which valid data ends

getCharsetName

protected String getCharsetName()

Returns:

the charset used for this pointer's encoding, or BINARY if no character data is encoded

assignFrom

public void assignFrom(Object obj)

Description copied from interface: AssignableValue

Assigns value from an Object.

Specified by:

assignFrom in interface AssignableValue

Parameters:

obj - value to assign, or null to set null

enforceBytePrecision

public void enforceBytePrecision(int precision,
                                 boolean needPad,
                                 byte padByte)

Pads or truncates this value according to the given precision.

Parameters:

precision - desired precision, in characters for character data, or bytes for binary data

needPad - true if short values should be padded

padByte - byte to pad with

substring

public void substring(int starting,
                      int length,
                      boolean useLength)

Reduces the value to a substring of the current value.

Parameters:

starting - desired starting position

length - the length.

useLength - to indicate whether length parameter should be used.

overlay

public void overlay(BytePointer bp1,
                    BytePointer bp2,
                    int starting,
                    int length,
                    boolean useLength)

Assigns this value to the result of inserting bp2's value into bp1's value at a specified starting point, possibly deleting a prefix of the remainder of bp1 of a given length. Implements the SQL string OVERLAY function.

Parameters:

bp1 - string1

bp2 - string2

starting - starting point

length - length

useLength - whether to use length parameter

finishOverlay

protected void finishOverlay(BytePointer bp1,
                             BytePointer bp2,
                             int starting)

concat

public void concat(BytePointer bp1,
                   BytePointer bp2)

Assigns this pointer to the result of concatenating two input strings.

Parameters:

bp1 - string1

bp2 - string2

getByteCount

public int getByteCount()

length

public int length()

Specified by:

length in interface CharSequence

setCharAt

protected void setCharAt(int index,
                         char c)

charAt

public char charAt(int index)

Specified by:

charAt in interface CharSequence

subSequence

public CharSequence subSequence(int start,
                                int end)

Specified by:

subSequence in interface CharSequence

upper

public void upper(BytePointer bp1)

upper the case for each character of the string

Parameters:

bp1 - string1

lower

public void lower(BytePointer bp1)

lower the case for each character of the string

Parameters:

bp1 - string1

initcap

public void initcap(BytePointer bp1)

initcap the string.

Parameters:

bp1 - string1

trim

public void trim(int trimOrdinal,
                 BytePointer bp1,
                 BytePointer bp2)

position

public int position(BytePointer bp1)

positionImpl

protected int positionImpl(BytePointer bp1,
                           int bytesPerChar)

copyFrom

protected void copyFrom(BytePointer bp1)

calcSubstringPointers

protected void calcSubstringPointers(int S,
                                     int L,
                                     int LC,
                                     boolean useLength)

Reference to SQL:2003 standard:

Part 2 Section 6.29 General Rule 3

allocateOwnBytes

protected void allocateOwnBytes(int n)

allocateOwnBytesForPrecision

protected void allocateOwnBytesForPrecision(int n)

getByteCountForPrecision

protected int getByteCountForPrecision(int n)

writeToBuffer

public final void writeToBuffer(ByteBuffer byteBuffer)

Writes the contents of this pointer to a ByteBuffer.

Parameters:

byteBuffer - target

writeToBufferAbsolute

public final void writeToBufferAbsolute(ByteBuffer byteBuffer,
                                        int offset)

Writes the contents of this pointer to a ByteBuffer at a given offset without modifying the current position.

Parameters:

byteBuffer - target

offset - starting byte offset within buffer

getBytesForString

protected byte[] getBytesForString(String string)

Gets the byte representation of a string. Subclasses may override.

Parameters:

string - source

Returns:

byte representation

compareBytes

public int compareBytes(BytePointer other)

Implementation for Comparable.compareTo() which assumes non-null and does byte-for-byte comparison.

Parameters:

other - another BytePointer to be compared

Returns:

same as compareTo

toString

public String toString()

Specified by:

toString in interface CharSequence

Overrides:

toString in class Object

cast

public void cast(float f,
                 int precision)

cast

public void cast(double d,
                 int precision)

castNoChecking

private void castNoChecking(double d,
                            int precision,
                            boolean isFloat)

cast

public void cast(boolean b,
                 int precision)

cast

public void cast(long l,
                 int precision)

cast

public void cast(EncodedSqlDecimal d,
                 int precision)

attemptFastAsciiByteToLong

public long attemptFastAsciiByteToLong()

Attempts to convert this pointer's contents from a single-byte-ASCII-encoded integer string into a long.

Returns:

converted value if successful, or Long.MAX_VALUE if unsuccessful (does not necessarily indicate that cast fails, just that this fast path can't handle it, e.g. negative/decimal/floating)

castDecimal

private void castDecimal(long l,
                         int precision,
                         int scale)

Casts a decimal into a string.

Parameters:

l - long value of decimal

precision - maximum length of string

scale - scale of decimal