Class ByteParser
- java.lang.Object
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- nom.tam.util.ByteParser
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public class ByteParser extends java.lang.Object
This class provides routines for efficient parsing of data stored in a byte array. This routine is optimized (in theory at least!) for efficiency rather than accuracy. The values read in for doubles or floats may differ in the last bit or so from the standard input utilities, especially in the case where a float is specified as a very long string of digits (substantially longer than the precision of the type).The get methods generally are available with or without a length parameter specified. When a length parameter is specified only the bytes with the specified range from the current offset will be search for the number. If no length is specified, the entire buffer from the current offset will be searched.
The getString method returns a string with leading and trailing white space left intact. For all other get calls, leading white space is ignored. If fillFields is set, then the get methods check that only white space follows valid data and a FormatException is thrown if that is not the case. If fillFields is not set and valid data is found, then the methods return having read as much as possible. E.g., for the sequence "T123.258E13", a getBoolean, getInteger and getFloat call would return true, 123, and 2.58e12 when called in succession.
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Constructor Summary
Constructors Constructor Description ByteParser(byte[] input)
Construct a parser.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
getBoolean()
boolean
getBoolean(int length)
byte[]
getBuffer()
double
getDouble()
Read in the buffer until a double is read.double
getDouble(int length)
float
getFloat()
float
getFloat(int length)
int
getInt()
int
getInt(int length)
long
getLong(int length)
int
getNumberLength()
int
getOffset()
Get the current offset.java.lang.String
getString(int length)
void
setBuffer(byte[] buf)
Set the buffer for the parser.void
setOffset(int offset)
Set the offset into the array.void
skip(int nBytes)
Skip bytes in the buffer.int
skipWhite(int length)
Skip white space.
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Method Detail
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getBoolean
public boolean getBoolean() throws FormatException
- Returns:
- a boolean value from the beginning of the buffer.
- Throws:
FormatException
- if the double was in an unknown format
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getBoolean
public boolean getBoolean(int length) throws FormatException
- Parameters:
length
- The maximum number of characters used to parse this boolean.- Returns:
- a boolean value from a specified region of the buffer
- Throws:
FormatException
- if the double was in an unknown format
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getBuffer
public byte[] getBuffer()
- Returns:
- the buffer being used by the parser
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getDouble
public double getDouble() throws FormatException
Read in the buffer until a double is read. This will read the entire buffer if fillFields is set.- Returns:
- The value found.
- Throws:
FormatException
- if the double was in an unknown format
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getDouble
public double getDouble(int length) throws FormatException
- Parameters:
length
- The maximum number of characters used to parse this number. If fillFields is specified then exactly only whitespace may follow a valid double value.- Returns:
- a parsed double from the buffer. Leading spaces are ignored.
- Throws:
FormatException
- if the double was in an unknown format
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getFloat
public float getFloat() throws FormatException
- Returns:
- a floating point value from the buffer. (see getDouble(int())
- Throws:
FormatException
- if the float was in an unknown format
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getFloat
public float getFloat(int length) throws FormatException
- Parameters:
length
- The maximum number of characters used to parse this float.- Returns:
- a floating point value in a region of the buffer
- Throws:
FormatException
- if the float was in an unknown format
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getInt
public int getInt() throws FormatException
- Returns:
- an integer at the beginning of the buffer
- Throws:
FormatException
- if the integer was in an unknown format
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getInt
public int getInt(int length) throws FormatException
- Parameters:
length
- The maximum number of characters used to parse this integer. @throws FormatException if the integer was in an unknown format- Returns:
- a region of the buffer to an integer
- Throws:
FormatException
- if the integer was in an unknown format
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getLong
public long getLong(int length) throws FormatException
- Parameters:
length
- The maximum number of characters used to parse this long.- Returns:
- a long in a specified region of the buffer
- Throws:
FormatException
- if the long was in an unknown format
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getNumberLength
public int getNumberLength()
- Returns:
- the number of characters used to parse the previous number (or the length of the previous String returned).
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getOffset
public int getOffset()
Get the current offset.- Returns:
- The current offset within the buffer.
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getString
public java.lang.String getString(int length)
- Parameters:
length
- The length of the string.- Returns:
- a string.
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setBuffer
public void setBuffer(byte[] buf)
Set the buffer for the parser.- Parameters:
buf
- buffer to set
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setOffset
public void setOffset(int offset)
Set the offset into the array.- Parameters:
offset
- The desired offset from the beginning of the array.
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skip
public void skip(int nBytes)
Skip bytes in the buffer.- Parameters:
nBytes
- number of bytes to skip
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skipWhite
public int skipWhite(int length)
Skip white space. This routine skips with space in the input .- Parameters:
length
- The maximum number of characters to skip.- Returns:
- the number of character skipped. White space is defined as ' ', '\t', '\n' or '\r'
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