AbstractFileReaderAndWriter.java
/*
* Copyright (C) 2012 Alberto Irurueta Carro (alberto@irurueta.com)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.irurueta.geometry.io;
import java.io.Closeable;
import java.io.IOException;
/**
* Abstract class that provides methods to access file data at random positions.
*/
public abstract class AbstractFileReaderAndWriter implements Closeable {
/**
* Reads one byte at current file position and advances one position.
*
* @return Next byte of data or -1 if end of file is reached.
* @throws IOException if an I/O error occurs. Not thrown if end-of-file has
* been reached.
*/
public abstract int read() throws IOException;
/**
* Reads up to b.length bytes of data from this file into an array of bytes.
* This method blocks until at least one byte of input is available.
*
* @param b The buffer into which the data is read.
* @return The total number of bytes read into the buffer, or -1 if there is
* no more data because the end of the file has been reached.
* @throws IOException If the first byte cannot be read for any reason other
* than end of file, or if the file has been closed, or if some other I/O
* error occurs.
*/
public abstract int read(final byte[] b) throws IOException;
/**
* Reads up to len bytes of data from this file into an array of bytes. This
* method blocks until at least one byte of input is available.
* This method behaves in exactly the same way as the
* InputStream.read(byte[], int, int) method of InputStream.
*
* @param b the buffer into which the data is read.
* @param off the start offset in array b at which the data is written.
* @param len the maximum number of bytes read.
* @return the total number of bytes read into the buffer, or -1 if there is
* no more data because the end of the file has been reached.
* @throws IOException If the first byte cannot be read for any reason other
* than end of file, or if the random access file has been closed, or if
* some other I/O error occurs.
*/
public abstract int read(final byte[] b, final int off, final int len) throws IOException;
/**
* Attempts to skip over n byte of input discarding the skipped bytes.
* <p>
* This method may skip over some number of bytes, possibly zero. This may
* result from any of a number of conditions; reaching end of file before n
* bytes have been skipped is only one possibility. The actual number of
* bytes skipped is returned. If n is negative, no bytes are skipped.
*
* @param n the number of bytes to be skipped.
* @return the actual number of bytes skipped.
* @throws IOException if an I/O error occurs.
*/
public abstract long skip(final long n) throws IOException;
/**
* Writes the specified byte to this file. The write starts at the current
* file pointer.
*
* @param b the byte to be written.
* @throws IOException if an I/O error occurs.
*/
public abstract void write(final int b) throws IOException;
/**
* Writes b.length bytes from the specified byte array to this file,
* starting at the current file pointer.
*
* @param b the data.
* @throws IOException if an I/O error occurs.
*/
public abstract void write(final byte[] b) throws IOException;
/**
* Writes len bytes from the specified byte array starting at offset off to
* this file.
*
* @param b the data.
* @param off the start offset in the data.
* @param len the number of bytes to write.
* @throws IOException if an I/O error occurs.
*/
public abstract void write(final byte[] b, final int off, final int len) throws IOException;
/**
* Returns the current offset in this file.
*
* @return the offset from the beginning of the file, in bytes, at which the
* next read or write occurs.
* @throws IOException in an I/O error occurs.
*/
public abstract long getPosition() throws IOException;
/**
* Determines whether end of file has been reached (next read() will return
* -1). or not.
*
* @return True if end of file has been reached, false otherwise.
* @throws IOException if an I/O error occurs.
*/
public abstract boolean isEndOfStream() throws IOException;
/**
* Sets the file-pointer offset, measured from the beginning of this file,
* at which the next read or write occurs. The offset may be set beyond the
* end of the file. Setting the offset beyond the end of the file does not
* change the file length.
* The file length will change only by writing after the offset has been set
* beyond the end of the file.
*
* @param pos the offset position, measured in bytes from the beginning of
* the file, at which to set the file pointer.
* @throws IOException if pos is less than 0 or if an I/O error occurs.
*/
public abstract void seek(final long pos) throws IOException;
/**
* Reads a boolean from this file. This method reads a single byte from the
* file, starting at the current file pointer. A value of 0 represents
* false. Any other value represents true. This method blocks until the byte
* is read, the end of the stream is detected, or an exception is thrown.
*
* @return the boolean value read.
* @throws IOException if an I/O error occurs.
*/
public abstract boolean readBoolean() throws IOException;
/**
* Reads a signed eight-bit value from this file. This method reads a byte
* from the file, starting from the current file pointer. If the byte read
* is b, where 0 <= b <= 255, then the result is: (byte)(b)
* This method blocks until the byte is read, the end of the stream is
* detected, or an exception is thrown.
*
* @return the next byte of this file is a signed eight-bit byte.
* @throws IOException if an I/O error occurs.
*/
public abstract byte readByte() throws IOException;
/**
* Reads an unsigned eight-bit number from this file. This method reads a
* byte from this file, starting at the current file pointer, and returns
* that byte.
* This method blocks until the byte is read, the end of the stream is
* detected, or an exception is thrown.
*
* @return the next byte of this file, interpreted as an unsigned eight-bit
* number.
* @throws IOException if an I/O error occurs.
*/
public abstract short readUnsignedByte() throws IOException;
/**
* Reads a signed 16-bit number from this file. The method reads two byte
* from this file, starting at the current file pointer. If the two bytes
* read, in order, are b1 and b2, where each of the two values is between 0
* and 255, inclusive, then the result is equal to: (short)(b1 << 8 |
* b2).
* This method blocks until the two bytes are read, the end of the stream is
* detected, or an exception is thrown.
*
* @return the next two bytes of this file, interpreted as a signed 16-bit
* number.
* @throws IOException if an I/O error occurs.
*/
public abstract short readShort() throws IOException;
/**
* Reads a signed 16-bit number from this file assuming that file is encoded
* using provided endian type. If endian type is big endian type, then
* natural binary order is preserved, otherwise byte order is reversed.
* This method blocks until the two bytes of the 16-bit number are read, the
* end of the stream is detected, or an exception is thrown.
*
* @param endianType Endian type. Big endian preserves natural binary order,
* little endian reverses byte order.
* @return the next two bytes of this file, interpreted as a signed 16-bit
* number encoded in provided endian type.
* @throws IOException if an I/O error occurs.
*/
public abstract short readShort(final EndianType endianType) throws IOException;
/**
* Reads an unsigned 16-bit number from this file. This method reads two
* bytes from this file, starting at the current file pointer. If the bytes
* read, in order, are b1 and b2, where 0 <= b1, b2 <= 255, then the
* result is equal to: (b1 << 8) | b2
* This method blocks until the two bytes are read, the end of the stream is
* detected, or an exception is thrown.
*
* @return the next two bytes of this file, interpreted as an unsigned
* 16-bit integer.
* @throws IOException if an I/O error occurs.
*/
public abstract int readUnsignedShort() throws IOException;
/**
* Reads an unsigned 16-bit number from this file. This method reads two
* bytes from this file, starting at the current file pointer and using
* provided endian type. If endian type is big endian, then natural binary
* order is preserved, otherwise byte order is reversed.
* This method blocks until the two bytes are read, the end of the stream is
* detected, or an exception is thrown.
*
* @param endianType Endian type. Big endian preserves natural binary order,
* little endian reverses byte order.
* @return the next two bytes of this file, interpreted as an unsigned
* 16-bit integer.
* @throws IOException if an I/O error occurs.
*/
public abstract int readUnsignedShort(final EndianType endianType)
throws IOException;
/**
* Reads a signed 32-bit integer from this file. This method reads 4 bytes
* from the file, starting at the current file pointer. If the bytes read,
* in order, are b1, b2, b3, and b4, where 0 <= b1, b3, b4 <= 255, then
* the result is equal to: (b1 << 24) | (b2 << 16) + (b3 << 8) +
* b4.
* This method blocks until the four bytes are read, the end of the stream
* is detected, or an exception is thrown.
*
* @return the next four bytes of this file, interpreted as an int.
* @throws IOException if an I/O error occurs.
*/
public abstract int readInt() throws IOException;
/**
* Reads a signed 32-bit integer from this file. This method reads 4 bytes
* from the file, starting at the current file pointer and using provided
* endian type. If endian type is big endian, then natural binary order is
* preserved, otherwise byte order is reversed.
* This method blocks until the four bytes are read, the end of the stream
* is detected, or an exception is thrown.
*
* @param endianType Endian type. Big endian preserves natural binary order,
* little endian reverses byte order.
* @return the next four bytes of this file, interpreted as an int.
* @throws IOException if an I/O error occurs.
*/
public abstract int readInt(final EndianType endianType) throws IOException;
/**
* Reads an unsigned 32-bit integer from this file. This method reads 4
* bytes from the file, starting at the current file pointer. If the bytes
* read, in order, are b1, b2, b3, and b4, where 0 <= b1, b3, b4 <= 255,
* then the result is equal to: (b1 << 24) | (b2 << 16) +
* (b3 << 8) + b4
* This method blocks until the four bytes are read, the end of the stream
* is detected, or an exception is thrown.
*
* @return the next four bytes of this file, interpreted as a long.
* @throws IOException if an I/O error occurs.
*/
public abstract long readUnsignedInt() throws IOException;
/**
* Reads an unsigned 32-bit integer from this file. This method reads 4
* bytes from the file, starting at the current file pointer and using
* provided endian type. If endian type is big endian, then natural binary
* order is preserved, otherwise byte order is reversed.
* This method blocks until the four bytes are read, the end of the stream
* is detected, or an exception is thrown.
*
* @param endianType Endian type. Big endian preserves natural binary order,
* little endian reverses byte order.
* @return the next four bytes of this file, interpreted as an int.
* @throws IOException if an I/O error occurs.
*/
public abstract long readUnsignedInt(final EndianType endianType)
throws IOException;
/**
* Reads a signed 64-bit integer from this file. This method reads eight
* bytes from the file, starting at the current file pointer. If the bytes
* read, in order, are b1, b2, b3, b4, b5, b6, b7, and b8, where:
* 0 <= b1, b2, b3, b4. b5. b6. b7. b8 <= 255,
* then the result is equal to:
* ((long)b1 << 56) + ((long)b2 << 48)
* + ((long)b3 << 40) + ((long)b4 << 32)
* + ((long)b5 << 24) + ((long)b6 << 16)
* + ((long)b7 << 8) + b8
* This method blocks until the eight bytes are read, the end of the stream
* is detected, or an exception is thrown.
*
* @return the next eight bytes of this file, interpreted as a long.
* @throws IOException if an I/O error occurs.
*/
public abstract long readLong() throws IOException;
/**
* Reads a signed 64-bit integer from this file. This method reads eight
* bytes from the file, starting at the current file pointer and using
* provided endian type. If endian type is big endian, then natural binary
* order is preserved, otherwise byte order is reversed.
* This method blocks until the eight bytes are read, the end of the stream
* is detected, or an exception is thrown.
*
* @param endianType Endian type. Big endian preserves natural binary order,
* little endian reverses byte order.
* @return the next eight bytes of this file, interpreted as a long
* @throws IOException if an I/O error occurs.
*/
public abstract long readLong(final EndianType endianType) throws IOException;
/**
* Reads a float from this file. This method reads an int value, starting at
* the current file pointer, as if by the readInt method and then converts
* that in to a float using the intBitsToFloat method in class Float.
* This method blocks until the four bytes are read, the end of the stream
* is detected, or an exception is thrown.
*
* @return the next four bytes of this file, interpreted as a float.
* @throws IOException if an I/O error occurs.
*/
public abstract float readFloat() throws IOException;
/**
* Reads a float from this file. This method reads four bytes using
* provided endian type. If endian type is big endian, then natural binary
* order is preserved, otherwise byte order is reversed.
* This method blocks until the four bytes are read, the end of the stream
* is detected, or an exception is thrown.
*
* @param endianType Endian type. Big endian preserves natural binary order,
* little endian reverses byte order.
* @return the next four bytes of this file, interpreted as a float.
* @throws IOException if an I/O error occurs.
*/
public abstract float readFloat(final EndianType endianType) throws IOException;
/**
* Reads a double from this file. This method reads a long value, starting
* at the current file pointer, as if by the readLong method and then
* converts that long to a double using the longBitsToDouble method in class
* Double.
* This method blocks until the eight bytes are read, the end of the stream
* is detected, or an exception is thrown.
*
* @return the next eight bytes of this file, interpreted as a double.
* @throws IOException if an I/O error occurs.
*/
public abstract double readDouble() throws IOException;
/**
* Reads a double from this file. This method reads eight bytes using
* provided endian type. If endian type is big endian, then natural binary
* order is preserved, otherwise byte order is reversed.
* This method blocks until the eight bytes are read, the end of the stream
* is detected, or an exception is thrown.
*
* @param endianType Endian type. Big endian preserves natural binary order,
* little endian reverses byte order.
* @return the next eight bytes of this file, interpreted as a double.
* @throws IOException if an I/O error occurs.
*/
public abstract double readDouble(final EndianType endianType) throws IOException;
/**
* Reads the next line of text from this file. This method successively
* reads bytes from the file, starting at the current file pointer, until it
* reaches a line terminator of the end of the file. Each byte is converted
* into a character by taking the byte's value for the lower eight bits of
* the character and setting the high eight bits of the character to zero.
* This method does not, therefore, support the full Unicode character set.
* A line of text is terminated by a carriage-return character ('\r'), a
* newline character('\n'), a carriage-return character immediately followed
* by a newline character, or the end of the file. Line-terminating
* characters are discarded and are not included as part of the string
* returned.
* This method blocks until a newline character is read, a carriage return
* and the byte following it are read (to see if it is a newline), the end
* of the file is reached, or an exception is thrown.
*
* @return the next line of text from this file, or null if end of file is
* encountered before even one byte is read.
* @throws IOException if an I/O error occurs.
*/
public abstract String readLine() throws IOException;
/**
* Sequentially reads characters starting at current file position until
* either carriage return, new line, tab or space character is found.
* The result is considered a word and it is returned.
*
* @return Next work starting at current file position or null if end of
* stream is reached.
* @throws IOException if an I/O error occurs.
*/
public String readWord() throws IOException {
// reads until space, line feed, carriage return or tab is found
if (isEndOfStream()) {
return null;
} else {
return readUntilAnyOfTheseCharactersIsFound(" \r\n\t");
}
}
/**
* Sequentially reads characters starting at current file position until one
* of the characters in provided pattern is found.
* All characters read so far will be returned without including any of the
* pattern characters.
*
* @param pattern Stop characters to stop reading when they are found.
* @return String read so far until any of the pattern characters was found.
* @throws IOException if an I/O error occurs.
* @throws IllegalArgumentException if no pattern characters are provided.
*/
public abstract String readUntilAnyOfTheseCharactersIsFound(final String pattern)
throws IOException;
/**
* Writes a boolean to the file as a one-byte value. The value true is
* written out as the value (byte)1; the value false is written out as the
* value (byte)0. The write starts at the current position of the file
* pointer.
*
* @param v a boolean value to be written.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeBoolean(final boolean v) throws IOException;
/**
* Writes a byte to the file as a one-byte value. The write starts at the
* current position of the file pointer.
*
* @param v a byte value to be written.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeByte(final byte v) throws IOException;
/**
* Writes provided value in the range 0-255 as an unsigned byte. The write
* starts at the current position of the file pointer.
*
* @param v a value to be written as an unsigned byte.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeUnsignedByte(final short v) throws IOException;
/**
* Writes a short to the file as two bytes, high byte first. The write
* starts at the current position of the file pointer.
*
* @param v a short to be written.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeShort(final short v) throws IOException;
/**
* Writes a short to the file as two bytes using provided endian type.
* If endian type is big endian, then natural byte order is preserved (and
* high byte is written first), if little endian order is chosen, then byte
* order is reversed.
*
* @param v a short to be written.
* @param endianType endian type. If it is big endian, natural byte order is
* preserved, otherwise byte order is reversed.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeShort(final short v, final EndianType endianType)
throws IOException;
/**
* Writes an unsigned short to the file as two bytes, high byte first.
* Provided integer value is converted to an unsigned short by taking into
* account only the two lower bytes. The write starts at the current
* position of the file pointer.
*
* @param v an unsigned short to be written (int is converted to unsigned
* short).
* @throws IOException if an I/O error occurs.
*/
public abstract void writeUnsignedShort(final int v) throws IOException;
/**
* Writes an unsigned short to the file as two bytes, using provided endian
* type.
* Provided integer value is converted to an unsigned short by taking into
* account only the two lower bytes.
* If endian type is big endian, then natural byte order is preserved (and
* high byte is written first), if little endian order is chosen, then byte
* order is reversed.
* The write starts at the current position of the file pointer.
*
* @param v an unsigned short to be written (int is converted to unsigned
* short).
* @param endianType endian type. If it is big endian, natural byte order is
* preserved, otherwise byte order is reversed.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeUnsignedShort(final int v, final EndianType endianType)
throws IOException;
/**
* Writes an int to the file as four bytes, high byte first. The write
* starts at the current position of the file pointer.
*
* @param v an int to be written.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeInt(final int v) throws IOException;
/**
* Writes an int to the file as four bytes, using provided endian type.
* If endian type is big endian, then natural byte order is preserved (and
* high byte is written first), if little endian order is chosen, then byte
* order is reversed.
* The write starts at the current position of the file pointer.
*
* @param v an int to be written.
* @param endianType endian type. If it is big endian, natural byte order is
* preserved, otherwise byte order is reversed.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeInt(final int v, final EndianType endianType)
throws IOException;
/**
* Writes an unsigned int to the file as four bytes, high byte first.
* Provided integer value is converted to an unsigned int by taking into
* account only the four lower bytes. The write starts at the current
* position of the file pointer.
*
* @param v an unsigned int to be written (long is converted to unsigned
* int).
* @throws IOException if an I/O error occurs.
*/
public abstract void writeUnsignedInt(final long v) throws IOException;
/**
* Writes an unsigned int to the file as four bytes, using provided endian
* type.
* Provided integer value is converted to an unsigned int by taking into
* account only the four lower bytes.
* If endian type is big endian, then natural byte order is preserved (and
* high byte is written first), if little endian order is chosen, then byte
* order is reversed.
* The write starts at the current position of the file pointer.
*
* @param v an unsigned int to be written (long is converted to unsigned
* short).
* @param endianType endian type. If it is big endian, natural byte order is
* preserved, otherwise byte order is reversed.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeUnsignedInt(final long v, final EndianType endianType)
throws IOException;
/**
* Writes a long to the file as eight bytes, high byte first. The write
* starts at the current position of the file pointer.
*
* @param v a long to be written.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeLong(final long v) throws IOException;
/**
* Writes a long to the file as eight bytes, using provided endian type.
* If endian type is big endian, then natural byte order is preserved (and
* high byte is written first), if little endian order is chosen, then byte
* order is reversed.
* The write starts at the current position of the file pointer.
*
* @param v a long to be written.
* @param endianType endian type. If it is big endian, natural byte order is
* preserved, otherwise byte order is reversed.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeLong(final long v, final EndianType endianType)
throws IOException;
/**
* Converts the float argument to an int using the floatToIntBits method in
* class Float, and then write that int value to the file as a four-byte
* quantity, high byte first. The write starts at the current position of
* the file pointer.
*
* @param v a float value to be written.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeFloat(final float v) throws IOException;
/**
* Converts the float argument to an int using the floatToIntBits method in
* class Float, and then write that int value to the file as a four-byte
* quantity, using provided endian type.
* If endian type is big endian, then natural byte order is preserved (and
* high byte is written first), if little endian order is chosen, then byte
* order is reversed.
* The write starts at the current position of the file pointer.
*
* @param v a float value to be written.
* @param endianType endian type. If it is big endian, natural byte order is
* preserved, otherwise byte order is reversed.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeFloat(final float v, final EndianType endianType)
throws IOException;
/**
* Converts the double argument to a long using the doubleToLongBits method
* in class Double, and then writes that long value to the file as an eight
* byte quantity, high byte first. The write starts at the current position
* of the file pointer.
*
* @param v a double value to be written.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeDouble(final double v) throws IOException;
/**
* Converts the double argument to a long using the doubleToLongBits method
* in class Double, and then writes that long value to the file as an eight
* byte quantity, using provided endian type.
* If endian type is big endian, then natural byte order is preserved (and
* high byte is written first), if little endian order is chosen, then byte
* order is reversed.
* The write starts at the current position of the file pointer.
*
* @param v a double value to be written.
* @param endianType endian type. If it is big endian, natural byte order is
* preserved, otherwise byte order is reversed.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeDouble(final double v, final EndianType endianType)
throws IOException;
/**
* Writes the string to the file as a sequence of bytes. Each character in
* the string is written out, in sequence, by discarding its high eight
* bits. The write starts at the current position of the file pointer.
*
* @param s a string of bytes to be written.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeASCII(final String s) throws IOException;
}