Package org.h2.mvstore

Class DataUtils

java.lang.Object
org.h2.mvstore.DataUtils
public final class DataUtils extends Object
Utility methods

  • Field Details

    • ERROR_READING_FAILED

      public static final int ERROR_READING_FAILED
      An error occurred while reading from the file.
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    • ERROR_WRITING_FAILED

      public static final int ERROR_WRITING_FAILED
      An error occurred when trying to write to the file.
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    • ERROR_INTERNAL

      public static final int ERROR_INTERNAL
      An internal error occurred. This could be a bug, or a memory corruption (for example caused by out of memory).
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    • ERROR_CLOSED

      public static final int ERROR_CLOSED
      The object is already closed.
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    • ERROR_UNSUPPORTED_FORMAT

      public static final int ERROR_UNSUPPORTED_FORMAT
      The file format is not supported.
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    • ERROR_FILE_CORRUPT

      public static final int ERROR_FILE_CORRUPT
      The file is corrupt or (for encrypted files) the encryption key is wrong.
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    • ERROR_FILE_LOCKED

      public static final int ERROR_FILE_LOCKED
      The file is locked.
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    • ERROR_SERIALIZATION

      public static final int ERROR_SERIALIZATION
      An error occurred when serializing or de-serializing.
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    • ERROR_CHUNK_NOT_FOUND

      public static final int ERROR_CHUNK_NOT_FOUND
      The application was trying to read data from a chunk that is no longer available.
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    • ERROR_BLOCK_NOT_FOUND

      public static final int ERROR_BLOCK_NOT_FOUND
      The block in the stream store was not found.
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    • ERROR_TRANSACTION_CORRUPT

      public static final int ERROR_TRANSACTION_CORRUPT
      The transaction store is corrupt.
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    • ERROR_TRANSACTION_LOCKED

      public static final int ERROR_TRANSACTION_LOCKED
      An entry is still locked by another transaction.
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    • ERROR_TOO_MANY_OPEN_TRANSACTIONS

      public static final int ERROR_TOO_MANY_OPEN_TRANSACTIONS
      There are too many open transactions.
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    • ERROR_TRANSACTION_ILLEGAL_STATE

      public static final int ERROR_TRANSACTION_ILLEGAL_STATE
      The transaction store is in an illegal state (for example, not yet initialized).
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    • ERROR_TRANSACTION_TOO_BIG

      public static final int ERROR_TRANSACTION_TOO_BIG
      The transaction contains too many changes.
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    • ERROR_TRANSACTIONS_DEADLOCK

      public static final int ERROR_TRANSACTIONS_DEADLOCK
      Deadlock discovered and one of transactions involved chosen as victim and rolled back.
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    • ERROR_UNKNOWN_DATA_TYPE

      public static final int ERROR_UNKNOWN_DATA_TYPE
      The transaction store can not be initialized because data type is not found in type registry.
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    • PAGE_TYPE_LEAF

      public static final int PAGE_TYPE_LEAF
      The type for leaf page.
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    • PAGE_TYPE_NODE

      public static final int PAGE_TYPE_NODE
      The type for node page.
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    • PAGE_COMPRESSED

      public static final int PAGE_COMPRESSED
      The bit mask for compressed pages (compression level fast).
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    • PAGE_COMPRESSED_HIGH

      public static final int PAGE_COMPRESSED_HIGH
      The bit mask for compressed pages (compression level high).
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    • COMPRESSED_VAR_INT_MAX

      public static final int COMPRESSED_VAR_INT_MAX
      The maximum integer that needs less space when using variable size encoding (only 3 bytes instead of 4).
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    • COMPRESSED_VAR_LONG_MAX

      public static final long COMPRESSED_VAR_LONG_MAX
      The maximum long that needs less space when using variable size encoding (only 7 bytes instead of 8).
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    • PAGE_LARGE

      public static final int PAGE_LARGE
      The marker size of a very large page.
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    • META_CHUNK

      public static final String META_CHUNK
      The prefix for chunks ("chunk."). This, plus the chunk id (hex encoded) is the key, and the serialized chunk metadata is the value.
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    • META_ROOT

      public static final String META_ROOT
      The prefix for root positions of maps ("root."). This, plus the map id (hex encoded) is the key, and the position (hex encoded) is the value.
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    • META_NAME

      public static final String META_NAME
      The prefix for names ("name."). This, plus the name of the map, is the key, and the map id (hex encoded) is the value.
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    • META_MAP

      public static final String META_MAP
      The prefix for maps ("map."). This, plus the map id (hex encoded) is the key, and the serialized in the map metadata is the value.
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  • Constructor Details

    • DataUtils

      public DataUtils()

  • Method Details

    • getVarIntLen

      public static int getVarIntLen(int x)
      Get the length of the variable size int.
      Parameters:
      x - the value
      Returns:
      the length in bytes

    • getVarLongLen

      public static int getVarLongLen(long x)
      Get the length of the variable size long.
      Parameters:
      x - the value
      Returns:
      the length in bytes

    • readVarInt

      public static int readVarInt(ByteBuffer buff)
      Read a variable size int.
      Parameters:
      buff - the source buffer
      Returns:
      the value

    • readVarLong

      public static long readVarLong(ByteBuffer buff)
      Read a variable size long.
      Parameters:
      buff - the source buffer
      Returns:
      the value

    • writeVarInt

      public static void writeVarInt(OutputStream out, int x) throws IOException
      Write a variable size int.
      Parameters:
      out - the output stream
      x - the value
      Throws:
      IOException - if some data could not be written

    • writeVarInt

      public static void writeVarInt(ByteBuffer buff, int x)
      Write a variable size int.
      Parameters:
      buff - the source buffer
      x - the value

    • writeStringData

      public static void writeStringData(ByteBuffer buff, String s, int len)
      Write characters from a string (without the length).
      Parameters:
      buff - the target buffer (must be large enough)
      s - the string
      len - the number of characters

    • readString

      public static String readString(ByteBuffer buff)
      Read a string.
      Parameters:
      buff - the source buffer
      Returns:
      the value

    • readString

      public static String readString(ByteBuffer buff, int len)
      Read a string.
      Parameters:
      buff - the source buffer
      len - the number of characters
      Returns:
      the value

    • writeVarLong

      public static void writeVarLong(ByteBuffer buff, long x)
      Write a variable size long.
      Parameters:
      buff - the target buffer
      x - the value

    • writeVarLong

      public static void writeVarLong(OutputStream out, long x) throws IOException
      Write a variable size long.
      Parameters:
      out - the output stream
      x - the value
      Throws:
      IOException - if some data could not be written

    • copyWithGap

      public static void copyWithGap(Object src, Object dst, int oldSize, int gapIndex)
      Copy the elements of an array, with a gap.
      Parameters:
      src - the source array
      dst - the target array
      oldSize - the size of the old array
      gapIndex - the index of the gap

    • copyExcept

      public static void copyExcept(Object src, Object dst, int oldSize, int removeIndex)
      Copy the elements of an array, and remove one element.
      Parameters:
      src - the source array
      dst - the target array
      oldSize - the size of the old array
      removeIndex - the index of the entry to remove

    • readFully

      public static void readFully(FileChannel file, long pos, ByteBuffer dst)
      Read from a file channel until the buffer is full. The buffer is rewind after reading.
      Parameters:
      file - the file channel
      pos - the absolute position within the file
      dst - the byte buffer
      Throws:
      MVStoreException - if some data could not be read

    • writeFully

      public static void writeFully(FileChannel file, long pos, ByteBuffer src)
      Write to a file channel.
      Parameters:
      file - the file channel
      pos - the absolute position within the file
      src - the source buffer

    • encodeLength

      public static int encodeLength(int len)
      Convert the length to a length code 0..31. 31 means more than 1 MB.
      Parameters:
      len - the length
      Returns:
      the length code

    • getPageChunkId

      public static int getPageChunkId(long pos)
      Get the chunk id from the position.
      Parameters:
      pos - the position
      Returns:
      the chunk id

    • getPageMapId

      public static int getPageMapId(long tocElement)
      Get the map id from the chunk's table of content element.
      Parameters:
      tocElement - packed table of content element
      Returns:
      the map id

    • getPageMaxLength

      public static int getPageMaxLength(long pos)
      Get the maximum length for the given page position.
      Parameters:
      pos - the position
      Returns:
      the maximum length

    • decodePageLength

      public static int decodePageLength(int code)
      Get the maximum length for the given code. For the code 31, PAGE_LARGE is returned.
      Parameters:
      code - encoded page length
      Returns:
      the maximum length

    • getPageOffset

      public static int getPageOffset(long tocElement)
      Get the offset from the position.
      Parameters:
      tocElement - packed table of content element
      Returns:
      the offset

    • getPageType

      public static int getPageType(long pos)
      Get the page type from the position.
      Parameters:
      pos - the position
      Returns:
      the page type (PAGE_TYPE_NODE or PAGE_TYPE_LEAF)

    • isLeafPosition

      public static boolean isLeafPosition(long pos)
      Determines whether specified file position corresponds to a leaf page
      Parameters:
      pos - the position
      Returns:
      true if it is a leaf, false otherwise

    • isPageSaved

      public static boolean isPageSaved(long pos)
      Find out if page was saved.
      Parameters:
      pos - the position
      Returns:
      true if page has been saved

    • composePagePos

      public static long composePagePos(int chunkId, int offset, int length, int type)
      Get the position of this page. The following information is encoded in the position: the chunk id, the page sequential number, the maximum length, and the type (node or leaf).
      Parameters:
      chunkId - the chunk id
      offset - the offset
      length - the length
      type - the page type (1 for node, 0 for leaf)
      Returns:
      the position

    • composePagePos

      public static long composePagePos(int chunkId, long tocElement)
      Convert tocElement into pagePos by replacing mapId with chunkId.
      Parameters:
      chunkId - the chunk id
      tocElement - the element
      Returns:
      the page position

    • composeTocElement

      public static long composeTocElement(int mapId, int offset, int length, int type)
      Create table of content element. The following information is encoded in it: the map id, the page offset, the maximum length, and the type (node or leaf).
      Parameters:
      mapId - the chunk id
      offset - the offset
      length - the length
      type - the page type (1 for node, 0 for leaf)
      Returns:
      the position

    • getCheckValue

      public static short getCheckValue(int x)
      Calculate a check value for the given integer. A check value is mean to verify the data is consistent with a high probability, but not meant to protect against media failure or deliberate changes.
      Parameters:
      x - the value
      Returns:
      the check value

    • appendMap

      public static StringBuilder appendMap(StringBuilder buff, HashMap<String,?> map)
      Append a map to the string builder, sorted by key.
      Parameters:
      buff - the target buffer
      map - the map
      Returns:
      the string builder

    • appendMap

      public static void appendMap(StringBuilder buff, String key, String value)
      Append a key-value pair to the string builder. Keys may not contain a colon. Values that contain a comma or a double quote are enclosed in double quotes, with special characters escaped using a backslash.
      Parameters:
      buff - the target buffer
      key - the key
      value - the value

    • appendMap

      public static void appendMap(StringBuilder buff, String key, long value)
      Append a key-value pair to the string builder. Keys may not contain a colon.
      Parameters:
      buff - the target buffer
      key - the key
      value - the value

    • appendMap

      public static void appendMap(StringBuilder buff, String key, int value)
      Append a key-value pair to the string builder. Keys may not contain a colon.
      Parameters:
      buff - the target buffer
      key - the key
      value - the value

    • parseMap

      public static HashMap<String,String> parseMap(String s)
      Parse a key-value pair list.
      Parameters:
      s - the list
      Returns:
      the map
      Throws:
      MVStoreException - if parsing failed

    • getMapName

      public static String getMapName(String s)
      Parse a name from key-value pair list.
      Parameters:
      s - the list
      Returns:
      value of name item, or null
      Throws:
      MVStoreException - if parsing failed

    • getFromMap

      public static String getFromMap(String s, String key)
      Parse a specified pair from key-value pair list.
      Parameters:
      s - the list
      key - the name of the key
      Returns:
      value of the specified item, or null
      Throws:
      MVStoreException - if parsing failed

    • getFletcher32

      public static int getFletcher32(byte[] bytes, int offset, int length)
      Calculate the Fletcher32 checksum.
      Parameters:
      bytes - the bytes
      offset - initial offset
      length - the message length (if odd, 0 is appended)
      Returns:
      the checksum

    • checkArgument

      public static void checkArgument(boolean test, String message, Object... arguments)
      Throw an IllegalArgumentException if the argument is invalid.
      Parameters:
      test - true if the argument is valid
      message - the message
      arguments - the arguments
      Throws:
      IllegalArgumentException - if the argument is invalid

    • newIllegalArgumentException

      public static IllegalArgumentException newIllegalArgumentException(String message, Object... arguments)
      Create a new IllegalArgumentException.
      Parameters:
      message - the message
      arguments - the arguments
      Returns:
      the exception

    • newUnsupportedOperationException

      public static UnsupportedOperationException newUnsupportedOperationException(String message)
      Create a new UnsupportedOperationException.
      Parameters:
      message - the message
      Returns:
      the exception

    • newMVStoreException

      public static MVStoreException newMVStoreException(int errorCode, String message, Object... arguments)
      Create a new MVStoreException.
      Parameters:
      errorCode - the error code
      message - the message
      arguments - the arguments
      Returns:
      the exception

    • formatMessage

      public static String formatMessage(int errorCode, String message, Object... arguments)
      Format an error message.
      Parameters:
      errorCode - the error code
      message - the message
      arguments - the arguments
      Returns:
      the formatted message

    • readHexLong

      public static long readHexLong(Map<String,?> map, String key, long defaultValue)
      Read a hex long value from a map.
      Parameters:
      map - the map
      key - the key
      defaultValue - if the value is null
      Returns:
      the parsed value
      Throws:
      MVStoreException - if parsing fails

    • parseHexLong

      public static long parseHexLong(String x)
      Parse an unsigned, hex long.
      Parameters:
      x - the string
      Returns:
      the parsed value
      Throws:
      MVStoreException - if parsing fails

    • parseHexInt

      public static int parseHexInt(String x)
      Parse an unsigned, hex long.
      Parameters:
      x - the string
      Returns:
      the parsed value
      Throws:
      MVStoreException - if parsing fails

    • convertToIOException

      public static IOException convertToIOException(Throwable e)
      Convert an exception to an IO exception.
      Parameters:
      e - the root cause
      Returns:
      the IO exception