Package proguard.classfile.attribute.signature.parsing

Class ParserContext

java.lang.Object
proguard.classfile.attribute.signature.parsing.ParserContext
public final class ParserContext extends Object
An object for storing the data of a currently running parsing operation. Wraps the input string and also stores the current offset that is being parsed.

  • Constructor Summary

    Constructors
    Constructor
    Description
    ParserContext(String input)
    Initialize a new parser context from the given input string.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    advance(int amount)
    Consume the given number of characters.
    String
    chopFront(int length)
    Consume length characters from the input string, return them in a newly constructed string.
    void
    commit()
    Drop the last snapshot, use the currently valid parser state.
    int
    indexOf(char c)
    Returns first index of a given character in the remaining part of the input string.
    char
    peekChar(int offset)
    Look-ahead at the input string.
    char
    peekCharUnchecked(int offset)
    Same as peekChar(int), but doesn't check for the end of the string.
    int
    remainingLength()
     
    void
    revert()
    Reverts to the last valid snapshot.
    void
    snapshot()
    Take a snapshot of the current state of the parser.
    boolean
    startsWith(String prefix)
    Tests whether the current state starts with the given string.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • ParserContext

      public ParserContext(String input)
      Initialize a new parser context from the given input string. Used for starting a new parser pass.
      Parameters:
      input - The input string to parse.

  • Method Details

    • snapshot

      public void snapshot()
      Take a snapshot of the current state of the parser. Useful for handling recursion, where children could fail parsing.

      Always MUST be paired with one of revert() or commit().

    • commit

      public void commit()
      Drop the last snapshot, use the currently valid parser state.

    • revert

      public void revert()
      Reverts to the last valid snapshot.

    • peekChar

      public char peekChar(int offset) throws EOFException
      Look-ahead at the input string.
      Parameters:
      offset - The number of characters that should be skipped. E.g. 0 means look at the currently parsed character.
      Returns:
      The character at the proper offset in the input.
      Throws:
      EOFException - When the read attempts to read anything past the end of the input string.

    • peekCharUnchecked

      public char peekCharUnchecked(int offset)
      Same as peekChar(int), but doesn't check for the end of the string. Useful in loops bounded by remainingLength() to avoid the need for a try-catch block.
      Parameters:
      offset - The offset of the character to look at.
      Returns:
      The character at the given position.

    • advance

      public void advance(int amount)
      Consume the given number of characters.
      Parameters:
      amount - The number of characters to consider parsed.

    • remainingLength

      public int remainingLength()
      Returns:
      The remaining length of the input string.

    • chopFront

      public String chopFront(int length)
      Consume length characters from the input string, return them in a newly constructed string.
      Parameters:
      length - The number of characters to consume from the beginning. (The method just calls advance(int) internally with this number.)
      Returns:
      A string of length length that appears at the current position in the input.

    • startsWith

      public boolean startsWith(String prefix)
      Tests whether the current state starts with the given string.
      Parameters:
      prefix - The prefix we are checking for.
      Returns:
      True if the current input at the current offset starts with the given string.

    • indexOf

      public int indexOf(char c)
      Returns first index of a given character in the remaining part of the input string.
      Parameters:
      c - The character to search for.
      Returns:
      The offset of the character from the current position, or -1 if not found.