Package org.apache.commons.compress.harmony.unpack200

Class SegmentConstantPool

  • public class SegmentConstantPool
extends java.lang.Object
    Manages the constant pool used for re-creating class files.

    • Constructor Detail

      • SegmentConstantPool

        public SegmentConstantPool​(CpBands bands)
        Constructs a new instance.
        Parameters:
        bands - Constant pool bands.

    • Method Detail

      • regexMatches

        protected static boolean regexMatches​(java.lang.String regexString,
                                      java.lang.String compareString)
        We don't want a dependency on regex in Pack200. The only place one exists is in matchSpecificPoolEntryIndex(). To eliminate this dependency, we've implemented the world's stupidest regexMatch. It knows about the two forms we care about: .* (aka REGEX_MATCH_ALL) ^<init>;.* (aka REGEX_MATCH_INIT) and will answer correctly if those are passed as the regexString.
        Parameters:
        regexString - String against which the compareString will be matched
        compareString - String to match against the regexString
        Returns:
        boolean true if the compareString matches the regexString; otherwise false.

      • getClassPoolEntry

        public ConstantPoolEntry getClassPoolEntry​(java.lang.String name)
                                    throws Pack200Exception
        Gets the CPClass associated with a class name. Returns null if the class doesn't exist.
        Parameters:
        name - Class name to look for (form: java/lang/Object)
        Returns:
        CPClass for that class name, or null if not found.
        Throws:
        Pack200Exception - if a type is not supported or an index not in the range [0, Integer.MAX_VALUE].

      • getClassSpecificPoolEntry

        public ConstantPoolEntry getClassSpecificPoolEntry​(int cp,
                                                   long desiredIndex,
                                                   java.lang.String desiredClassName)
                                            throws Pack200Exception
        Gets the subset constant pool of the specified type to be just that which has the specified class name. Answer the ConstantPoolEntry at the desiredIndex of the subset pool.
        Parameters:
        cp - type of constant pool array to search.
        desiredIndex - index of the constant pool.
        desiredClassName - class to use to generate a subset of the pool.
        Returns:
        ConstantPoolEntry
        Throws:
        Pack200Exception - if a type is not supported or an index not in the range [0, Integer.MAX_VALUE].

      • getConstantPoolEntry

        public ConstantPoolEntry getConstantPoolEntry​(int type,
                                              long index)
                                       throws Pack200Exception
        Gets the constant pool entry of the given type and index.
        Parameters:
        type - Constant pool type.
        index - Index into a specific constant pool.
        Returns:
        a constant pool entry.
        Throws:
        Pack200Exception - if a type is not supported or the index not in the range [0, Integer.MAX_VALUE].

      • getInitMethodPoolEntry

        public ConstantPoolEntry getInitMethodPoolEntry​(int cp,
                                                long value,
                                                java.lang.String desiredClassName)
                                         throws Pack200Exception
        Gets the init method for the specified class.
        Parameters:
        cp - constant pool to search, must be CP_METHOD.
        value - index of init method.
        desiredClassName - String class name of the init method.
        Returns:
        CPMethod init method.
        Throws:
        Pack200Exception - if a type is not supported or an index not in the range [0, Integer.MAX_VALUE].

      • matchSpecificPoolEntryIndex

        protected int matchSpecificPoolEntryIndex​(java.lang.String[] nameArray,
                                          java.lang.String compareString,
                                          int desiredIndex)
        A number of things make use of subsets of structures. In one particular example, _super bytecodes will use a subset of method or field classes which have just those methods / fields defined in the superclass. Similarly, _this bytecodes use just those methods/fields defined in this class, and _init bytecodes use just those methods that start with <init>.

        This method takes an array of names, a String to match for, an index and a boolean as parameters, and answers the array position in the array of the indexth element which matches (or equals) the String (depending on the state of the boolean)

        In other words, if the class array consists of: Object [position 0, 0th instance of Object] String [position 1, 0th instance of String] String [position 2, 1st instance of String] Object [position 3, 1st instance of Object] Object [position 4, 2nd instance of Object] then matchSpecificPoolEntryIndex(..., "Object", 2, false) will answer 4. matchSpecificPoolEntryIndex(..., "String", 0, false) will answer 1.

        Parameters:
        nameArray - Array of Strings against which the compareString is tested
        compareString - String for which to search
        desiredIndex - nth element with that match (counting from 0)
        Returns:
        int index into nameArray, or -1 if not found.

      • matchSpecificPoolEntryIndex

        protected int matchSpecificPoolEntryIndex​(java.lang.String[] primaryArray,
                                          java.lang.String[] secondaryArray,
                                          java.lang.String primaryCompareString,
                                          java.lang.String secondaryCompareRegex,
                                          int desiredIndex)
        This method's function is to look through pairs of arrays. It keeps track of the number of hits it finds using the following basis of comparison for a hit: - the primaryArray[index] must be .equals() to the primaryCompareString - the secondaryArray[index] .matches() the secondaryCompareString. When the desiredIndex number of hits has been reached, the index into the original two arrays of the element hit is returned.
        Parameters:
        primaryArray - The first array to search
        secondaryArray - The second array (must be same .length as primaryArray)
        primaryCompareString - The String to compare against primaryArray using .equals()
        secondaryCompareRegex - The String to compare against secondaryArray using .matches()
        desiredIndex - The nth hit whose position we're seeking
        Returns:
        int index that represents the position of the nth hit in primaryArray and secondaryArray