Package com.fasterxml.jackson.core.sym

Class ByteQuadsCanonicalizer

  • public final class ByteQuadsCanonicalizer
extends java.lang.Object
    Replacement for BytesToNameCanonicalizer which aims at more localized memory access due to flattening of name quad data. Performance improvement modest for simple JSON document data binding (maybe 3%), but should help more for larger symbol tables, or for binary formats like Smile.

    Hash area is divided into 4 sections:

    1. Primary area (1/2 of total size), direct match from hash (LSB)
    2. Secondary area (1/4 of total size), match from hash (LSB) >> 1
    3. Tertiary area (1/8 of total size), match from hash (LSB) >> 2
    4. Spill-over area (remaining 1/8) with linear scan, insertion order
    and within every area, entries are 4 ints, where 1 - 3 ints contain 1 - 12 UTF-8 encoded bytes of name (null-padded), and last int is offset in _names that contains actual name Strings.
    Since:
    2.6

    • Method Detail

      • createRoot

        public static ByteQuadsCanonicalizer createRoot()
        Factory method to call to create a symbol table instance with a randomized seed value.
        Returns:
        Root instance to use for constructing new child instances

      • makeChild

        public ByteQuadsCanonicalizer makeChild​(int flags)
        Factory method used to create actual symbol table instance to use for parsing.
        Parameters:
        flags - Bit flags of active JsonFactory.Features enabled.
        Returns:
        Actual canonicalizer instance that can be used by a parser

      • makeChildOrPlaceholder

        public ByteQuadsCanonicalizer makeChildOrPlaceholder​(int flags)
        Method similar to makeChild(int) but one that only creates real instance of JsonFactory.Feature.CANONICALIZE_FIELD_NAMES is enabled: otherwise a "bogus" instance is created.
        Parameters:
        flags - Bit flags of active JsonFactory.Features enabled.
        Returns:
        Actual canonicalizer instance that can be used by a parser if (and only if) canonicalization is enabled; otherwise a non-null "placeholder" instance.
        Since:
        2.13

      • release

        public void release()
        Method called by the using code to indicate it is done with this instance. This lets instance merge accumulated changes into parent (if need be), safely and efficiently, and without calling code having to know about parent information.

      • size

        public int size()
        Returns:
        Number of symbol entries contained by this canonicalizer instance

      • bucketCount

        public int bucketCount()
        Returns:
        number of primary slots table has currently

      • maybeDirty

        public boolean maybeDirty()
        Method called to check to quickly see if a child symbol table may have gotten additional entries. Used for checking to see if a child table should be merged into shared table.
        Returns:
        Whether main hash area has been modified

      • hashSeed

        public int hashSeed()

      • isCanonicalizing

        public boolean isCanonicalizing()
        Returns:
        True for "real", canonicalizing child tables; false for root table as well as placeholder "child" tables.
        Since:
        2.13

      • primaryCount

        public int primaryCount()
        Method mostly needed by unit tests; calculates number of entries that are in the primary slot set. These are "perfect" entries, accessible with a single lookup
        Returns:
        Number of entries in the primary hash area

      • secondaryCount

        public int secondaryCount()
        Method mostly needed by unit tests; calculates number of entries in secondary buckets
        Returns:
        Number of entries in the secondary hash area

      • tertiaryCount

        public int tertiaryCount()
        Method mostly needed by unit tests; calculates number of entries in tertiary buckets
        Returns:
        Number of entries in the tertiary hash area

      • spilloverCount

        public int spilloverCount()
        Method mostly needed by unit tests; calculates number of entries in shared spill-over area
        Returns:
        Number of entries in the linear spill-over areay

      • totalCount

        public int totalCount()

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • findName

        public java.lang.String findName​(int q1)

      • findName

        public java.lang.String findName​(int q1,
                                 int q2)

      • findName

        public java.lang.String findName​(int q1,
                                 int q2,
                                 int q3)

      • findName

        public java.lang.String findName​(int[] q,
                                 int qlen)

      • addName

        public java.lang.String addName​(java.lang.String name,
                                int q1)

      • addName

        public java.lang.String addName​(java.lang.String name,
                                int q1,
                                int q2)

      • addName

        public java.lang.String addName​(java.lang.String name,
                                int q1,
                                int q2,
                                int q3)

      • addName

        public java.lang.String addName​(java.lang.String name,
                                int[] q,
                                int qlen)

      • calcHash

        public int calcHash​(int q1)

      • calcHash

        public int calcHash​(int q1,
                    int q2)

      • calcHash

        public int calcHash​(int q1,
                    int q2,
                    int q3)

      • calcHash

        public int calcHash​(int[] q,
                    int qlen)