jdk

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/*
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 * Copyright (c) 1998, 2023, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 *
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 */
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// Dictionaries - An Abstract Data Type
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#include "adlc.hpp"
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// #include "dict.hpp"
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//------------------------------data-----------------------------------------
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// String hash tables
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#define MAXID 20
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static char initflag = 0;       // True after 1st initialization
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static char shft[MAXID + 1] = {1,2,3,4,5,6,7,1,2,3,4,5,6,7,1,2,3,4,5,6,7};
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static short xsum[MAXID];
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//------------------------------bucket---------------------------------------
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class bucket {
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public:
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  int          _cnt, _max;      // Size of bucket
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  const void **_keyvals;        // Array of keys and values
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};
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//------------------------------Dict-----------------------------------------
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// The dictionary is kept has a hash table.  The hash table is a even power
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// of two, for nice modulo operations.  Each bucket in the hash table points
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// to a linear list of key-value pairs; each key & value is just a (void *).
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// The list starts with a count.  A hash lookup finds the list head, then a
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// simple linear scan finds the key.  If the table gets too full, it's
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// doubled in size; the total amount of EXTRA times all hash functions are
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// computed for the doubling is no more than the current size - thus the
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// doubling in size costs no more than a constant factor in speed.
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Dict::Dict(CmpKey initcmp, Hash inithash) : _hash(inithash), _cmp(initcmp), _arena(nullptr) {
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  init();
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}
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Dict::Dict(CmpKey initcmp, Hash inithash, AdlArena *arena) : _hash(inithash), _cmp(initcmp), _arena(arena) {
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  init();
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}
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void Dict::init() {
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  int i;
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  // Precompute table of null character hashes
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  if (!initflag) {              // Not initializated yet?
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    xsum[0] = (short) ((1 << shft[0]) + 1);  // Initialize
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    for( i = 1; i < MAXID; i++) {
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      xsum[i] = (short) ((1 << shft[i]) + 1 + xsum[i-1]);
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    }
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    initflag = 1;               // Never again
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  }
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  _size = 16;                   // Size is a power of 2
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  _cnt = 0;                     // Dictionary is empty
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  _bin = (bucket*)_arena->AmallocWords(sizeof(bucket) * _size);
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  memset(_bin, 0, sizeof(bucket) * _size);
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}
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//------------------------------~Dict------------------------------------------
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// Delete an existing dictionary.
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Dict::~Dict() {
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}
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//------------------------------Clear----------------------------------------
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// Zap to empty; ready for re-use
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void Dict::Clear() {
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  _cnt = 0;                     // Empty contents
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  for( int i=0; i<_size; i++ )
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    _bin[i]._cnt = 0;           // Empty buckets, but leave allocated
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  // Leave _size & _bin alone, under the assumption that dictionary will
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  // grow to this size again.
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}
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//------------------------------doubhash---------------------------------------
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// Double hash table size.  If can't do so, just suffer.  If can, then run
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// thru old hash table, moving things to new table.  Note that since hash
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// table doubled, exactly 1 new bit is exposed in the mask - so everything
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// in the old table ends up on 1 of two lists in the new table; a hi and a
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// lo list depending on the value of the bit.
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void Dict::doubhash(void) {
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  int oldsize = _size;
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  _size <<= 1;                  // Double in size
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  _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*oldsize, sizeof(bucket)*_size );
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  memset( &_bin[oldsize], 0, oldsize*sizeof(bucket) );
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  // Rehash things to spread into new table
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  for( int i=0; i < oldsize; i++) { // For complete OLD table do
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    bucket *b = &_bin[i];       // Handy shortcut for _bin[i]
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    if( !b->_keyvals ) continue;        // Skip empties fast
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    bucket *nb = &_bin[i+oldsize];  // New bucket shortcut
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    int j = b->_max;                // Trim new bucket to nearest power of 2
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    while( j > b->_cnt ) j >>= 1;   // above old bucket _cnt
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    if( !j ) j = 1;             // Handle zero-sized buckets
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    nb->_max = j<<1;
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    // Allocate worst case space for key-value pairs
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    nb->_keyvals = (const void**)_arena->AmallocWords( sizeof(void *)*nb->_max*2 );
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    int nbcnt = 0;
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    for( j=0; j<b->_cnt; j++ ) {  // Rehash all keys in this bucket
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      const void *key = b->_keyvals[j+j];
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      if( (_hash( key ) & (_size-1)) != i ) { // Moving to hi bucket?
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        nb->_keyvals[nbcnt+nbcnt] = key;
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        nb->_keyvals[nbcnt+nbcnt+1] = b->_keyvals[j+j+1];
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        nb->_cnt = nbcnt = nbcnt+1;
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        b->_cnt--;              // Remove key/value from lo bucket
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        b->_keyvals[j+j  ] = b->_keyvals[b->_cnt+b->_cnt  ];
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        b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
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        j--;                    // Hash compacted element also
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      }
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    } // End of for all key-value pairs in bucket
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  } // End of for all buckets
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}
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//------------------------------Dict-----------------------------------------
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// Deep copy a dictionary.
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Dict::Dict( const Dict &d ) : _size(d._size), _cnt(d._cnt), _hash(d._hash),_cmp(d._cmp), _arena(d._arena) {
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  _bin = (bucket*)_arena->AmallocWords(sizeof(bucket)*_size);
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  memcpy( _bin, d._bin, sizeof(bucket)*_size );
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  for( int i=0; i<_size; i++ ) {
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    if( !_bin[i]._keyvals ) continue;
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    _bin[i]._keyvals=(const void**)_arena->AmallocWords( sizeof(void *)*_bin[i]._max*2);
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    memcpy( _bin[i]._keyvals, d._bin[i]._keyvals,_bin[i]._cnt*2*sizeof(void*));
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  }
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}
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//------------------------------Dict-----------------------------------------
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// Deep copy a dictionary.
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Dict &Dict::operator =( const Dict &d ) {
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  if( _size < d._size ) {       // If must have more buckets
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    _arena = d._arena;
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    _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*_size, sizeof(bucket)*d._size );
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    memset( &_bin[_size], 0, (d._size-_size)*sizeof(bucket) );
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    _size = d._size;
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  }
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  for( int i=0; i<_size; i++ ) // All buckets are empty
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    _bin[i]._cnt = 0;           // But leave bucket allocations alone
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  _cnt = d._cnt;
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  *(Hash*)(&_hash) = d._hash;
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  *(CmpKey*)(&_cmp) = d._cmp;
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  for(int k=0; k<_size; k++ ) {
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    bucket *b = &d._bin[k];     // Shortcut to source bucket
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    for( int j=0; j<b->_cnt; j++ )
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      Insert( b->_keyvals[j+j], b->_keyvals[j+j+1] );
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  }
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  return *this;
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}
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//------------------------------Insert---------------------------------------
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// Insert or replace a key/value pair in the given dictionary.  If the
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// dictionary is too full, it's size is doubled.  The prior value being
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// replaced is returned (null if this is a 1st insertion of that key).  If
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// an old value is found, it's swapped with the prior key-value pair on the
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// list.  This moves a commonly searched-for value towards the list head.
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const void *Dict::Insert(const void *key, const void *val) {
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  int hash = _hash( key );      // Get hash key
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  int i = hash & (_size-1);     // Get hash key, corrected for size
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  bucket *b = &_bin[i];         // Handy shortcut
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  for( int j=0; j<b->_cnt; j++ )
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    if( !_cmp(key,b->_keyvals[j+j]) ) {
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      const void *prior = b->_keyvals[j+j+1];
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      b->_keyvals[j+j  ] = key; // Insert current key-value
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      b->_keyvals[j+j+1] = val;
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      return prior;             // Return prior
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    }
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  if( ++_cnt > _size ) {        // Hash table is full
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    doubhash();                 // Grow whole table if too full
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    i = hash & (_size-1);       // Rehash
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    b = &_bin[i];               // Handy shortcut
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  }
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  if( b->_cnt == b->_max ) {    // Must grow bucket?
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    if( !b->_keyvals ) {
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      b->_max = 2;              // Initial bucket size
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      b->_keyvals = (const void**)_arena->AmallocWords( sizeof(void *)*b->_max*2 );
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    } else {
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      b->_keyvals = (const void**)_arena->Arealloc( b->_keyvals, sizeof(void *)*b->_max*2, sizeof(void *)*b->_max*4 );
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      b->_max <<= 1;            // Double bucket
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    }
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  }
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  b->_keyvals[b->_cnt+b->_cnt  ] = key;
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  b->_keyvals[b->_cnt+b->_cnt+1] = val;
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  b->_cnt++;
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  return nullptr;               // Nothing found prior
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}
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//------------------------------Delete---------------------------------------
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// Find & remove a value from dictionary. Return old value.
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const void *Dict::Delete(void *key) {
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  int i = _hash( key ) & (_size-1);     // Get hash key, corrected for size
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  bucket *b = &_bin[i];         // Handy shortcut
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  for( int j=0; j<b->_cnt; j++ )
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    if( !_cmp(key,b->_keyvals[j+j]) ) {
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      const void *prior = b->_keyvals[j+j+1];
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      b->_cnt--;                // Remove key/value from lo bucket
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      b->_keyvals[j+j  ] = b->_keyvals[b->_cnt+b->_cnt  ];
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      b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
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      _cnt--;                   // One less thing in table
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      return prior;
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    }
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  return nullptr;
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}
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//------------------------------FindDict-------------------------------------
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// Find a key-value pair in the given dictionary.  If not found, return null.
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// If found, move key-value pair towards head of list.
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const void *Dict::operator [](const void *key) const {
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  int i = _hash( key ) & (_size-1);     // Get hash key, corrected for size
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  bucket *b = &_bin[i];         // Handy shortcut
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  for( int j=0; j<b->_cnt; j++ )
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    if( !_cmp(key,b->_keyvals[j+j]) )
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      return b->_keyvals[j+j+1];
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  return nullptr;
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}
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//------------------------------CmpDict--------------------------------------
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// CmpDict compares two dictionaries; they must have the same keys (their
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// keys must match using CmpKey) and they must have the same values (pointer
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// comparison).  If so 1 is returned, if not 0 is returned.
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int Dict::operator ==(const Dict &d2) const {
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  if( _cnt != d2._cnt ) return 0;
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  if( _hash != d2._hash ) return 0;
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  if( _cmp != d2._cmp ) return 0;
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  for( int i=0; i < _size; i++) {       // For complete hash table do
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    bucket *b = &_bin[i];       // Handy shortcut
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    if( b->_cnt != d2._bin[i]._cnt ) return 0;
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    if( memcmp(b->_keyvals, d2._bin[i]._keyvals, b->_cnt*2*sizeof(void*) ) )
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      return 0;                 // Key-value pairs must match
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  }
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  return 1;                     // All match, is OK
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}
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//------------------------------print----------------------------------------
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static void printvoid(const void* x) { printf("%p", x);  }
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void Dict::print() {
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  print(printvoid, printvoid);
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}
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void Dict::print(PrintKeyOrValue print_key, PrintKeyOrValue print_value) {
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  for( int i=0; i < _size; i++) {       // For complete hash table do
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    bucket *b = &_bin[i];       // Handy shortcut
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    for( int j=0; j<b->_cnt; j++ ) {
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      print_key(  b->_keyvals[j+j  ]);
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      printf(" -> ");
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      print_value(b->_keyvals[j+j+1]);
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      printf("\n");
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    }
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  }
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}
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//------------------------------Hashing Functions----------------------------
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// Convert string to hash key.  This algorithm implements a universal hash
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// function with the multipliers frozen (ok, so it's not universal).  The
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// multipliers (and allowable characters) are all odd, so the resultant sum
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// is odd - guaranteed not divisible by any power of two, so the hash tables
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// can be any power of two with good results.  Also, I choose multipliers
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// that have only 2 bits set (the low is always set to be odd) so
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// multiplication requires only shifts and adds.  Characters are required to
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// be in the range 0-127 (I double & add 1 to force oddness).  Keys are
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// limited to MAXID characters in length.  Experimental evidence on 150K of
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// C text shows excellent spreading of values for any size hash table.
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int hashstr(const void *t) {
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  char c, k = 0;
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  int sum = 0;
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  const char *s = (const char *)t;
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  while (((c = s[k]) != '\0') && (k < MAXID-1)) { // Get characters till nul
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    c = (char) ((c << 1) + 1);    // Characters are always odd!
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    sum += c + (c << shft[k++]);  // Universal hash function
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  }
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  assert(k < (MAXID), "Exceeded maximum name length");
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  return (int)((sum+xsum[k]) >> 1); // Hash key, un-modulo'd table size
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}
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//------------------------------hashptr--------------------------------------
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// Slimey cheap hash function; no guaranteed performance.  Better than the
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// default for pointers, especially on MS-DOS machines.
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int hashptr(const void *key) {
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#ifdef __TURBOC__
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    return (int)((intptr_t)key >> 16);
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#else  // __TURBOC__
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    return (int)((intptr_t)key >> 2);
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#endif
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}
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// Slimey cheap hash function; no guaranteed performance.
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int hashkey(const void *key) {
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  return (int)((intptr_t)key);
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}
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//------------------------------Key Comparator Functions---------------------
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int cmpstr(const void *k1, const void *k2) {
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  return strcmp((const char *)k1,(const char *)k2);
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}
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// Cheap key comparator.
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int cmpkey(const void *key1, const void *key2) {
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  if (key1 == key2) return 0;
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  intptr_t delta = (intptr_t)key1 - (intptr_t)key2;
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  if (delta > 0) return 1;
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  return -1;
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}
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//=============================================================================
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//------------------------------reset------------------------------------------
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// Create an iterator and initialize the first variables.
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void DictI::reset( const Dict *dict ) {
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  _d = dict;                    // The dictionary
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  _i = (int)-1;         // Before the first bin
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  _j = 0;                       // Nothing left in the current bin
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  ++(*this);                    // Step to first real value
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}
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//------------------------------next-------------------------------------------
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// Find the next key-value pair in the dictionary, or return a null key and
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// value.
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void DictI::operator ++(void) {
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  if( _j-- ) {                  // Still working in current bin?
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    _key   = _d->_bin[_i]._keyvals[_j+_j];
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    _value = _d->_bin[_i]._keyvals[_j+_j+1];
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    return;
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  }
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  while( ++_i < _d->_size ) {   // Else scan for non-zero bucket
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    _j = _d->_bin[_i]._cnt;
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    if( !_j ) continue;
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    _j--;
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    _key   = _d->_bin[_i]._keyvals[_j+_j];
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    _value = _d->_bin[_i]._keyvals[_j+_j+1];
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    return;
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  }
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  _key = _value = nullptr;
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}
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