Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "libadt/dict.hpp"

 #include "memory/allocation.inline.hpp"

 #include "memory/resourceArea.hpp"

 #include "runtime/thread.hpp"

 // Dictionaries - An Abstract Data Type

 // %%%%% includes not needed with AVM framework - Ungar

 // #include "port.hpp"

 //IMPLEMENTATION

 // #include "dict.hpp"

 #include <assert.h>

 // The iostream is not needed and it gets confused for gcc by the

 // define of bool.

 //

 // #include <iostream.h>

 //------------------------------data-----------------------------------------

 // String hash tables

 #define MAXID 20

 static byte initflag = 0;       // True after 1st initialization

 static const char shft[MAXID] = {1,2,3,4,5,6,7,1,2,3,4,5,6,7,1,2,3,4,5,6};

 static short xsum[MAXID];

 //------------------------------bucket---------------------------------------

 class bucket : public ResourceObj {

 public:

   uint _cnt, _max;              // Size of bucket

   void **_keyvals;              // Array of keys and values

 };

 //------------------------------Dict-----------------------------------------

 // The dictionary is kept has a hash table.  The hash table is a even power

 // of two, for nice modulo operations.  Each bucket in the hash table points

 // to a linear list of key-value pairs; each key & value is just a (void *).

 // The list starts with a count.  A hash lookup finds the list head, then a

 // simple linear scan finds the key.  If the table gets too full, it's

 // doubled in size; the total amount of EXTRA times all hash functions are

 // computed for the doubling is no more than the current size - thus the

 // doubling in size costs no more than a constant factor in speed.

 Dict::Dict(CmpKey initcmp, Hash inithash) : _hash(inithash), _cmp(initcmp),

   _arena(Thread::current()->resource_area()) {

   int i;

   // Precompute table of null character hashes

   if( !initflag ) {             // Not initializated yet?

     xsum[0] = (1<<shft[0])+1;   // Initialize

     for(i=1; i<MAXID; i++) {

       xsum[i] = (1<<shft[i])+1+xsum[i-1];

     }

     initflag = 1;               // Never again

   }

   _size = 16;                   // Size is a power of 2

   _cnt = 0;                     // Dictionary is empty

   _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);

   memset(_bin,0,sizeof(bucket)*_size);

 }

 Dict::Dict(CmpKey initcmp, Hash inithash, Arena *arena, int size)

 : _hash(inithash), _cmp(initcmp), _arena(arena) {

   int i;

   // Precompute table of null character hashes

   if( !initflag ) {             // Not initializated yet?

     xsum[0] = (1<<shft[0])+1;   // Initialize

     for(i=1; i<MAXID; i++) {

       xsum[i] = (1<<shft[i])+1+xsum[i-1];

     }

     initflag = 1;               // Never again

   }

   i=16;

   while( i < size ) i <<= 1;

   _size = i;                    // Size is a power of 2

   _cnt = 0;                     // Dictionary is empty

   _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);

   memset(_bin,0,sizeof(bucket)*_size);

 }

 //------------------------------~Dict------------------------------------------

 // Delete an existing dictionary.

 Dict::~Dict() {

   /*

   tty->print("~Dict %d/%d: ",_cnt,_size);

   for( uint i=0; i < _size; i++) // For complete new table do

     tty->print("%d ",_bin[i]._cnt);

   tty->print("\n");*/

   /*for( uint i=0; i<_size; i++ ) {

     FREE_FAST( _bin[i]._keyvals );

     } */

 }

 //------------------------------Clear----------------------------------------

 // Zap to empty; ready for re-use

 void Dict::Clear() {

   _cnt = 0;                     // Empty contents

   for( uint i=0; i<_size; i++ )

     _bin[i]._cnt = 0;           // Empty buckets, but leave allocated

   // Leave _size & _bin alone, under the assumption that dictionary will

   // grow to this size again.

 }

 //------------------------------doubhash---------------------------------------

 // Double hash table size.  If can't do so, just suffer.  If can, then run

 // thru old hash table, moving things to new table.  Note that since hash

 // table doubled, exactly 1 new bit is exposed in the mask - so everything

 // in the old table ends up on 1 of two lists in the new table; a hi and a

 // lo list depending on the value of the bit.

 void Dict::doubhash(void) {

   uint oldsize = _size;

   _size <<= 1;                  // Double in size

   _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*oldsize, sizeof(bucket)*_size );

   memset( &_bin[oldsize], 0, oldsize*sizeof(bucket) );

   // Rehash things to spread into new table

   for( uint i=0; i < oldsize; i++) { // For complete OLD table do

     bucket *b = &_bin[i];       // Handy shortcut for _bin[i]

     if( !b->_keyvals ) continue;        // Skip empties fast

     bucket *nb = &_bin[i+oldsize];  // New bucket shortcut

     uint j = b->_max;               // Trim new bucket to nearest power of 2

     while( j > b->_cnt ) j >>= 1;   // above old bucket _cnt

     if( !j ) j = 1;             // Handle zero-sized buckets

     nb->_max = j<<1;

     // Allocate worst case space for key-value pairs

     nb->_keyvals = (void**)_arena->Amalloc_4( sizeof(void *)*nb->_max*2 );

     uint nbcnt = 0;

     for( j=0; j<b->_cnt; j++ ) {  // Rehash all keys in this bucket

       void *key = b->_keyvals[j+j];

       if( (_hash( key ) & (_size-1)) != i ) { // Moving to hi bucket?

         nb->_keyvals[nbcnt+nbcnt] = key;

         nb->_keyvals[nbcnt+nbcnt+1] = b->_keyvals[j+j+1];

         nb->_cnt = nbcnt = nbcnt+1;

         b->_cnt--;              // Remove key/value from lo bucket

         b->_keyvals[j+j  ] = b->_keyvals[b->_cnt+b->_cnt  ];

         b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];

         j--;                    // Hash compacted element also

       }

     } // End of for all key-value pairs in bucket

   } // End of for all buckets

 }

 //------------------------------Dict-----------------------------------------

 // Deep copy a dictionary.

 Dict::Dict( const Dict &d ) : _size(d._size), _cnt(d._cnt), _hash(d._hash),_cmp(d._cmp), _arena(d._arena) {

   _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);

   memcpy( _bin, d._bin, sizeof(bucket)*_size );

   for( uint i=0; i<_size; i++ ) {

     if( !_bin[i]._keyvals ) continue;

     _bin[i]._keyvals=(void**)_arena->Amalloc_4( sizeof(void *)*_bin[i]._max*2);

     memcpy( _bin[i]._keyvals, d._bin[i]._keyvals,_bin[i]._cnt*2*sizeof(void*));

   }

 }

 //------------------------------Dict-----------------------------------------

 // Deep copy a dictionary.

 Dict &Dict::operator =( const Dict &d ) {

   if( _size < d._size ) {       // If must have more buckets

     _arena = d._arena;

     _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*_size, sizeof(bucket)*d._size );

     memset( &_bin[_size], 0, (d._size-_size)*sizeof(bucket) );

     _size = d._size;

   }

   uint i;

   for( i=0; i<_size; i++ ) // All buckets are empty

     _bin[i]._cnt = 0;           // But leave bucket allocations alone

   _cnt = d._cnt;

   *(Hash*)(&_hash) = d._hash;

   *(CmpKey*)(&_cmp) = d._cmp;

   for( i=0; i<_size; i++ ) {

     bucket *b = &d._bin[i];     // Shortcut to source bucket

     for( uint j=0; j<b->_cnt; j++ )

       Insert( b->_keyvals[j+j], b->_keyvals[j+j+1] );

   }

   return *this;

 }

 //------------------------------Insert----------------------------------------

 // Insert or replace a key/value pair in the given dictionary.  If the

 // dictionary is too full, it's size is doubled.  The prior value being

 // replaced is returned (NULL if this is a 1st insertion of that key).  If

 // an old value is found, it's swapped with the prior key-value pair on the

 // list.  This moves a commonly searched-for value towards the list head.

 void *Dict::Insert(void *key, void *val, bool replace) {

   uint hash = _hash( key );     // Get hash key

   uint i = hash & (_size-1);    // Get hash key, corrected for size

   bucket *b = &_bin[i];         // Handy shortcut

   for( uint j=0; j<b->_cnt; j++ ) {

     if( !_cmp(key,b->_keyvals[j+j]) ) {

       if (!replace) {

         return b->_keyvals[j+j+1];

       } else {

         void *prior = b->_keyvals[j+j+1];

         b->_keyvals[j+j  ] = key;       // Insert current key-value

         b->_keyvals[j+j+1] = val;

         return prior;           // Return prior

       }

     }

   }

   if( ++_cnt > _size ) {        // Hash table is full

     doubhash();                 // Grow whole table if too full

     i = hash & (_size-1);       // Rehash

     b = &_bin[i];               // Handy shortcut

   }

   if( b->_cnt == b->_max ) {    // Must grow bucket?

     if( !b->_keyvals ) {

       b->_max = 2;              // Initial bucket size

       b->_keyvals = (void**)_arena->Amalloc_4(sizeof(void*) * b->_max * 2);

     } else {

       b->_keyvals = (void**)_arena->Arealloc(b->_keyvals, sizeof(void*) * b->_max * 2, sizeof(void*) * b->_max * 4);

       b->_max <<= 1;            // Double bucket

     }

   }

   b->_keyvals[b->_cnt+b->_cnt  ] = key;

   b->_keyvals[b->_cnt+b->_cnt+1] = val;

   b->_cnt++;

   return NULL;                  // Nothing found prior

 }

 //------------------------------Delete---------------------------------------

 // Find & remove a value from dictionary. Return old value.

 void *Dict::Delete(void *key) {

   uint i = _hash( key ) & (_size-1);    // Get hash key, corrected for size

   bucket *b = &_bin[i];         // Handy shortcut

   for( uint j=0; j<b->_cnt; j++ )

     if( !_cmp(key,b->_keyvals[j+j]) ) {

       void *prior = b->_keyvals[j+j+1];

       b->_cnt--;                // Remove key/value from lo bucket

       b->_keyvals[j+j  ] = b->_keyvals[b->_cnt+b->_cnt  ];

       b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];

       _cnt--;                   // One less thing in table

       return prior;

     }

   return NULL;

 }

 //------------------------------FindDict-------------------------------------

 // Find a key-value pair in the given dictionary.  If not found, return NULL.

 // If found, move key-value pair towards head of list.

 void *Dict::operator [](const void *key) const {

   uint i = _hash( key ) & (_size-1);    // Get hash key, corrected for size

   bucket *b = &_bin[i];         // Handy shortcut

   for( uint j=0; j<b->_cnt; j++ )

     if( !_cmp(key,b->_keyvals[j+j]) )

       return b->_keyvals[j+j+1];

   return NULL;

 }

 //------------------------------CmpDict--------------------------------------

 // CmpDict compares two dictionaries; they must have the same keys (their

 // keys must match using CmpKey) and they must have the same values (pointer

 // comparison).  If so 1 is returned, if not 0 is returned.

 int32 Dict::operator ==(const Dict &d2) const {

   if( _cnt != d2._cnt ) return 0;

   if( _hash != d2._hash ) return 0;

   if( _cmp != d2._cmp ) return 0;

   for( uint i=0; i < _size; i++) {      // For complete hash table do

     bucket *b = &_bin[i];       // Handy shortcut

     if( b->_cnt != d2._bin[i]._cnt ) return 0;

     if( memcmp(b->_keyvals, d2._bin[i]._keyvals, b->_cnt*2*sizeof(void*) ) )

       return 0;                 // Key-value pairs must match

   }

   return 1;                     // All match, is OK

 }

 //------------------------------print------------------------------------------

 // Handier print routine

 void Dict::print() {

   DictI i(this); // Moved definition in iterator here because of g++.

   tty->print("Dict@0x%lx[%d] = {", this, _cnt);

   for( ; i.test(); ++i ) {

     tty->print("(0x%lx,0x%lx),", i._key, i._value);

   }

   tty->print_cr("}");

 }

 //------------------------------Hashing Functions----------------------------

 // Convert string to hash key.  This algorithm implements a universal hash

 // function with the multipliers frozen (ok, so it's not universal).  The

 // multipliers (and allowable characters) are all odd, so the resultant sum

 // is odd - guaranteed not divisible by any power of two, so the hash tables

 // can be any power of two with good results.  Also, I choose multipliers

 // that have only 2 bits set (the low is always set to be odd) so

 // multiplication requires only shifts and adds.  Characters are required to

 // be in the range 0-127 (I double & add 1 to force oddness).  Keys are

 // limited to MAXID characters in length.  Experimental evidence on 150K of

 // C text shows excellent spreading of values for any size hash table.

 int hashstr(const void *t) {

   register char c, k = 0;

   register int32 sum = 0;

   register const char *s = (const char *)t;

   while( ((c = *s++) != '\0') && (k < MAXID-1) ) { // Get characters till null or MAXID-1

     c = (c<<1)+1;               // Characters are always odd!

     sum += c + (c<<shft[k++]);  // Universal hash function

   }

   return (int)((sum+xsum[k]) >> 1); // Hash key, un-modulo'd table size

 }

 //------------------------------hashptr--------------------------------------

 // Slimey cheap hash function; no guaranteed performance.  Better than the

 // default for pointers, especially on MS-DOS machines.

 int hashptr(const void *key) {

 #ifdef __TURBOC__

     return ((intptr_t)key >> 16);

 #else  // __TURBOC__

     return ((intptr_t)key >> 2);

 #endif

 }

 // Slimey cheap hash function; no guaranteed performance.

 int hashkey(const void *key) {

   return (intptr_t)key;

 }

 //------------------------------Key Comparator Functions---------------------

 int32 cmpstr(const void *k1, const void *k2) {

   return strcmp((const char *)k1,(const char *)k2);

 }

 // Cheap key comparator.

 int32 cmpkey(const void *key1, const void *key2) {

   if (key1 == key2) return 0;

   intptr_t delta = (intptr_t)key1 - (intptr_t)key2;

   if (delta > 0) return 1;

   return -1;

 }

 //=============================================================================

 //------------------------------reset------------------------------------------

 // Create an iterator and initialize the first variables.

 void DictI::reset( const Dict *dict ) {

   _d = dict;                    // The dictionary

   _i = (uint)-1;                // Before the first bin

   _j = 0;                       // Nothing left in the current bin

   ++(*this);                    // Step to first real value

 }

 //------------------------------next-------------------------------------------

 // Find the next key-value pair in the dictionary, or return a NULL key and

 // value.

 void DictI::operator ++(void) {

   if( _j-- ) {                  // Still working in current bin?

     _key   = _d->_bin[_i]._keyvals[_j+_j];

     _value = _d->_bin[_i]._keyvals[_j+_j+1];

     return;

   }

   while( ++_i < _d->_size ) {   // Else scan for non-zero bucket

     _j = _d->_bin[_i]._cnt;

     if( !_j ) continue;

     _j--;

     _key   = _d->_bin[_i]._keyvals[_j+_j];

     _value = _d->_bin[_i]._keyvals[_j+_j+1];

     return;

   }

   _key = _value = NULL;

 }