jdk8-mips64-public/hotspot: src/share/vm/libadt/dict.cpp@98cb887364d3 (annotated)

src/share/vm/libadt/dict.cpp@98cb887364d3 (annotated)

src/share/vm/libadt/dict.cpp

Fri, 27 Feb 2009 13:27:09 -0800

author: twisti
date: Fri, 27 Feb 2009 13:27:09 -0800
changeset 1040: 98cb887364d3
parent 997: 1580954e694c
child 1063: 7bb995fbd3c0
permissions: -rw-r--r--

6810672: Comment typos
Summary: I have collected some typos I have found while looking at the code.
Reviewed-by: kvn, never

 /*
  * Copyright 1997-2003 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */
 // Dictionaries - An Abstract Data Type
 #include "incls/_precompiled.incl"
 #include "incls/_dict.cpp.incl"
 // %%%%% 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;
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/libadt/dict.cpp@98cb887364d3 (annotated)

src/share/vm/libadt/dict.cpp