/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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*
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* 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).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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// Dictionaries - An Abstract Data Type
#include "adlc.hpp"
// #include "dict.hpp"
//------------------------------data-----------------------------------------
// String hash tables
#define MAXID 20
static char initflag = 0; // True after 1st initialization
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};
static short xsum[MAXID];
//------------------------------bucket---------------------------------------
class bucket {
public:
int _cnt, _max; // Size of bucket
const 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(NULL) {
init();
}
Dict::Dict(CmpKey initcmp, Hash inithash, Arena *arena) : _hash(inithash), _cmp(initcmp), _arena(arena) {
init();
}
void Dict::init() {
int i;
// Precompute table of null character hashes
if (!initflag) { // Not initializated yet?
xsum[0] = (short) ((1 << shft[0]) + 1); // Initialize
for( i = 1; i < MAXID; i++) {
xsum[i] = (short) ((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------------------------------------------
// Delete an existing dictionary.
Dict::~Dict() {
}
//------------------------------Clear----------------------------------------
// Zap to empty; ready for re-use
void Dict::Clear() {
_cnt = 0; // Empty contents
for( int 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) {
int 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( int 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
int 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 = (const void**)_arena->Amalloc_4( sizeof(void *)*nb->_max*2 );
int nbcnt = 0;
for( j=0; j<b->_cnt; j++ ) { // Rehash all keys in this bucket
const 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( int i=0; i<_size; i++ ) {
if( !_bin[i]._keyvals ) continue;
_bin[i]._keyvals=(const 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;
}
for( int 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(int k=0; k<_size; k++ ) {
bucket *b = &d._bin[k]; // Shortcut to source bucket
for( int 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.
const void *Dict::Insert(const void *key, const void *val) {
int hash = _hash( key ); // Get hash key
int i = hash & (_size-1); // Get hash key, corrected for size
bucket *b = &_bin[i]; // Handy shortcut
for( int j=0; j<b->_cnt; j++ )
if( !_cmp(key,b->_keyvals[j+j]) ) {
const 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 = (const void**)_arena->Amalloc_4( sizeof(void *)*b->_max*2 );
} else {
b->_keyvals = (const 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.
const void *Dict::Delete(void *key) {
int i = _hash( key ) & (_size-1); // Get hash key, corrected for size
bucket *b = &_bin[i]; // Handy shortcut
for( int j=0; j<b->_cnt; j++ )
if( !_cmp(key,b->_keyvals[j+j]) ) {
const 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.
const void *Dict::operator [](const void *key) const {
int i = _hash( key ) & (_size-1); // Get hash key, corrected for size
bucket *b = &_bin[i]; // Handy shortcut
for( int 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.
int 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( int 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----------------------------------------
static void printvoid(const void* x) { printf("%p", x); }
void Dict::print() {
print(printvoid, printvoid);
}
void Dict::print(PrintKeyOrValue print_key, PrintKeyOrValue print_value) {
for( int i=0; i < _size; i++) { // For complete hash table do
bucket *b = &_bin[i]; // Handy shortcut
for( int j=0; j<b->_cnt; j++ ) {
print_key( b->_keyvals[j+j ]);
printf(" -> ");
print_value(b->_keyvals[j+j+1]);
printf("\n");
}
}
}
//------------------------------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 int sum = 0;
register const char *s = (const char *)t;
while (((c = s[k]) != '\0') && (k < MAXID-1)) { // Get characters till nul
c = (char) ((c << 1) + 1); // Characters are always odd!
sum += c + (c << shft[k++]); // Universal hash function
}
assert(k < (MAXID), "Exceeded maximum name length");
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 (int)((intptr_t)key >> 16);
#else // __TURBOC__
return (int)((intptr_t)key >> 2);
#endif
}
// Slimey cheap hash function; no guaranteed performance.
int hashkey(const void *key) {
return (int)((intptr_t)key);
}
//------------------------------Key Comparator Functions---------------------
int cmpstr(const void *k1, const void *k2) {
return strcmp((const char *)k1,(const char *)k2);
}
// Cheap key comparator.
int 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 = (int)-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;
}