mdtools/BASS_parse/BASS_parse.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "BASS_parse.h"

#define HASH_SIZE 211 // the size of the hash table
#define SHIFT 4 // the bit shift for the hash index calculation


//*** Global functions, variables, and structures ************

unsigned short is_initialized = 0; // tells whether to init the linked list

// reserved word elements for the hash table
struct res_element{
  char word[100];        //the reserved word
  int token;             //the token to return;
  struct res_element* next;
};

struct res_element** reserved = NULL; //the table of reserved words

void initialize_res_list(void); // function to initialize the list

int hash ( char* text ); // generates the hash key

void add_res_element( char* text, int the_token ); //adds elements to the table

// the elements of the defined Hash table
struct defined_element{
  char defined[100];
  char definition[DEFINED_BUFFER_SIZE];
  struct defined_element* next;
};

struct defined_element** defined_list = NULL; // the defined hash table


//*** The Functions *******************************************


/*
  function to initialize the list of reserved words into memory.
*/

void initialize_res_list(){
  
  register unsigned short i; // loop counter

  reserved = ( struct res_element ** ) 
    calloc( HASH_SIZE, sizeof( struct hash__element* ) );

  for( i=0; i < HASH_SIZE; i++ ){
    
    reserved[i] = NULL;
  }

  // add the reserved words

  add_res_element( "molecule", MOLECULE );
  add_res_element( "atom", ATOM );
  add_res_element( "bond", BOND );
  add_res_element( "bend", BEND );
  add_res_element( "torsion", TORSION );
  add_res_element( "position", POSITION );
  add_res_element( "members", MEMBERS );
  add_res_element( "constraint", CONSTRAINT );
  add_res_element( "component", COMPONENT );
  add_res_element( "startIndex", START_INDEX );
  add_res_element( "orientation", ORIENTATION );
  
  is_initialized = 1; // set the initialization boolean to true
}


/*
   checks for reserved words.
   If a reserved word is found, returns the token,
   else returns 0.
*/

int res_word( char* text ){
  
  register unsigned short int i; // loop counter
  int matched = 0;
  int key; // the hash key
  struct res_element* current_ptr; // points to the current hash element
  struct defined_element* def_ptr; // points to the current define element

  if( !is_initialized ){ // initialize the list if not already done

    initialize_res_list();
  }
  
  // get the hash key

  key = hash( text );
  current_ptr = reserved[key];

  // walk through possible mutiple entries

  while( current_ptr != NULL ){
    
    matched = !strcmp( text, current_ptr->word );
    if( matched ) return current_ptr->token; // search successful

    current_ptr = current_ptr->next;
  }

  // if no keywords turn up, check the word against the list of defines
  
  if( defined_list != NULL ){
    def_ptr = defined_list[key];
    
    while( def_ptr != NULL ){
      
      matched = !strcmp( text, def_ptr->defined );
      if( matched ) return DEFINED;
      
      def_ptr = def_ptr->next;
    }
  }

  return 0; //search failed
}

/*
 * This is used to test whether a given word is defined
 * returns 1 if true, 0 if False.
 */

int is_defined( char* text ){

  int matched = 0;
  int key;
  struct defined_element* def_ptr; // points to the current define element
  
  key = hash( text );

  if( defined_list != NULL ){
        def_ptr = defined_list[key];
    
    while( def_ptr != NULL ){
      
      matched = !strcmp( text, def_ptr->defined );
      if( matched ) return 1; // search succesful
      
      def_ptr = def_ptr->next;
    }
  }

  return 0; //search failed
}

/*
 * The next bit returns the text to substitute for any given define.
 */

char* get_definition( char* defined ){
  int key;
  int matched = 0;
  struct defined_element* def_ptr;
  
  if( defined_list != NULL ){

    key = hash( defined );
    def_ptr = defined_list[key];
    
    while( def_ptr != NULL ){
      
      matched = !strcmp( defined, def_ptr->defined );
      if( matched ) return def_ptr->definition;
      
      def_ptr = def_ptr->next;
    }
  }
  
  // search failed, therefore there is an error

  fprintf( stderr, "%s was not found in the defined list\n", defined );
  exit(1);
}
 
/*
 * Add a define statement to the hash table
 */

void insert_define( char* defined, char* definition ){
  
  int i, key;
  struct defined_element* element;

  if( defined_list == NULL ){
    
    defined_list = ( struct defined_element** )
      calloc( HASH_SIZE, sizeof( struct defined_element* ) );
    
    for( i=0; i<HASH_SIZE; i++ ){

      defined_list[i] = NULL;
    }
  }

  key = hash( defined );
  element = (struct defined_element* )
    malloc( sizeof( struct defined_element ) );

  // fill the element
  
  strcpy( element->defined, defined );
  strcpy( element->definition, definition );

  // add the element to the table

  element->next = defined_list[key];
  defined_list[key] = element;
}

/*
 * adds an element to the hash table
 */

void add_res_element( char* text, int the_token ){
  
  int key; // the calculated hash key;
  struct res_element* element; // the element being added

  key = hash( text );
  element = (struct res_element *) malloc( sizeof( struct res_element ) );
  
  // fill the element

  strcpy( element->word, text );
  element->token = the_token;

  // add the element to the table

  element->next = reserved[key];
  reserved[key] = element;
}

/*
  generartes the hash key from the given word.
*/

int hash ( char* text ){

  register unsigned short int i = 0; // loop counter
  int key = 0; // the hash key

  while( text[i] != '\0' ){

    key = ( ( key << SHIFT ) + text[i] ) % HASH_SIZE;
    
    i++;
  }
  
  if( key < 0 ){

    // if the key is less than zero, we've had an overflow error

    fprintf( stderr,
             "There has been an overflow error in the hash key.");
    exit(0);
  }
  
  return key;
}

/*
  function to clean up the memory after we are finished with the lists
*/

void kill_lists( ){
  
  struct res_element* current_res_ptr;
  struct res_element* temp_res_ptr;

  struct defined_element* current_def_ptr;
  struct defined_element* temp_def_ptr;

  register unsigned short int i;

  if( reserved != NULL ){

    for( i=0; i < HASH_SIZE; i++){
      
      current_res_ptr = reserved[i];
      
      while( current_res_ptr != NULL ){
        
        temp_res_ptr = current_res_ptr->next;
        free( current_res_ptr );
        current_res_ptr = temp_res_ptr;
      }
    }    

    free( reserved );
  }

  if( defined_list != NULL ){

    for( i=0; i < HASH_SIZE; i++){
      
      current_def_ptr = defined_list[i];
      
      while( current_def_ptr != NULL ){
        
        temp_def_ptr = current_def_ptr->next;
        free( current_def_ptr );
        current_def_ptr = temp_def_ptr;
      }
    }    

    free( defined_list );
  }

  reserved = NULL;
  defined_list = NULL;

  is_initialized = 0; // initialization is now false
}
Revision:	10
Committed:	Tue Jul 9 18:40:59 2002 UTC (21 years, 11 months ago) by mmeineke
Content type:	text/plain
Original Path:	*branches/mmeineke/mdtools/BASS_parse/BASS_parse.c*
File size:	6963 byte(s)
Log Message:	everything you need to make libmdtools
#	Content
1	#include <stdio.h>
2	#include <stdlib.h>
3	#include <string.h>
4
5	#include "BASS_parse.h"
6
7	#define HASH_SIZE 211 // the size of the hash table
8	#define SHIFT 4 // the bit shift for the hash index calculation
9
10
11
12	//* Global functions, variables, and structures **********
13
14	unsigned short is_initialized = 0; // tells whether to init the linked list
15
16	// reserved word elements for the hash table
17	struct res_element{
18	char word[100]; //the reserved word
19	int token; //the token to return;
20	struct res_element* next;
21	};
22
23	struct res_element** reserved = NULL; //the table of reserved words
24
25	void initialize_res_list(void); // function to initialize the list
26
27	int hash ( char* text ); // generates the hash key
28
29	void add_res_element( char* text, int the_token ); //adds elements to the table
30
31	// the elements of the defined Hash table
32	struct defined_element{
33	char defined[100];
34	char definition[DEFINED_BUFFER_SIZE];
35	struct defined_element* next;
36	};
37
38	struct defined_element** defined_list = NULL; // the defined hash table
39
40
41
42	//* The Functions *****************************************
43
44
45	/*
46	function to initialize the list of reserved words into memory.
47	*/
48
49	void initialize_res_list(){
50
51	register unsigned short i; // loop counter
52
53	reserved = ( struct res_element ** )
54	calloc( HASH_SIZE, sizeof( struct hash__element* ) );
55
56	for( i=0; i < HASH_SIZE; i++ ){
57
58	reserved[i] = NULL;
59	}
60
61	// add the reserved words
62
63	add_res_element( "molecule", MOLECULE );
64	add_res_element( "atom", ATOM );
65	add_res_element( "bond", BOND );
66	add_res_element( "bend", BEND );
67	add_res_element( "torsion", TORSION );
68	add_res_element( "position", POSITION );
69	add_res_element( "members", MEMBERS );
70	add_res_element( "constraint", CONSTRAINT );
71	add_res_element( "component", COMPONENT );
72	add_res_element( "startIndex", START_INDEX );
73	add_res_element( "orientation", ORIENTATION );
74
75	is_initialized = 1; // set the initialization boolean to true
76	}
77
78
79	/*
80	checks for reserved words.
81	If a reserved word is found, returns the token,
82	else returns 0.
83	*/
84
85	int res_word( char* text ){
86
87	register unsigned short int i; // loop counter
88	int matched = 0;
89	int key; // the hash key
90	struct res_element* current_ptr; // points to the current hash element
91	struct defined_element* def_ptr; // points to the current define element
92
93	if( !is_initialized ){ // initialize the list if not already done
94
95	initialize_res_list();
96	}
97
98	// get the hash key
99
100	key = hash( text );
101	current_ptr = reserved[key];
102
103	// walk through possible mutiple entries
104
105	while( current_ptr != NULL ){
106
107	matched = !strcmp( text, current_ptr->word );
108	if( matched ) return current_ptr->token; // search successful
109
110	current_ptr = current_ptr->next;
111	}
112
113	// if no keywords turn up, check the word against the list of defines
114
115	if( defined_list != NULL ){
116	def_ptr = defined_list[key];
117
118	while( def_ptr != NULL ){
119
120	matched = !strcmp( text, def_ptr->defined );
121	if( matched ) return DEFINED;
122
123	def_ptr = def_ptr->next;
124	}
125	}
126
127	return 0; //search failed
128	}
129
130	/*
131	* This is used to test whether a given word is defined
132	* returns 1 if true, 0 if False.
133	*/
134
135	int is_defined( char* text ){
136
137	int matched = 0;
138	int key;
139	struct defined_element* def_ptr; // points to the current define element
140
141	key = hash( text );
142
143	if( defined_list != NULL ){
144	def_ptr = defined_list[key];
145
146	while( def_ptr != NULL ){
147
148	matched = !strcmp( text, def_ptr->defined );
149	if( matched ) return 1; // search succesful
150
151	def_ptr = def_ptr->next;
152	}
153	}
154
155	return 0; //search failed
156	}
157
158	/*
159	* The next bit returns the text to substitute for any given define.
160	*/
161
162	char* get_definition( char* defined ){
163	int key;
164	int matched = 0;
165	struct defined_element* def_ptr;
166
167	if( defined_list != NULL ){
168
169	key = hash( defined );
170	def_ptr = defined_list[key];
171
172	while( def_ptr != NULL ){
173
174	matched = !strcmp( defined, def_ptr->defined );
175	if( matched ) return def_ptr->definition;
176
177	def_ptr = def_ptr->next;
178	}
179	}
180
181	// search failed, therefore there is an error
182
183	fprintf( stderr, "%s was not found in the defined list\n", defined );
184	exit(1);
185	}
186
187	/*
188	* Add a define statement to the hash table
189	*/
190
191	void insert_define( char* defined, char* definition ){
192
193	int i, key;
194	struct defined_element* element;
195
196	if( defined_list == NULL ){
197
198	defined_list = ( struct defined_element** )
199	calloc( HASH_SIZE, sizeof( struct defined_element* ) );
200
201	for( i=0; i<HASH_SIZE; i++ ){
202
203	defined_list[i] = NULL;
204	}
205	}
206
207	key = hash( defined );
208	element = (struct defined_element* )
209	malloc( sizeof( struct defined_element ) );
210
211	// fill the element
212
213	strcpy( element->defined, defined );
214	strcpy( element->definition, definition );
215
216	// add the element to the table
217
218	element->next = defined_list[key];
219	defined_list[key] = element;
220	}
221
222	/*
223	* adds an element to the hash table
224	*/
225
226	void add_res_element( char* text, int the_token ){
227
228	int key; // the calculated hash key;
229	struct res_element* element; // the element being added
230
231	key = hash( text );
232	element = (struct res_element *) malloc( sizeof( struct res_element ) );
233
234	// fill the element
235
236	strcpy( element->word, text );
237	element->token = the_token;
238
239	// add the element to the table
240
241	element->next = reserved[key];
242	reserved[key] = element;
243	}
244
245	/*
246	generartes the hash key from the given word.
247	*/
248
249	int hash ( char* text ){
250
251	register unsigned short int i = 0; // loop counter
252	int key = 0; // the hash key
253
254	while( text[i] != '\0' ){
255
256	key = ( ( key << SHIFT ) + text[i] ) % HASH_SIZE;
257
258	i++;
259	}
260
261	if( key < 0 ){
262
263	// if the key is less than zero, we've had an overflow error
264
265	fprintf( stderr,
266	"There has been an overflow error in the hash key.");
267	exit(0);
268	}
269
270	return key;
271	}
272
273	/*
274	function to clean up the memory after we are finished with the lists
275	*/
276
277	void kill_lists( ){
278
279	struct res_element* current_res_ptr;
280	struct res_element* temp_res_ptr;
281
282	struct defined_element* current_def_ptr;
283	struct defined_element* temp_def_ptr;
284
285	register unsigned short int i;
286
287	if( reserved != NULL ){
288
289	for( i=0; i < HASH_SIZE; i++){
290
291	current_res_ptr = reserved[i];
292
293	while( current_res_ptr != NULL ){
294
295	temp_res_ptr = current_res_ptr->next;
296	free( current_res_ptr );
297	current_res_ptr = temp_res_ptr;
298	}
299	}
300
301	free( reserved );
302	}
303
304	if( defined_list != NULL ){
305
306	for( i=0; i < HASH_SIZE; i++){
307
308	current_def_ptr = defined_list[i];
309
310	while( current_def_ptr != NULL ){
311
312	temp_def_ptr = current_def_ptr->next;
313	free( current_def_ptr );
314	current_def_ptr = temp_def_ptr;
315	}
316	}
317
318	free( defined_list );
319	}
320
321	reserved = NULL;
322	defined_list = NULL;
323
324	is_initialized = 0; // initialization is now false
325	}