Minor performance tweak: Do not allocate any heap memory for hash_table_t until an element is inserted. That way, hash tables that never contain any data will not cause a call to malloc()

darcs-hash:20051026144823-ac50b-570dfe169a2ce693458c493e8f103884de3c5078.gz

expand.c

@@ -88,11 +88,11 @@ parameter expansion.
 #define UNCLEAN L"$*?\\\"'({})"
 
 /**
-   Test if the specified argument is clean, i.e. it does not contin
-   any tokens which are expanded. Clean strings can be passed through
-   expand_string and expand_one without changing them. About 90% of
-   all strings are clean, so skipping expantion on them actually does
-   save a small amount of time.
+   Test if the specified argument is clean, i.e. it does not contain
+   any tokens which need to be expanded or otherwise altered. Clean
+   strings can be passed through expand_string and expand_one without
+   changing them. About 90% of all strings are clean, so skipping
+   expantion on them actually does save a small amount of time.
 */
 static int is_clean( const wchar_t *in )
 {
@@ -114,7 +114,7 @@ static int is_clean( const wchar_t *in )
 }
 
 /**
-   Return the environment variable value for the string starting at in 
+   Return the environment variable value for the string starting at \c in. 
 */
 static wchar_t *expand_var( wchar_t *in )
 {

util.c

@@ -27,11 +27,16 @@
 #include "wutil.h"
 
 /**
-	Minimum allocated size for data structures. Used to avoid excessive
-	memory allocations for lists, hash tables, etc, which are nearly
-	empty.
+   Minimum allocated size for data structures. Used to avoid excessive
+   memory allocations for lists, hash tables, etc, which are nearly
+   empty.
 */
-#define MIN_SIZE 128
+#define MIN_SIZE 32
+
+/**
+   Minimum size for hash tables
+*/
+#define HASH_MIN_SIZE 7
 
 /**
    Maximum number of characters that can be inserted using a single
@@ -191,7 +196,11 @@ void hash_init( hash_table_t *h,
 				int (*hash_func)(const void *key),
 				int (*compare_func)(const void *key1, const void *key2) )
 {
-	hash_init2( h, hash_func, compare_func, 31 );	
+	h->arr = 0;
+	h->size = 0;
+	h->count=0;
+	h->hash_func = hash_func;
+	h->compare_func = compare_func;
 }
 
 
@@ -207,8 +216,11 @@ void hash_destroy( hash_table_t *h )
 static int hash_search( hash_table_t *h,
 						const void *key )
 {
-	int hv = h->hash_func( key );
-	int pos = abs(hv) % h->size;
+	int hv;
+	int pos;
+
+	hv = h->hash_func( key );
+	pos = abs(hv) % h->size;
 	while(1)
 	{
 		if( (h->arr[pos].key == 0 ) ||
@@ -229,9 +241,9 @@ static int hash_realloc( hash_table_t *h,
 {
 
 	/* Avoid reallocating when using pathetically small tables */
-	if( ( sz < h->size ) && (h->size < MIN_SIZE))
+	if( ( sz < h->size ) && (h->size < HASH_MIN_SIZE))
 		return 1;
-	sz = maxi( sz, MIN_SIZE );
+	sz = maxi( sz, HASH_MIN_SIZE );
 	
 	hash_struct_t *old_arr = h->arr;
 	int old_size = h->size;
@@ -294,6 +306,9 @@ int hash_put( hash_table_t *h,
 const void *hash_get( hash_table_t *h,
 					  const void *key )
 {
+	if( !h->count )
+		return 0;
+	
 	int pos = hash_search( h, key );	
 	if( h->arr[pos].key == 0 )
 		return 0;
@@ -304,6 +319,9 @@ const void *hash_get( hash_table_t *h,
 const void *hash_get_key( hash_table_t *h,
 						  const void *key )
 {	
+	if( !h->count )
+		return 0;
+	
 	int pos = hash_search( h, key );
 	if( h->arr[pos].key == 0 )
 		return 0;
@@ -321,6 +339,16 @@ void hash_remove( hash_table_t *h,
 				  const void **old_key,
 				  const void **old_val )
 {
+	if( !h->count )
+	{
+
+		if( old_key != 0 )
+			*old_key = 0;
+		if( old_val != 0 )
+			*old_val = 0;
+		return;
+	}
+
 	int pos = hash_search( h, key );
 	int next_pos;
 
@@ -377,6 +405,9 @@ void hash_remove( hash_table_t *h,
 int hash_contains( hash_table_t *h,
 				   const void *key )
 {
+	if( !h->count )
+		return 0;
+	
 	int pos = hash_search( h, key );
 	return h->arr[pos].key != 0;
 }

util.h

@@ -136,14 +136,17 @@ typedef buffer_t string_buffer_t;
    Returns the larger of two ints
 */
 int maxi( int a, int b );
+
 /**
    Returns the smaller of two ints
  */
 int mini( int a, int b );
+
 /**
    Returns the larger of two floats
 */
 float maxf( float a, float b );
+
 /**
    Returns the smaller of two floats
 */
@@ -161,14 +164,19 @@ float minf( float a, float b );
     returned. 
 */
 void q_init( dyn_queue_t *q );
+
 /** Destroy the queue */
 void q_destroy( dyn_queue_t *q );
+
 /** Insert element into queue */
 int q_put( dyn_queue_t *q, void *e );
+
 /** Remove and return next element from queue */
 void *q_get( dyn_queue_t *q);
+
 /** Return next element from queue without removing it */
 void *q_peek( dyn_queue_t *q);
+
 /** Returns 1 if the queue is empty, 0 otherwise */
 int q_empty( dyn_queue_t *q );
 
@@ -224,6 +232,7 @@ void hash_remove( hash_table_t *h,
 				  const void *key, 
 				  const void **old_key,
 				  const void **old_data );
+
 /**
    Checks whether the specified key is in the hash table
 */
@@ -235,16 +244,23 @@ int hash_contains( hash_table_t *h,
 */
 void hash_get_keys( hash_table_t *h,
 					array_list_t *arr );
+
 /**
    Appends all data elements in the table to the specified list
 */
 void hash_get_data( hash_table_t *h,
 					array_list_t *arr );
-/** Call the function func for each key/data pair in the table*/
+
+/** 
+	Call the function func for each key/data pair in the table
+*/
 void hash_foreach( hash_table_t *h, 
 				   void (*func)( const void *, const void * ) );
-/** Same as hash_foreach, but the function func takes an additional
- * argument, which is provided by the caller in the variable aux */
+
+/** 
+	Same as hash_foreach, but the function func takes an additional
+	argument, which is provided by the caller in the variable aux 
+*/
 void hash_foreach2( hash_table_t *h, void (*func)( const void *, 
 												 const void *, 
 												 void *), 
@@ -269,10 +285,11 @@ int hash_wcs_func( const void *data );
 */
 int hash_wcs_cmp( const void *a, const void *b );
 
-/** Initialize the priority queue
+/** 
+	Initialize the priority queue
 	
- \param q the queue to initialize
- \param compare a comparison function that can compare two entries in the queue
+	\param q the queue to initialize
+	\param compare a comparison function that can compare two entries in the queue
 */
 void pq_init( priority_queue_t *q,
 			  int (*compare)(void *e1, void *e2) );
@@ -289,6 +306,7 @@ int pq_put( priority_queue_t *q,
   Removes and returns the last entry in the priority queue
 */
 void *pq_get( priority_queue_t *q );
+
 /**
   Returns the last entry in the priority queue witout removing it.
 */
@@ -314,10 +332,16 @@ void pq_destroy(  priority_queue_t *q );
 */
 array_list_t *al_new();
 
-/** Initialize the list. */
+/** 
+	Initialize the list. 
+*/
 void al_init( array_list_t *l );
-/** Destroy the list and free memory used by it.*/
+
+/** 
+	Destroy the list and free memory used by it.
+*/
 void al_destroy( array_list_t *l );
+
 /**
    Append element to list
 
@@ -327,6 +351,7 @@ void al_destroy( array_list_t *l );
    \return 1 if succesfull, 0 otherwise
 */
 int al_push( array_list_t *l, const void *o );
+
 /**
    Append all elements of a list to another
 
@@ -335,6 +360,7 @@ int al_push( array_list_t *l, const void *o );
    \return 1 if succesfull, 0 otherwise
 */
 int al_push_all( array_list_t *a, array_list_t *b );
+
 /**
    Sets the element at the specified index
 
@@ -343,6 +369,7 @@ int al_push_all( array_list_t *a, array_list_t *b );
    \param o The element 
 */
 int al_set( array_list_t *l, int pos, const void *o );
+
 /**
    Returns the element at the specified index
 
@@ -351,26 +378,37 @@ int al_set( array_list_t *l, int pos, const void *o );
    \return The element 
 */
 const void *al_get( array_list_t *l, int pos );
+
 /**
   Truncates the list to new_sz items.
 */
 void al_truncate( array_list_t *l, int new_sz );
+
 /**
   Removes and returns the last entry in the list
 */
 const void *al_pop( array_list_t *l );
+
 /**
    Returns the number of elements in the list
 */
 int al_get_count( array_list_t *l );
+
 /**
   Returns the last entry in the list witout removing it.
 */
 const void *al_peek( array_list_t *l );
-/** Returns 1 if the list is empty, 0 otherwise*/
+
+/**
+   Returns 1 if the list is empty, 0 otherwise
+*/
 int al_empty( array_list_t *l);
-/** Call the function func for each entry in the list*/
+
+/** 
+	Call the function func for each entry in the list
+*/
 void al_foreach( array_list_t *l, void (*func)(const void * ));
+
 /** 
 	Same as al_foreach, but the function func takes an additional
 	argument, which is provided by the caller in the variable aux
@@ -400,7 +438,9 @@ void al_foreach2( array_list_t *l, void (*func)(const void *, void *), void *aux
 
    Which most people would find more intuitive.
 
-   The system breaks down if the user is using numbers of a base larger than 10.
+   This won't return the optimum results for numbers in bases higher
+   than ten, such as hexadecimal, but at least a stable sort order
+   will result.
 */
 int wcsfilecmp( const wchar_t *a, const wchar_t *b );
 
@@ -432,19 +472,21 @@ void sb_append_char( string_buffer_t *, wchar_t );
    Append a null terminated list of strings to the buffer.
    Example:
 
-   sb_append2( my_buff, L"foo", L"bar", 0 );
+   sb_append2( my_buff, L"foo", L"bar", (void *)0 );
+
+   Do not forget to cast the last 0 to (void *), or you might encounter errors on 64-bit platforms!
 */
 void sb_append2( string_buffer_t *, ... );
 
 /**
    Append formated string data to the buffer. This function internally
    relies on \c vswprintf, so any filter options supported by that
-   function is also supported by this function
+   function is also supported by this function.
 */
 int sb_printf( string_buffer_t *buffer, const wchar_t *format, ... );
 
 /**
-   Vararg version of sb_printf
+   Vararg version of sb_printf.
 */
 int sb_vprintf( string_buffer_t *buffer, const wchar_t *format, va_list va_orig );
 
@@ -454,15 +496,16 @@ int sb_vprintf( string_buffer_t *buffer, const wchar_t *format, va_list va_orig
 void sb_destroy( string_buffer_t * );
 
 /**
-   Truncate the buffer.
+   Truncate the buffer. This will not deallocate the memory used, it will only set the contents of the string to L"\0".
 */
 void sb_clear( string_buffer_t * );
 
 
 /**
    Initialize the specified buffer_t
- */
+*/
 void b_init( buffer_t *b);
+
 /**
    Destroy the specified buffer_t
 */