/* HTAtom.c
** ATOMS: STRINSGS TO NUMBERS
**
** (c) COPYRIGHT MIT 1995.
** Please first read the full copyright statement in the file COPYRIGH.
** @(#) $Id: HTAtom.c,v 2.23 1996/06/03 19:25:06 eric Exp $
**
** Atoms are names which are given representative pointer values
** so that they can be stored more efficiently, and comparisons
** for equality done more efficiently.
**
** Atoms are kept in a hash table consisting of an array of linked lists.
**
** Authors:
** TBL Tim Berners-Lee, WorldWideWeb project, CERN
**
*/
/* Library include files */
#include "sysdep.h"
#include "HTUtils.h"
#include "HTString.h"
#include "HTList.h"
#include "HTAtom.h"
#define HASH_SIZE 101 /* Tunable */
PRIVATE HTAtom * hash_table[HASH_SIZE];
PRIVATE BOOL initialised = NO;
/*
** Finds an atom representation for a string. The atom doesn't have to be
** a new one but can be an already existing atom.
*/
PUBLIC HTAtom * HTAtom_for (const char * string)
{
int hash;
const char * p;
HTAtom * a;
/* First time around, clear hash table
*/
if (!initialised) {
memset((void *) hash_table, '\0', sizeof(HTAtom *) * HASH_SIZE);
initialised = YES;
}
/* Generate hash function
*/
for (p=string, hash=0; *p; p++) {
hash = (hash * 3 +(*(unsigned char *) p)) % HASH_SIZE;
}
/* Search for the string in the list
*/
for (a=hash_table[hash]; a; a=a->next) {
if (0==strcmp(a->name, string)) {
/* if (WWWTRACE) HTTrace(
"HTAtom: Old atom %p for `%s'\n", a, string); */
return a; /* Found: return it */
}
}
/* Generate a new entry
*/
if ((a = (HTAtom *) HT_MALLOC(sizeof(*a))) == NULL)
HT_OUTOFMEM("HTAtom_for");
if ((a->name = (char *) HT_MALLOC(strlen(string)+1)) == NULL)
HT_OUTOFMEM("HTAtom_for");
strcpy(a->name, string);
a->next = hash_table[hash]; /* Put onto the head of list */
hash_table[hash] = a;
/* if (WWWTRACE) HTTrace("HTAtom: New atom %p for `%s'\n", a, string); */
return a;
}
/*
** CASE INSENSITIVE VERSION OF HTAtom_for()
** Finds an atom representation for a string. The atom doesn't have to be
** a new one but can be an already existing atom.
*/
PUBLIC HTAtom * HTAtom_caseFor (const char * string)
{
int hash;
const char * p;
HTAtom * a;
/* First time around, clear hash table
*/
if (!initialised) {
memset((void *) hash_table, '\0', sizeof(HTAtom *) * HASH_SIZE);
initialised = YES;
}
/* Generate hash function
*/
for(p=string, hash=0; *p; p++) {
hash = (hash * 3 + *p) % HASH_SIZE;
}
/* Search for the string in the list
*/
for (a=hash_table[hash]; a; a=a->next) {
if (!strcasecomp(a->name, string)) {
return a; /* Found: return it */
}
}
/* Generate a new entry
*/
if ((a = (HTAtom *) HT_MALLOC(sizeof(*a))) == NULL)
HT_OUTOFMEM("HTAtom_for");
if ((a->name = (char *) HT_MALLOC(strlen(string)+1)) == NULL)
HT_OUTOFMEM("HTAtom_for");
strcpy(a->name, string);
a->next = hash_table[hash]; /* Put onto the head of list */
hash_table[hash] = a;
return a;
}
/*
** This function cleans up the memory used by atoms.
** Written by Eric Sink, eric@spyglass.com
*/
PUBLIC void HTAtom_deleteAll (void)
{
int i;
HTAtom *cur;
HTAtom *next;
for (i=0; i<HASH_SIZE; i++) {
if (hash_table[i]) {
cur = hash_table[i];
while (cur) {
next = cur->next;
HT_FREE(cur->name);
HT_FREE(cur);
cur = next;
}
}
}
initialised = NO;
}
PRIVATE BOOL mime_match (const char * name, const char * templ)
{
if (name && templ) {
static char *n1 = NULL;
static char *t1 = NULL;
char *n2;
char *t2;
StrAllocCopy(n1, name); /* These also HT_FREE the ones */
StrAllocCopy(t1, templ); /* from previous call. */
if (!(n2 = strchr(n1, '/')) || !(t2 = strchr(t1, '/')))
return NO;
*(n2++) = (char)0;
*(t2++) = (char)0;
if ((0==strcmp(t1, "*") || 0==strcmp(t1, n1)) &&
(0==strcmp(t2, "*") || 0==strcmp(t2, n2)))
return YES;
}
return NO;
}
PUBLIC HTList *HTAtom_templateMatches (const char * templ)
{
HTList *matches = HTList_new();
if (initialised && templ) {
int i;
HTAtom *cur;
for (i=0; i<HASH_SIZE; i++) {
for (cur = hash_table[i]; cur; cur=cur->next) {
if (mime_match(cur->name, templ))
HTList_addObject(matches, (void*)cur);
}
}
}
return matches;
}
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