xref: /xsrc/external/mit/bdftopcf/dist/atom.c

/*

Copyright 1990, 1994, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.

*/

/*
 * Author:  Keith Packard, MIT X Consortium
 */

/* lame atom replacement routines for font applications */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "fontmisc.h"

typedef struct _AtomList {
    char        *name;
    unsigned int len;
    int          hash;
    Atom         atom;
} AtomListRec, *AtomListPtr;

static AtomListPtr *hashTable;

static unsigned hashSize, hashUsed;
static unsigned hashMask;
static unsigned rehash;

static AtomListPtr *reverseMap;
static size_t reverseMapSize;
static Atom lastAtom;

static unsigned
Hash(const char *string, unsigned len)
{
    unsigned h = 0;

    while (len--)
        h = (h << 3) ^ *string++;

    return h;
}

static int
ResizeHashTable(void)
{
    unsigned newHashSize;
    unsigned newHashMask;
    AtomListPtr *newHashTable;
    unsigned newRehash;

    if (hashSize == 0)
        newHashSize = 1024;
    else
        newHashSize = hashSize * 2;
    newHashTable = calloc(newHashSize, sizeof(AtomListPtr));
    if (!newHashTable) {
        fprintf(stderr, "ResizeHashTable(): Error: Couldn't allocate"
                " newHashTable (%ld)\n",
                newHashSize * (unsigned long) sizeof(AtomListPtr));
        return FALSE;
    }
    newHashMask = newHashSize - 1;
    newRehash = (newHashMask - 2);
    for (int i = 0; i < hashSize; i++) {
        if (hashTable[i]) {
            unsigned h = (hashTable[i]->hash) & newHashMask;
            if (newHashTable[h]) {
                unsigned r = hashTable[i]->hash % newRehash | 1;
                do {
                    h += r;
                    if (h >= newHashSize)
                        h -= newHashSize;
                } while (newHashTable[h]);
            }
            newHashTable[h] = hashTable[i];
        }
    }
    free(hashTable);
    hashTable = newHashTable;
    hashSize = newHashSize;
    hashMask = newHashMask;
    rehash = newRehash;
    return TRUE;
}

static int
ResizeReverseMap(void)
{
    AtomListPtr *newMap;
    size_t newMapSize;

    if (reverseMapSize == 0)
        newMapSize = 1000;
    else
        newMapSize = reverseMapSize * 2;
    newMap = realloc(reverseMap, newMapSize * sizeof(AtomListPtr));
    if (newMap == NULL) {
        fprintf(stderr, "ResizeReverseMap(): Error: Couldn't reallocate"
                " reverseMap (%ld)\n",
                newMapSize * (unsigned long) sizeof(AtomListPtr));
        return FALSE;
    }
    reverseMap = newMap;
    reverseMapSize = newMapSize;
    return TRUE;
}

static int
NameEqual(const char *a, const char *b, int l)
{
    while (l--)
        if (*a++ != *b++)
            return FALSE;
    return TRUE;
}

Atom
MakeAtom(const char *string, unsigned len, int makeit)
{
    AtomListPtr a;
    unsigned hash;
    unsigned h = 0;
    unsigned r;

    hash = Hash(string, len);
    if (hashTable) {
        h = hash & hashMask;
        if (hashTable[h]) {
            if (hashTable[h]->hash == hash && hashTable[h]->len == len &&
                NameEqual(hashTable[h]->name, string, len)) {
                return hashTable[h]->atom;
            }
            r = (hash % rehash) | 1;
            for (;;) {
                h += r;
                if (h >= hashSize)
                    h -= hashSize;
                if (!hashTable[h])
                    break;
                if (hashTable[h]->hash == hash && hashTable[h]->len == len &&
                    NameEqual(hashTable[h]->name, string, len)) {
                    return hashTable[h]->atom;
                }
            }
        }
    }
    if (!makeit)
        return None;
    a = malloc(sizeof(AtomListRec) + len + 1);
    if (a == NULL) {
        fprintf(stderr, "MakeAtom(): Error: Couldn't allocate AtomListRec"
                " (%ld)\n", (unsigned long) sizeof(AtomListRec) + len + 1);
        return None;
    }
    a->name = (char *) (a + 1);
    a->len = len;
    strncpy(a->name, string, len);
    a->name[len] = '\0';
    a->atom = ++lastAtom;
    a->hash = hash;
    if (hashUsed >= hashSize / 2) {
        ResizeHashTable();
        h = hash & hashMask;
        if (hashTable[h]) {
            r = (hash % rehash) | 1;
            do {
                h += r;
                if (h >= hashSize)
                    h -= hashSize;
            } while (hashTable[h]);
        }
    }
    hashTable[h] = a;
    hashUsed++;
    if (reverseMapSize <= a->atom) {
        if (!ResizeReverseMap())
            return None;
    }
    reverseMap[a->atom] = a;
    return a->atom;
}

char *
NameForAtom(Atom atom)
{
    if (atom != None && atom <= lastAtom)
        return reverseMap[atom]->name;
    return NULL;
}