/* -*-c-*-
*
- * $Id: sym.c,v 1.6 1999/05/26 21:08:31 mdw Exp $
+ * $Id: sym.c,v 1.7 1999/06/01 09:49:08 mdw Exp $
*
* Symbol table management
*
/*----- Revision history --------------------------------------------------*
*
* $Log: sym.c,v $
+ * Revision 1.7 1999/06/01 09:49:08 mdw
+ * Allow things to be looked up by just their caller-supplied hashes. This
+ * actually needs to be thought through better.
+ *
* Revision 1.6 1999/05/26 21:08:31 mdw
* Rename symbols in line with newer conventions.
*
/* --- Local headers --- */
#include "alloc.h"
+#include "bits.h"
#include "crc32.h"
#include "exc.h"
#include "sub.h"
* may be given, in which case the name may contain arbitrary
* binary data, or it may be given as a negative number, in
* which case the length of the name is calculated as
- * @strlen(n) + 1@.
+ * @strlen(n) + 1@. The name pointer @n@ may also be zero; in
+ * this case, @l@ is taken to be a raw hash, and any element
+ * with a matching hash is taken to be the one wanted.
*
* The return value is the address of a pointer to a @sym_base@
* block (which may have other things on the end, as above). If
void *sym_find(sym_table *t, const char *n, long l, size_t sz, unsigned *f)
{
- unsigned long hash; /* Hash value for user's name */
- size_t len = l < 0 ? strlen(n) + 1 : l; /* Find length of user's name */
- sym_base *bin; /* Bin containing our item */
- sym_base *p, *q; /* Pointer wandering through list */
+ uint32 hash;
+ size_t len = 0;
+ sym_base *bin;
+ sym_base *p, *q;
/* --- Find the correct bin --- */
- CRC32(hash, 0, n, len); /* Find hash value for this name */
+ if (n) {
+ len = l < 0 ? strlen(n) + 1 : l;
+ CRC32(hash, 0, n, len);
+ } else
+ hash = (uint32)l;
bin = p = (sym_base *)(t->a + (hash & t->mask));
/* --- Search the bin list --- */
while (p->next) {
- if (hash == p->next->hash && /* Check full hash values first */
- len == p->next->len && /* Then compare string lengths */
- !memcmp(n, SYM_NAME(p->next), len)) /* And finally compare names */
+ if (hash == p->next->hash &&
+ (n == 0 || (len == p->next->len &&
+ !memcmp(n, SYM_NAME(p->next), len))))
{
/* --- Found a match --- *
*
* front of its bin list.
*/
- q = p->next; /* Find the actual symbol block */
- p->next = q->next; /* Extract block from bin list */
- q->next = bin->next; /* Set up symbol's next pointer */
- bin->next = q; /* And reinsert the block */
+ q = p->next;
+ p->next = q->next;
+ q->next = bin->next;
+ bin->next = q;
/* --- Return the block --- */
- if (f) *f = 1; /* Didn't fail to find the item */
- return (q); /* And return the block */
+ if (f) *f = 1;
+ return (q);
}
- p = p->next; /* Move onto the next item */
+ p = p->next;
}
/* --- Couldn't find the item there --- */
- if (f) *f = 0; /* Failed to find the block */
- if (!sz) return (0); /* Return zero if not creating */
+ if (f) *f = 0;
+ if (!sz) return (0);
/* --- Create a new symbol block and initialize it --- */
TRACK_CTX("new symbol creation");
TRACK_PUSH;
- p = xmalloc(sz); /* Create a new symbol block */
- p->next = bin->next; /* Set up the next pointer */
- p->hash = hash; /* Set up the hash value too */
- p->len = len; /* And set up the string length */
- if (len <= SYM_BUFSZ)
- memcpy(p->name.b, n, len); /* And copy the string over */
- else {
- TRY {
- p->name.p = sub_alloc(len); /* Allocate a block for the name */
- memcpy(p->name.p, n, len); /* And copy the string over */
- } CATCH {
- free(p);
- TRACK_POP;
- RETHROW;
- } END_TRY;
+ p = xmalloc(sz);
+ p->next = bin->next;
+ p->hash = hash;
+ p->len = len;
+ if (n) {
+ if (len <= SYM_BUFSZ)
+ memcpy(p->name.b, n, len);
+ else {
+ TRY {
+ p->name.p = sub_alloc(len);
+ memcpy(p->name.p, n, len);
+ } CATCH {
+ free(p);
+ TRACK_POP;
+ RETHROW;
+ } END_TRY;
+ }
}
TRACK_POP;
}
- bin->next = p; /* Put the pointer into the bin */
+ bin->next = p;
/* --- Consider growing the array --- */
if (t->c)
t->c--;
if (!t->c) {
- unsigned long m = t->mask + 1; /* Next set bit in has word */
- sym_base *p, *q, *r; /* More useful pointers */
- size_t i, lim; /* Loop counter and limit */
+ uint32 m = t->mask + 1;
+ sym_base *p, *q, *r;
+ size_t i, lim;
TRACK_CTX("symbol table extension");
TRACK_PUSH;
RETHROW;
} END_TRY;
- t->c = SYM_LIMIT(t->mask + 1); /* Set load value */
- t->mask = (t->mask + 1) * 2 - 1; /* Set the new mask value */
+ t->c = SYM_LIMIT(t->mask + 1);
+ t->mask = (t->mask + 1) * 2 - 1;
/* --- Now wander through the table rehashing things --- *
*
lim = (t->mask + 1) >> 1;
for (i = 0; i < lim; i++) {
- /* --- Some initialisation --- */
+ /* --- Some initialization --- */
- r = t->a[i]; /* Find the list we're dissecting */
- p = (sym_base *)(t->a + i); /* Find bit-clear list */
- q = (sym_base *)(t->a + i + lim); /* And the bit-set lsit */
+ r = t->a[i];
+ p = (sym_base *)(t->a + i);
+ q = (sym_base *)(t->a + i + lim);
/* --- Now go through the @r@ list --- */
while (r) {
- if (r->hash & m) /* Is the next bit set? */
- q = q->next = r; /* Yes, so fit up previous link */
+ if (r->hash & m)
+ q = q->next = r;
else
- p = p->next = r; /* No, so fit up previous link */
- r = r->next; /* Move onto the next item */
+ p = p->next = r;
+ r = r->next;
}
- p->next = q->next = 0; /* Null terminate the new lists */
+ p->next = q->next = 0;
}
TRACK_POP;
~mdw / mLib / blobdiff