X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/mLib/blobdiff_plain/c6e0eaf00cd09a4e5237e70d8351049ec91d7653..7292c4c6e2b50cc43f17507745ff6c3e2d0057f3:/sym.c

diff --git a/sym.c b/sym.c
index a4445de..3aea8c7 100644
--- a/sym.c
+++ b/sym.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: sym.c,v 1.10 1999/12/10 23:42:04 mdw Exp $
+ * $Id: sym.c,v 1.13 2001/01/25 21:14:49 mdw Exp $
  *
  * Symbol table management
  *
@@ -30,6 +30,18 @@
 /*----- Revision history --------------------------------------------------*
  *
  * $Log: sym.c,v $
+ * Revision 1.13  2001/01/25 21:14:49  mdw
+ * Always add a terminating null, and don't count it in the length.
+ *
+ * Revision 1.12  2001/01/20 11:49:37  mdw
+ * Export tuning parameters from header file, for the benefit of other
+ * hashtable implementations.  Change the storage of symbol names: store
+ * the name after the allocated symbol block in all cases.  This replaces
+ * the previous complicated and slightly wasteful arrangement.
+ *
+ * Revision 1.11  2000/06/17 10:37:39  mdw
+ * Add support for arena management.
+ *
  * Revision 1.10  1999/12/10 23:42:04  mdw
  * Change header file guard names.
  *
@@ -74,34 +86,13 @@
 /* --- Local headers --- */
 
 #include "alloc.h"
+#include "arena.h"
 #include "bits.h"
 #include "crc32.h"
 #include "exc.h"
 #include "hash.h"
 #include "sub.h"
 #include "sym.h"
-#include "track.h"
-
-/*----- Tuning parameters -------------------------------------------------*/
-
-/* --- Initial hash table size --- *
- *
- * This is the initial @mask@ value.  It must be of the form %$2^n - 1$%,
- * so that it can be used to mask of the bottom bits of a hash value.
- */
-
-#define SYM_INITSZ 64			/* Size of a new hash table */
-
-/* --- Maximum load factor --- *
- *
- * This parameter controls how much the table has to be loaded before the
- * table is extended.  The number of elements %$n$%, the number of bins %$b$%
- * and the limit %$l$% satisfy the relation %$n < bl$%; if a new item is
- * added to the table and this relation is found to be false, the table is
- * doubled in size.
- */
-
-#define SYM_LIMIT(n) ((n) * 2)		/* Load factor for growing table */
 
 /*----- Main code ---------------------------------------------------------*/
 
@@ -117,11 +108,9 @@
 
 void sym_create(sym_table *t)
 {
-  TRACK_CTX("symbol table creation");
-  TRACK_PUSH;
   hash_create(&t->t, SYM_INITSZ);
+  t->s = &sub_global;
   t->load = SYM_LIMIT(SYM_INITSZ);
-  TRACK_POP;
 }
 
 /* --- @sym_destroy@ --- *
@@ -138,22 +127,15 @@ void sym_destroy(sym_table *t)
 {
   sym_iter i;
 
-  TRACK_CTX("symbol table destruction");
-  TRACK_PUSH;
-
   SYM_MKITER(&i, t);
   for (;;) {
     sym_base *p;
     SYM_NEXT(&i, p);
     if (!p)
       break;
-    if (p->len > SYM_BUFSZ)
-      sub_free(p->name.p, p->len);
-    free(p);
+    x_free(t->t.a, p);
   }
   hash_destroy(&t->t);
-
-  TRACK_POP;
 }
 
 /* --- @sym_find@ --- *
@@ -196,7 +178,7 @@ void *sym_find(sym_table *t, const char *n, long l, size_t sz, unsigned *f)
 
   /* --- Find the correct bin --- */
 
-  len = l < 0 ? strlen(n) + 1 : l;
+  len = l < 0 ? strlen(n) : l;
   CRC32(hash, 0, n, len);
   bin = HASH_BIN(&t->t, hash);
 
@@ -228,34 +210,18 @@ void *sym_find(sym_table *t, const char *n, long l, size_t sz, unsigned *f)
   if (f) *f = 0;
   if (!sz) return (0);
 
-  /* --- Create a new symbol block and initialize it --- */
-
-  {
-    TRACK_CTX("new symbol creation");
-    TRACK_PUSH;
-
-    q = xmalloc(sz);
-    q->b.next = *bin;
-    q->b.hash = hash;
-    q->len = len;
-    if (n) {
-      if (len <= SYM_BUFSZ)
-	memcpy(q->name.b, n, len);
-      else {
-	TRY {
-	  q->name.p = sub_alloc(len);
-	  memcpy(q->name.p, n, len);
-	} CATCH {
-	  free(q);
-	  TRACK_POP;
-	  RETHROW;
-	} END_TRY;
-      }
-    }
-
-    TRACK_POP;
-  }
-
+  /* --- Create a new symbol block and initialize it --- *
+   *
+   * The name is attached to the end of the symbol block.
+   */
+
+  q = x_alloc(t->t.a, sz + len + 1);
+  q->b.next = *bin;
+  q->b.hash = hash;
+  q->name = (char *)q + sz;
+  memcpy(q->name, n, len);
+  q->name[len] = 0;
+  q->len = len;
   *bin = &q->b;
 
   /* --- Consider growing the array --- */
@@ -263,7 +229,7 @@ void *sym_find(sym_table *t, const char *n, long l, size_t sz, unsigned *f)
   if (t->load)
     t->load--;
   if (!t->load && hash_extend(&t->t))
-    t->load = SYM_LIMIT(t->t.mask / 2 + 1);
+    t->load = SYM_LIMIT(t->t.mask + 1);
 
   /* --- Finished that, so return the new symbol block --- */
 
@@ -286,9 +252,7 @@ void sym_remove(sym_table *t, void *p)
 {
   sym_base *q = p;
   hash_remove(&t->t, &q->b);
-  if (q->len > SYM_BUFSZ)
-    sub_free(q->name.p, q->len);
-  free(q);
+  xfree(q);
   t->load++;
 }