From: Robert Spalek <robert@ucw.cz>
Date: Sun, 30 Apr 2006 16:53:19 +0000 (+0200)
Subject: conf: redesign dynamic arrays; things get cleaner and start to work now
X-Git-Tag: holmes-import~645^2~3
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=894ab13170a1f14ec1920976c531fe02ffb5a2ab;p=libucw.git

conf: redesign dynamic arrays; things get cleaner and start to work now
---

diff --git a/lib/conf-dump.c b/lib/conf-dump.c
index fe4a7c24..ee137ab1 100644
--- a/lib/conf-dump.c
+++ b/lib/conf-dump.c
@@ -75,7 +75,7 @@ dump_item(struct fastbuf *fb, struct cf_item *item, int level, void *ptr)
   } else if (item->cls == CC_DYNAMIC) {
     ptr = * (void**) ptr;
     if (ptr) {
-      int real_nr = * (int*) (ptr - size);
+      int real_nr = DARY_LEN(ptr);
       bprintf(fb, "N%d ", real_nr);
       for (i=0; i<real_nr; i++)
 	dump_basic(fb, ptr + i * size, type, &item->u);
diff --git a/lib/conf-internal.h b/lib/conf-internal.h
index b31fc8c1..3760d0e5 100644
--- a/lib/conf-internal.h
+++ b/lib/conf-internal.h
@@ -20,7 +20,6 @@ enum cf_operation;
 extern byte *cf_op_names[];
 
 uns cf_type_size(enum cf_type type, struct cf_user_type *utype);
-byte *cf_interpret_clear(struct cf_item *item, void *ptr);
 byte *cf_interpret_line(byte *name, enum cf_operation op, int number, byte **pars);
 void cf_init_stack(void);
 int cf_check_stack(void);
diff --git a/lib/conf-intr.c b/lib/conf-intr.c
index 0b84707e..7b1564e2 100644
--- a/lib/conf-intr.c
+++ b/lib/conf-intr.c
@@ -109,8 +109,8 @@ interpret_set_dynamic(struct cf_item *item, int number, byte **pars, void **ptr)
   // boundary checks done by the caller
   uns size = cf_type_size(item->type, item->u.utype);
   ASSERT(size >= sizeof(uns));
-  *ptr = cf_malloc((number+1) * size) + size;
-  * (uns*) (*ptr - size) = number;
+  *ptr = cf_malloc(sizeof(uns) + number * size) + sizeof(uns);
+  DARY_LEN(*ptr) = number;
   return cf_parse_ary(number, pars, *ptr, type, &item->u);
 }
 
@@ -121,12 +121,12 @@ interpret_add_dynamic(struct cf_item *item, int number, byte **pars, int *proces
   void *old_p = *ptr;
   uns size = cf_type_size(item->type, item->u.utype);
   ASSERT(size >= sizeof(uns));
-  int old_nr = old_p ? * (int*) (old_p - size) : 0;
+  int old_nr = old_p ? DARY_LEN(old_p) : 0;
   int taken = MIN(number, ABS(item->number)-old_nr);
   *processed = taken;
   // stretch the dynamic array
-  void *new_p = cf_malloc((old_nr + taken + 1) * size) + size;
-  * (uns*) (new_p - size) = old_nr + taken;
+  void *new_p = cf_malloc(sizeof(uns) + (old_nr + taken) * size) + sizeof(uns);
+  DARY_LEN(new_p) = old_nr + taken;
   cf_journal_block(ptr, sizeof(void*));
   *ptr = new_p;
   if (op == OP_APPEND) {
@@ -264,20 +264,16 @@ interpret_set_item(struct cf_item *item, int number, byte **pars, int *processed
   }
 }
 
-byte *
-cf_interpret_clear(struct cf_item *item, void *ptr)
+static byte *
+interpret_clear(struct cf_item *item, void *ptr)
 {
   if (item->cls == CC_LIST) {
     cf_journal_block(ptr, sizeof(clist));
     clist_init(ptr);
   } else if (item->cls == CC_DYNAMIC) {
     cf_journal_block(ptr, sizeof(void *));
-    uns size = cf_type_size(item->type, item->u.utype);
-    static u64 zero = 0;
-    if (size <= sizeof(zero))
-      *(void**)ptr = (&zero) + 1;
-    else
-      *(void**)ptr = cf_malloc_zero(size) + size;
+    static uns zero = 0;
+    * (void**) ptr = (&zero) + 1;
   } else if (item->cls == CC_STATIC && item->type == CT_STRING) {
     cf_journal_block(ptr, item->number * sizeof(byte*));
     bzero(ptr, item->number * sizeof(byte*));
@@ -492,7 +488,7 @@ cf_interpret_line(byte *name, enum cf_operation op, int number, byte **pars)
 
   int taken;			// process as many parameters as possible
   if (op == OP_CLEAR)
-    taken = 0, msg = cf_interpret_clear(item, ptr);
+    taken = 0, msg = interpret_clear(item, ptr);
   else if (op == OP_SET)
     msg = interpret_set_item(item, number, pars, &taken, ptr, 1);
   else if (item->cls == CC_DYNAMIC)
@@ -536,7 +532,7 @@ cf_write_item(struct cf_item *item, enum cf_operation op, int number, byte **par
       break;
     case OP_CLEAR:
       taken = 0;
-      msg = cf_interpret_clear(item, item->ptr);
+      msg = interpret_clear(item, item->ptr);
       break;
     case OP_APPEND:
     case OP_PREPEND:
diff --git a/lib/conf-section.c b/lib/conf-section.c
index b3d16ed2..a916d7d8 100644
--- a/lib/conf-section.c
+++ b/lib/conf-section.c
@@ -170,8 +170,10 @@ commit_section(struct cf_section *sec, void *ptr, uns commit_all)
 	}
     } else if (ci->cls == CC_DYNAMIC) {
       void **dyn = ptr + (addr_int_t) ci->ptr;
-      if (!*dyn)			// replace NULL by an empty array
-	cf_interpret_clear(ci, dyn);
+      if (!*dyn) {			// replace NULL by an empty array
+	static uns zero = 0;
+	*dyn = (&zero) + 1;
+      }
     }
   if (sec->commit) {
     /* We have to process the whole tree of sections even if just a few changes
diff --git a/lib/conf-test.c b/lib/conf-test.c
index 0a4209da..cefaa212 100644
--- a/lib/conf-test.c
+++ b/lib/conf-test.c
@@ -30,10 +30,8 @@ static struct sub_sect_1 sec1 = { {}, "Charlie", 0, "WBAFC", { 0, -1}, DARY_ALLO
 static byte *
 init_sec_1(struct sub_sect_1 *s)
 {
-  if (s == &sec1) {			// this is a static variable; skip clearing
-    DARY_LEN(sec1.list) = 3;		// XXX: fix for the bug in DARY_ALLOC()
+  if (s == &sec1)			// this is a static variable; skip clearing
     return NULL;
-  }
   s->name = "unknown";
   s->level = "default";
   s->confidence[0] = 5;
diff --git a/lib/conf.h b/lib/conf.h
index beb4c449..82b46dd0 100644
--- a/lib/conf.h
+++ b/lib/conf.h
@@ -129,10 +129,10 @@ struct cf_section {
 /* If you aren't picky about the number of parameters */
 #define CF_ANY_NUM		-0x7fffffff
 
-#define DARY_LEN(a) *(uns*)(a-1)
+#define DARY_LEN(a) ((uns*)a)[-1]
   // length of a dynamic array
-#define DARY_ALLOC(type,len,val...) (type[]) { (type)len, ##val } + 1
-  // creates a static instance of a dynamic array, works only for integer and pointer types
+#define DARY_ALLOC(type,len,val...) ((struct { uns l; type a[len]; }) { .l = len, .a = { val } }).a
+  // creates a static instance of a dynamic array
 
 /* Memory allocation: conf-alloc.c */
 struct mempool;