From f3124e728b7386f7361d0459ad0e3431e16865ff Mon Sep 17 00:00:00 2001
From: Bruno Raoult <braoult@gmail.com>
Date: Sat, 30 Oct 2021 11:42:01 +0200
Subject: [PATCH] pool.c: remove pool (list_head) offset, std: c99 -> gnu99

---
 .gitignore |  3 ++-
 Makefile   | 13 +++++++++----
 src/pool.c | 32 ++++++++++++--------------------
 src/pool.h |  6 ++----
 4 files changed, 25 insertions(+), 29 deletions(-)

diff --git a/.gitignore b/.gitignore
index 15ae6f7..30aeb2f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,4 +2,5 @@ core
 GPATH
 GRTAGS
 GTAGS
-fen
\ No newline at end of file
+fen
+pool
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 0d8565d..e8cfdd6 100644
--- a/Makefile
+++ b/Makefile
@@ -5,14 +5,14 @@ SRCDIR=./src
 
 SRC=$(wildcard $(SRCDIR)/*.c)
 INC=$(wildcard $(SRCDIR)/*.h)
-BIN=fen
+BIN=fen pool
 
-CFLAGS += -std=c99
+CFLAGS += -std=gnu99
 CFLAGS += -g
 CFLAGS += -Wall
 CFLAGS += -Wextra
-CFLAGS += -pedantic
-CFLAGS += -Wno-pointer-arith
+#CFLAGS += -pedantic
+#CFLAGS += -Wno-pointer-arith
 #CFLAGS += -Werror
 CFLAGS += -Wmissing-declarations
 
@@ -26,3 +26,8 @@ fen: CFLAGS+=-DFENBIN
 fen: $(SRC)
 	echo SRC=$(SRC)
 	$(CC) $(CFLAGS) $? -o $@
+
+pool: CFLAGS+=-DPOOLBIN
+pool: $(SRC)
+	echo SRC=$(SRC)
+	$(CC) $(CFLAGS) $? -o $@
diff --git a/src/pool.c b/src/pool.c
index f48e722..7b60b14 100644
--- a/src/pool.c
+++ b/src/pool.c
@@ -18,11 +18,8 @@
 
 #include <stddef.h>
 #include <malloc.h>
-//extern char* strdup(const char*);
 #include <string.h>
 #include <stdlib.h>
-//#include <stdio.h>
-
 #include "list.h"
 #include "pool.h"
 
@@ -34,23 +31,23 @@ void pool_stats(pool_t *pool)
         printf("alloc:%u ", pool->allocated);
         printf("grow:%u ", pool->growsize);
         printf("eltsize:%lu ", pool->eltsize);
-        printf("offset:%lu ", pool->list_offset);
         printf("\n");
     }
 }
 
-pool_t *pool_init(const char *name, uint32_t growsize, size_t eltsize,
-                  ptrdiff_t list_offset)
+pool_t *pool_init(const char *name, uint32_t growsize, size_t eltsize)
 {
     pool_t *pool;
 
+    /* we need at least this space in struct */
+    if (eltsize < sizeof (struct list_head))
+        return NULL;
     if ((pool = malloc(sizeof (*pool)))) {
         pool->name = strdup(name);
         pool->growsize = growsize;
         pool->eltsize = eltsize;
         pool->available = 0;
         pool->allocated = 0;
-        pool->list_offset = list_offset;
         INIT_LIST_HEAD(&pool->head);
     }
     return pool;
@@ -74,8 +71,7 @@ static uint32_t _pool_add(pool_t *pool, struct list_head *elt)
 
 uint32_t pool_add(pool_t *pool, void *elt)
 {
-    struct list_head *plist = elt + pool->list_offset;;
-    return _pool_add(pool, plist);
+    return _pool_add(pool, elt);
 }
 
 static struct list_head *_pool_get(pool_t *pool)
@@ -83,7 +79,7 @@ static struct list_head *_pool_get(pool_t *pool)
     struct list_head *res = pool->head.next;
     pool->available--;
     list_del(res);
-    //printf("%s: res=%p\n", __func__, (void *)res);
+    // printf("%s: res=%p\n", __func__, (void *)res);
     return res;
 }
 
@@ -96,7 +92,6 @@ void *pool_get(pool_t *pool)
                pool->allocated);
         void *alloc = malloc(pool->eltsize * pool->growsize);
         void *cur;
-        struct list_head *plist;
         uint32_t i;
 
         if (!alloc)
@@ -105,16 +100,13 @@ void *pool_get(pool_t *pool)
         //printf("       (old=%u)\n", pool->allocated);
         for (i = 0; i < pool->growsize; ++i) {
             cur = alloc + i * pool->eltsize;
-            plist = cur + pool->list_offset;
-            printf("%s: alloc=%p cur=%p plist=%p off=%lu\n", __func__,
-                   alloc, cur, (void *)plist, (void *)plist-cur);
-            _pool_add(pool, plist);
+            printf("%s: alloc=%p cur=%p\n", __func__,
+                   alloc, cur);
+            _pool_add(pool, (struct list_head *)cur);
         }
     }
-    //list_del(pool->head.next);
-    void *res = _pool_get(pool);
-    printf("%s: returning %p pointer\n", __func__, res);
-    return res - pool->list_offset;
+    //printf("%s: returning %p pointer\n", __func__, res);
+    return  _pool_get(pool);
 }
 
 #ifdef POOLBIN
@@ -138,7 +130,7 @@ int main(int ac, char**av)
     printf("%s: sizeof(d)=%lu sizeof(*d)=%lu off=%lu\n", *av, sizeof(elt),
            sizeof(*elt), offsetof(struct d, list));
 
-    if ((pool = pool_init("dummy", 3, sizeof(*elt), offsetof(struct d, list)))) {
+    if ((pool = pool_init("dummy", 3, sizeof(*elt)))) {
         pool_stats(pool);
         for (int cur=1; cur<ac; ++cur) {
             total = atoi(av[cur]);
diff --git a/src/pool.h b/src/pool.h
index 7ee6f74..fb144aa 100644
--- a/src/pool.h
+++ b/src/pool.h
@@ -1,4 +1,4 @@
-/* pool.h - A simple pool manager.
+/* pool.h - A simple memory pool manager.
  *
  * Copyright (C) 2021 Bruno Raoult ("br")
  * Licensed under the GNU General Public License v3.0 or later.
@@ -24,13 +24,11 @@ typedef struct {
     uint32_t allocated;
     uint32_t growsize;
     size_t eltsize;
-    ptrdiff_t list_offset;
     struct list_head head;
 } pool_t;
 
 void pool_stats(pool_t *pool);
-pool_t *pool_init(const char *name, uint32_t grow, size_t size, ptrdiff_t offset);
-//pool_t *pool_init(const char *name, uint32_t grow, size_t size);
+pool_t *pool_init(const char *name, uint32_t grow, size_t size);
 void *pool_get(pool_t *pool);
 uint32_t pool_add(pool_t *pool, void *elt);