1 files changed, 113 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/com32/lib/free.c b/contrib/syslinux-4.02/com32/lib/free.c
new file mode 100644
index 0000000..be23865
--- /dev/null
+++ b/contrib/syslinux-4.02/com32/lib/free.c
@@ -0,0 +1,113 @@
+/*
+ * free.c
+ *
+ * Very simple linked-list based malloc()/free().
+ */
+
+#include <stdlib.h>
+#include "malloc.h"
+
+static struct free_arena_header *__free_block(struct free_arena_header *ah)
+{
+    struct free_arena_header *pah, *nah;
+
+    pah = ah->a.prev;
+    nah = ah->a.next;
+    if (pah->a.type == ARENA_TYPE_FREE &&
+	(char *)pah + pah->a.size == (char *)ah) {
+	/* Coalesce into the previous block */
+	pah->a.size += ah->a.size;
+	pah->a.next = nah;
+	nah->a.prev = pah;
+
+#ifdef DEBUG_MALLOC
+	ah->a.type = ARENA_TYPE_DEAD;
+#endif
+
+	ah = pah;
+	pah = ah->a.prev;
+    } else {
+	/* Need to add this block to the free chain */
+	ah->a.type = ARENA_TYPE_FREE;
+
+	ah->next_free = __malloc_head.next_free;
+	ah->prev_free = &__malloc_head;
+	__malloc_head.next_free = ah;
+	ah->next_free->prev_free = ah;
+    }
+
+    /* In either of the previous cases, we might be able to merge
+       with the subsequent block... */
+    if (nah->a.type == ARENA_TYPE_FREE &&
+	(char *)ah + ah->a.size == (char *)nah) {
+	ah->a.size += nah->a.size;
+
+	/* Remove the old block from the chains */
+	nah->next_free->prev_free = nah->prev_free;
+	nah->prev_free->next_free = nah->next_free;
+	ah->a.next = nah->a.next;
+	nah->a.next->a.prev = ah;
+
+#ifdef DEBUG_MALLOC
+	nah->a.type = ARENA_TYPE_DEAD;
+#endif
+    }
+
+    /* Return the block that contains the called block */
+    return ah;
+}
+
+/*
+ * This is used to insert a block which is not previously on the
+ * free list.  Only the a.size field of the arena header is assumed
+ * to be valid.
+ */
+void __inject_free_block(struct free_arena_header *ah)
+{
+    struct free_arena_header *nah;
+    size_t a_end = (size_t) ah + ah->a.size;
+    size_t n_end;
+
+    for (nah = __malloc_head.a.next; nah->a.type != ARENA_TYPE_HEAD;
+	 nah = nah->a.next) {
+	n_end = (size_t) nah + nah->a.size;
+
+	/* Is nah entirely beyond this block? */
+	if ((size_t) nah >= a_end)
+	    break;
+
+	/* Is this block entirely beyond nah? */
+	if ((size_t) ah >= n_end)
+	    continue;
+
+	/* Otherwise we have some sort of overlap - reject this block */
+	return;
+    }
+
+    /* Now, nah should point to the successor block */
+    ah->a.next = nah;
+    ah->a.prev = nah->a.prev;
+    nah->a.prev = ah;
+    ah->a.prev->a.next = ah;
+
+    __free_block(ah);
+}
+
+void free(void *ptr)
+{
+    struct free_arena_header *ah;
+
+    if (!ptr)
+	return;
+
+    ah = (struct free_arena_header *)
+	((struct arena_header *)ptr - 1);
+
+#ifdef DEBUG_MALLOC
+    assert(ah->a.type == ARENA_TYPE_USED);
+#endif
+
+    __free_block(ah);
+
+    /* Here we could insert code to return memory to the system. */
+}