(2006-08-06) rescue-bootcd

extra/syslinux-3.09/com32/lib/realloc.c

@@ -0,0 +1,49 @@
+/*
+ * realloc.c
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "malloc.h"
+
+/* FIXME: This is cheesy, it should be fixed later */
+
+void *realloc(void *ptr, size_t size)
+{
+  struct free_arena_header *ah;
+  void *newptr;
+  size_t oldsize;
+
+  if ( !ptr )
+    return malloc(size);
+
+  if ( size == 0 ) {
+    free(ptr);
+    return NULL;
+  }
+
+  /* Add the obligatory arena header, and round up */
+  size = (size+2*sizeof(struct arena_header)-1) & ARENA_SIZE_MASK;
+
+  ah = (struct free_arena_header *)
+    ((struct arena_header *)ptr - 1);
+
+  if ( ah->a.size >= size && size >= (ah->a.size >> 2) ) {
+    /* This field is a good size already. */
+    return ptr;
+  } else {
+    /* Make me a new block.  This is kind of bogus; we should
+       be checking the adjacent blocks to see if we can do an
+       in-place adjustment... fix that later. */
+    
+    oldsize = ah->a.size - sizeof(struct arena_header);
+
+    newptr = malloc(size);
+    memcpy(newptr, ptr, (size < oldsize) ? size : oldsize);
+    free(ptr);
+
+    return newptr;
+  }
+}
+