lib: Add data_stack_frame_contains()

diff --git a/src/lib/data-stack.c b/src/lib/data-stack.c
index a0d2581dd7e3f97fb3c07516dd1cd61a4f0e766c..85b284d8ebedbd7d410519848b30f43b63ced4bb 100644 (file)
--- a/src/lib/data-stack.c
+++ b/src/lib/data-stack.c
@@ -580,6 +580,49 @@ void data_stack_set_clean_after_pop(bool enable ATTR_UNUSED)
 #endif
 }
 
+bool data_stack_frame_contains(data_stack_frame_t *id, const void *_ptr)
+{
+       const unsigned char *block_data, *ptr = _ptr;
+       const struct stack_block *block;
+       unsigned int wanted_frame_id;
+       size_t block_start_pos, block_used;
+
+       /* first handle the fast path - NULL can never be within the frame */
+       if (ptr == NULL)
+               return FALSE;
+
+#ifndef STATIC_CHECKER
+       wanted_frame_id = *id;
+#else
+       wanted_frame_id = (*id)->id;
+#endif
+       /* Too much effort to support more than the latest frame.
+          It's the only thing that is currently needed anyway. */
+       i_assert(wanted_frame_id+1 == data_stack_frame_id);
+       block = current_frame_block->block[frame_pos];
+       i_assert(block != NULL);
+
+       /* See if it's in the frame's first block. Only the data after
+          block_start_pos belong to this frame. */
+       block_data = STACK_BLOCK_DATA(block);
+       block_start_pos = block->size -
+               current_frame_block->block_space_left[frame_pos];
+       block_used = block->size - block->left;
+       if (ptr >= block_data + block_start_pos &&
+           ptr <= block_data + block_used)
+               return TRUE;
+
+       /* See if it's in the other blocks. All the data in them belong to
+          this frame. */
+       for (block = block->next; block != NULL; block = block->next) {
+               block_data = STACK_BLOCK_DATA(block);
+               block_used = block->size - block->left;
+               if (ptr >= block_data && ptr < block_data + block_used)
+                       return TRUE;
+       }
+       return FALSE;
+}
+
 size_t data_stack_get_alloc_size(void)
 {
        struct stack_block *block;

diff --git a/src/lib/data-stack.h b/src/lib/data-stack.h
index a4f4980efbdcdc7ae272fce68baf38565c26ce5c..3f3d41ec4e53373ee252e69c3b2b790c9b36c3ad 100644 (file)
--- a/src/lib/data-stack.h
+++ b/src/lib/data-stack.h
@@ -116,6 +116,9 @@ void t_buffer_alloc_last_full(void);
 
 /* If enabled, all the used memory is cleared after t_pop(). */
 void data_stack_set_clean_after_pop(bool enable);
+/* Returns TRUE if ptr is allocated within the given data stack frame.
+   Currently this assert-crashes if the data stack frame isn't the latest. */
+bool data_stack_frame_contains(data_stack_frame_t *id, const void *ptr);
 
 /* Returns the number of bytes malloc()ated for data stack. */
 size_t data_stack_get_alloc_size(void);