From 040f7e6ba2e2282b80f332a031b77d7d34b4fc85 Mon Sep 17 00:00:00 2001
From: Joshua Haberman <joshua@reverberate.org>
Date: Mon, 24 Aug 2009 21:44:22 -0700
Subject: Significant memory-management refactoring any Python extension.

---
 src/upb_struct.h | 119 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 src/upb_struct.h

(limited to 'src/upb_struct.h')

diff --git a/src/upb_struct.h b/src/upb_struct.h
new file mode 100644
index 0000000..9c1bb2e
--- /dev/null
+++ b/src/upb_struct.h
@@ -0,0 +1,119 @@
+/*
+ * upb - a minimalist implementation of protocol buffers.
+ *
+ * Copyright (c) 2009 Joshua Haberman.  See LICENSE for details.
+ *
+ * This file defines the in-memory format for messages, arrays, and strings
+ * (which are the three dynamically-allocated structures that make up all
+ * protobufs). */
+
+#ifndef UPB_STRUCT_H
+#define UPB_STRUCT_H
+
+#include "upb.h"
+
+/* mmhead -- this is a "base class" for strings, arrays, and messages ********/
+
+struct upb_mm_ref;
+struct upb_mmhead {
+  struct upb_mm_ref *refs;  /* Head of linked list. */
+  uint32_t refcount;
+};
+
+INLINE void upb_mmhead_init(struct upb_mmhead *head) {
+  head->refs = NULL;
+  head->refcount = 1;
+}
+
+INLINE bool upb_mmhead_norefs(struct upb_mmhead *head) {
+  return head->refcount == 0 && head->refs == NULL;
+}
+
+INLINE bool upb_mmhead_unref(struct upb_mmhead *head) {
+  head->refcount--;
+  return upb_mmhead_norefs(head);
+}
+
+INLINE void upb_mmhead_ref(struct upb_mmhead *head) {
+  head->refcount++;
+}
+
+/* Structures for msg, string, and array. *************************************/
+
+/* These are all self describing. */
+
+struct upb_msgdef;
+struct upb_msg_fielddef;
+
+struct upb_msg {
+  struct upb_mmhead mmhead;
+  struct upb_msgdef *def;
+  uint8_t data[1];
+};
+
+typedef uint32_t upb_arraylen_t;  /* can be at most 2**32 elements long. */
+struct upb_array {
+  struct upb_mmhead mmhead;
+  struct upb_msg_fielddef *fielddef;  /* Defines the type of the array. */
+  union upb_value_ptr elements;
+  upb_arraylen_t len;     /* Number of elements in "elements". */
+  upb_arraylen_t size;    /* Memory we own (0 if by reference). */
+};
+
+struct upb_string {
+  struct upb_mmhead mmhead;
+  /* We expect the data to be 8-bit clean (uint8_t), but char* is such an
+   * ingrained convention that we follow it. */
+  char *ptr;
+  uint32_t byte_len;
+  uint32_t byte_size;  /* How many bytes of ptr we own, 0 if we reference. */
+};
+
+/* Type-specific overlays on upb_array. ***************************************/
+
+#define UPB_DEFINE_ARRAY_TYPE(name, type) \
+  struct name ## _array { \
+    struct upb_mmhead mmhead; \
+    struct upb_msg_fielddef *fielddef; \
+    type elements; \
+    upb_arraylen_t len; \
+    upb_arraylen_t size; \
+  };
+
+UPB_DEFINE_ARRAY_TYPE(upb_double, double)
+UPB_DEFINE_ARRAY_TYPE(upb_float,  float)
+UPB_DEFINE_ARRAY_TYPE(upb_int32,  int32_t)
+UPB_DEFINE_ARRAY_TYPE(upb_int64,  int64_t)
+UPB_DEFINE_ARRAY_TYPE(upb_uint32, uint32_t)
+UPB_DEFINE_ARRAY_TYPE(upb_uint64, uint64_t)
+UPB_DEFINE_ARRAY_TYPE(upb_bool,   bool)
+UPB_DEFINE_ARRAY_TYPE(upb_string, struct upb_string*)
+UPB_DEFINE_ARRAY_TYPE(upb_msg,    void*)
+
+/* Defines an array of a specific message type (an overlay of upb_array). */
+#define UPB_MSG_ARRAY(msg_type) struct msg_type ## _array
+#define UPB_DEFINE_MSG_ARRAY(msg_type) \
+  UPB_MSG_ARRAY(msg_type) { \
+    struct upb_mmhead mmhead; \
+    struct upb_msg_fielddef *fielddef; \
+    msg_type **elements; \
+    upb_arraylen_t len; \
+    upb_arraylen_t size; \
+    };
+
+/* mmptr -- a pointer which polymorphically points to one of the above. *******/
+
+union upb_mmptr {
+  struct upb_msg *msg;
+  struct upb_array *arr;
+  struct upb_string *str;
+};
+
+enum {
+  UPB_MM_MSG_REF,
+  UPB_MM_STR_REF,
+  UPB_MM_ARR_REF
+};
+typedef uint8_t upb_mm_ptrtype;
+
+#endif
-- 
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