1 files changed, 226 insertions, 0 deletions
diff --git a/upb_msg.h b/upb_msg.h
new file mode 100644
index 0000000..c6a3766
--- /dev/null
+++ b/upb_msg.h
@@ -0,0 +1,226 @@
+/*
+ * upb - a minimalist implementation of protocol buffers.
+ *
+ * Copyright (c) 2009 Joshua Haberman.  See LICENSE for details.
+ *
+ * upb_msg contains a full description of a message as defined in a .proto file.
+ * This allows for run-time reflection over .proto types, but also defines an
+ * in-memory byte-level format for storing protobufs.
+ *
+ * The in-memory format is very much like a C struct that you can define at
+ * run-time, but also supports reflection.  Like C structs it supports
+ * offset-based access, as opposed to the much slower name-based lookup.  The
+ * format represents both the values themselves and bits describing whether each
+ * field is set or not.
+ *
+ * The upb compiler emits C structs that mimic this definition exactly, so that
+ * you can access the same hunk of memory using either this run-time
+ * reflection-supporting interface or a C struct that was generated by the upb
+ * compiler.
+ *
+ * Like C structs the format depends on the endianness of the host machine, so
+ * it is not suitable for exchanging across machines of differing endianness.
+ * But there is no reason to do that -- the protobuf serialization format is
+ * designed already for serialization/deserialization, and is more compact than
+ * this format.  This format is designed to allow the fastest possible random
+ * access of individual fields.
+ *
+ * Note that no memory management is defined, which should make it easier to
+ * integrate this format with existing memory-management schemes.  Any memory
+ * management semantics can be used with the format as defined here.
+ */
+
+#ifndef PBSTRUCT_H_
+#define PBSTRUCT_H_
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "upb.h"
+#include "upb_table.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Structure definition. ******************************************************/
+
+/* One single field of the struct. */
+struct upb_msg_field {
+  uint32_t byte_offset;        /* Where to find the data. */
+  uint16_t isset_byte_offset;  /* The byte where the "set" bit lives. */
+  uint8_t isset_byte_mask;
+  uint8_t type;         /* Copied from the descriptor for cache-friendliness. */
+  struct google_protobuf_FieldDescriptorProto *descriptor;
+  union {
+    struct upb_msg *msg;
+    struct upb_enum *_enum;
+  } ref;
+};
+
+/* Definition of a complete struct. */
+struct upb_msg {
+  struct google_protobuf_DescriptorProto *descriptor;
+  size_t size;
+  int num_fields;
+  int set_flags_bytes;
+  int num_required_fields;  /* Required fields have the lowest set bytemasks. */
+  struct upb_inttable fields_by_num;
+  struct upb_strtable fields_by_name;
+  struct upb_msg_field fields[];
+};
+
+/* While these are written to be as fast as possible, it will still be faster
+ * to cache the results of this lookup if possible.  These return NULL if no
+ * such field is found. */
+struct upb_msg_field *upb_msg_fieldbyname(struct upb_msg *m, char *name);
+struct upb_msg_field *upb_msg_fieldbynumber(struct upb_msg *m, uint32_t number);
+
+/* Variable-length data (strings and arrays).**********************************/
+
+/* Represents an array (a repeated field) of any type.  The interpretation of
+ * the data in the array depends on the type. */
+struct upb_array {
+  void *data;  /* Size of individual elements is based on type. */
+  uint32_t len;     /* Measured in elements. */
+};
+
+/* A generic array of structs, using void* instead of specific types. */
+struct upb_msg_array {
+  void **elements;
+  uint32_t len;
+};
+
+/* An array of strings. */
+struct upb_string_array {
+  struct upb_string **elements;
+  uint32_t len;
+};
+
+/* Specific arrays of all the primitive types. */
+#define UPB_DEFINE_PRIMITIVE_ARRAY(type, name) \
+  struct upb_ ## name ## _array { \
+    size_t len; \
+    type *elements; \
+  };
+
+UPB_DEFINE_PRIMITIVE_ARRAY(double,   double)
+UPB_DEFINE_PRIMITIVE_ARRAY(float,    float)
+UPB_DEFINE_PRIMITIVE_ARRAY(int32_t,  int32)
+UPB_DEFINE_PRIMITIVE_ARRAY(int64_t,  int64)
+UPB_DEFINE_PRIMITIVE_ARRAY(uint32_t, uint32)
+UPB_DEFINE_PRIMITIVE_ARRAY(uint64_t, uint64)
+UPB_DEFINE_PRIMITIVE_ARRAY(bool,     bool)
+#undef UPB_DEFINE_PRMITIVE_ARRAY
+
+#define UPB_STRUCT_ARRAY(struct_type) struct struct_type ## _array
+
+#define UPB_DEFINE_STRUCT_ARRAY(struct_type) \
+  UPB_STRUCT_ARRAY(struct_type) { \
+    size_t len; \
+    struct_type **elements; \
+  };
+
+/* Accessors for primitive types.  ********************************************/
+
+/* For each primitive type we define a set of six functions:
+ *
+ *  // For fetching out of a struct (s points to the raw struct data).
+ *  int32_t *upb_msg_get_int32_ptr(void *s, struct upb_msg_field *f);
+ *  int32_t upb_msg_get_int32(void *s, struct upb_msg_field *f);
+ *  void upb_msg_set_int32(void *s, struct upb_msg_field *f, int32_t val);
+ *
+ *  // For fetching out of an array.
+ *  int32_t *upb_array_get_int32_ptr(struct upb_array *a, int n);
+ *  int32_t upb_array_get_int32(struct upb_array *a, int n);
+ *  void upb_array_set_int32(struct upb_array *a, int n, ctype val);
+ *
+ * For arrays we provide only the first three because protobufs do not support
+ * arrays of arrays.
+ *
+ * These do no existence checks, bounds checks, or type checks. */
+
+#define UPB_DEFINE_ACCESSORS(ctype, name, INLINE) \
+  INLINE ctype *upb_msg_get_ ## name ## _ptr( \
+      void *s, struct upb_msg_field *f) { \
+    return (ctype*)((char*)s + f->byte_offset); \
+  } \
+  INLINE ctype upb_msg_get_ ## name( \
+      void *s, struct upb_msg_field *f) { \
+    return *upb_msg_get_ ## name ## _ptr(s, f); \
+  } \
+  INLINE void upb_msg_set_ ## name( \
+      void *s, struct upb_msg_field *f, ctype val) { \
+    *upb_msg_get_ ## name ## _ptr(s, f) = val; \
+  }
+
+#define UPB_DEFINE_ARRAY_ACCESSORS(ctype, name, INLINE) \
+  INLINE ctype *upb_array_get_ ## name ## _ptr(struct upb_array *a, int n) { \
+    return ((ctype*)a->data) + n; \
+  } \
+  INLINE ctype upb_array_get_ ## name(struct upb_array *a, int n) { \
+    return *upb_array_get_ ## name ## _ptr(a, n); \
+  } \
+  INLINE void upb_array_set_ ## name(struct upb_array *a, int n, ctype val) { \
+    *upb_array_get_ ## name ## _ptr(a, n) = val; \
+  }
+
+#define UPB_DEFINE_ALL_ACCESSORS(ctype, name, INLINE) \
+  UPB_DEFINE_ACCESSORS(ctype, name, INLINE) \
+  UPB_DEFINE_ARRAY_ACCESSORS(ctype, name, INLINE)
+
+UPB_DEFINE_ALL_ACCESSORS(double,   double, INLINE)
+UPB_DEFINE_ALL_ACCESSORS(float,    float,  INLINE)
+UPB_DEFINE_ALL_ACCESSORS(int32_t,  int32,  INLINE)
+UPB_DEFINE_ALL_ACCESSORS(int64_t,  int64,  INLINE)
+UPB_DEFINE_ALL_ACCESSORS(uint32_t, uint32, INLINE)
+UPB_DEFINE_ALL_ACCESSORS(uint64_t, uint64, INLINE)
+UPB_DEFINE_ALL_ACCESSORS(bool,     bool,   INLINE)
+UPB_DEFINE_ALL_ACCESSORS(struct upb_string*, bytes, INLINE)
+UPB_DEFINE_ALL_ACCESSORS(struct upb_string*, string, INLINE)
+UPB_DEFINE_ALL_ACCESSORS(void*, substruct, INLINE)
+UPB_DEFINE_ACCESSORS(struct upb_array*, array, INLINE)
+
+/* Functions for reading and writing the "set" flags in the pbstruct.  Note
+ * that these do not perform any memory management associated with any dynamic
+ * memory these fields may be referencing; that is the client's responsibility.
+ * These *only* set and test the flags. */
+INLINE void upb_msg_set(void *s, struct upb_msg_field *f)
+{
+  ((char*)s)[f->isset_byte_offset] |= f->isset_byte_mask;
+}
+
+INLINE void upb_msg_unset(void *s, struct upb_msg_field *f)
+{
+  ((char*)s)[f->isset_byte_offset] &= ~f->isset_byte_mask;
+}
+
+INLINE bool upb_msg_is_set(void *s, struct upb_msg_field *f)
+{
+  return ((char*)s)[f->isset_byte_offset] & f->isset_byte_mask;
+}
+
+INLINE bool upb_msg_all_required_fields_set(void *s, struct upb_msg *m)
+{
+  int num_fields = m->num_required_fields;
+  int i = 0;
+  while(num_fields > 8) {
+    if(((uint8_t*)s)[i++] != 0xFF) return false;
+    num_fields -= 8;
+  }
+  if(((uint8_t*)s)[i] != (1 << num_fields) - 1) return false;
+  return true;
+}
+
+INLINE void upb_msg_clear(void *s, struct upb_msg *m)
+{
+  memset(s, 0, m->set_flags_bytes);
+}
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif  /* PBSTRUCT_H_ */