Protocol Buffers - Google's data interchange format (grpc依赖) https://developers.google.com/protocol-buffers/
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/*
* 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. ******************************************************/
struct upb_msg_field {
uint32_t byte_offset; /* Where to find the data. */
uint32_t field_index:24; /* Indexes upb_msg.fields. Also indicates set bit */
upb_field_type_t type; /* Copied from descriptor for cache-friendliness. */
union {
struct upb_msg *msg; /* Set if type == MESSAGE */
struct upb_enum *_enum; /* Set if type == ENUM */
} ref;
};
struct upb_fieldsbynum_entry {
struct upb_inttable_entry e;
struct upb_msg_field f;
};
struct upb_fieldsbyname_entry {
struct upb_strtable_entry e;
struct upb_msg_field f;
};
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;
};
/* Initialize and free a upb_msg. Caller retains ownership of d, but the msg
* will contain references to it, so it must outlive the msg. Note that init
* does not resolve upb_msg_field.ref -- that is left to the caller. */
bool upb_msg_init(struct upb_msg *m, struct google_protobuf_DescriptorProto *d);
void upb_msg_free(struct upb_msg *m);
/* 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. */
INLINE struct upb_msg_field *upb_msg_fieldbynum(struct upb_msg *m,
uint32_t number) {
struct upb_fieldsbynum_entry *e = upb_inttable_lookup(
&m->fields_by_num, number, sizeof(struct upb_fieldsbynum_entry));
return e ? &e->f : NULL;
}
INLINE struct upb_msg_field *upb_msg_fieldbyname(struct upb_msg *m,
struct upb_string *name) {
struct upb_fieldsbyname_entry *e =
upb_strtable_lookup(&m->fields_by_name, name);
return e ? &e->f : NULL;
}
/* 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)
INLINE size_t upb_isset_offset(uint32_t field_index) {
return field_index / 8;
}
INLINE size_t upb_isset_mask(uint32_t field_index) {
return 1 << (field_index % 8);
}
/* 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)[upb_isset_offset(f->field_index)] |= upb_isset_mask(f->field_index);
}
INLINE void upb_msg_unset(void *s, struct upb_msg_field *f)
{
((char*)s)[upb_isset_offset(f->field_index)] &= ~upb_isset_mask(f->field_index);
}
INLINE bool upb_msg_is_set(void *s, struct upb_msg_field *f)
{
return ((char*)s)[upb_isset_offset(f->field_index)] & upb_isset_mask(f->field_index);
}
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_ */