Protocol Buffers - Google's data interchange format (grpc依赖) https://developers.google.com/protocol-buffers/
 
 
 
 
 
 

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// Protocol Buffers - Google's data interchange format
// Copyright 2023 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#ifndef UPB_WIRE_READER_H_
#define UPB_WIRE_READER_H_
#include "upb/base/internal/endian.h"
#include "upb/wire/eps_copy_input_stream.h"
#include "upb/wire/internal/reader.h"
#include "upb/wire/types.h" // IWYU pragma: export
// Must be last.
#include "upb/port/def.inc"
// The upb_WireReader interface is suitable for general-purpose parsing of
// protobuf binary wire format. It is designed to be used along with
// upb_EpsCopyInputStream for buffering, and all parsing routines in this file
// assume that at least kUpb_EpsCopyInputStream_SlopBytes worth of data is
// available to read without any bounds checks.
#ifdef __cplusplus
extern "C" {
#endif
// Parses a tag into `tag`, and returns a pointer past the end of the tag, or
// NULL if there was an error in the tag data.
//
// REQUIRES: there must be at least 10 bytes of data available at `ptr`.
// Bounds checks must be performed before calling this function, preferably
// by calling upb_EpsCopyInputStream_IsDone().
UPB_FORCEINLINE const char* upb_WireReader_ReadTag(const char* ptr,
uint32_t* tag) {
uint64_t val;
ptr = UPB_PRIVATE(_upb_WireReader_ReadVarint)(ptr, &val, 5, UINT32_MAX);
if (!ptr) return NULL;
*tag = val;
return ptr;
}
// Given a tag, returns the field number.
UPB_API_INLINE uint32_t upb_WireReader_GetFieldNumber(uint32_t tag);
// Given a tag, returns the wire type.
UPB_API_INLINE uint8_t upb_WireReader_GetWireType(uint32_t tag);
UPB_INLINE const char* upb_WireReader_ReadVarint(const char* ptr,
uint64_t* val) {
return UPB_PRIVATE(_upb_WireReader_ReadVarint)(ptr, val, 10, UINT64_MAX);
}
// Skips data for a varint, returning a pointer past the end of the varint, or
// NULL if there was an error in the varint data.
//
// REQUIRES: there must be at least 10 bytes of data available at `ptr`.
// Bounds checks must be performed before calling this function, preferably
// by calling upb_EpsCopyInputStream_IsDone().
UPB_INLINE const char* upb_WireReader_SkipVarint(const char* ptr) {
uint64_t val;
return upb_WireReader_ReadVarint(ptr, &val);
}
// Reads a varint indicating the size of a delimited field into `size`, or
// NULL if there was an error in the varint data.
//
// REQUIRES: there must be at least 10 bytes of data available at `ptr`.
// Bounds checks must be performed before calling this function, preferably
// by calling upb_EpsCopyInputStream_IsDone().
UPB_INLINE const char* upb_WireReader_ReadSize(const char* ptr, int* size) {
uint64_t size64;
ptr = upb_WireReader_ReadVarint(ptr, &size64);
if (!ptr || size64 >= INT32_MAX) return NULL;
*size = size64;
return ptr;
}
// Reads a fixed32 field, performing byte swapping if necessary.
//
// REQUIRES: there must be at least 4 bytes of data available at `ptr`.
// Bounds checks must be performed before calling this function, preferably
// by calling upb_EpsCopyInputStream_IsDone().
UPB_INLINE const char* upb_WireReader_ReadFixed32(const char* ptr, void* val) {
uint32_t uval;
memcpy(&uval, ptr, 4);
uval = upb_BigEndian32(uval);
memcpy(val, &uval, 4);
return ptr + 4;
}
// Reads a fixed64 field, performing byte swapping if necessary.
//
// REQUIRES: there must be at least 4 bytes of data available at `ptr`.
// Bounds checks must be performed before calling this function, preferably
// by calling upb_EpsCopyInputStream_IsDone().
UPB_INLINE const char* upb_WireReader_ReadFixed64(const char* ptr, void* val) {
uint64_t uval;
memcpy(&uval, ptr, 8);
uval = upb_BigEndian64(uval);
memcpy(val, &uval, 8);
return ptr + 8;
}
const char* UPB_PRIVATE(_upb_WireReader_SkipGroup)(
const char* ptr, uint32_t tag, int depth_limit,
upb_EpsCopyInputStream* stream);
// Skips data for a group, returning a pointer past the end of the group, or
// NULL if there was an error parsing the group. The `tag` argument should be
// the start group tag that begins the group. The `depth_limit` argument
// indicates how many levels of recursion the group is allowed to have before
// reporting a parse error (this limit exists to protect against stack
// overflow).
//
// TODO: evaluate how the depth_limit should be specified. Do users need
// control over this?
UPB_INLINE const char* upb_WireReader_SkipGroup(
const char* ptr, uint32_t tag, upb_EpsCopyInputStream* stream) {
return UPB_PRIVATE(_upb_WireReader_SkipGroup)(ptr, tag, 100, stream);
}
UPB_INLINE const char* _upb_WireReader_SkipValue(
const char* ptr, uint32_t tag, int depth_limit,
upb_EpsCopyInputStream* stream) {
switch (upb_WireReader_GetWireType(tag)) {
case kUpb_WireType_Varint:
return upb_WireReader_SkipVarint(ptr);
case kUpb_WireType_32Bit:
return ptr + 4;
case kUpb_WireType_64Bit:
return ptr + 8;
case kUpb_WireType_Delimited: {
int size;
ptr = upb_WireReader_ReadSize(ptr, &size);
if (!ptr) return NULL;
ptr += size;
return ptr;
}
case kUpb_WireType_StartGroup:
return UPB_PRIVATE(_upb_WireReader_SkipGroup)(ptr, tag, depth_limit,
stream);
case kUpb_WireType_EndGroup:
return NULL; // Should be handled before now.
default:
return NULL; // Unknown wire type.
}
}
// Skips data for a wire value of any type, returning a pointer past the end of
// the data, or NULL if there was an error parsing the group. The `tag` argument
// should be the tag that was just parsed. The `depth_limit` argument indicates
// how many levels of recursion a group is allowed to have before reporting a
// parse error (this limit exists to protect against stack overflow).
//
// REQUIRES: there must be at least 10 bytes of data available at `ptr`.
// Bounds checks must be performed before calling this function, preferably
// by calling upb_EpsCopyInputStream_IsDone().
//
// TODO: evaluate how the depth_limit should be specified. Do users need
// control over this?
UPB_INLINE const char* upb_WireReader_SkipValue(
const char* ptr, uint32_t tag, upb_EpsCopyInputStream* stream) {
return _upb_WireReader_SkipValue(ptr, tag, 100, stream);
}
#ifdef __cplusplus
} /* extern "C" */
#endif
#include "upb/port/undef.inc"
#endif // UPB_WIRE_READER_H_