xref: /aosp_15_r20/external/grpc-grpc/third_party/upb/upb/wire/internal/reader.h (revision cc02d7e222339f7a4f6ba5f422e6413f4bd931f2)
1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2023 Google LLC.  All rights reserved.
3 //
4 // Use of this source code is governed by a BSD-style
5 // license that can be found in the LICENSE file or at
6 // https://developers.google.com/open-source/licenses/bsd
7 
8 #ifndef UPB_WIRE_INTERNAL_READER_H_
9 #define UPB_WIRE_INTERNAL_READER_H_
10 
11 // Must be last.
12 #include "upb/port/def.inc"
13 
14 #define kUpb_WireReader_WireTypeBits 3
15 #define kUpb_WireReader_WireTypeMask 7
16 
17 typedef struct {
18   const char* ptr;
19   uint64_t val;
20 } UPB_PRIVATE(_upb_WireReader_LongVarint);
21 
22 #ifdef __cplusplus
23 extern "C" {
24 #endif
25 
26 UPB_PRIVATE(_upb_WireReader_LongVarint)
27 UPB_PRIVATE(_upb_WireReader_ReadLongVarint)(const char* ptr, uint64_t val);
28 
UPB_PRIVATE(_upb_WireReader_ReadVarint)29 static UPB_FORCEINLINE const char* UPB_PRIVATE(_upb_WireReader_ReadVarint)(
30     const char* ptr, uint64_t* val, int maxlen, uint64_t maxval) {
31   uint64_t byte = (uint8_t)*ptr;
32   if (UPB_LIKELY((byte & 0x80) == 0)) {
33     *val = (uint32_t)byte;
34     return ptr + 1;
35   }
36   const char* start = ptr;
37   UPB_PRIVATE(_upb_WireReader_LongVarint)
38   res = UPB_PRIVATE(_upb_WireReader_ReadLongVarint)(ptr, byte);
39   if (!res.ptr || (maxlen < 10 && res.ptr - start > maxlen) ||
40       res.val > maxval) {
41     return NULL;  // Malformed.
42   }
43   *val = res.val;
44   return res.ptr;
45 }
46 
UPB_PRIVATE(_upb_WireReader_GetFieldNumber)47 UPB_INLINE uint32_t UPB_PRIVATE(_upb_WireReader_GetFieldNumber)(uint32_t tag) {
48   return tag >> kUpb_WireReader_WireTypeBits;
49 }
50 
UPB_PRIVATE(_upb_WireReader_GetWireType)51 UPB_INLINE uint8_t UPB_PRIVATE(_upb_WireReader_GetWireType)(uint32_t tag) {
52   return tag & kUpb_WireReader_WireTypeMask;
53 }
54 
55 #ifdef __cplusplus
56 } /* extern "C" */
57 #endif
58 
59 #include "upb/port/undef.inc"
60 
61 #endif  // UPB_WIRE_INTERNAL_READER_H_
62