mini_table/internal/enum.h

0001 // Protocol Buffers - Google's data interchange format
0002 // Copyright 2023 Google LLC.  All rights reserved.
0003 //
0004 // Use of this source code is governed by a BSD-style
0005 // license that can be found in the LICENSE file or at
0006 // https://developers.google.com/open-source/licenses/bsd
0007
0008 #ifndef UPB_MINI_TABLE_INTERNAL_ENUM_H_
0009 #define UPB_MINI_TABLE_INTERNAL_ENUM_H_
0010
0011 #include <stdint.h>
0012
0013 // Must be last.
0014 #include "upb/port/def.inc"
0015
0016 struct upb_MiniTableEnum {
0017   uint32_t UPB_PRIVATE(mask_limit);   // Highest that can be tested with mask.
0018   uint32_t UPB_PRIVATE(value_count);  // Number of values after the bitfield.
0019   uint32_t UPB_PRIVATE(data)[];       // Bitmask + enumerated values follow.
0020 };
0021
0022 #ifdef __cplusplus
0023 extern "C" {
0024 #endif
0025
0026 UPB_API_INLINE bool upb_MiniTableEnum_CheckValue(
0027     const struct upb_MiniTableEnum* e, uint32_t val) {
0028   if (UPB_LIKELY(val < 64)) {
0029     const uint64_t mask =
0030         e->UPB_PRIVATE(data)[0] | ((uint64_t)e->UPB_PRIVATE(data)[1] << 32);
0031     const uint64_t bit = 1ULL << val;
0032     return (mask & bit) != 0;
0033   }
0034   if (UPB_LIKELY(val < e->UPB_PRIVATE(mask_limit))) {
0035     const uint32_t mask = e->UPB_PRIVATE(data)[val / 32];
0036     const uint32_t bit = 1ULL << (val % 32);
0037     return (mask & bit) != 0;
0038   }
0039
0040   // OPT: binary search long lists?
0041   const uint32_t* start =
0042       &e->UPB_PRIVATE(data)[e->UPB_PRIVATE(mask_limit) / 32];
0043   const uint32_t* limit = &e->UPB_PRIVATE(
0044       data)[e->UPB_PRIVATE(mask_limit) / 32 + e->UPB_PRIVATE(value_count)];
0045   for (const uint32_t* p = start; p < limit; p++) {
0046     if (*p == val) return true;
0047   }
0048   return false;
0049 }
0050
0051 #ifdef __cplusplus
0052 } /* extern "C" */
0053 #endif
0054
0055 #include "upb/port/undef.inc"
0056
0057 #endif /* UPB_MINI_TABLE_INTERNAL_ENUM_H_ */