BlockBoolUtil< BlockSize > Class Template Reference

读写对齐布尔位图块的工具 (Helpers for reading and writing aligned boolean flag blocks). More...

#include <layout.hpp>

Static Public Member Functions
static void	SetFlag (BlockBoolData< BlockSize > &obj, bool value)
	把一个布尔值编码进位图块 (Encode one boolean value into a flag block).
static bool	ReadFlag (const BlockBoolData< BlockSize > &obj)
	从位图块读取布尔值 (Decode one boolean value from a flag block).
static bool	Valid (const BlockBoolData< BlockSize > &obj)
	检查位图块内容是否仍是合法编码 (Check whether a flag block still contains a valid encoding).

Detailed Description

template<size_t BlockSize>
class BlockBoolUtil< BlockSize >

读写对齐布尔位图块的工具 (Helpers for reading and writing aligned boolean flag blocks).

Template Parameters

BlockSize

位图块字节数 (Flag-block size in bytes).

Definition at line 35 of file layout.hpp.

Member Function Documentation

ReadFlag()

template<size_t BlockSize>

static bool BlockBoolUtil< BlockSize >::ReadFlag ( const BlockBoolData< BlockSize > & obj )

inlinestatic

从位图块读取布尔值 (Decode one boolean value from a flag block).

Parameters

obj	待读取位图块 (Flag block to inspect).

Returns

解码出的布尔值 (Decoded boolean value).

Definition at line 57 of file layout.hpp.

    {
      uint8_t last_4bits = obj.data[BlockSize - 1] & 0x0F;
      return last_4bits == 0x0F;
    }

SetFlag()

template<size_t BlockSize>

static void BlockBoolUtil< BlockSize >::SetFlag ( BlockBoolData< BlockSize > & obj, bool value )

inlinestatic

把一个布尔值编码进位图块 (Encode one boolean value into a flag block).

Parameters

obj	目标位图块 (Target flag block).
value	待编码布尔值 (Boolean value to encode).

Definition at line 43 of file layout.hpp.

    {
      Memory::FastSet(obj.data, 0xFF, BlockSize);
      if (!value)
      {
        obj.data[BlockSize - 1] &= 0xF0;
      }
    }

Valid()

template<size_t BlockSize>

static bool BlockBoolUtil< BlockSize >::Valid ( const BlockBoolData< BlockSize > & obj )

inlinestatic

检查位图块内容是否仍是合法编码 (Check whether a flag block still contains a valid encoding).

Parameters

obj	待检查位图块 (Flag block to validate).

Returns

若编码合法则返回 true (Returns true when the encoding is valid).

Definition at line 69 of file layout.hpp.

    {
      if (BlockSize == 0)
      {
        return false;
      }
 
      for (size_t i = 0; i < BlockSize - 1; ++i)
      {
        if (obj.data[i] != 0xFF)
        {
          return false;
        }
      }
 
      uint8_t last_byte = obj.data[BlockSize - 1];
      if ((last_byte & 0xF0) != 0xF0)
      {
        return false;
      }
 
      uint8_t last_4bits = last_byte & 0x0F;
      if (!(last_4bits == 0x0F || last_4bits == 0x00))
      {
        return false;
      }
 
      return true;
    }

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The documentation for this class was generated from the following file:

• src/middleware/database/raw/layout.hpp