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.

Note

标志只会从 true（擦除态）写成 false，且只写一次；只要有一位已被编程， 就说明这次写入已经开始，因此只有整块都是 0xFF 才读作 true。被掉电打断的 写入读作它要写成的 false。 A flag is written at most once, from true (erased) to false; any programmed bit means that write has started, so only a fully erased block reads as true, and a write cut by a power loss reads as the false it was writing.

Definition at line 64 of file layout.hpp.

  {
    for (size_t i = 0; i < BlockSize; ++i)
    {
      if (obj.data[i] != 0xFF)
      {
        return false;
      }
    }
    return true;
  }

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 82 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