如果没有定义过 byte_t 类型：

#include <stdint.h>
typedef uint8_t byte_t;
//typedef unsigned char byte_t; // 1 个 byte 字节，8位，一般系统中能表示的最小字节数据。

 

// 位写入函数
uint32_t bit_set(byte_t* data, size_t x, size_t bits, uint32_t value)
{
    uint32_t mask;
    if(bits == 32){
        reinterpret_cast<uint32_t*>(data)[x] = value;
    }
    else if(bits == 24){
        mask = 0x00FFFFFF;
        data += x*3;
        uint32_t* p = reinterpret_cast<uint32_t*>(data);
        *p &= ~mask;
        value &= mask;
        *p |= value;
    }
    else if(bits == 16){
        reinterpret_cast<uint16_t*>(data)[x] = value;
    }
    else if(bits == 8){
        data[x] = value;
    }
    else if(bits < 8){
        mask = (1<<bits)-1;
        x *= bits;
        data += x/8;
        value &= mask;
        x &= 7;
        value <<= x;
        mask <<= x;
        mask = ~mask;
        byte_t n = data[0];
        n &= mask;
        n |= value;
        data[0] = n;
    }
    return 0;
}
// 位读取函数
uint32_t bit_get(const byte_t* data, int x, int bits)
{
    uint32_t mask;
    if(bits == 32){
        return reinterpret_cast<const uint32_t*>(data)[x];
    }
    else if(bits == 24){
        mask = 0x00FFFFFF;
        data += x*3;
        const uint32_t* p = reinterpret_cast<const uint32_t*>(data);
        return *p & mask;
    }
    else if(bits == 16){
        return reinterpret_cast<const uint16_t*>(data)[x];
    }
    else if(bits == 8){
        return data[x];
    }
    else if(bits < 8){
        mask = (1<<bits)-1;
        x *= bits;
        data += x/8;
        x &= 7;
        return (data[0]>>x) & mask;
    }
}

这个 bitset<> 是 c++ bitset 的扩展版，支持任意长度的数据：

template<std::size_t BITSIZE>
struct bitset
{
public:
    const static std::size_t byte_size = BITSIZE/8 + (BITSIZE&0x07 ? 1 : 0);
public:
    bitset()
    {
        this->reset();
    }
 
    size_t size()const
    {
        return BITSIZE;
    }
 
    bool bit(size_t id)const
    {
        return (data[id/8]>>(id&0x07))&0x01;
    };
    bool operator[](size_t id)const
    {
        return this->bit(id);
    }
 
    void set()
    {
        memset(data, 0xFF, byte_size);
    }
    bool set(size_t id)
    {
        byte_t& b = data[id/8];
        b |= 1<<(id&0x07);
        return true;
    }
    void reset()
    {
        memset(data, 0, byte_size);
    }
    bool reset(size_t id)
    {
        byte_t& b = data[id/8];
           b &= ~(1<<(id&0x07));
        return false;
    }
public:
    byte_t data[byte_size];
};

文章发布于 2017-02-04 07:26:45 CSDN，现转博客园。