基于C语言实现泛型编程详解

2022-11-13 11:11:17 语言 编程 详解

心理历程

写了一段时间c++后,真心感觉STL里的容器是个好东西。一个容器可以容纳任意类型,容器对外的接口可以操作任意类型的数据,甚至包括自定义类型的数据。这种泛型编程的思想,对于大型项目而言是非常有好处的。

对于C而言,想实现泛型编程并非易事,甚至可以说非常繁琐,一大堆坑。最主要也没有现成的轮子可用。当然也有一些通过宏实现了泛型的基础功能,但是可读性,可调试性太差了。

于是就想自己造一个轮子,实现基于C对窗口(顺序表)的泛化,目标就是实现不同类型下,规范接口的一致性。抛砖引玉。

轮子用法

int main( void )
{
	// 1、创建一个窗口,并初始化它,大小为10,类型为double
    Valuewindowsquential tmp;
    InitValueWindow( &tmp, kValueTypeList[ DOUBLE ], 10 );

    double insert_data = 0;
    for ( int i = 0; i < tmp.max_size; i++ )
    {
    	// 2、填充这个窗口,直到窗口填满
        insert_data = i * 10;
        if ( kWindowAlreadyFull == ValueWindowFixedInsert( &tmp, &insert_data ) )
        {
        	// 3、打印整个窗口
            printf( "start sort \r\n" );
            ShowTheWindow( &tmp );
	
			// 4、整个窗口排序
            ValueWindowSelectSort( &tmp );
	
			// 5、打印排序后的窗口
            printf( "end sort \r\n" );
            ShowTheWindow( &tmp );

            break;
        }
    }

    printf( "test generics \r\n" );
    return 0;
}

打印log如下:

这时想换成创建一个uint8_t类型的串口,只需要改两个地方,这两个地方在C++里也避免不了。

int main( void )
{
    ValueWindowSquential tmp;
    InitValueWindow( &tmp, kValueTypeList[ UINT8 ], 10 );

    uint8_t insert_data = 0;
    for ( int i = 0; i < tmp.max_size; i++ )
    {
        insert_data = ( tmp.max_size - i ) * 1;
        if ( kWindowAlreadyFull == ValueWindowFixedInsert( &tmp, &insert_data ) )
        {
            printf( "start sort \r\n" );
            ShowTheWindow( &tmp );

            ValueWindowSelectSort( &tmp );

            printf( "end sort \r\n" );
            ShowTheWindow( &tmp );

            break;
        }
    }

    printf( "test generics \r\n" );
    return 0;
}

大体流程

1.首先初始化一个空窗口对象,然后调用 InitValueWindow 传入窗口类型,大小,然后初始化它。

2.调用 ValueWindowFixedInsert 往窗口中插入值,直到窗口满后反馈状态。

3.打印整个窗口

4.对窗口排序

5.打印整个窗口

这里的泛型主要通过查表实现了,将希望包含的类型加入表中,然后初始化时传入其类型和大小。

插入数据的时候,需要保证数据类型和窗口类型统一,这算是个局限性了。

窗口被填充完毕后,会有反馈窗口状态,这时可以调用 ShowTheWindow 将原始窗口打印。

在调用 ValueWindowSelectSort 将窗口排序。排序完后再次打印。

可以看到除了初始化的时候,需要设定窗口的类型,这和 std::vector< double > 没什么两样,插入数据时需要调用者确保数据类型与窗口统一。

部分源码

#ifndef __TEST_GENERICS_h
#define __TEST_GENERICS_h

#include <stdio.h>
#include <string.h>
#include <malloc.h>
#include <stdlib.h>

#include <assert.h>

typedef signed char   int8_t;
typedef unsigned char uint8_t;

typedef signed short   int16_t;
typedef unsigned short uint16_t;

typedef signed int   int32_t;
typedef unsigned int uint32_t;

typedef enum
{
    UINT8 = 0,
    INT,
    FLOAT,
    DOUBLE,

    ERROR

} TypeName;

const char* kValueTypeList[ ERROR + 1 ] = {

    "uint8_t",

    "int",
    "float",
    "double",

    "error",
};

TypeName ChangeStringToEnum( const char* tmp );


typedef struct ValueWindowSquential
{
    char* type;
    void* data;

    uint32_t max_size;

    uint32_t sequence;

} ValueWindowSquential;


void InitValueWindow( ValueWindowSquential* tmp, const char* type, uint32_t max_size );


void ResetValueWindow( ValueWindowSquential* tmp );

typedef enum
{
    kWindowIsNotFull = ( 0 ),
    kWindowIsSliding,

    kWindowCanNotInsert,
    kWindowInputFail,

} SlideWindowState;

SlideWindowState ValueWindowSlideInsert( ValueWindowSquential* tmp, void* data );

typedef enum
{
    kWindowNotFull = ( 0 ),
    kWindowAlreadyFull,

    kFixWindowCanNotInsert,
    kFixWindowInputFail,

} FixedWindowState;

FixedWindowState ValueWindowFixedInsert( ValueWindowSquential* tmp, void* data );


void ShowTheWindow( ValueWindowSquential* tmp );

#endif // __TEST_GENERICS_h

#include "test_generics.h"

#include "generics_impl.h"


TypeName ChangeStringToEnum( const char* tmp )
{
    assert( tmp != NULL );

    TypeName return_tmp = ERROR;

    if ( strcmp( tmp, kValueTypeList[ UINT8 ] ) == 0 )
    {
        return_tmp = UINT8;
    }
    else if ( strcmp( tmp, kValueTypeList[ FLOAT ] ) == 0 )
    {
        return_tmp = FLOAT;
    }
    else if ( strcmp( tmp, kValueTypeList[ DOUBLE ] ) == 0 )
    {
        return_tmp = DOUBLE;
    }
    else if ( strcmp( tmp, kValueTypeList[ INT ] ) == 0 )
    {
        return_tmp = INT;
    }
    else
    {
        printf( "error char* input !!!" );
        assert( 0 );
    }
    return return_tmp;
}

// 初始化窗口
// Initialize window
void InitValueWindow( ValueWindowSquential* tmp, const char* type, uint32_t max_size )
{
    assert( tmp != NULL );

    tmp->type = ( char* ) malloc( strlen( type ) * sizeof( char ) );
    strncpy( tmp->type, type, strlen( type ) );

    tmp->max_size = max_size;
    tmp->sequence = 0;

    switch ( ChangeStringToEnum( tmp->type ) )
    {
        case UINT8: {
            tmp->data = ( uint8_t* ) malloc( max_size * sizeof( uint8_t ) );
            memset( tmp->data, 0, tmp->max_size );
        }
        break;

        case INT: {
            tmp->data = ( int* ) malloc( max_size * sizeof( int ) );
            memset( tmp->data, 0, tmp->max_size );
        }
        break;

        case FLOAT: {
            tmp->data = ( float* ) malloc( max_size * sizeof( float ) );
            memset( tmp->data, 0, tmp->max_size );
        }
        break;

        case DOUBLE: {
            tmp->data = ( double* ) malloc( max_size * sizeof( double ) );
            memset( tmp->data, 0, tmp->max_size );
        }
        break;

        default: {
            printf( "error tmp->type input !!!" );
            assert( 0 );
        }
        break;
    }

    printf( "type is : %s , number is : %d  \r\n", tmp->type, max_size );
}

// 重置/销毁窗口
void ResetValueWindow( ValueWindowSquential* tmp )
{
    tmp->sequence = 0;
    tmp->max_size = 0;

    if ( tmp->data != NULL )
    {
        free( tmp->data );
        tmp->data = NULL;
    }

    if ( tmp->type != NULL )
    {
        free( tmp->type );
        tmp->type = NULL;
    }
}

// 滑动往窗口插入数据
SlideWindowState ValueWindowSlideInsert( ValueWindowSquential* tmp, void* data )
{
    SlideWindowState return_tmp = kWindowIsNotFull;

    switch ( ChangeStringToEnum( tmp->type ) )
    {
        case UINT8: {
            uint8_t* tmp_buffer = ( uint8_t* ) tmp->data;
            for ( int i = 1; i < tmp->max_size; i++ )
            {
                tmp_buffer[ i - 1 ] = tmp_buffer[ i ];
            }
            uint8_t* res                    = ( uint8_t* ) data;
            tmp_buffer[ tmp->max_size - 1 ] = *res;
        }
        break;

        case INT: {
            int* tmp_buffer = ( int* ) tmp->data;
            for ( int i = 1; i < tmp->max_size; i++ )
            {
                tmp_buffer[ i - 1 ] = tmp_buffer[ i ];
            }
            int* res                        = ( int* ) data;
            tmp_buffer[ tmp->max_size - 1 ] = *res;
        }
        break;

        case FLOAT: {
            float* tmp_buffer = ( float* ) tmp->data;
            for ( int i = 1; i < tmp->max_size; i++ )
            {
                tmp_buffer[ i - 1 ] = tmp_buffer[ i ];
            }
            float* res                      = ( float* ) data;
            tmp_buffer[ tmp->max_size - 1 ] = *res;
        }
        break;

        case DOUBLE: {
            double* tmp_buffer = ( double* ) tmp->data;
            for ( int i = 1; i < tmp->max_size; i++ )
            {
                tmp_buffer[ i - 1 ] = tmp_buffer[ i ];
            }
            double* res                     = ( double* ) data;
            tmp_buffer[ tmp->max_size - 1 ] = *res;
        }
        break;

        default: {
            printf( "error tmp->type input !!!" );
            assert( 0 );
        }
        break;
    }
    if ( ++tmp->sequence > tmp->max_size )
    {
        return_tmp    = kWindowIsSliding;
        tmp->sequence = tmp->max_size;
    }

    return return_tmp;
}

// 插入数据直到填满整个窗口
FixedWindowState ValueWindowFixedInsert( ValueWindowSquential* tmp, void* data )
{
    FixedWindowState return_tmp = kWindowNotFull;

    switch ( ChangeStringToEnum( tmp->type ) )
    {
        case UINT8: {
            uint8_t* tmp_buffer = ( uint8_t* ) tmp->data;
            uint8_t* res        = ( uint8_t* ) data;

            tmp_buffer[ tmp->sequence ] = *res;
        }
        break;

        case INT: {
            int* tmp_buffer = ( int* ) tmp->data;
            int* res        = ( int* ) data;

            tmp_buffer[ tmp->sequence ] = *res;
        }
        break;

        case FLOAT: {
            float* tmp_buffer = ( float* ) tmp->data;
            float* res        = ( float* ) data;

            tmp_buffer[ tmp->sequence ] = *res;
        }
        break;

        case DOUBLE: {
            double* tmp_buffer = ( double* ) tmp->data;
            double* res        = ( double* ) data;

            tmp_buffer[ tmp->sequence ] = *res;
        }
        break;

        default: {
            printf( "error tmp->type input !!!" );
            assert( 0 );
        }
        break;
    }

    if ( ++tmp->sequence >= tmp->max_size )
    {
        tmp->sequence = 0;
        return_tmp    = kWindowAlreadyFull;
    }
    return return_tmp;
}

// 打印窗口内全部值
void ShowTheWindow( ValueWindowSquential* tmp )
{
    // printf("current_type:{%d}", ChangeStringToEnum(tmp->type));
    switch ( ChangeStringToEnum( tmp->type ) )
    {
        case UINT8: {
            uint8_t* msg = ( uint8_t* ) tmp->data;
            for ( int i = 0; i < tmp->max_size; ++i )
            {
                printf( "i : {%d} , %d \r\n", i, msg[ i ] );
            }
        }
        break;

        case INT: {
            int* msg = ( int* ) tmp->data;
            for ( int i = 0; i < tmp->max_size; ++i )
            {
                printf( "i : {%d} , %d \r\n", i, msg[ i ] );
            }
        }
        break;

        case FLOAT: {
            float* msg = ( float* ) tmp->data;
            for ( int i = 0; i < tmp->max_size; ++i )
            {
                printf( "i : {%d} , %f \r\n", i, msg[ i ] );
            }
        }
        break;

        case DOUBLE: {
            double* msg = ( double* ) tmp->data;
            for ( int i = 0; i < tmp->max_size; ++i )
            {
                printf( "i : {%d} , %f \r\n", i, msg[ i ] );
            }
        }
        break;

        default: {
            printf( "error tmp->type input !!!" );
            assert( 0 );
        }
        break;
    }
}

int main( void )
{
    ValueWindowSquential tmp;
    InitValueWindow( &tmp, kValueTypeList[ DOUBLE ], 10 );

    double insert_data = 0;
    for ( int i = 0; i < tmp.max_size; i++ )
    {
        insert_data = ( tmp.max_size - i ) * 10;
        if ( kWindowAlreadyFull == ValueWindowFixedInsert( &tmp, &insert_data ) )
        {
            printf( "start sort \r\n" );
            ShowTheWindow( &tmp );

            ValueWindowSelectSort( &tmp );

            printf( "end sort \r\n" );
            ShowTheWindow( &tmp );

            break;
        }
    }
    ResetValueWindow(&tmp);

    printf( "test generics \r\n" );
    return 0;
}

这是最开始的一版源码,基本的思路是基于 void* 实现对窗口的泛化,把窗口的地址,大小,类型 在初始化时设定好,以后所有的结构便基于这些信息,实现接口一致性。

目前实现了两种窗口类型, ValueWindowSlideInsert (滑动窗) 和 ValueWindowFixedInsert(固定窗) 。 两者不同之处只是插入数据时的处理不同。滑动窗遵循FIFO模型,即先入先出,窗口状态有未满和开始滑动,一般开始滑动后再对窗口进行操作。

固定窗有未满和已满两种状态,已满后会清空窗口,重新开始填充,这也是两种常见的窗口模型。

在STL里,当有一些底层数据结构去存储数据时,要有一些容器的方法(算法),比如排序等,这里先实现了一些基础的泛型算法接口:

#ifndef GENERICS_IMPL_H
#define GENERICS_IMPL_H

#include <stdbool.h>

#include "test_generics.h"




static void swap( ValueWindowSquential* tmp, uint32_t i, uint32_t j )
{
    assert( tmp != NULL );
    // assert( i > tmp->max_size || j > tmp->max_size );
    // assert( i >= tmp->max_size || j >= tmp->max_size );

    switch ( ChangeStringToEnum( tmp->type ) )
    {
        case UINT8: {
            uint8_t* tmp_buffer = ( uint8_t* ) tmp->data;
            uint8_t  res        = tmp_buffer[ i ];

            tmp_buffer[ i ] = tmp_buffer[ j ];
            tmp_buffer[ j ] = res;
        }
        break;

        case INT: {
            int* tmp_buffer = ( int* ) tmp->data;
            int  res        = tmp_buffer[ i ];

            tmp_buffer[ i ] = tmp_buffer[ j ];
            tmp_buffer[ j ] = res;
        }
        break;

        case FLOAT: {
            float* tmp_buffer = ( float* ) tmp->data;
            float  res        = tmp_buffer[ i ];

            tmp_buffer[ i ] = tmp_buffer[ j ];
            tmp_buffer[ j ] = res;
        }
        break;

        case DOUBLE: {
            double* tmp_buffer = ( double* ) tmp->data;
            double  res        = tmp_buffer[ i ];

            tmp_buffer[ i ] = tmp_buffer[ j ];
            tmp_buffer[ j ] = res;
        }
        break;

        default: {
            printf( "error tmp->type input !!!" );
            assert( 0 );
        }
        break;
    }
}

static inline void ValueWindowBubbleSort( ValueWindowSquential* tmp )
{
    switch ( ChangeStringToEnum( tmp->type ) )
    {
        case UINT8: {
            uint8_t* tmp_buffer = ( uint8_t* ) tmp->data;

            bool is_end_loop = true;
            for ( int i = 0; i < tmp->max_size && is_end_loop; i++ )
            {
                is_end_loop = false;

                for ( int j = tmp->max_size - 1; j >= i; j-- )
                {
                    if ( tmp_buffer[ j - 1 ] > tmp_buffer[ j ] )
                    {
                        swap( tmp, j - 1, j );
                        is_end_loop = true;
                    }
                }
            }
        }
        break;

        case INT: {
            int* tmp_buffer = ( int* ) tmp->data;

            bool is_end_loop = true;
            for ( int i = 0; i < tmp->max_size && is_end_loop; i++ )
            {
                is_end_loop = false;

                for ( int j = tmp->max_size - 1; j >= i; j-- )
                {
                    if ( tmp_buffer[ j - 1 ] > tmp_buffer[ j ] )
                    {
                        swap( tmp, j - 1, j );
                        is_end_loop = true;
                    }
                }
            }
        }
        break;

        case FLOAT: {
            float* tmp_buffer = ( float* ) tmp->data;

            bool is_end_loop = true;
            for ( int i = 0; i < tmp->max_size && is_end_loop; i++ )
            {
                is_end_loop = false;

                for ( int j = tmp->max_size - 1; j >= i; j-- )
                {
                    if ( tmp_buffer[ j - 1 ] > tmp_buffer[ j ] )
                    {
                        swap( tmp, j - 1, j );
                        is_end_loop = true;
                    }
                }
            }
        }
        break;

        case DOUBLE: {
            double* tmp_buffer = ( double* ) tmp->data;

            bool is_end_loop = true;
            for ( int i = 0; i < tmp->max_size && is_end_loop; i++ )
            {
                is_end_loop = false;

                for ( int j = tmp->max_size - 1; j >= i; j-- )
                {
                    if ( tmp_buffer[ j - 1 ] > tmp_buffer[ j ] )
                    {
                        swap( tmp, j - 1, j );
                        is_end_loop = true;
                    }
                }
            }
        }
        break;

        default: {
            printf( "error tmp->type input !!!" );
            assert( 0 );
        }
        break;
    }
}

static inline void ValueWindowSelectSort( ValueWindowSquential* tmp )
{
    switch ( ChangeStringToEnum( tmp->type ) )
    {
        case UINT8: {
            uint8_t* tmp_buffer = ( uint8_t* ) tmp->data;

            int tmp_data = 0;
            for ( int i = 0; i < tmp->max_size; i++ )
            {
                tmp_data = i;
                for ( int j = i; j < tmp->max_size; j++ )
                {
                    if ( tmp_buffer[ tmp_data ] > tmp_buffer[ j ] )
                    {
                        tmp_data = j;
                    }
                }
                if ( tmp_data != i )
                {
                    swap( tmp, i, tmp_data );
                }
            }
        }
        break;

        case INT: {
            int* tmp_buffer = ( int* ) tmp->data;

            int tmp_data = 0;
            for ( int i = 0; i < tmp->max_size; i++ )
            {
                tmp_data = i;
                for ( int j = i; j < tmp->max_size; j++ )
                {
                    if ( tmp_buffer[ tmp_data ] > tmp_buffer[ j ] )
                    {
                        tmp_data = j;
                    }
                }
                if ( tmp_data != i )
                {
                    swap( tmp, i, tmp_data );
                }
            }
        }
        break;

        case FLOAT: {
            float* tmp_buffer = ( float* ) tmp->data;

            int tmp_data = 0;
            for ( int i = 0; i < tmp->max_size; i++ )
            {
                tmp_data = i;
                for ( int j = i; j < tmp->max_size; j++ )
                {
                    if ( tmp_buffer[ tmp_data ] > tmp_buffer[ j ] )
                    {
                        tmp_data = j;
                    }
                }
                if ( tmp_data != i )
                {
                    swap( tmp, i, tmp_data );
                }
            }
        }
        break;

        case DOUBLE: {
            double* tmp_buffer = ( double* ) tmp->data;

            int tmp_data = 0;
            for ( int i = 0; i < tmp->max_size; i++ )
            {
                tmp_data = i;
                for ( int j = i; j < tmp->max_size; j++ )
                {
                    if ( tmp_buffer[ tmp_data ] > tmp_buffer[ j ] )
                    {
                        tmp_data = j;
                    }
                }
                if ( tmp_data != i )
                {
                    swap( tmp, i, tmp_data );
                }
            }
        }
        break;

        default: {
            printf( "error tmp->type input !!!" );
            assert( 0 );
        }
        break;
    }
}

static inline void ValueWindowInsertSort( ValueWindowSquential* tmp )
{
    switch ( ChangeStringToEnum( tmp->type ) )
    {
        case UINT8: {
            uint8_t* tmp_buffer = ( uint8_t* ) tmp->data;

            uint8_t tmp_data = 0;
            int     j        = 0;
            for ( int i = 1; i < tmp->max_size; i++ )
            {
                if ( tmp_buffer[ i ] < tmp_buffer[ i - 1 ] )
                {
                    tmp_data = tmp_buffer[ i ];
                    // TAG : 数据整体向后迁移,寻找数值更大的成员
                    for ( j = i - 1; tmp_buffer[ j ] > tmp_data && j >= 0; j-- )
                    {
                        tmp_buffer[ j + 1 ] = tmp_buffer[ j ];
                    }
                    tmp_buffer[ j + 1 ] = tmp_data;
                }
            }
        }
        break;

        case INT: {
            int* tmp_buffer = ( int* ) tmp->data;

            int tmp_data = 0;
            int j        = 0;
            for ( int i = 1; i < tmp->max_size; i++ )
            {
                if ( tmp_buffer[ i ] < tmp_buffer[ i - 1 ] )
                {
                    tmp_data = tmp_buffer[ i ];
                    // TAG : 数据整体向后迁移,寻找数值更大的成员
                    for ( j = i - 1; tmp_buffer[ j ] > tmp_data && j >= 0; j-- )
                    {
                        tmp_buffer[ j + 1 ] = tmp_buffer[ j ];
                    }
                    tmp_buffer[ j + 1 ] = tmp_data;
                }
            }
        }
        break;

        case FLOAT: {
            float* tmp_buffer = ( float* ) tmp->data;

            float tmp_data = 0;
            int   j        = 0;
            for ( int i = 1; i < tmp->max_size; i++ )
            {
                if ( tmp_buffer[ i ] < tmp_buffer[ i - 1 ] )
                {
                    tmp_data = tmp_buffer[ i ];
                    // TAG : 数据整体向后迁移,寻找数值更大的成员
                    for ( j = i - 1; tmp_buffer[ j ] > tmp_data && j >= 0; j-- )
                    {
                        tmp_buffer[ j + 1 ] = tmp_buffer[ j ];
                    }
                    tmp_buffer[ j + 1 ] = tmp_data;
                }
            }
        }
        break;

        case DOUBLE: {
            double* tmp_buffer = ( double* ) tmp->data;

            double tmp_data = 0;
            int    j        = 0;
            for ( int i = 1; i < tmp->max_size; i++ )
            {
                if ( tmp_buffer[ i ] < tmp_buffer[ i - 1 ] )
                {
                    tmp_data = tmp_buffer[ i ];
                    // TAG : 数据整体向后迁移,寻找数值更大的成员
                    for ( j = i - 1; tmp_buffer[ j ] > tmp_data && j >= 0; j-- )
                    {
                        tmp_buffer[ j + 1 ] = tmp_buffer[ j ];
                    }
                    tmp_buffer[ j + 1 ] = tmp_data;
                }
            }
        }
        break;

        default: {
            printf( "error tmp->type input !!!" );
            assert( 0 );
        }
        break;
    }
}
#endif // GENERICS_IMPL_H

以上就是基于C语言实现泛型编程详解的详细内容,更多关于C语言 泛型编程的资料请关注其它相关文章!

相关文章