showMem.c setMem.c 及其改进

#ifndef MEMUTIL_H_INCLUDED
#define MEMUTIL_H_INCLUDED

// Show memory
void showMem(void *, unsigned);

// Setup memory
int setMem(void *, const char *);

#endif // MEMUTIL_H_INCLUDED

　　

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

// Display memory
void showMem(void *p, unsigned size)
{
    char *buf = 0;
    int prs = 0;
    unsigned i;

	buf = (char *)malloc(size * 9);
    printf("Show %p, count %u bits.\n", p, size * 8);
    for (i = 0; i < size; i++)
    {
        char ch = ((char *)p)[i]; // Get char p[i]
        int j;

        for (j = 0; j < 8; j++) // p[i] to 8 bit unsigned int
        {
            unsigned tmp = 0;

            tmp = ch >> (8 - j - 1) & 1;
            sprintf(&buf[prs], "%u", tmp % 2);
            prs = strlen(buf);
        }
        sprintf(&buf[prs], " ");
        prs++;
    }
    buf[prs - 1] = '\0';
    puts(buf);
}

　　

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

#include "MemUtil.h"

// Setup memory
// Return:
// 0  -Setting succeed
// !0 -Setting failed
int setMem(void *p, const char *c)
{
    int le;
    char *str = 0; // 去除空格的副本
    int i;
    int j;
    char ch;

    le = strlen(c);
    i = le - 1;
    str = (char *)malloc(le * 8 / 9 + 2);
    str[0] = '\0';

    // 去除空格
    i = 0;
    while ((ch = *(char *)c++) != '\0')
    {
        if (ch == ' ')
            continue;
        if (ch == '1' || ch == '0')
        {
            str[i++] = ch;
            str[i] = '\0';
        } else {
            printf("错误, 未知的字符: %c.", ch);
            return !0;
        }
    }
    if ((le = strlen(str)) % 8 != 0)
    {
        printf("拒绝执行, 长度错误: %d.\n", le % 8);
        return !0;
    }

    i = 0;
    j = le / 8;
    for (; i < j; i++)
    {
        char tmp = 0;
        int k = 0;

        for (; k < 8; k++)
        {
            tmp |= (str[i * 8 + k] ^ 0x30) << (7 - k);
        }
        ((char *)p)[i] = tmp;
    }
    return 0;
}

　　上面这些代码看似可以工作, 然而!!!!!!!!!!!

　　就在某一天我准备使用它打造一个二进制文件工具的时候, 发生了爆炸!!!!!!! showMem 处理 200 KB居然耗时 80 s !!!!!!!!!!!!!!!!!!!! 当然其中 puts 占用了绝大部分"功劳", 试着优化一下

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

 char *showMem(void *p, unsigned size)
 {
     char *buf = ;
     int prs = ;
     unsigned i = ;
     unsigned j = ;
     char ch = '\0';
     unsigned tmp = ;

     if ((buf = (char *)malloc(size * )) == )
     {
         fprintf(stderr, "Execute failed, PC have not memory.\n");
         return ;
     }

     printf("Show %p, count %u bits.\n", p, size * );
     for (i = ; i < size; i++)
     {
         ch = ((char *)p)[i]; // Get char p[i]

         for (j = ; j < ; j++) // p[i] to 8 bit unsigned int
         {
             tmp = ch >> ( - j) & ;
             buf[prs++] = (tmp ==  ? 0x30 : 0x31);
         }
         buf[prs++] = ' ';
     }
     buf[prs - ] = '\0';
     puts(buf);
     return buf;
 }

showMem.c 性能40+倍提升( -_-! )

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

 #include "MemUtil.h"

 // Setting memory
 // Return:
 //      设置完成的字节数
 //      -1 代表错误
 int setMem(void *p, const char *c)
 {
     int le = ;
     char *str = ; // 去除空格的副本
     int i = ;
     int j = ;
     char ch = ;

     le = strlen(c);
     str = (char *)malloc(le);

     // 去除空格和换行
     while ((ch = *(char *)c++) != '\0')
     {
         if (ch == ' ' || ch == '\n')
             continue;
         if (ch == 0x31 || ch == 0x30)
         {
             str[i++] = ch;
         } else {
             printf("Oops, dead character %c.", ch);
             return -;
         }
     }
     str[i] = '\0';

     if ((le = strlen(str)) %  != )
     {
         printf("You setting data is fucking, 错误的余数 %d.\n", le % );
         return -;
     }

     i = ;
     j = le / ;
     for (; i < j; i++)
     {
         char tmp = ;
         int k = ;

         for (; k < ; k++)
         {
             tmp |= (str[i *  + k] ^ 0x30) << ( - k);
         }
         ((char *)p)[i] = tmp;
     }
     return j;
 }

setMem.c 优化调整