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.
", 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] = '';
    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] = '';

    // 去除空格
    i = 0;
    while ((ch = *(char *)c++) != '')
    {
        if (ch == ' ')
            continue;
        if (ch == '1' || ch == '0')
        {
            str[i++] = ch;
            str[i] = '';
        } 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.
", 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 = 0;
    int prs = 0;
    unsigned i = 0;
    unsigned j = 0;
    char ch = '';
    unsigned tmp = 0;

    if ((buf = (char *)malloc(size * 9)) == 0)
    {
        fprintf(stderr, "Execute failed, PC have not memory.
");
        return 0;
    }

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


        for (j = 0; j < 8; j++) // p[i] to 8 bit unsigned int
        {
            tmp = ch >> (7 - j) & 1;
            buf[prs++] = (tmp == 0 ? 0x30 : 0x31);
        }
        buf[prs++] = ' ';
    }
    buf[prs - 1] = '';
    puts(buf);
    return buf;
}

#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 = 0;
    char *str = 0; // 去除空格的副本
    int i = 0;
    int j = 0;
    char ch = 0;

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

    // 去除空格和换行
    while ((ch = *(char *)c++) != '')
    {
        if (ch == ' ' || ch == '
')
            continue;
        if (ch == 0x31 || ch == 0x30)
        {
            str[i++] = ch;
        } else {
            printf("Oops, dead character %c.", ch);
            return -1;
        }
    }
    str[i] = '';

    if ((le = strlen(str)) % 8 != 0)
    {
        printf("You setting data is fucking, 错误的余数 %d.
", le % 8);
        return -1;
    }

    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 j;
}