码迷，mamicode.com
首页 > 其他好文 > 详细

对图片进行Base64转码和解码

时间：2020-11-24 12:13:36      阅读：7      评论：0      收藏：0      [点我收藏+]

标签：free   读取   std   read   sig   proc   signed   class   strlen   

Base64代码

base64.c

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

// bindata待编码数据buffer  base64 编码后数据buffer  binlength 待编码数据大小
char* base64_encode(const unsigned char* bindata, char* base64, int binlength);
// base64编码字符串 bindata 解码后buffer
int base64_decode(const char* base64, unsigned char* bindata);

int main()
{
    FILE* fp = NULL;
    unsigned int imageSize;        //图片字节数
    char* imageBin;
    char* imageBase64;
    char* imageOutput;
    size_t result;
    char* ret;
    unsigned int base64StrLength;

    fp = fopen("lena.bmp", "rb");   //待编码图片
    if (NULL == fp)
    {
        printf("file open file");
        return -1;
    }
    //获取图片大小
    fseek(fp, 0L, SEEK_END);
    imageSize = ftell(fp);
    fseek(fp, 0L, SEEK_SET);

    //分配内存存储整个图片
    imageBin = (char*)malloc(sizeof(char) * imageSize);
    if (NULL == imageBin)
    {
        printf("malloc failed");
        return -1;
    }

    //读取图片
    result = fread(imageBin, 1, imageSize, fp);
    if (result != imageSize)
    {
        printf("file read failed");
        return -1;
    }
    fclose(fp);

    //分配编码后图片所在buffer
    imageBase64 = (char*)malloc(sizeof(char) * imageSize * 2);//因为编码一版会比源数据大1/3的样子，这里直接申请源文件一倍的空间
    if (NULL == imageBase64)
    {
        printf("malloc failed");
        return -1;
    }

    //base64编码
    base64_encode(imageBin, imageBase64, imageSize);
    base64StrLength = strlen(imageBase64);
    printf("base64 str length:%d\n", base64StrLength);
    printf("将图片读入out.txt中\n");
    FILE* file = fopen("out.txt", "wb");
    if (file == NULL)
    {
        printf("Error!");
        exit(1);
    }
    //将Base64编码写入文件
    int i = 0;
    while (imageBase64[i] != NULL)
    {
        fputc(imageBase64[i++], file);
    }
    fclose(file);

    //分配存储解码数据buffer
    imageOutput = (char*)malloc(sizeof(char) * imageSize);//解码后应该和源图片大小一致
    if (NULL == imageBase64)
    {
        printf("malloc failed");
        return -1;
    }
    base64_decode(imageBase64, imageOutput);

    fp = fopen("output.bmp", "wb");
    if (NULL == fp)
    {
        printf("file open file");
        return -1;
    }
    fwrite(imageOutput, 1, imageSize, fp);
    fclose(fp);

    free(imageBin);
    free(imageBase64);
    free(imageOutput);

    return 0;
}

const char* base64char = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
char* base64_encode(const unsigned char* bindata, char* base64, int binlength)
{
    int i, j;
    unsigned char current;

    for (i = 0, j = 0; i < binlength; i += 3)
    {
        current = (bindata[i] >> 2);
        current &= (unsigned char)0x3F;
        base64[j++] = base64char[(int)current];

        current = ((unsigned char)(bindata[i] << 4)) & ((unsigned char)0x30);
        if (i + 1 >= binlength)
        {
            base64[j++] = base64char[(int)current];
            base64[j++] = ‘=‘;
            base64[j++] = ‘=‘;
            break;
        }
        current |= ((unsigned char)(bindata[i + 1] >> 4)) & ((unsigned char)0x0F);
        base64[j++] = base64char[(int)current];

        current = ((unsigned char)(bindata[i + 1] << 2)) & ((unsigned char)0x3C);
        if (i + 2 >= binlength)
        {
            base64[j++] = base64char[(int)current];
            base64[j++] = ‘=‘;
            break;
        }
        current |= ((unsigned char)(bindata[i + 2] >> 6)) & ((unsigned char)0x03);
        base64[j++] = base64char[(int)current];

        current = ((unsigned char)bindata[i + 2]) & ((unsigned char)0x3F);
        base64[j++] = base64char[(int)current];
    }
    base64[j] = ‘\0‘;
    return 0;
}

int base64_decode(const char* base64, unsigned char* bindata)
{
    int i, j;
    unsigned char k;
    unsigned char temp[4];
    for (i = 0, j = 0; base64[i] != ‘\0‘; i += 4)
    {
        memset(temp, 0xFF, sizeof(temp));
        for (k = 0; k < 64; k++)
        {
            if (base64char[k] == base64[i])
                temp[0] = k;
        }
        for (k = 0; k < 64; k++)
        {
            if (base64char[k] == base64[i + 1])
                temp[1] = k;
        }
        for (k = 0; k < 64; k++)
        {
            if (base64char[k] == base64[i + 2])
                temp[2] = k;
        }
        for (k = 0; k < 64; k++)
        {
            if (base64char[k] == base64[i + 3])
                temp[3] = k;
        }

        bindata[j++] = ((unsigned char)(((unsigned char)(temp[0] << 2)) & 0xFC)) |
            ((unsigned char)((unsigned char)(temp[1] >> 4) & 0x03));
        if (base64[i + 2] == ‘=‘)
            break;

        bindata[j++] = ((unsigned char)(((unsigned char)(temp[1] << 4)) & 0xF0)) |
            ((unsigned char)((unsigned char)(temp[2] >> 2) & 0x0F));
        if (base64[i + 3] == ‘=‘)
            break;

        bindata[j++] = ((unsigned char)(((unsigned char)(temp[2] << 6)) & 0xF0)) |
            ((unsigned char)(temp[3] & 0x3F));
    }
    return j;
}

unistd.h 

#pragma once
/** This file is part of the Mingw32 package.
unistd.h maps (roughly) to io.h
*/
#ifndef _UNISTD_H
#define _UNISTD_H
#include <io.h>
#include <process.h>
#endif /* _UNISTD_H */

将Base64编码存于文件中

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

// bindata待编码数据buffer  base64 编码后数据buffer  binlength 待编码数据大小
char* base64_encode(const unsigned char* bindata, char* base64, int binlength);
// base64编码字符串 bindata 解码后buffer
int base64_decode(const char* base64, unsigned char* bindata);

int main()
{
    FILE* fp = NULL;
    unsigned int imageSize;        //图片字节数
    char* imageBin;
    char* imageBase64;
    char* imageOutput;
    size_t result;
    char* ret;
    unsigned int base64StrLength;

    fp = fopen("lena.bmp", "rb");   //待编码图片
    if (NULL == fp)
    {
        printf("file open file");
        return -1;
    }
    //获取图片大小
    fseek(fp, 0L, SEEK_END);
    imageSize = ftell(fp);
    fseek(fp, 0L, SEEK_SET);

    //分配内存存储整个图片
    imageBin = (char*)malloc(sizeof(char) * imageSize);
    if (NULL == imageBin)
    {
        printf("malloc failed");
        return -1;
    }

    //读取图片
    result = fread(imageBin, 1, imageSize, fp);
    if (result != imageSize)
    {
        printf("file read failed");
        return -1;
    }
    fclose(fp);

    //分配编码后图片所在buffer
    imageBase64 = (char*)malloc(sizeof(char) * imageSize * 2);//因为编码一版会比源数据大1/3的样子，这里直接申请源文件一倍的空间
    if (NULL == imageBase64)
    {
        printf("malloc failed");
        return -1;
    }

    //base64编码
    base64_encode(imageBin, imageBase64, imageSize);
    base64StrLength = strlen(imageBase64);
    printf("base64 str length:%d\n", base64StrLength);
    printf("将图片读入out.txt中\n");
    FILE* file = fopen("out.txt", "wb");
    if (file == NULL)
    {
        printf("Error!");
        exit(1);
    }
    //将Base64编码写入文件
    int i = 0;
    while (imageBase64[i] != NULL)
    {
        fputc(imageBase64[i++], file);
    }
    fclose(file);

    //分配存储解码数据buffer
    imageOutput = (char*)malloc(sizeof(char) * imageSize);//解码后应该和源图片大小一致
    if (NULL == imageBase64)
    {
        printf("malloc failed");
        return -1;
    }
    base64_decode(imageBase64, imageOutput);

    fp = fopen("output.bmp", "wb");
    if (NULL == fp)
    {
        printf("file open file");
        return -1;
    }
    fwrite(imageOutput, 1, imageSize, fp);
    fclose(fp);

    free(imageBin);
    free(imageBase64);
    free(imageOutput);

    return 0;
}

const char* base64char = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
char* base64_encode(const unsigned char* bindata, char* base64, int binlength)
{
    int i, j;
    unsigned char current;

    for (i = 0, j = 0; i < binlength; i += 3)
    {
        current = (bindata[i] >> 2);
        current &= (unsigned char)0x3F;
        base64[j++] = base64char[(int)current];

        current = ((unsigned char)(bindata[i] << 4)) & ((unsigned char)0x30);
        if (i + 1 >= binlength)
        {
            base64[j++] = base64char[(int)current];
            base64[j++] = ‘=‘;
            base64[j++] = ‘=‘;
            break;
        }
        current |= ((unsigned char)(bindata[i + 1] >> 4)) & ((unsigned char)0x0F);
        base64[j++] = base64char[(int)current];

        current = ((unsigned char)(bindata[i + 1] << 2)) & ((unsigned char)0x3C);
        if (i + 2 >= binlength)
        {
            base64[j++] = base64char[(int)current];
            base64[j++] = ‘=‘;
            break;
        }
        current |= ((unsigned char)(bindata[i + 2] >> 6)) & ((unsigned char)0x03);
        base64[j++] = base64char[(int)current];

        current = ((unsigned char)bindata[i + 2]) & ((unsigned char)0x3F);
        base64[j++] = base64char[(int)current];
    }
    base64[j] = ‘\0‘;
    return 0;
}

int base64_decode(const char* base64, unsigned char* bindata)
{
    int i, j;
    unsigned char k;
    unsigned char temp[4];
    for (i = 0, j = 0; base64[i] != ‘\0‘; i += 4)
    {
        memset(temp, 0xFF, sizeof(temp));
        for (k = 0; k < 64; k++)
        {
            if (base64char[k] == base64[i])
                temp[0] = k;
        }
        for (k = 0; k < 64; k++)
        {
            if (base64char[k] == base64[i + 1])
                temp[1] = k;
        }
        for (k = 0; k < 64; k++)
        {
            if (base64char[k] == base64[i + 2])
                temp[2] = k;
        }
        for (k = 0; k < 64; k++)
        {
            if (base64char[k] == base64[i + 3])
                temp[3] = k;
        }

        bindata[j++] = ((unsigned char)(((unsigned char)(temp[0] << 2)) & 0xFC)) |
            ((unsigned char)((unsigned char)(temp[1] >> 4) & 0x03));
        if (base64[i + 2] == ‘=‘)
            break;

        bindata[j++] = ((unsigned char)(((unsigned char)(temp[1] << 4)) & 0xF0)) |
            ((unsigned char)((unsigned char)(temp[2] >> 2) & 0x0F));
        if (base64[i + 3] == ‘=‘)
            break;

        bindata[j++] = ((unsigned char)(((unsigned char)(temp[2] << 6)) & 0xF0)) |
            ((unsigned char)(temp[3] & 0x3F));
    }
    return j;
}

对图片进行Base64转码和解码

标签：free   读取   std   read   sig   proc   signed   class   strlen   

原文地址：https://www.cnblogs.com/pam-sh/p/14008284.html
踩
(0)
赞
(0)
   
举报
评论 一句话评论（0）
登录后才能评论！
分享档案
更多>
2021年07月29日 (22)
2021年07月28日 (40)
2021年07月27日 (32)
2021年07月26日 (79)
2021年07月23日 (29)
2021年07月22日 (30)
2021年07月21日 (42)
2021年07月20日 (16)
2021年07月19日 (90)
2021年07月16日 (35)
周排行
mamicode.com排行更多图片
更多
友情链接
兰亭集智   国之画   百度统计   站长统计   阿里云   chrome插件   新版天听网
关于我们 - 联系我们 - 留言反馈
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码！