本文主要是介绍QT Base64 编解码，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
#ifndef BASE64_H
#define BASE64_H#include <QString>class Base64
{
public:/** 功能：静态成员函数，将字节数组转换为Base64编码字符串* 参数说明：* binaryData：要转换的字节数组* 返回值：* 转换后得到的Base64编码字符串* 异常抛出：* 无* 说明：* 空说明列表指出函数不抛出任何异常* 如果一个函数声明没有指定异常说明，则该函数可以抛出任意类型的异常*/static QString encode(const QByteArray & binaryData) throw();/** 功能：静态成员函数，将Base64编码字符串解码为字节数组* 参数说明：* base64String：要转换的Base64编码字符串* 返回值：* 解码后得到的字节数组* 异常抛出：* 抛出整型异常* -1：数据错误* 说明：* 字符串中允许任意的空白字符、回车换行符、连字符*/static QByteArray decode(const QString & base64String) throw(int);
};#endif // BASE64_H
#include "Base64.h"
#include <QDataStream>static const char* DATA_BIN2ASCII = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";// Base64编码，该函数不抛出任何异常
QString Base64::encode(const QByteArray & binaryData) throw()
{if(binaryData.isEmpty())return QString();QString sb;int index = 0;for(int i = binaryData.length(); i > 0; i -= 3){ // 将3字节数据转换成4个ASCII字符if(i >= 3){int b0 = binaryData[index++] & 0xFF;int b1 = binaryData[index++] & 0xFF;int b2 = binaryData[index++] & 0xFF;sb.append(DATA_BIN2ASCII[b0 >> 2]);sb.append(DATA_BIN2ASCII[((b0 << 4) | (b1 >> 4)) & 0x3F]);sb.append(DATA_BIN2ASCII[((b1 << 2) | (b2 >> 6)) & 0x3F]);sb.append(DATA_BIN2ASCII[b2 & 0x3F]);}else{int b0 = binaryData[index++] & 0xFF;int b1;if(i == 2)b1 = binaryData[index++] & 0xFF;elseb1 = 0;sb.append(DATA_BIN2ASCII[b0 >> 2]);sb.append(DATA_BIN2ASCII[((b0 << 4) | (b1 >> 4)) & 0x3F]);if(i == 1)sb.append('='); // 填充字符elsesb.append(DATA_BIN2ASCII[(b1 << 2) & 0x3F]);sb.append('='); // 填充字符}}return sb;
}#define B64_EOLN 0xF0 // 换行\n
#define B64_CR 0xF1 // 回车\r
#define B64_EOF 0xF2 // 连字符-
#define B64_WS 0xE0 // 跳格或者空格（\t、space）
#define B64_ERROR 0xFF // 错误字符
#define B64_NOT_BASE64 0xF3 // 空白字符、回车换行字符、连字符static const quint8 DATA_ASCII2BIN[128] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xE0,0xF0,0xFF,0xFF,0xF1,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xE0,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0x3E,0xFF,0xF2,0xFF,0x3F,0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,0xFF,0xFF,0xFF,0x00,0xFF,0xFF,0xFF,0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F,0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28,0x29,0x2A,0x2B,0x2C,0x2D,0x2E,0x2F,0x30,0x31,0x32,0x33,0xFF,0xFF,0xFF,0xFF,0xFF
};// Base64解码，该函数抛出整型异常
QByteArray Base64::decode(const QString & base64String) throw(int)
{if(base64String.isEmpty()) return QByteArray();int length = base64String.length(); // 字符串长度QByteArray ba; // 字节数组QDataStream out(&ba, QIODevice::WriteOnly); // 写入数据流int index = 0;int previous = 0;for(int i = 0; i < length; i++){int charValue = base64String[i].unicode(); // 字符的Unicode编码if(charValue >= 0x80) throw(-1); // 数据错误int orderValue = DATA_ASCII2BIN[charValue];if(orderValue == B64_ERROR) throw(-1); // 数据错误// 跳过空白字符、回车换行字符、连字符if((orderValue | 0x13) == B64_NOT_BASE64)continue;if(index == 0){if(charValue == '=') throw(-1); // 数据错误previous = orderValue;index++;}else if(index == 1){if(charValue == '=') throw(-1); // 数据错误out << static_cast<quint8>((previous << 2) | (orderValue >> 4));previous = orderValue;index++;}else if(index == 2){if(charValue == '='){ // 简化处理，不再判断第二个'='index = 0;break;}out << static_cast<quint8>((previous << 4) | (orderValue >> 2));previous = orderValue;index++;}else{index = 0;if(charValue == '=')break;out << static_cast<quint8>((previous << 6) | orderValue);}} // End forif(index == 0) // 有效字符个数必须是4的倍数return ba;elsethrow(-1); // 数据错误
}
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