NSdata与NSString，Byte数组，UIImage的相互转换

NSdata与NSString，Byte数组，UIImage的相互转换

1、NSData与NSString
NSData－> NSString
NSString *aString = [[NSString alloc] initWithData:adata encoding:NSUTF8StringEncoding];

NSString－> NSData
NSString *aString = @"1234abcd";
NSData *aData = [aString dataUsingEncoding: NSUTF8StringEncoding];

2、NSData与Byte
NSData－> Byte数组
NSString *testString = @"1234567890";
NSData *testData = [testString dataUsingEncoding: NSUTF8StringEncoding];
Byte *testByte = (Byte *)[testData bytes];
for (int i = 0;i < [testData length];i++)
{
printf("testByte = %d\n",testByte[i]);
}

Byte数组－> NSData
Byte byte[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23};
NSData *adata = [[NSData alloc] initWithBytes:byte length:24];

Byte数组－>16进制数
Byte *bytes = (Byte *)[aData bytes];
NSString *hexStr = @"";
for (int i = 0;i < [encryData length];i++)
{
NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff]; // 16进制数
if ([newHexStr length] == 1)
{
hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];
}
else
{
hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
}
}
NSLog(@"bytes
的16进制数为:%@",hexStr);

16进制数－>Byte数组
//
将16进制数据转化成Byte
数组
NSString *hexString = @"3e435fab9c34891f"; // 16进制字符串
int j = 0;
Byte bytes[128]; // 3ds key的Byte
数组， 128位
for (int i = 0;i < [hexString length];i++)
{
int int_ch; //
两位16进制数转化后的10进制数

unichar hex_char1 = [hexString characterAtIndex:i]; //
两位16进制数中的第一位(高位*16)
int int_ch1;
if (hex_char1 >= '0' && hex_char1 <='9')
{
int_ch1 = (hex_char1-48) * 16; // 0
的Ascll - 48
}
else if(hex_char1 >= 'A' && hex_char1 <='F')
{
int_ch1 = (hex_char1-55)*16; // A
的Ascll - 65
}
else
{
int_ch1 = (hex_char1-87)*16; // a
的Ascll - 97
i++;
}

unichar hex_char2 = [hexString characterAtIndex:i]; //
两位16进制数中的第二位(低位)
int int_ch2;
if (hex_char2 >= '0' && hex_char2 <='9')
{
int_ch2 = (hex_char2-48); // 0
的Ascll - 48
}
else if(hex_char1 >= 'A' && hex_char1 <='F')
{
int_ch2 = hex_char2-55; // A
的Ascll - 65
}
else
{
int_ch2 = hex_char2-87; // a
的Ascll - 97
}

int_ch = int_ch1+int_ch2;
NSLog(@"int_ch=%d",int_ch);
bytes[j] = int_ch; //
将转化后的数放入Byte数组里
j++;
}

NSData *newData = [[NSData alloc] initWithBytes:bytes length:128];
NSLog(@"newData=%@",newData);

3. NSData
与 UIImage
NSData－>UIImage
UIImage *aimage = [UIImage imageWithData: imageData];

//
例：从本地文件沙盒中取图片并转换为NSData
NSString *path = [[NSBundle mainBundle] bundlePath];
NSString *name = [NSString stringWithFormat:@"ceshi.png"];
NSString *finalPath = [path stringByAppendingPathComponent:name];
NSData *imageData = [NSData dataWithContentsOfFile: finalPath];
UIImage *aimage = [UIImage imageWithData: imageData];

UIImage－> NSData
NSData *imageData = UIImagePNGRepresentation(aimae);