从 UIImage 生成哈希 [英] Generate hash from UIImage
问题描述
我正在尝试比较文件系统中的两个 UIImage 以查看它们是否相同.显然,我不能使用 NSObject 的 hash 方法,因为它返回的是对象的散列,而不是实际的图像数据.
I'm trying to compare two UIImages from the file system to see if they are the same. Obviously, I can't use NSObject's hash method, since this returns a hash of the object, and not the actual image data.
我发现代码从字符串生成 MD5 哈希,但我还没有发现如何为 UIImage 实现它.
I found code generate an MD5 hash from a string, but I haven't discovered how to implement it for a UIImage.
我应该如何散列 UIImage?或者我的对比图像的方法完全不可行?
How should I go about hashing a UIImage? Or is my method for comparing to images totally off?
推荐答案
我最终使用以下代码来完成任务.请注意,这需要您导入
:
I wound up using the following code to accomplish the task. Note that this requires that you import <CommonCrypto/CommonDigest.h>
:
unsigned char result[CC_MD5_DIGEST_LENGTH];
NSData *imageData = [NSData dataWithData:UIImagePNGRepresentation(inImage)];
CC_MD5([imageData bytes], [imageData length], result);
NSString *imageHash = [NSString stringWithFormat:
@"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",
result[0], result[1], result[2], result[3],
result[4], result[5], result[6], result[7],
result[8], result[9], result[10], result[11],
result[12], result[13], result[14], result[15]
];
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