NSData+ImageContentType.m

//
// Created by Fabrice Aneche on 06/01/14.
// Copyright (c) 2014 Dailymotion. All rights reserved.
//

#import "NSData+ImageContentType.h"


@implementation NSData (ImageContentType)

+ (NSString *)contentTypeForImageData:(NSData *)data
{
    uint8_t c;
    [data getBytes:&c length:1];
    switch (c)
    {
        case 0xFF:
            return @"image/jpeg";
        case 0x89:
            return @"image/png";
        case 0x47:
            return @"image/gif";
        case 0x49:
        case 0x4D:
            return @"image/tiff";
        case 0x52:
            // R as RIFF for WEBP
            if ([data length] < 12)
            {
                return nil;
            }
            
            NSString *testString = [[NSString alloc] initWithData:[data subdataWithRange:NSMakeRange(0, 12)] encoding:NSASCIIStringEncoding];
            if ([testString hasPrefix:@"RIFF"] && [testString hasSuffix:@"WEBP"])
            {
                return @"image/webp";
            }
            
            return nil;
    }
    return nil;
}

@end