81 lines
2.4 KiB
Mathematica
81 lines
2.4 KiB
Mathematica
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/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#import "FBImageUtils.h"
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#import "FBMacros.h"
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#import "FBConfiguration.h"
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// https://en.wikipedia.org/wiki/List_of_file_signatures
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static uint8_t PNG_MAGIC[] = { 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A };
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static const NSUInteger PNG_MAGIC_LEN = 8;
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static uint8_t JPG_MAGIC[] = { 0xff, 0xd8, 0xff };
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static const NSUInteger JPG_MAGIC_LEN = 3;
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BOOL FBIsPngImage(NSData *imageData)
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{
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if (nil == imageData || [imageData length] < PNG_MAGIC_LEN) {
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return NO;
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}
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static NSData* pngMagicStartData = nil;
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static dispatch_once_t oncePngToken;
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dispatch_once(&oncePngToken, ^{
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pngMagicStartData = [NSData dataWithBytesNoCopy:(void*)PNG_MAGIC length:PNG_MAGIC_LEN freeWhenDone:NO];
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});
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#pragma clang diagnostic push
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#pragma clang diagnostic ignored "-Wassign-enum"
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NSRange range = [imageData rangeOfData:pngMagicStartData options:kNilOptions range:NSMakeRange(0, PNG_MAGIC_LEN)];
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#pragma clang diagnostic pop
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return range.location != NSNotFound;
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}
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NSData *FBToPngData(NSData *imageData) {
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if (nil == imageData || [imageData length] < PNG_MAGIC_LEN) {
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return nil;
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}
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if (FBIsPngImage(imageData)) {
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return imageData;
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}
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UIImage *image = [UIImage imageWithData:imageData];
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return nil == image ? nil : (NSData *)UIImagePNGRepresentation(image);
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}
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BOOL FBIsJpegImage(NSData *imageData)
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{
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if (nil == imageData || [imageData length] < JPG_MAGIC_LEN) {
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return NO;
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}
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static NSData* jpgMagicStartData = nil;
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static dispatch_once_t onceJpgToken;
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dispatch_once(&onceJpgToken, ^{
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jpgMagicStartData = [NSData dataWithBytesNoCopy:(void*)JPG_MAGIC length:JPG_MAGIC_LEN freeWhenDone:NO];
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});
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#pragma clang diagnostic push
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#pragma clang diagnostic ignored "-Wassign-enum"
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NSRange range = [imageData rangeOfData:jpgMagicStartData options:kNilOptions range:NSMakeRange(0, JPG_MAGIC_LEN)];
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#pragma clang diagnostic pop
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return range.location != NSNotFound;
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}
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NSData *FBToJpegData(NSData *imageData, CGFloat compressionQuality) {
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if (nil == imageData || [imageData length] < JPG_MAGIC_LEN) {
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return nil;
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}
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if (FBIsJpegImage(imageData)) {
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return imageData;
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}
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UIImage *image = [UIImage imageWithData:imageData];
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return nil == image ? nil : (NSData *)UIImageJPEGRepresentation(image, compressionQuality);
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}
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