//
|
// ImageFormat.swift
|
// Kingfisher
|
//
|
// Created by onevcat on 2018/09/28.
|
//
|
// Copyright (c) 2019 Wei Wang <onevcat@gmail.com>
|
//
|
// Permission is hereby granted, free of charge, to any person obtaining a copy
|
// of this software and associated documentation files (the "Software"), to deal
|
// in the Software without restriction, including without limitation the rights
|
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
// copies of the Software, and to permit persons to whom the Software is
|
// furnished to do so, subject to the following conditions:
|
//
|
// The above copyright notice and this permission notice shall be included in
|
// all copies or substantial portions of the Software.
|
//
|
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
// THE SOFTWARE.
|
|
import Foundation
|
|
/// Represents image format.
|
///
|
/// - unknown: The format cannot be recognized or not supported yet.
|
/// - PNG: PNG image format.
|
/// - JPEG: JPEG image format.
|
/// - GIF: GIF image format.
|
public enum ImageFormat {
|
/// The format cannot be recognized or not supported yet.
|
case unknown
|
/// PNG image format.
|
case PNG
|
/// JPEG image format.
|
case JPEG
|
/// GIF image format.
|
case GIF
|
|
struct HeaderData {
|
static var PNG: [UInt8] = [0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A]
|
static var JPEG_SOI: [UInt8] = [0xFF, 0xD8]
|
static var JPEG_IF: [UInt8] = [0xFF]
|
static var GIF: [UInt8] = [0x47, 0x49, 0x46]
|
}
|
|
/// https://en.wikipedia.org/wiki/JPEG
|
public enum JPEGMarker {
|
case SOF0 //baseline
|
case SOF2 //progressive
|
case DHT //Huffman Table
|
case DQT //Quantization Table
|
case DRI //Restart Interval
|
case SOS //Start Of Scan
|
case RSTn(UInt8) //Restart
|
case APPn //Application-specific
|
case COM //Comment
|
case EOI //End Of Image
|
|
var bytes: [UInt8] {
|
switch self {
|
case .SOF0: return [0xFF, 0xC0]
|
case .SOF2: return [0xFF, 0xC2]
|
case .DHT: return [0xFF, 0xC4]
|
case .DQT: return [0xFF, 0xDB]
|
case .DRI: return [0xFF, 0xDD]
|
case .SOS: return [0xFF, 0xDA]
|
case .RSTn(let n): return [0xFF, 0xD0 + n]
|
case .APPn: return [0xFF, 0xE0]
|
case .COM: return [0xFF, 0xFE]
|
case .EOI: return [0xFF, 0xD9]
|
}
|
}
|
}
|
}
|
|
|
extension Data: KingfisherCompatibleValue {}
|
|
// MARK: - Misc Helpers
|
extension KingfisherWrapper where Base == Data {
|
/// Gets the image format corresponding to the data.
|
public var imageFormat: ImageFormat {
|
guard base.count > 8 else { return .unknown }
|
|
var buffer = [UInt8](repeating: 0, count: 8)
|
base.copyBytes(to: &buffer, count: 8)
|
|
if buffer == ImageFormat.HeaderData.PNG {
|
return .PNG
|
|
} else if buffer[0] == ImageFormat.HeaderData.JPEG_SOI[0],
|
buffer[1] == ImageFormat.HeaderData.JPEG_SOI[1],
|
buffer[2] == ImageFormat.HeaderData.JPEG_IF[0]
|
{
|
return .JPEG
|
|
} else if buffer[0] == ImageFormat.HeaderData.GIF[0],
|
buffer[1] == ImageFormat.HeaderData.GIF[1],
|
buffer[2] == ImageFormat.HeaderData.GIF[2]
|
{
|
return .GIF
|
}
|
|
return .unknown
|
}
|
|
public func contains(jpeg marker: ImageFormat.JPEGMarker) -> Bool {
|
guard imageFormat == .JPEG else {
|
return false
|
}
|
|
var buffer = [UInt8](repeating: 0, count: base.count)
|
base.copyBytes(to: &buffer, count: base.count)
|
for (index, item) in buffer.enumerated() {
|
guard
|
item == marker.bytes.first,
|
buffer.count > index + 1,
|
buffer[index + 1] == marker.bytes[1] else {
|
continue
|
}
|
return true
|
}
|
return false
|
}
|
}
|
