Interacting with C APIs

shibuyaswift #4

Transcript

1. Interacting with C APIs shibuya.swift #4 @nakajijapan Use GIFLIB in Swift
2. About Me
3. @nakajijapan Software Engineer GMO PEPABO inc. iOS / Web / OS X
4. NKJMultiMovieCaptureView NKJMovieComposer NKJPagerViewController PhotoSlider Teiten
5. ϋϯυϝΠυ࡞඼Λ ചΕΔɺങ͑Δɻ ࠃ಺࠷େڃͷ ϋϯυϝΠυϚʔέοτ
6. ࠷ۙ
7. Teiten Teiten is an app that fixed-point observation a lot earnestly yourself by using a PC camera. http://teiten.nakajijapan.net/
8. Sengiri " Sengiri " from the screen recording until the animated GIF file , you can create as soon as a simple operation . Sengiri, in English, is the shred. http://sengiri.nakajijapan.net/
9. Stop SFDPSE
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   Crop Record
10. Sengiri is • OS X Application • ࠷খݶͷૢ࡞ͰGIFಈըΛ࡞੒͢Δ • ࢓ࣄޮ཰Խπʔϧ • OSS (coming soon…)
12. ΋͏গ͠ؤுΖ͏
13. ࣌ʑɺը࣭͕ ྼԽ ͯ͠͠·͏
14. ΋͏গ͠ ਂງ͍͖͍ͯͨ͠
15. ௐࠪ • FFmpeg • GIFLIB
16. FFmpeg
17. FFmpeg • ༷ʑͳencode/decodeʹରԠ • ࢓༷Λ೺Ѳ͢Δ͜ͱ͔Β • ๲େ • ίʔυྔ͕ଟ͍ •
18. GIFLIB
19. GIFLIB • GIFͷencode/decodeʹಛԽ • ࢓༷Λ೺Ѳ͠΍͍͢ • ίʔυྔ͕গͳ͍ • FFmpegΑΓ͸গͳ͍
20. But
21. C
22. Use C API in Swift
23. Talk about
24. Interacting with C APIs Use giflib in Swift
25. Premise
26. C int number = 10; int *p; *p = 100; printf("%d %x \n", *p, p); p = &number; printf("%d %x \n", *p, p);
27. C 516918f8 p number 10 516918dc p = &number;
28. C char c[] = “abcd"; char *p; p = &c; printf("*p = %c\n",*p); printf("p = %s\n", p); printf("*(p + 1) = %c\n", *(c + 1)); printf("*p + 1 = %c\n", *c + 1); printf("c[1] = %c\n", c[1]); // *p = a // p = abcd // *(p + 1) = b // *p + 1 = b // c[1] = b
29. C 516918f8 p c[] 516918dc p = &c; a b c d *(c + 1) *(c + 2) *(c + 3)
30. C API -> Swift
31. Primitive Types
32. Primitive Types or Int8 or Int or Int32
33. $ 4XJGU 1PJOUFS DPOTU
    5ZQF
    6OTBGF1PJOUFS5ZQF 5ZQF
    6OTBGF.VUBCMF1PJOUFS5ZQF WPJE
    6OTBGF.VUBCMF1PJOUFS7PJE Pointer
34. C int number = 10; int *p; *p = 100; printf("%d %x \n", *p, p); p = &number; printf("%d %x \n", *p, p);
35. Swift // int *p; var p:UnsafeMutablePointer<CInt>
36. Swift // int *p; var p = UnsafeMutablePointer<CInt>.alloc(1) // *p = 100; p.memory = 100
37. Swift // int *p; var p = UnsafeMutablePointer<CInt>.alloc(1) // *p = 100; p.memory = 100
38. Swift // int *p; var p = UnsafeMutablePointer<CInt>.alloc(1) // *p = 100; p.memory = 100
39. Swift // int *p; var p = UnsafeMutablePointer<CInt>.alloc(1) // *p = 100; p.memory = 100 WBS
    NFNPSZ
    .FNPSZ
    \
    HFU
    OPONVUBUJOH
    TFU
    ^ 6OTBGF.VUBCMF1PJOUFS
40. C unsigned char c[] = “abcd"; unsigned char *p; p = &c; printf("*p = %c\n",*p); printf("p = %s\n", p); printf("*(p + 1) = %c\n", *(c + 1)); printf("*p + 1 = %c\n", *c + 1); printf("c[1] = %c\n", c[1]); // *p = a // p = abcd // *(p + 1) = b // *p + 1 = b // c[1] = b
41. Swift let p = UnsafeMutablePointer<CUnsignedChar>.alloc(4) or let p = UnsafeMutablePointer<UInt8>.alloc(4)
42. C unsigned char c[] = “abcd"; unsigned char *p; p = &c; printf("*p = %c\n",*p); printf("p = %s\n", p); printf("*(p + 1) = %c\n", *(c + 1)); printf("*p + 1 = %c\n", *c + 1); printf("c[1] = %c\n", c[1]); // *p = a // p = abcd // *(p + 1) = b // *p + 1 = b // c[1] = b
43. Swift let p = UnsafeMutablePointer<CUnsignedChar>.alloc(4) p.advancedBy(1).memory
44. Swift let p = UnsafeMutablePointer<CUnsignedChar>.alloc(4) p.advancedBy(1).memory TVCTDSJQU
    @
    J
    *OU
    
    .FNPSZ
    \
    HFU
    OPONVUBUJOH
    TFU
    ^
45. Swift let p = UnsafeMutablePointer<CUnsignedChar>.alloc(4) p[1]
46. Swift for i in 0..<256 { colorTypes.advancedBy(i).memory.Red = pixelColorMaps.advancedBy(i).memory.red colorTypes.advancedBy(i).memory.Green = pixelColorMaps.advancedBy(i).memory.green colorTypes.advancedBy(i).memory.Blue = pixelColorMaps.advancedBy(i).memory.blue }
47. Swift for i in 0..<256 { colorTypes[i].Red = pixelColorMaps[i].red colorTypes[i].Green = pixelColorMaps[i].green colorTypes[i].Blue = pixelColorMaps[i].blue }
48. Swift unsigned char controlExtension[3] = {0x04, 0x00, 0x00, 0xff};
49. Swift let controlExtension = UnsafeMutablePointer<UInt8>.alloc(4) controlExtension[0] = 0x04 controlExtension[1] = 0x00 controlExtension[2] = 0x00 controlExtension[3] = 0xff
50. Type Casting
51. Type Casting UnsafeMutablePointer<UInt8>.self UnsafeMutablePointer<Void>.self
52. Type Casting let address = baseAddress as UnsafeMutablePointer<UInt8>
53. Type Casting let address = baseAddress as UnsafeMutablePointer<UInt8>
54. Type Casting /// Returns the bits of `x`, interpreted as having type `U`. /// /// - Warning: Breaks the guarantees of Swift's type system; use /// with extreme care. There's almost always a better way to do /// anything. /// @warn_unused_result public func unsafeBitCast<T, U>(x: T, _: U.Type) -> U
55. Swift let address = CVPixelBufferGetBaseAddress(imageBuffer!) let address2 = unsafeBitCast( baseAddress, UnsafeMutablePointer<UInt8>.self )
56. Type Casting /// Returns the bits of `x`, interpreted as having type `U`. /// /// - Warning: Breaks the guarantees of Swift's type system; use /// with extreme care. There's almost always a better way to do /// anything. /// @warn_unused_result public func unsafeBitCast<T, U>(x: T, _: U.Type) -> U
57. Memory Management
58. Memory Management • SwiftͰCͷؔ਺͕ར༻Ͱ͖Δ • ࢖͍ํ͸ಉ͡ • UnsafeMutablePointer<T>Ͱಉ༷ͷϝιου͕༻ ҙ͞Ε͍ͯΔ
59. Memory Management /* ANSI-C */ public func memchr(_: UnsafePointer<Void>, _: Int32, _: Int) -> UnsafeMutablePointer<Void> public func memcmp(_: UnsafePointer<Void>, _: UnsafePointer<Void>, _: Int) -> Int32 public func memcpy(_: UnsafeMutablePointer<Void>, _: UnsafePointer<Void>, _: Int) -> UnsafeMutablePointer<Void> public func memmove(_: UnsafeMutablePointer<Void>, _: UnsafePointer<Void>, _: Int) -> UnsafeMutablePointer<Void> public func memset(_: UnsafeMutablePointer<Void>, _: Int32, _: Int) -> UnsafeMutablePointer<Void>
60. Swift let buffer = UnsafeMutablePointer<UInt8>.alloc( width * height * 4 ) memset(buffer, 0, width * height * 4) (…snip…) free(buffer)
61. Swift let buffer = UnsafeMutablePointer<UInt8>.alloc( width * height * 4 ) memset(buffer, 0, width * height * 4) (…snip…) free(buffer) buffer.destroy()
62. C APIs
63. C APIs • Swift͸C APIʹΞΫηεग़དྷΔे෼ͳ ػೳΛ࣋ͪ߹Θ͍ͤͯΔ௿ϨΠϠʔ ͳϞδϡʔϧʹ௚઀Ͱ͖Δͷศར • ϙΠϯλɺϝϞϦ؅ཧͷ஌ࣝ͸ඞਢ
64. UnsafeMutablePointer IUUQTEFWFMPQFSBQQMFDPNMJCSBSZXBUDIPTEPDVNFOUBUJPO4XJGU 3FGFSFODF4XJGU@6OTBGF.VUBCMF1PJOUFS@4USVDUVSFJOEFYIUNM
65. GIFLIBΛ࢖͍͍ͨ
66. • ࢓༷೺Ѳෆ଍… • ΧϥʔϚοϓ • ؔ਺
67. ࠂ஌
68. iOSDC
69. Thanks.