Swift 协议(protocol)性能-6ren

Swift 协议(protocol)性能

转载作者：IT王子更新时间：2023-10-29 05:14:42

这个问题涉及在 Swift 2.2 中作为协议(protocol)扩展编写的函数的效率。有谁知道加快运行时间的方法吗？

假设我有一个 Int 符合的协议(protocol) Number

protocol Number: Equatable, IntegerLiteralConvertible {
    init(_ int: Int)
    init(_ number: Self)
    func +(lhs: Self, rhs: Self) -> Self
    func *(lhs: Self, rhs: Self) -> Self
    func -(lhs: Self, rhs: Self) -> Self
    func /(lhs: Self, rhs: Self) -> Self
}
extension Int: Number { }

现在我想写一个阶乘函数作为 Number 的扩展

extension Number {
    func factorialNumber() -> Self {
       if self == 0 { return 1 }
       return self * (self - 1).factorialNumber()
    }
}

我也写了同样的函数作为Int的扩展

extension Int {
    func factorialInt() -> Int {
        if self == 0 { return 1 }
        return self * (self - 1).factorialInt()
    }
}

当我测量这些函数中的每一个的运行时时，都存在巨大差异。

Runtime Screenshot

此屏幕截图启用了全模块优化。

我猜泛型会在运行时产生一些开销。有一个更好的方法吗？只编写相同的函数作为 Int、Double、Float 的扩展而不是尝试编写一个协议(protocol)函数是否有意义。

谢谢

最佳答案

如果我们查看反汇编函数，我们会发现性能下降的原因 - factorialInt 的指令比 factorialNumber 少得多。

以下是使用 Swift 3 构建时这两种方法的外观，Whole Module Optimization 已启用(性能测量给出的输出与 Swift 2 中的问题输出类似):

阶乘整数:

0000000000001e80         push       rbp                                         ; XREF=__TFE8TestFMWKSi12factorialIntfT_Si+27, __TFE8TestFMWKSi19factorialIntWithMulfT_Si+22
0000000000001e81         mov        rbp, rsp
0000000000001e84         push       rbx
0000000000001e85         push       rax
0000000000001e86         mov        rbx, rdi
0000000000001e89         mov        eax, 0x1
0000000000001e8e         test       rbx, rbx
0000000000001e91         je         0x1ea9

0000000000001e93         mov        rdi, rbx
0000000000001e96         dec        rdi
0000000000001e99         jo         0x1eb0

0000000000001e9b         call       __TFE8TestFMWKSi12factorialIntfT_Si
0000000000001ea0         imul       rbx, rax
0000000000001ea4         mov        rax, rbx
0000000000001ea7         jo         0x1eb2

0000000000001ea9         add        rsp, 0x8                                    ; XREF=__TFE8TestFMWKSi12factorialIntfT_Si+17
0000000000001ead         pop        rbx
0000000000001eae         pop        rbp
0000000000001eaf         ret        

0000000000001eb0         ud2                                                    ; XREF=__TFE8TestFMWKSi12factorialIntfT_Si+25

0000000000001eb2         ud2                                                    ; XREF=__TFE8TestFMWKSi12factorialIntfT_Si+39
                        ; endp
0000000000001eb4         nop        word [cs:rax+rax]

阶乘数:

0000000000001770         push       rbp                                         ; XREF=__TFE8TestFMWKPS_6Number15factorialNumberfT_x+1648
0000000000001771         mov        rbp, rsp
0000000000001774         push       r15
0000000000001776         push       r14
0000000000001778         push       r13
000000000000177a         push       r12
000000000000177c         push       rbx
000000000000177d         sub        rsp, 0x208
0000000000001784         mov        qword [ss:rbp+var_128], rcx
000000000000178b         mov        rbx, rdx
000000000000178e         mov        qword [ss:rbp+var_F8], rbx
0000000000001795         mov        r14, rsi
0000000000001798         mov        qword [ss:rbp+var_C8], rdi
000000000000179f         mov        rax, qword [ds:rbx]
00000000000017a2         mov        qword [ss:rbp+var_110], rax
00000000000017a9         mov        rdx, qword [ds:rax]
00000000000017ac         mov        qword [ss:rbp+var_E8], rdx
00000000000017b3         mov        rax, qword [ds:r14-8]
00000000000017b7         mov        qword [ss:rbp+var_C0], rax
00000000000017be         mov        rax, qword [ds:rax+0x28]
00000000000017c2         mov        qword [ss:rbp+var_130], rax
00000000000017c9         lea        rdi, qword [ss:rbp+var_40]
00000000000017cd         mov        rsi, rcx
00000000000017d0         mov        rdx, r14
00000000000017d3         call       rax
00000000000017d5         mov        qword [ss:rbp+var_118], rax
00000000000017dc         mov        r15, qword [ds:rbx+8]
00000000000017e0         mov        qword [ss:rbp+var_E0], r15
00000000000017e7         mov        rax, qword [ds:r15+0x10]
00000000000017eb         mov        qword [ss:rbp+var_D0], rax
00000000000017f2         mov        rdi, r14
00000000000017f5         mov        rsi, r15
00000000000017f8         call       qword [ds:r15]
00000000000017fb         mov        r13, rax
00000000000017fe         mov        qword [ss:rbp+var_D8], r13
0000000000001805         mov        rdi, r13
0000000000001808         mov        rsi, r14
000000000000180b         mov        rdx, r15
000000000000180e         call       qword [ds:r15+8]
0000000000001812         mov        rbx, rax
0000000000001815         mov        qword [ss:rbp+var_100], rbx
000000000000181c         mov        r12, qword [ds:rbx]
000000000000181f         mov        qword [ss:rbp+var_F0], r12
0000000000001826         mov        rax, qword [ds:r13-8]
000000000000182a         mov        qword [ss:rbp+var_120], rax
0000000000001831         mov        rax, qword [ds:rax+0x58]
0000000000001835         mov        qword [ss:rbp+var_108], rax
000000000000183c         lea        rdi, qword [ss:rbp+var_58]
0000000000001840         mov        rsi, r13
0000000000001843         call       rax
0000000000001845         mov        qword [ss:rsp+0x230+var_148], rbx
000000000000184d         mov        qword [ss:rsp+0x230+var_150], r13
0000000000001855         mov        qword [ss:rsp+0x230+var_158], r13
000000000000185d         mov        qword [ss:rsp+0x230+var_160], 0x0
0000000000001869         mov        qword [ss:rsp+0x230+var_168], 0x0
0000000000001875         mov        qword [ss:rsp+0x230+var_170], 0x0
0000000000001881         mov        qword [ss:rsp+0x230+var_178], 0x0
000000000000188d         mov        qword [ss:rsp+0x230+var_180], 0x0
0000000000001899         mov        qword [ss:rsp+0x230+var_188], 0x0
00000000000018a5         mov        qword [ss:rsp+0x230+var_190], 0x0
00000000000018b1         mov        qword [ss:rsp+0x230+var_198], 0x0
00000000000018bd         mov        qword [ss:rsp+0x230+var_1A0], 0x0
00000000000018c9         mov        qword [ss:rsp+0x230+var_1A8], 0x0
00000000000018d5         mov        qword [ss:rsp+0x230+var_1B0], 0x0
00000000000018e1         mov        qword [ss:rsp+0x230+var_1B8], 0x0
00000000000018ea         mov        qword [ss:rsp+0x230+var_1C0], 0x0
00000000000018f3         mov        qword [ss:rsp+0x230+var_1C8], 0x0
00000000000018fc         mov        qword [ss:rsp+0x230+var_1D0], 0x0
0000000000001905         mov        qword [ss:rsp+0x230+var_1D8], 0x0
000000000000190e         mov        qword [ss:rsp+0x230+var_1E0], 0x0
0000000000001917         mov        qword [ss:rsp+0x230+var_1E8], 0x0
0000000000001920         mov        qword [ss:rsp+0x230+var_1F0], 0x0
0000000000001929         mov        qword [ss:rsp+0x230+var_1F8], 0x0
0000000000001932         mov        qword [ss:rsp+0x230+var_200], 0x0
000000000000193b         mov        qword [ss:rsp+0x230+var_208], 0x0
0000000000001944         mov        qword [ss:rsp+0x230+var_210], 0x0
000000000000194d         mov        qword [ss:rsp+0x230+var_218], 0x0
0000000000001956         mov        qword [ss:rsp+0x230+var_220], 0x0
000000000000195f         mov        qword [ss:rsp+0x230+var_228], 0x0
0000000000001968         mov        qword [ss:rsp+0x230+var_230], 0x0
0000000000001970         xor        esi, esi
0000000000001972         xor        edx, edx
0000000000001974         xor        ecx, ecx
0000000000001976         xor        r8d, r8d
0000000000001979         xor        r9d, r9d
000000000000197c         mov        rbx, rax
000000000000197f         mov        rdi, rbx
0000000000001982         call       r12
0000000000001985         mov        rax, qword [ss:rbp+var_C0]
000000000000198c         mov        rax, qword [ds:rax+0x58]
0000000000001990         mov        qword [ss:rbp+var_138], rax
0000000000001997         lea        rdi, qword [ss:rbp+var_70]
000000000000199b         mov        rsi, r14
000000000000199e         call       rax
00000000000019a0         mov        r12, rax
00000000000019a3         mov        rdi, r12
00000000000019a6         mov        rsi, rbx
00000000000019a9         mov        rdx, r14
00000000000019ac         mov        rcx, r14
00000000000019af         mov        r8, r15
00000000000019b2         mov        rbx, r13
00000000000019b5         call       qword [ss:rbp+var_D0]
00000000000019bb         mov        rdi, qword [ss:rbp+var_118]
00000000000019c2         mov        rsi, r12
00000000000019c5         mov        rdx, r14
00000000000019c8         mov        rcx, r14
00000000000019cb         mov        r8, qword [ss:rbp+var_110]
00000000000019d2         call       qword [ss:rbp+var_E8]
00000000000019d8         mov        r12b, al
00000000000019db         mov        rax, qword [ss:rbp+var_C0]
00000000000019e2         mov        r13, qword [ds:rax+0x18]
00000000000019e6         lea        rdi, qword [ss:rbp+var_70]
00000000000019ea         mov        rsi, r14
00000000000019ed         call       r13
00000000000019f0         mov        rax, qword [ss:rbp+var_120]
00000000000019f7         mov        rax, qword [ds:rax+0x18]
00000000000019fb         mov        qword [ss:rbp+var_E8], rax
0000000000001a02         lea        rdi, qword [ss:rbp+var_58]
0000000000001a06         mov        rsi, rbx
0000000000001a09         call       rax
0000000000001a0b         lea        rdi, qword [ss:rbp+var_40]
0000000000001a0f         mov        rsi, r14
0000000000001a12         call       r13
0000000000001a15         test       r12b, 0x1
0000000000001a19         je         0x1bb1

0000000000001a1f         lea        r15, qword [ss:rbp+var_40]
0000000000001a23         mov        rdi, r15
0000000000001a26         mov        rbx, qword [ss:rbp+var_D8]
0000000000001a2d         mov        rsi, rbx
0000000000001a30         call       qword [ss:rbp+var_108]
0000000000001a36         mov        r13, rax
0000000000001a39         mov        rax, qword [ss:rbp+var_100]
0000000000001a40         mov        qword [ss:rsp+0x230+var_148], rax
0000000000001a48         mov        qword [ss:rsp+0x230+var_150], rbx
0000000000001a50         mov        qword [ss:rsp+0x230+var_158], rbx
0000000000001a58         mov        qword [ss:rsp+0x230+var_160], 0x0
0000000000001a64         mov        qword [ss:rsp+0x230+var_168], 0x0
0000000000001a70         mov        qword [ss:rsp+0x230+var_170], 0x0
0000000000001a7c         mov        qword [ss:rsp+0x230+var_178], 0x0
0000000000001a88         mov        qword [ss:rsp+0x230+var_180], 0x0
0000000000001a94         mov        qword [ss:rsp+0x230+var_188], 0x0
0000000000001aa0         mov        qword [ss:rsp+0x230+var_190], 0x0
0000000000001aac         mov        qword [ss:rsp+0x230+var_198], 0x0
0000000000001ab8         mov        qword [ss:rsp+0x230+var_1A0], 0x0
0000000000001ac4         mov        qword [ss:rsp+0x230+var_1A8], 0x0
0000000000001ad0         mov        qword [ss:rsp+0x230+var_1B0], 0x0
0000000000001adc         mov        qword [ss:rsp+0x230+var_1B8], 0x0
0000000000001ae5         mov        qword [ss:rsp+0x230+var_1C0], 0x0
0000000000001aee         mov        qword [ss:rsp+0x230+var_1C8], 0x0
0000000000001af7         mov        qword [ss:rsp+0x230+var_1D0], 0x0
0000000000001b00         mov        qword [ss:rsp+0x230+var_1D8], 0x0
0000000000001b09         mov        qword [ss:rsp+0x230+var_1E0], 0x0
0000000000001b12         mov        qword [ss:rsp+0x230+var_1E8], 0x0
0000000000001b1b         mov        qword [ss:rsp+0x230+var_1F0], 0x0
0000000000001b24         mov        qword [ss:rsp+0x230+var_1F8], 0x0
0000000000001b2d         mov        qword [ss:rsp+0x230+var_200], 0x0
0000000000001b36         mov        qword [ss:rsp+0x230+var_208], 0x0
0000000000001b3f         mov        qword [ss:rsp+0x230+var_210], 0x0
0000000000001b48         mov        qword [ss:rsp+0x230+var_218], 0x0
0000000000001b51         mov        qword [ss:rsp+0x230+var_220], 0x0
0000000000001b5a         mov        qword [ss:rsp+0x230+var_228], 0x0
0000000000001b63         mov        qword [ss:rsp+0x230+var_230], 0x0
0000000000001b6b         mov        esi, 0x1
0000000000001b70         xor        edx, edx
0000000000001b72         xor        ecx, ecx
0000000000001b74         xor        r8d, r8d
0000000000001b77         xor        r9d, r9d
0000000000001b7a         mov        rdi, r13
0000000000001b7d         call       qword [ss:rbp+var_F0]
0000000000001b83         mov        rdi, qword [ss:rbp+var_C8]
0000000000001b8a         mov        rsi, r13
0000000000001b8d         mov        rdx, r14
0000000000001b90         mov        rcx, r14
0000000000001b93         mov        r8, qword [ss:rbp+var_E0]
0000000000001b9a         call       qword [ss:rbp+var_D0]
0000000000001ba0         mov        rdi, r15
0000000000001ba3         mov        rsi, rbx
0000000000001ba6         call       qword [ss:rbp+var_E8]
0000000000001bac         jmp        0x1e5a

0000000000001bb1         mov        rbx, qword [ss:rbp+var_F8]                  ; XREF=__TFE8TestFMWKPS_6Number15factorialNumberfT_x+681
0000000000001bb8         mov        rax, qword [ds:rbx+0x28]
0000000000001bbc         mov        qword [ss:rbp+var_110], rax
0000000000001bc3         lea        rdi, qword [ss:rbp+var_40]
0000000000001bc7         mov        r12, qword [ss:rbp+var_128]
0000000000001bce         mov        rsi, r12
0000000000001bd1         mov        rdx, r14
0000000000001bd4         mov        r15, qword [ss:rbp+var_130]
0000000000001bdb         call       r15
0000000000001bde         mov        qword [ss:rbp+var_118], rax
0000000000001be5         mov        rax, qword [ds:rbx+0x30]
0000000000001be9         mov        qword [ss:rbp+var_120], rax
0000000000001bf0         lea        rdi, qword [ss:rbp+var_58]
0000000000001bf4         mov        rsi, r12
0000000000001bf7         mov        rdx, r14
0000000000001bfa         call       r15
0000000000001bfd         mov        r15, rax
0000000000001c00         lea        rdi, qword [ss:rbp+var_70]
0000000000001c04         mov        rbx, qword [ss:rbp+var_D8]
0000000000001c0b         mov        rsi, rbx
0000000000001c0e         call       qword [ss:rbp+var_108]
0000000000001c14         mov        qword [ss:rbp+var_108], r13
0000000000001c1b         mov        r13, rax
0000000000001c1e         mov        rax, qword [ss:rbp+var_100]
0000000000001c25         mov        qword [ss:rsp+0x230+var_148], rax
0000000000001c2d         mov        qword [ss:rsp+0x230+var_150], rbx
0000000000001c35         mov        qword [ss:rsp+0x230+var_158], rbx
0000000000001c3d         mov        qword [ss:rsp+0x230+var_160], 0x0
0000000000001c49         mov        qword [ss:rsp+0x230+var_168], 0x0
0000000000001c55         mov        qword [ss:rsp+0x230+var_170], 0x0
0000000000001c61         mov        qword [ss:rsp+0x230+var_178], 0x0
0000000000001c6d         mov        qword [ss:rsp+0x230+var_180], 0x0
0000000000001c79         mov        qword [ss:rsp+0x230+var_188], 0x0
0000000000001c85         mov        qword [ss:rsp+0x230+var_190], 0x0
0000000000001c91         mov        qword [ss:rsp+0x230+var_198], 0x0
0000000000001c9d         mov        qword [ss:rsp+0x230+var_1A0], 0x0
0000000000001ca9         mov        qword [ss:rsp+0x230+var_1A8], 0x0
0000000000001cb5         mov        qword [ss:rsp+0x230+var_1B0], 0x0
0000000000001cc1         mov        qword [ss:rsp+0x230+var_1B8], 0x0
0000000000001cca         mov        qword [ss:rsp+0x230+var_1C0], 0x0
0000000000001cd3         mov        qword [ss:rsp+0x230+var_1C8], 0x0
0000000000001cdc         mov        qword [ss:rsp+0x230+var_1D0], 0x0
0000000000001ce5         mov        qword [ss:rsp+0x230+var_1D8], 0x0
0000000000001cee         mov        qword [ss:rsp+0x230+var_1E0], 0x0
0000000000001cf7         mov        qword [ss:rsp+0x230+var_1E8], 0x0
0000000000001d00         mov        qword [ss:rsp+0x230+var_1F0], 0x0
0000000000001d09         mov        qword [ss:rsp+0x230+var_1F8], 0x0
0000000000001d12         mov        qword [ss:rsp+0x230+var_200], 0x0
0000000000001d1b         mov        qword [ss:rsp+0x230+var_208], 0x0
0000000000001d24         mov        qword [ss:rsp+0x230+var_210], 0x0
0000000000001d2d         mov        qword [ss:rsp+0x230+var_218], 0x0
0000000000001d36         mov        qword [ss:rsp+0x230+var_220], 0x0
0000000000001d3f         mov        qword [ss:rsp+0x230+var_228], 0x0
0000000000001d48         mov        qword [ss:rsp+0x230+var_230], 0x0
0000000000001d50         mov        esi, 0x1
0000000000001d55         xor        edx, edx
0000000000001d57         xor        ecx, ecx
0000000000001d59         xor        r8d, r8d
0000000000001d5c         xor        r9d, r9d
0000000000001d5f         mov        rdi, r13
0000000000001d62         call       qword [ss:rbp+var_F0]
0000000000001d68         lea        rdi, qword [ss:rbp+var_88]
0000000000001d6f         mov        rsi, r14
0000000000001d72         mov        rbx, qword [ss:rbp+var_138]
0000000000001d79         call       rbx
0000000000001d7b         mov        r12, rax
0000000000001d7e         mov        rdi, r12
0000000000001d81         mov        rsi, r13
0000000000001d84         mov        rdx, r14
0000000000001d87         mov        rcx, r14
0000000000001d8a         mov        r8, qword [ss:rbp+var_E0]
0000000000001d91         call       qword [ss:rbp+var_D0]
0000000000001d97         lea        rdi, qword [ss:rbp+var_A0]
0000000000001d9e         mov        rsi, r14
0000000000001da1         call       rbx
0000000000001da3         mov        r13, rax
0000000000001da6         mov        rdi, r13
0000000000001da9         mov        rsi, r15
0000000000001dac         mov        rdx, r12
0000000000001daf         mov        rcx, r14
0000000000001db2         mov        r8, r14
0000000000001db5         mov        r15, qword [ss:rbp+var_F8]
0000000000001dbc         mov        r9, r15
0000000000001dbf         call       qword [ss:rbp+var_120]
0000000000001dc5         lea        rdi, qword [ss:rbp+var_B8]
0000000000001dcc         mov        rsi, r14
0000000000001dcf         call       rbx
0000000000001dd1         mov        r12, rax
0000000000001dd4         mov        rdi, r12                                    ; argument #1 for method __TFE8TestFMWKPS_6Number15factorialNumberfT_x
0000000000001dd7         mov        rsi, r14                                    ; argument #2 for method __TFE8TestFMWKPS_6Number15factorialNumberfT_x
0000000000001dda         mov        rdx, r15                                    ; argument #3 for method __TFE8TestFMWKPS_6Number15factorialNumberfT_x
0000000000001ddd         mov        rcx, r13                                    ; argument #4 for method __TFE8TestFMWKPS_6Number15factorialNumberfT_x
0000000000001de0         call       __TFE8TestFMWKPS_6Number15factorialNumberfT_x
0000000000001de5         mov        rdi, qword [ss:rbp+var_C8]
0000000000001dec         mov        rsi, qword [ss:rbp+var_118]
0000000000001df3         mov        rdx, r12
0000000000001df6         mov        rcx, r14
0000000000001df9         mov        r8, r14
0000000000001dfc         mov        r9, r15
0000000000001dff         call       qword [ss:rbp+var_110]
0000000000001e05         lea        rdi, qword [ss:rbp+var_B8]
0000000000001e0c         mov        rsi, r14
0000000000001e0f         mov        rbx, qword [ss:rbp+var_108]
0000000000001e16         call       rbx
0000000000001e18         lea        rdi, qword [ss:rbp+var_A0]
0000000000001e1f         mov        rsi, r14
0000000000001e22         mov        rax, qword [ss:rbp+var_C0]
0000000000001e29         call       qword [ds:rax]
0000000000001e2b         lea        rdi, qword [ss:rbp+var_88]
0000000000001e32         mov        rsi, r14
0000000000001e35         call       rbx
0000000000001e37         lea        rdi, qword [ss:rbp+var_70]
0000000000001e3b         mov        rsi, qword [ss:rbp+var_D8]
0000000000001e42         call       qword [ss:rbp+var_E8]
0000000000001e48         lea        rdi, qword [ss:rbp+var_58]
0000000000001e4c         mov        rsi, r14
0000000000001e4f         call       rbx
0000000000001e51         lea        rdi, qword [ss:rbp+var_40]
0000000000001e55         mov        rsi, r14
0000000000001e58         call       rbx

0000000000001e5a         mov        rax, qword [ss:rbp+var_C8]                  ; XREF=__TFE8TestFMWKPS_6Number15factorialNumberfT_x+1084
0000000000001e61         add        rsp, 0x208
0000000000001e68         pop        rbx
0000000000001e69         pop        r12
0000000000001e6b         pop        r13
0000000000001e6d         pop        r14
0000000000001e6f         pop        r15
0000000000001e71         pop        rbp
0000000000001e72         ret        
                        ; endp
0000000000001e73         nop        word [cs:rax+rax]

通过协议(protocol)进行调度是有代价的——方法不再是静态调度的，必须在接收者所属数据类型的调度表中进行查找。

事实证明，此查找需要完成一些指令，从而导致您注意到的性能差异。

关于Swift 协议(protocol)性能，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/38152433/

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protocols - 无状态协议(protocol)是否被认为比有状态协议(protocol)更好用？
我可以看到有状态的协议(protocol)可以减少像 cookie 这样的“模拟状态”。但是测试变得更加难以确保您的实现正确并重新连接，并且 session 继续可能很难处理。始终使用无状态协议(
protocols - 通用二进制协议(protocol)
我正在尝试为我的下一个分布式应用程序找到合适的协议(protocol)中间件。在过去的几天里，我找到了几个规范，想知道我是否错过了一个重要的规范？它应该是二进制协议(protocol)，支持 RPC，
protocols - 我在哪里可以找到自动柜员机使用的交易协议(protocol)？
我正在做一个研究生院软件工程项目，我正在寻找管理 ATM 和银行网络之间通信的协议(protocol)。我已经在谷歌上搜索了很长一段时间，虽然我找到了各种有关 ATM 的有趣信息，但我惊讶地发现似乎
protocol-buffers - 如何使用 Protocol Buffers 构建第三方串行通信协议(protocol)？
我正在开发一个 ECG 模块，它以字节为单位给出数据。有一个关于它的协议(protocol)文档解释了如何构建从模块中出来的数据包。我想解码该数据。我很困惑 Protocol Buffer 是否会对此
network-protocols - 面向消息的协议(protocol)和面向流的协议(protocol)之间的区别
关闭。这个问题不符合Stack Overflow guidelines .它目前不接受答案。想改进这个问题？将问题更新为 on-topic对于堆栈溢出。 3年前关闭。 Improve this qu
protocols - 理解ZMODEM协议(protocol)
我需要在我的程序中包含基本的文件发送和文件接收例程，并且需要通过 ZMODEM 协议(protocol)。问题是我无法理解规范。供引用，here is the specification . 规范没
protocols - 什么是联合协议(protocol)？
我最近听到这个术语来描述 Google 的新环聊协议(protocol)和 Whisper System 的新 encrypted texting app . The new TextSecure p
ios7 - 内容协议(protocol)。协议(protocol)不可转换为协议(protocol)
如何检查某个对象是否符合协议(protocol)？我试过这种方式，但出现错误: if lCell.conformsToProtocol(ContentProtocol) { } 最佳
ios - 协议(protocol)类型不能符合协议(protocol)，因为只有具体类型才能符合协议(protocol)
在应用程序中，我们有两种类型的贴纸，字符串和位图。每个贴纸包都可以包含两种类型。这就是我声明模型的方式: // Mark: - Models protocol Sticker: Codable { }
swift - 无法使用另一个符合协议(protocol)的协议(protocol)来符合协议(protocol)
这个问题在这里已经有了答案: Why can't a get-only property requirement in a protocol be satisfied by a property w
swift - 不支持使用 'Protocol' 作为符合协议(protocol) 'Protocol' 的具体类型
我有以下快速代码: protocol Animal { var name: String { get } } struct Bird: Animal { var name: String
iphone - 协议(protocol)中的协议(protocol)是否可以被视为包含它们采用的协议(protocol)？
我在遵循继承树的几个类中分配协议(protocol)。像这样: 头等舱 @protocol LevelOne - (void) functionA @end @interface BaseClass
fix-protocol - OUCH 协议(protocol)和 FIX 协议(protocol)有什么区别。两种协议(protocol)的消息看起来非常相似
我们之前使用的是 fix，但客户说使用 OUCH 进行交易，因为这样速度更快。我在互联网上查了一下，消息看起来很相似。它如何获得速度优势。请给我一些示例消息最佳答案基本上，FIX 消息以文本格式传
swift - 如何使协议(protocol)关联类型需要协议(protocol)继承而不是协议(protocol)采用
在我的 swift 项目中，我有一个使用协议(protocol)继承的案例，如下所示 protocol A : class{ } protocol B : A{ } 接下来我要实现的目标是声明另一个具
protocols - OPC UA 协议(protocol)与 MQTT 协议(protocol)
我想根据这两种协议(protocol)的一般特征(例如开销(数据包)、安全性、信息建模和可靠性)来比较 OPC UA 和 MQTT。我在哪里可以找到每个协议(protocol)的开销和其他特性的一些示
ios - 如何使一个协议(protocol)具有另一个协议(protocol)的属性，同时确保可以限制符合第一个协议(protocol)的类
本质上，我的最终目标是拥有一个协议(protocol) Log，它强制所有符合它的对象都有一个符合另一个协议(protocol) [LogEvent] 的对象数组. 但是，符合Log的类需要有特定类型
ios - 如何根据实现该协议(protocol)的两个实例的身份为协议(protocol)实现 Equatable 协议(protocol)？
我正在尝试为基于左操作数和右操作数标识的协议(protocol)实现 Equatable 协议(protocol)。换句话说:我如何为一个协议(protocol)实现 Equatable 协议(pro
protocols - smb协议(protocol)漏洞解决方案
问题不在于编程。我正在使用一台旧机器，微软停止了这些机器的补丁。有没有人针对攻击者已知的使用端口 445 的 SMB 协议(protocol)漏洞的解决方案？任何棘手的解决方案？换句话说，我想
protocols - Protocol Buffer 日志记录
在我们的业务中，我们需要记录到达我们服务器的每个请求/响应。目前，我们使用 xml 作为标准实现。如果我们需要调试/跟踪某些错误，则使用日志文件。如果我们切换到 Protocol Buffer
protocols - 协议(protocol)定义语言
你推荐什么协议(protocol)定义？我评估了 Google 的 Protocol Buffer ，但它不允许我控制正在构建的数据包中字段的位置。我认为 Thrift 也是如此。我的要求是: 指定

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