正在将swift字符串复制到固定大小的字符[][]

我有一个这样的C结构

struct someStruct {
char path[10][MAXPATHLEN];
};

我想将Swift字符串列表复制到char[10][]数组中

---

对我来说，在Swift中处理c二维字符数组是非常有挑战性的。有人能分享一些可以与Swift 5一起使用的代码吗？谢谢

C数组作为元组导入Swift。这里我们有一个二维C数组，它在Swift中成为嵌套元组：

public struct someStruct {

    public var path: (
        (Int8, ...,  Int8),
        (Int8, ...,  Int8),
        ...
        (Int8, ...,  Int8)
    )
}

据我所知，没有真正“好”的解决方案，但利用Swift保留了导入的C结构（）的内存布局这一事实，可以通过一些指针魔术来实现这一目标：

var s = someStruct()

let totalSize = MemoryLayout.size(ofValue: s.path)
let itemSize = MemoryLayout.size(ofValue: s.path.0)
let numItems = totalSize / itemSize

withUnsafeMutablePointer(to: &s.path) {
    $0.withMemoryRebound(to: Int8.self, capacity: totalSize) { ptr in
        for i in 0..<numItems {
            let itemPtr = ptr + i * itemSize
            strlcpy(itemPtr, "String \(i)", itemSize)
        }
        print(ptr)
    }
}

var s=someStruct（）
让totalSize=MemoryLayout.size（of值：s.path）
让itemSize=MemoryLayout.size（of值：s.path.0）
设numItems=totalSize/itemSize
WithUnsafemutable指针（指向：&s.path）{
$0.withMemoryRebound（to:Int8.self，容量：totalSize）{ptr in
对于0..中的i，我强烈建议您使用一些辅助方法

示例：

/* writes str to someStruct instance at index */
void writePathToStruct(struct someStruct* s, size_t index, const char* str) {
    assert(index < 10 && "Specified index is out of bounds");
    strcpy(s->path[index], str);
}

根据设计，元组不能通过变量索引访问。因此，静态读取可以在没有辅助函数的情况下完成

let pathRead = withUnsafeBytes(of: &someStructInstance.path.3) { pointer -> String? in
    return String(cString: pointer.baseAddress!.assumingMemoryBound(to: CChar.self), encoding: encoding)
}

print(pathRead ?? "<Empty path>")

非常感谢你的绝妙建议。它真的救了我的命！
let pathRead = withUnsafeBytes(of: &someStructInstance.path.3) { pointer -> String? in
    return String(cString: pointer.baseAddress!.assumingMemoryBound(to: CChar.self), encoding: encoding)
}

print(pathRead ?? "<Empty path>")

const char* readPathFromStruct(const struct someStruct* s, size_t index) {
    assert(index < 10 && "Specified index is out of bounds");
    return s->path[index];
}

pathRead = withUnsafePointer(to: &someStructInstance) { pointer -> String? in
    return String(cString: readPathFromStruct(pointer, 3), encoding: encoding)
}