read.swift

import Foundation
#if os(OSX)
    import Darwin
#else
    import Glibc
#endif


let path = __FILE__
public struct ReadError : ErrorType {let reason: String}

try NSString(string:"Foo").writeToFile("/tmp/text.txt", atomically: true, encoding: 4)

func readFromPath(path: String) throws -> String {
    guard let fp: UnsafeMutablePointer<FILE> = fopen(path, "r") else {
        throw ReadError(reason: "Unable to open file")
    }; defer{fclose(fp)}
    
    let buffer: UnsafeMutablePointer<UInt8> = UnsafeMutablePointer.alloc(1024); defer {buffer.dealloc(1024)}
    var bytes: [UInt8] = []
    var totalCount = 0
    repeat {
        let count: Int = fread(buffer, 1, 1024, fp)
        guard ferror(fp) == 0 else {
            throw ReadError(reason: "Encountered error while reading stream")
        }
        if count > 0 {
            bytes.appendContentsOf(Array(UnsafeBufferPointer(start:buffer, count:count)))
            totalCount += count
        }
    } while feof(fp) == 0
    
//    let data = NSData(bytes: &bytes, length: totalCount)
    guard let string = String(bytesNoCopy: &bytes, length: totalCount, encoding: 4, freeWhenDone: true) else {
        throw ReadError(reason: "Could not convert to string")
    }
    return string
}

do {
    let string = try readFromPath(path)
    print(string)
} catch {print(error)}