Fix/modify pwm api (#20)

* Modify PWM API

Signed-off-by: Andy Liu <andy@madmachine.io>

* Modify File operation API

Signed-off-by: Andy Liu <andy@madmachine.io>

* Update open file process

Signed-off-by: Andy Liu <andy@madmachine.io>

---------

Signed-off-by: Andy Liu <andy@madmachine.io>

Examples/MakerKit/Mission4_Potentiometer_RGB/Sources/Mission4_Potentiometer_RGB/Mission4_Potentiometer_RGB.swift

@@ -29,7 +29,7 @@ public struct Mission4_Potentiometer_RGB {
             led.toggle()
 
             // Return the percentage of the voltage in the range of 0.0 to 1.0.
-            let analogValue = a0.readPercent()
+            let analogValue = a0.readPercentage()
             let delayTime = Int(analogValue * 500)
 
             // Stop the program for a certain period based on the value to keep current led state.

Examples/MakerKit/Mission5_Buzzer/Sources/Mission5_Buzzer/Mission5_Buzzer.swift

@@ -32,9 +32,9 @@ public struct Mission5_Buzzer {
 
         while true {
             // Read the input voltage.
-            let value = a0.readPercent()
+            let value = a0.readPercentage()
 
-            //let value = a0.readPercent()
+            //let value = a0.readPercentage()
             let frequency = Int(400 + 2000 * value) // calculate the float value into Int type to serve as frequency.
             buzzer.set(frequency: frequency, dutycycle: 0.5) // Set PWM parameters.
 

Examples/MakerKit/Mission7_DC_Motors/Sources/Mission7_DC_Motors/Mission7_DC_Motors.swift

@@ -28,7 +28,7 @@ public struct Mission7_DC_Motors {
 
         while true {
             // Read the input value and use it to set the duty cycle of pwm.
-            let value = a0.readPercent()
+            let value = a0.readPercentage()
             motor.setDutycycle(value) 
             sleep(ms: 50)
         }

Examples/MakerKit/Mission8_Servo_Motor/Sources/Mission8_Servo_Motor/Mission8_Servo_Motor.swift

@@ -37,7 +37,7 @@ public struct Mission8_Servo_Motor {
         let servo = PWMOut(Id.PWM4A)
 
         while true {
-            let value = a0.readPercent() // Read the analog value and return a value between 0.0 and 1.0.
+            let value = a0.readPercentage() // Read the analog value and return a value between 0.0 and 1.0.
             let pulse = Int(500 + 2000 * value) // Calculate the value to get the pulse duration.
             servo.set(period: 20000, pulse: pulse) // Set the servo position according to the scaled value.
 

Examples/SwiftIOPlayground/04Potentiometer/DoubleLEDDimmer/Sources/main.swift

@@ -22,10 +22,10 @@ while true {
     // Map the analog value from the range 0-1 to the range minIntensity-maxIntensity. 
     // It decides the max duty cycle for the PWM signal.
     // That's to say, it changes the maximum intensity of the LED.
-    let maxDutycycle = intensityPot.readPercent() * (maxIntensity - minIntensity) + minIntensity
+    let maxDutycycle = intensityPot.readPercentage() * (maxIntensity - minIntensity) + minIntensity
 
     // Read the analog value (0-1) from the pin A0 which serves as ratio for final duty cycle.
-    let dutycycleRatio = brightnessPot.readPercent()
+    let dutycycleRatio = brightnessPot.readPercentage()
 
     // Calculate the final duty cycle value (0-maxDutycycle).
     // Set the PWM output using the result.

Examples/SwiftIOPlayground/04Potentiometer/LEDBlinkControl/Sources/main.swift

@@ -20,7 +20,7 @@ while true {
 
     // Read value from the analog pin. 
     // It serves as duty cycle for PWM to set LED brightness.
-    led.setDutycycle(brightnessPot.readPercent())
+    led.setDutycycle(brightnessPot.readPercentage())
     sleep(ms: blinkTime)
 
     // After a specified time, suspend the output to turn off the LED.

Examples/SwiftIOPlayground/04Potentiometer/LEDDimmer/Sources/main.swift

@@ -11,7 +11,7 @@ let led = PWMOut(Id.PWM4A)
 // The value is represented in percentage, while the duty cycle is also between 0 and 1, 
 // so you can directly use the reading value to set the PWM.
 while true {
-    let dutycycle = pot.readPercent()
+    let dutycycle = pot.readPercentage()
     led.setDutycycle(dutycycle)
 
     sleep(ms: 20)

Examples/SwiftIOPlayground/04Potentiometer/PitchControl/Sources/main.swift

@@ -11,7 +11,7 @@ let buzzer = PWMOut(Id.PWM5A)
 // Then calculate the value into the frequency. 
 // Set the PWM with the frequency and a duty cycle.
 while true {
-    let potPercentage = pot.readPercent()
+    let potPercentage = pot.readPercentage()
     let frequency = 50 + Int(1000 * potPercentage)
     buzzer.set(frequency: frequency, dutycycle: 0.5)
     sleep(ms: 20)

Examples/SwiftIOPlayground/11MoreProjects/Pong/Sources/Pong/Game.swift

@@ -177,15 +177,25 @@ struct PongGame {
     func readSoundData(from path: String) -> [UInt8] {
         let headerSize = 0x2C
 
-        let file = FileDescriptor.open(path)
-        defer { file.close() }
+        guard let file = try? FileDescriptor.open(path) else {
+            print("Read sound data \(path) failed!")
+            return []
+        }
+
+        var buffer = [UInt8]()
 
-        file.seek(offset: 0, from: FileDescriptor.SeekOrigin.end)
-        let size = file.tell() - headerSize
+        do {
+            try file.seek(offset: 0, from: FileDescriptor.SeekOrigin.end)
+            let size = try file.tell() - headerSize
 
-        var buffer = [UInt8](repeating: 0, count: size)
-        buffer.withUnsafeMutableBytes { rawBuffer in 
-            _ = file.read(fromAbsoluteOffest: headerSize, into: rawBuffer, count: size)
+            buffer = [UInt8](repeating: 0, count: size)
+            try buffer.withUnsafeMutableBytes { rawBuffer in 
+                _ = try file.read(fromAbsoluteOffest: headerSize, into: rawBuffer, count: size)
+            }
+            try file.close()
+        } catch {
+            print("File \(path) handle error: \(error)")
+            return []
         }
 
         return buffer