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//
// main.swift
// WaterfallFile
//
// Created by Jacky Jack on 23/12/2024.
//
import Foundation
import Accelerate
print("Read binary file")
let input_filename="rtlsdr_100M_m.cu8"
//get data from u8 file
let dir = getCurrentExecutableDir()
let filemgr = FileManager.default
if !filemgr.fileExists(atPath: input_filename) {
print("Cant find file \(input_filename)")
exit(0)
}
let fileHandle: FileHandle? = FileHandle(forReadingAtPath: dir+"/"+input_filename)
var i8_arr:[Int8]? = nil
if let file = fileHandle {
file.seek(toFileOffset: 0)
do {
if let databuf = try file.readToEnd() {
print("read \(databuf.count) \(databuf) bytes")
//let temp_arr = [Int8](databuf)
i8_arr = [Int8](repeating: 0, count: databuf.count)
for i in 0..<i8_arr!.count {
print(String(format:"%02X", databuf[i]),terminator: "")
//convert from 0..255 to -127..128
let val = databuf[i]
if val <= 127 {
i8_arr![i] = Int8(val)-127
} else {
i8_arr![i] = Int8(val-128)
}
//print(String(format:"%02X", i8_arr![i]),terminator: "")
}
}
} catch {
print(error)
exit(0)
}
}
fileHandle?.closeFile()
//all data in buffer lets process data
//convert all u8 data to float's
//is there other ways to do that?
/*for i in 0..<dataFloat.count {
dataFloat[i] = Float(u8_arr![i])
}*/
//will generate 512x512 image
let sampleCount = 512
let img = SimpleImage(width: sampleCount, height: sampleCount)
let number_of_lines = (i8_arr!.count/sampleCount)
let forwardDCT = vDSP.DCT(count: sampleCount, transformType: .II)!
var frequencyDomain:[Float] = []
var transform_result:[Float] = .init(repeating: 0.0, count: sampleCount)
var dataFloat = [Float](repeating: 0.0, count: sampleCount)
for i in 0..<sampleCount {
let sample_idx = i*sampleCount
if i < number_of_lines {
let processingSlice = i8_arr![sample_idx...sample_idx+512-1]
let processingArray = Array(processingSlice)
vDSP.convertElements(of: processingArray, to: &dataFloat)
//dataFloat = vDSP.add(127.0, dataFloat)
//print(dataFloat)
//move from -127.0 to 128.0 range -1.0...1.0
//var adjusted = vDSP.divide(dataFloat, Float(sampleCount))
var adjusted = dataFloat
//print(adjusted)
transform_result = forwardDCT.transform(adjusted)
transform_result = vDSP.absolute(transform_result)
let max = vDSP.maximum(transform_result)
//print("max=\(max)")
//frequencyDomain.append(contentsOf: transform_result)
img.drawPalletLine(line: i, pixelLine: transform_result)
//print(transform_result)
} else {
img.drawPalletLine(line: i, pixelLine: transform_result)
}
}
img.drawPixel(0, 0, PixelData(a: 255, r: 255, g: 0, b: 0))
img.drawPixel(sampleCount-1, 0, PixelData(a: 255, r: 0, g: 255, b: 0))
img.drawPixel(0, sampleCount-1, PixelData(a: 255, r: 0, g: 255, b: 0))
img.drawPixel(sampleCount-1, sampleCount-1, PixelData(a: 255, r: 0, g: 0, b: 255))
//print(dataFloat)
//output data to image file
img.saveAsJPEG("fft_100m_512.jpeg")
print("All computations are done")
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