From 7682c16831e16b8cfe043f068df6b66060e4361a Mon Sep 17 00:00:00 2001
From: nino-porcino <nino.porcino@gmail.com>
Date: Thu, 13 Jan 2022 14:11:03 +0100
Subject: [PATCH] add wav converter utilities

---
 README.md                     |   5 +-
 package-lock.json             |  24 +++++-
 package.json                  |   4 +-
 tools/wavconv/aci.js          |   6 ++
 tools/wavconv/bits2samples.js |  26 ++++++
 tools/wavconv/bytes2bits.js   |  12 +++
 tools/wavconv/checksum.js     |   9 +++
 tools/wavconv/hex.js          |   7 ++
 tools/wavconv/parseOptions.js |  12 +++
 tools/wavconv/prg2wav.js      |  65 +++++++++++++++
 tools/wavconv/samples2wav.js  |  15 ++++
 tools/wavconv/wav2prg.js      | 145 ++++++++++++++++++++++++++++++++++
 12 files changed, 327 insertions(+), 3 deletions(-)
 create mode 100644 tools/wavconv/aci.js
 create mode 100644 tools/wavconv/bits2samples.js
 create mode 100644 tools/wavconv/bytes2bits.js
 create mode 100644 tools/wavconv/checksum.js
 create mode 100644 tools/wavconv/hex.js
 create mode 100644 tools/wavconv/parseOptions.js
 create mode 100644 tools/wavconv/prg2wav.js
 create mode 100644 tools/wavconv/samples2wav.js
 create mode 100644 tools/wavconv/wav2prg.js

diff --git a/README.md b/README.md
index 8152a44..cd53457 100644
--- a/README.md
+++ b/README.md
@@ -10,10 +10,13 @@ demos/
    demo/     demo program that makes use of the library
    picshow/  demo program that shows a picture in bitmap mode
    tetris/   a game
+   montyr/   "Monty on the Run" SID tune by R. Hubbard
+   tapemon/  tape monitor utility
 docs/        TMS9918 and Apple-1 manuals
 kickc/       target configuration files for KickC
 lib/         the library files to include in your project
-tools/       some build tools
+tools/       
+   wavconv/  prg <-> WAV file converter   
 ```
 
 ## Introduction
diff --git a/package-lock.json b/package-lock.json
index 006cb93..06d5af0 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,7 +9,9 @@
       "version": "1.0.0",
       "license": "MIT",
       "dependencies": {
-        "command-line-args": "^5.2.0"
+        "command-line-args": "^5.2.0",
+        "wav-decoder": "^1.3.0",
+        "wav-encoder": "^1.3.0"
       }
     },
     "node_modules/array-back": {
@@ -57,6 +59,16 @@
       "engines": {
         "node": ">=8"
       }
+    },
+    "node_modules/wav-decoder": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/wav-decoder/-/wav-decoder-1.3.0.tgz",
+      "integrity": "sha512-4U6O/JNb1dPO90CO2YMTQ5N2plJcntm39vNMvRq9VZ4Vy5FzS7Lnx95N2QcYUyKYcZfCbhI//W3dSHA8YnOQyQ=="
+    },
+    "node_modules/wav-encoder": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/wav-encoder/-/wav-encoder-1.3.0.tgz",
+      "integrity": "sha512-FXJdEu2qDOI+wbVYZpu21CS1vPEg5NaxNskBr4SaULpOJMrLE6xkH8dECa7PiS+ZoeyvP7GllWUAxPN3AvFSEw=="
     }
   },
   "dependencies": {
@@ -93,6 +105,16 @@
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/typical/-/typical-4.0.0.tgz",
       "integrity": "sha512-VAH4IvQ7BDFYglMd7BPRDfLgxZZX4O4TFcRDA6EN5X7erNJJq+McIEp8np9aVtxrCJ6qx4GTYVfOWNjcqwZgRw=="
+    },
+    "wav-decoder": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/wav-decoder/-/wav-decoder-1.3.0.tgz",
+      "integrity": "sha512-4U6O/JNb1dPO90CO2YMTQ5N2plJcntm39vNMvRq9VZ4Vy5FzS7Lnx95N2QcYUyKYcZfCbhI//W3dSHA8YnOQyQ=="
+    },
+    "wav-encoder": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/wav-encoder/-/wav-encoder-1.3.0.tgz",
+      "integrity": "sha512-FXJdEu2qDOI+wbVYZpu21CS1vPEg5NaxNskBr4SaULpOJMrLE6xkH8dECa7PiS+ZoeyvP7GllWUAxPN3AvFSEw=="
     }
   }
 }
diff --git a/package.json b/package.json
index c7fd0cb..47d58db 100644
--- a/package.json
+++ b/package.json
@@ -21,6 +21,8 @@
   },
   "homepage": "https://github.com/nippur72/apple1-videocard-lib#readme",
   "dependencies": {
-    "command-line-args": "^5.2.0"
+    "command-line-args": "^5.2.0",
+    "wav-decoder": "^1.3.0",
+    "wav-encoder": "^1.3.0"
   }
 }
diff --git a/tools/wavconv/aci.js b/tools/wavconv/aci.js
new file mode 100644
index 0000000..21d2e87
--- /dev/null
+++ b/tools/wavconv/aci.js
@@ -0,0 +1,6 @@
+let ACI = {
+   zero: 2000,   // frequency for "0" bit
+   one:  800     // frequency for "1" bit
+};
+
+module.exports = { ACI };
\ No newline at end of file
diff --git a/tools/wavconv/bits2samples.js b/tools/wavconv/bits2samples.js
new file mode 100644
index 0000000..6ff5422
--- /dev/null
+++ b/tools/wavconv/bits2samples.js
@@ -0,0 +1,26 @@
+function bitsToSamples(bits, samplerate, one_freq, zero_freq) {
+
+   let clock = 1000000;
+
+   let cycles = bits.map(b=>{
+      if(b==1) return samplerate / one_freq;    // 1000 Hz
+      else     return samplerate / zero_freq;   // 2000 Hz
+   });
+
+   let samples = [];
+   let volume = 0.75;
+
+   let ptr = 0;
+   for(let i=0;i<cycles.length;i++) {
+      let nsamples = cycles[i];
+      while(ptr<nsamples) {
+         if(ptr<nsamples/2) samples.push(volume);
+         else               samples.push(-volume);
+         ptr++;
+      }
+      ptr-=nsamples;
+   }
+   return samples;
+}
+
+module.exports = { bitsToSamples };
\ No newline at end of file
diff --git a/tools/wavconv/bytes2bits.js b/tools/wavconv/bytes2bits.js
new file mode 100644
index 0000000..13d399a
--- /dev/null
+++ b/tools/wavconv/bytes2bits.js
@@ -0,0 +1,12 @@
+function bytesToBits(data) {
+   let bits = [];
+   data.forEach(byte => {
+      for(let t=7;t>=0;t--) {
+         let bit = (byte >> t) & 1;
+         bits.push(bit);
+      }
+   });
+   return bits;
+}
+
+module.exports = { bytesToBits };
\ No newline at end of file
diff --git a/tools/wavconv/checksum.js b/tools/wavconv/checksum.js
new file mode 100644
index 0000000..e5d9f85
--- /dev/null
+++ b/tools/wavconv/checksum.js
@@ -0,0 +1,9 @@
+function checksum_byte(bytes) {
+   let checksum = 0xFF;
+   for(let t=0; t<bytes.length; t++) {
+      checksum = (checksum ^ bytes[t]) & 0xFF;
+   }
+   return checksum;
+}
+
+module.exports = { checksum_byte };
\ No newline at end of file
diff --git a/tools/wavconv/hex.js b/tools/wavconv/hex.js
new file mode 100644
index 0000000..13f30a3
--- /dev/null
+++ b/tools/wavconv/hex.js
@@ -0,0 +1,7 @@
+function hex(value, size) {
+   if(size === undefined) size = 2;
+   let s = "0".repeat(size) + value.toString(16);
+   return s.substr(s.length - size).toUpperCase();
+}
+
+module.exports = { hex };
\ No newline at end of file
diff --git a/tools/wavconv/parseOptions.js b/tools/wavconv/parseOptions.js
new file mode 100644
index 0000000..2380d12
--- /dev/null
+++ b/tools/wavconv/parseOptions.js
@@ -0,0 +1,12 @@
+const commandLineArgs = require('command-line-args');
+
+function parseOptions(optionDefinitions) {
+    try {
+       return commandLineArgs(optionDefinitions);
+    } catch(ex) {
+       console.log(ex.message);
+       process.exit(-1);
+    }
+ }
+
+ module.exports = parseOptions;
diff --git a/tools/wavconv/prg2wav.js b/tools/wavconv/prg2wav.js
new file mode 100644
index 0000000..2e9ad7c
--- /dev/null
+++ b/tools/wavconv/prg2wav.js
@@ -0,0 +1,65 @@
+#!/usr/bin/env node
+
+const fs = require('fs');
+const parseOptions = require("./parseOptions");
+const { samples2wav } = require("./samples2wav");
+const { bytesToBits } = require("./bytes2bits");
+const { bitsToSamples } = require("./bits2samples");
+const { checksum_byte } = require("./checksum");
+const { hex } = require("./hex");
+const { ACI } = require("./aci");
+
+const options = parseOptions([
+   { name: 'input', alias: 'i', type: String },
+   { name: 'output', alias: 'o', type: String },
+   { name: 'samplerate', alias: 's', type: Number },
+   { name: 'binary', alias: 'b', type: String }
+]);
+
+if(options.input === undefined || options.output === undefined) {
+   console.log("usage: prg2wav -i inputfile.prg -o outputfile [-s samplerate] [-b hexaddress]");
+   console.log("");
+   console.log("The input is a binary file with two bytes start address header (usually with .prg extension).");
+   console.log("If -b <hexaddress> is specified, the input file is treated as a binary with no header");
+   console.log("and the start address must be specified (in hexadecimal format).");
+   console.log("Samplerate is the rate of the output WAV file (44100 Hz default)");
+   process.exit(-1);
+}
+
+let samplerate = options.samplerate == undefined ? 44100 : options.samplerate;
+
+let binfile,startaddress;
+if(options.binary) {
+   binfile = fs.readFileSync(options.input);
+   startaddress = parseInt(options.binary,16);
+}
+else {
+   let prgfile = fs.readFileSync(options.input);
+   startaddress = prgfile[0]+prgfile[1]*256;
+   binfile = prgfile.slice(2);
+}
+let endaddress = startaddress + binfile.length - 1;
+
+// header is composed of a 10 seconds of long cycles ("1") ending with a short cyles ("0")
+let header = new Uint8Array(1250).fill(255);
+let startbyte = 254; // 7 long cycles and a short one as start bit
+let checksum = checksum_byte(binfile);
+let slipbytes = [ 0xEE, 0xEE, 0xEE, 0xEE, 0xEE, 0xEE, 0xEE, 0xEE ];
+
+let data = [ ...header, startbyte, ...binfile, checksum, ...slipbytes ];
+
+let bits = bytesToBits(data);
+let samples = bitsToSamples(bits, samplerate, ACI.one, ACI.zero);
+let wavfile = samples2wav(samples, samplerate);
+let wavName = options.output;
+
+let s_start = hex(startaddress,4);
+let s_end   = hex(endaddress,4);
+wavName = `${wavName}_${s_start}.${s_end}R.wav`;
+
+fs.writeFileSync(wavName, wavfile);
+
+console.log(`file "${wavName}" generated, load it on the Apple-1 with:`);
+console.log(`C100R (RETURN) ${s_start}.${s_end}R (RETURN)`);
+console.log(``);
+
diff --git a/tools/wavconv/samples2wav.js b/tools/wavconv/samples2wav.js
new file mode 100644
index 0000000..37eea41
--- /dev/null
+++ b/tools/wavconv/samples2wav.js
@@ -0,0 +1,15 @@
+const WavEncoder = require("wav-encoder");
+
+// turns the samples into an actual WAV file
+// returns the array of bytes to be written to file
+
+function samples2wav(samples, samplerate) {
+   const wavData = {
+       sampleRate: samplerate,
+       channelData: [ new Float32Array(samples) ]
+   };
+   const buffer = WavEncoder.encode.sync(wavData, { bitDepth: 16, float: false });
+   return Buffer.from(buffer)
+}
+
+module.exports = { samples2wav };
diff --git a/tools/wavconv/wav2prg.js b/tools/wavconv/wav2prg.js
new file mode 100644
index 0000000..dabeb3d
--- /dev/null
+++ b/tools/wavconv/wav2prg.js
@@ -0,0 +1,145 @@
+#!/usr/bin/env node
+
+const fs = require('fs');
+const WavDecoder = require("wav-decoder");
+const parseOptions = require("./parseOptions");
+const { ACI } = require("./aci");
+
+function samples2phases(samples) {
+   let phases = [];
+
+   // quantize data
+   let s = samples.map(e=> e<0 ? 0 : 1);
+
+   let counter = 0;
+   let last_state = 0;
+
+   for(let i=0;i<s.length-1;i++) {
+      counter++;
+      if(last_state != s[i]) {
+         let phase_width = counter;
+         counter = 0;
+         last_state = s[i];
+         phases.push(phase_width);
+      }
+   }
+   return phases;
+}
+
+function getDataPhases(phases, mid_point) {
+
+   // how many header long phases before the short phase of the starting bit
+   let header_len = (8*2)*256;
+
+   for(let t=header_len;t<phases.length;t++) {
+      if(phases[t] <= mid_point) {
+         // if we found a starting bit half phase, check the header before
+         let start_found = true;
+         for(let i=1;i<header_len;i++) {
+            if(phases[t-i] <= mid_point) {
+               start_found = false;
+               break;
+            }
+         }
+         if(start_found) {
+            return phases.slice(t+2); // also skip the second phase of the start bit
+         }
+      }
+   }
+   throw "start bit not found";
+}
+
+function phases2bits(pulses, mid_point) {
+   let cycles = [];
+
+   // compat two consecutive half phases into one full cycle
+   for(let t=0; t<pulses.length; t+=2) {
+      cycles.push(pulses[t]+pulses[t+1]);
+   }
+
+   let bits = [];
+   for(let t=0; t<cycles.length; t++) {
+      let width = cycles[t];
+      if(width > mid_point) bits.push(1);
+      else bits.push(0);
+   }
+
+   return bits;
+}
+
+function bits2bytes(bits) {
+   let bytes = [];
+   for(let t=0; t<bits.length; t+=8) {
+      let byte =
+         (bits[t+0] << 7) +
+         (bits[t+1] << 6) +
+         (bits[t+2] << 5) +
+         (bits[t+3] << 4) +
+         (bits[t+4] << 3) +
+         (bits[t+5] << 2) +
+         (bits[t+6] << 1) +
+         (bits[t+7] << 0) ;
+      bytes.push(byte);
+   }
+   return bytes;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////
+
+const options = parseOptions([
+    { name: 'input', alias: 'i', type: String },
+    { name: 'output', alias: 'o', type: String },
+    { name: 'start', alias: 's', type: String },
+    { name: 'end', alias: 'e', type: String }
+ ]);
+
+if(options.input === undefined || options.output === undefined) {
+    console.log("usage: wav2prg -i inputfile.wav -o outputfile [-s hexstart] [-e hexend]");
+    process.exit(-1);
+}
+
+
+let wavfile = fs.readFileSync(options.input);
+let audioData = WavDecoder.decode.sync(wavfile);
+let samples = audioData.channelData[0];
+
+let samplerate = audioData.sampleRate;
+
+const long_cycle  = samplerate / ACI.one;
+const short_cyle = samplerate / ACI.zero;
+const cycle_mid_point = (long_cycle + short_cyle) / 2;
+const phase_mid_point = cycle_mid_point / 2;
+
+let phases = samples2phases(samples);
+let dataPhases = getDataPhases(phases, phase_mid_point);
+let bits = phases2bits(dataPhases, cycle_mid_point);
+let bytes = bits2bytes(bits);
+
+if(options.start !== undefined && options.end !== undefined) {
+   let start_address = parseInt(options.start,16);
+   let end_address = parseInt(options.end,16);
+   let len = end_address - start_address + 1;  // end address included
+   if(bytes.length<len) throw `decoded file (${bytes.length} bytes) smaller than specified (${len} bytes)`;
+
+   // cut file
+   bytes = bytes.slice(0,len);
+
+   // add prg header
+   let hi = (start_address >> 8) & 0xff;
+   let lo = (start_address >> 0) & 0xff;
+   bytes = [ lo, hi, ...bytes];
+
+   let prgFile = new Uint8Array(bytes);
+   let prgName = `${options.output}.prg`;
+   fs.writeFileSync(prgName, prgFile);
+   console.log(`file "${prgName}" generated (it has two bytes header start address)`);
+}
+else
+{
+   let binFile = new Uint8Array(bytes);
+   let binName = `${options.output}.bin`;
+   fs.writeFileSync(binName, binFile);
+   console.log(`no address specified, writing raw binary`);
+   console.log(`file "${binName}" generated`);
+}
+