From 357679f03c16732faf1ac9ea304353bb318de667 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Leonardo=20Mur=C3=A7a?= <leo@leomurca.xyz>
Date: Fri, 2 Dec 2022 18:49:27 -0300
Subject: [PATCH] Add exp format support

---
 README.md                  |  2 +-
 src/file-renderer/index.js |  3 +++
 src/format-readers/exp.js  | 50 ++++++++++++++++++++++++++++++++++++++
 src/lib/FileViewer.svelte  |  2 +-
 4 files changed, 55 insertions(+), 2 deletions(-)
 create mode 100644 src/format-readers/exp.js

diff --git a/README.md b/README.md
index 60f8842..50904b3 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,6 @@ Available at https://embroideryviewer.xyz.
 
 ![Demo](/demo.gif)
 
-Current supported formats: **.pes, .dst, .pec and .jef**.
+Current supported formats: **.pes, .dst, .pec, .jef and .exp**.
 
 Inspired by https://github.com/redteam316/html5-embroidery.git.
diff --git a/src/file-renderer/index.js b/src/file-renderer/index.js
index eca64c7..fa77679 100644
--- a/src/file-renderer/index.js
+++ b/src/file-renderer/index.js
@@ -4,6 +4,7 @@ import { dstRead } from "../format-readers/dst";
 import { Pattern } from "./pattern";
 import { pecRead } from "../format-readers/pec";
 import { jefRead } from "../format-readers/jef";
+import { expRead } from "../format-readers/exp";
 
 String.prototype.endsWith = function (suffix) {
   return this.indexOf(suffix, this.length - suffix.length) !== -1;
@@ -21,6 +22,8 @@ function displayFileText(filename, evt, canvas) {
     pecRead(view, pattern);
   } else if (filename.endsWith("jef")) {
     jefRead(view, pattern);
+  } else if (filename.endsWith("exp")) {
+    expRead(view, pattern);
   }
   pattern.moveToPositive();
   pattern.drawShape(canvas);
diff --git a/src/format-readers/exp.js b/src/format-readers/exp.js
new file mode 100644
index 0000000..58d29ae
--- /dev/null
+++ b/src/format-readers/exp.js
@@ -0,0 +1,50 @@
+import { stitchTypes } from "../file-renderer/pattern";
+
+function expDecode(input) {
+  return input > 128 ? -(~input & 255) - 1 : input;
+}
+
+export function expRead(file, pattern) {
+  let b0 = 0,
+    b1 = 0,
+    dx = 0,
+    dy = 0,
+    flags = 0,
+    i = 0,
+    byteCount = file.byteLength;
+  while (i < byteCount) {
+    flags = stitchTypes.normal;
+    b0 = file.getInt8(i);
+    i += 1;
+    b1 = file.getInt8(i);
+    i += 1;
+    if (b0 === -128) {
+      if (b1 & 1) {
+        b0 = file.getInt8(i);
+        i += 1;
+        b1 = file.getInt8(i);
+        i += 1;
+        flags = stitchTypes.stop;
+      } else if (b1 === 2 || b1 === 4) {
+        b0 = file.getInt8(i);
+        i += 1;
+        b1 = file.getInt8(i);
+        i += 1;
+        flags = stitchTypes.trim;
+      } else if (b1 === -128) {
+        b0 = file.getInt8(i);
+        i += 1;
+        b1 = file.getInt8(i);
+        i += 1;
+        b0 = 0;
+        b1 = 0;
+        flags = stitchTypes.trim;
+      }
+    }
+    dx = expDecode(b0);
+    dy = expDecode(b1);
+    pattern.addStitchRel(dx, dy, flags, true);
+  }
+  pattern.addStitchRel(0, 0, stitchTypes.end);
+  pattern.invertPatternVertical();
+}
diff --git a/src/lib/FileViewer.svelte b/src/lib/FileViewer.svelte
index d1a85f2..514606b 100644
--- a/src/lib/FileViewer.svelte
+++ b/src/lib/FileViewer.svelte
@@ -9,7 +9,7 @@
   let rejectedFiles;
   let areAcceptedFilesRendered = false;
   const fileRequirements = {
-    supportedFormats: [".pes", ".dst", ".pec", ".jef"],
+    supportedFormats: [".pes", ".dst", ".pec", ".jef", ".exp"],
     maxSize: 700000,
   };