Browser lib

1 files changed, 79 insertions, 0 deletions

diff --git a/browser/src/elac.js b/browser/src/elac.js
new file mode 100644
index 0000000..fddab1a
--- /dev/null
+++ b/browser/src/elac.js
@@ -0,0 +1,79 @@
+class EQMCData extends Object {
+    constructor(obj) {
+        super();
+
+        for (let key of Object.keys(obj)) {
+            this[key] = obj[key];
+        }
+    }
+}
+
+class EQMCAudioStream extends Object {
+    constructor(obj) {
+        super();
+
+        for (let key of Object.keys(obj)) {
+            this[key] = obj[key];
+        }
+    }
+}
+
+class EQMCError extends Error {
+    constructor(props) {
+        super(props);
+        this.name = "EQMCError";
+    }
+}
+
+window.EQMC = {
+    _base64ToArrayBuffer: (base64) => {
+        var binary_string = window.atob(base64);
+        var len = binary_string.length;
+        var bytes = new Uint8Array(len);
+        for (var i = 0; i < len; i++) {
+            bytes[i] = binary_string.charCodeAt(i);
+        }
+        return bytes.buffer;
+    },
+
+    isEQMCData: async (data) => {
+        return data instanceof EQMCData && data["_eqmc"];
+    },
+
+    isEQMCAudioStream: async (data) => {
+        return data instanceof EQMCAudioStream && data["data"];
+    },
+
+    create: async (file) => {
+        try {
+            return new EQMCData(JSON.parse(new TextDecoder("utf-8").decode(pako.inflate(new Uint8Array((await (await (await window.fetch(file)).blob()).arrayBuffer()))))));
+        } catch (e) {
+            console.error(e);
+            throw new EQMCError("Failed to construct EQMCData object");
+        }
+    },
+
+    decodeFile: async (data, file) => {
+        if (!await EQMC.isEQMCData(data)) throw new EQMCError("Invalid input, expected EQMCData");
+
+        if (data.files.length - 1 >= file) {
+            let s = data.files[file];
+            s["data"] = new Blob([pako.inflate(EQMC._base64ToArrayBuffer(s.data))]);
+            return new EQMCAudioStream(s);
+        } else {
+            throw new EQMCError("File index is out of range");
+        }
+    },
+
+    toAudio: async (data) => {
+        if (!await EQMC.isEQMCAudioStream(data)) throw new EQMCError("Invalid input, expected EQMCAudioStream");
+
+        return new Audio(window.URL.createObjectURL(data.data));
+    },
+
+    quickAudio: async (url, id) => {
+        let eqmc = await EQMC.create(url);
+        let file = await EQMC.decodeFile(eqmc, id);
+        return await EQMC.toAudio(file);
+    }
+}
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