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// -------------------------------------------------
// ------------------ Marshall ---------------------
// -------------------------------------------------
// helper functions for virtio and 9p.
import { dbg_log } from "./../src/log.js";
const textde = new TextDecoder();
const texten = new TextEncoder();
// Inserts data from an array to a byte aligned struct in memory
export function Marshall(typelist, input, struct, offset) {
var item;
var size = 0;
for(var i=0; i < typelist.length; i++) {
item = input[i];
switch(typelist[i]) {
case "w":
struct[offset++] = item & 0xFF;
struct[offset++] = (item >> 8) & 0xFF;
struct[offset++] = (item >> 16) & 0xFF;
struct[offset++] = (item >> 24) & 0xFF;
size += 4;
break;
case "d": // double word
struct[offset++] = item & 0xFF;
struct[offset++] = (item >> 8) & 0xFF;
struct[offset++] = (item >> 16) & 0xFF;
struct[offset++] = (item >> 24) & 0xFF;
struct[offset++] = 0x0;
struct[offset++] = 0x0;
struct[offset++] = 0x0;
struct[offset++] = 0x0;
size += 8;
break;
case "h":
struct[offset++] = item & 0xFF;
struct[offset++] = item >> 8;
size += 2;
break;
case "b":
struct[offset++] = item;
size += 1;
break;
case "s":
var lengthoffset = offset;
var length = 0;
struct[offset++] = 0; // set the length later
struct[offset++] = 0;
size += 2;
var stringBytes = texten.encode(item);
size += stringBytes.byteLength;
length += stringBytes.byteLength;
struct.set(stringBytes, offset);
offset += stringBytes.byteLength;
struct[lengthoffset+0] = length & 0xFF;
struct[lengthoffset+1] = (length >> 8) & 0xFF;
break;
case "Q":
Marshall(["b", "w", "d"], [item.type, item.version, item.path], struct, offset);
offset += 13;
size += 13;
break;
default:
dbg_log("Marshall: Unknown type=" + typelist[i]);
break;
}
}
return size;
}
// Extracts data from a byte aligned struct in memory to an array
export function Unmarshall(typelist, struct, state) {
let offset = state.offset;
var output = [];
for(var i=0; i < typelist.length; i++) {
switch(typelist[i]) {
case "w":
var val = struct[offset++];
val += struct[offset++] << 8;
val += struct[offset++] << 16;
val += (struct[offset++] << 24) >>> 0;
output.push(val);
break;
case "d":
var val = struct[offset++];
val += struct[offset++] << 8;
val += struct[offset++] << 16;
val += (struct[offset++] << 24) >>> 0;
offset += 4;
output.push(val);
break;
case "h":
var val = struct[offset++];
output.push(val + (struct[offset++] << 8));
break;
case "b":
output.push(struct[offset++]);
break;
case "s":
var len = struct[offset++];
len += struct[offset++] << 8;
var stringBytes = struct.slice(offset, offset + len);
offset += len;
output.push(textde.decode(stringBytes));
break;
case "Q":
state.offset = offset;
const qid = Unmarshall(["b", "w", "d"], struct, state);
offset = state.offset;
output.push({
type: qid[0],
version: qid[1],
path: qid[2],
});
break;
default:
dbg_log("Error in Unmarshall: Unknown type=" + typelist[i]);
break;
}
}
state.offset = offset;
return output;
}
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