add hexdump

Author: prohazko2

exec.ts

@@ -79,7 +79,11 @@ export async function exec(cmd: string | string[], stdin = "") {
   return new TextDecoder().decode(stdout).trim();
 }
 
-export async function* tail(cmd: string | string[], stdin = "") {
+export type TailOptions = {
+  fromStderr: boolean;
+};
+
+export async function* tail(cmd: string | string[], _opts?: TailOptions) {
   if (!Array.isArray(cmd)) {
     cmd = cmd.split(" ");
   }
@@ -90,26 +94,22 @@ export async function* tail(cmd: string | string[], stdin = "") {
     cmd,
   };
 
-  if (stdin) {
-    opts.stdin = "piped";
-  }
-
   const p = Deno.run(opts);
-  if (stdin) {
-    const encoder = new TextEncoder();
-    await p.stdin!.write(encoder.encode(stdin));
-    p.stdin!.close();
+  let s = p.stdout!;
+
+  if (_opts?.fromStderr) {
+    s = p.stderr!;
   }
 
   for (;;) {
     const buf = new Uint8Array(4096);
-    const n = await p.stdout?.read(buf);
+    const n = await s.read(buf);
 
     if (n === null || n === undefined) {
       break;
     }
 
-    const text = new TextDecoder().decode(buf);
+    const text = new TextDecoder().decode(buf.slice(0, n));
     yield text;
   }
 

hex.ts

@@ -0,0 +1,38 @@
+export function isprint(x: number) {
+  return x >= 0x20 && x <= 0x7e;
+}
+
+export function dump(buf: Uint8Array | string) {
+  if (typeof buf === "string") {
+    buf = new TextEncoder().encode(buf);
+  }
+
+  let out = "";
+
+  let i = 0;
+  let j = 0;
+
+  for (i = 0; i < buf.length; i += 16) {
+    out += i.toString(16).padStart(6, "0");
+    out += ": ";
+
+    for (j = 0; j < 16; j++) {
+      if (i + j < buf.length) {
+        out += buf[i + j].toString(16).padStart(2, "0");
+        out += " ";
+      } else {
+        out += "   ";
+      }
+    }
+    out += " ";
+
+    for (j = 0; j < 16; j++) {
+      if (i + j < buf.length) {
+        out += isprint(buf[i + j]) ? String.fromCharCode(buf[i + j]) : ".";
+      }
+    }
+    out += "\n";
+  }
+
+  return out;
+}