feat: Use 1-based unsigned VLQs for binding expressions

"0" becomes the unavailability marker.

Author: szuend

src/decode/decode.ts

@@ -163,7 +163,7 @@ class Decoder {
           const valueIdxs: number[] = [];
 
           while (iter.hasNext() && iter.peek() !== ",") {
-            valueIdxs.push(iter.nextSignedVLQ());
+            valueIdxs.push(iter.nextUnsignedVLQ());
           }
 
           this.#handleGeneratedRangeBindingsItem(valueIdxs);
@@ -343,10 +343,10 @@ class Decoder {
     }
 
     for (const valueIdx of valueIdxs) {
-      if (valueIdx === -1) {
+      if (valueIdx === 0) {
         range.values.push(null);
       } else {
-        range.values.push(this.#resolveName(valueIdx));
+        range.values.push(this.#resolveName(valueIdx - 1));
       }
     }
   }

src/encode/encoder.ts

@@ -204,9 +204,9 @@ export class Encoder {
     this.#encodeTag(EncodedTag.GENERATED_RANGE_BINDINGS);
     for (const val of range.values) {
       if (val === null || val == undefined) {
-        this.#encodeSigned(-1);
+        this.#encodeUnsigned(0);
       } else if (typeof val === "string") {
-        this.#encodeSigned(this.#resolveNamesIdx(val));
+        this.#encodeUnsigned(this.#resolveNamesIdx(val) + 1);
       } else {
         throw new Error("Sub-range bindings not implemented yet!");
       }