From c8c027f762f5ffe09664f7e4b2d39e05b3c929b4 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Tue, 2 Mar 2021 16:38:40 +0100
Subject: [PATCH] Repair javascript integer codec

---
 implementations/javascript/package.json |   2 +-
 implementations/javascript/src/codec.ts |   6 +++---
 tests/samples.bin                       | Bin 7996 -> 8033 bytes
 tests/samples.txt                       |   1 +
 4 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/implementations/javascript/package.json b/implementations/javascript/package.json
index d1c7af7..c6f3aa6 100644
--- a/implementations/javascript/package.json
+++ b/implementations/javascript/package.json
@@ -1,6 +1,6 @@
 {
   "name": "preserves",
-  "version": "0.6.0",
+  "version": "0.6.1",
   "description": "Experimental data serialization format",
   "homepage": "https://gitlab.com/preserves/preserves",
   "license": "Apache-2.0",
diff --git a/implementations/javascript/src/codec.ts b/implementations/javascript/src/codec.ts
index d7be394..d69e478 100644
--- a/implementations/javascript/src/codec.ts
+++ b/implementations/javascript/src/codec.ts
@@ -128,7 +128,7 @@ export class Decoder<T extends object> {
         if (n === 0) return 0;
         let acc = this.nextbyte();
         if (acc & 0x80) acc -= 256;
-        for (let i = 1; i < n; i++) acc = (acc << 8) | this.nextbyte();
+        for (let i = 1; i < n; i++) acc = (acc * 256) + this.nextbyte();
         return acc;
     }
 
@@ -311,7 +311,7 @@ export class Encoder<T extends object> {
 
     encodeint(v: number) {
         // TODO: Bignums :-/
-        const plain_bitcount = Math.floor(Math.log2(v > 0 ? v : ~v)) + 1;
+        const plain_bitcount = Math.floor(Math.log2(v > 0 ? v : -(1 + v))) + 1;
         const signed_bitcount = plain_bitcount + 1;
         const bytecount = (signed_bitcount + 7) >> 3;
         if (bytecount <= 16) {
@@ -322,7 +322,7 @@ export class Encoder<T extends object> {
         }
         const enc = (n: number, x: number) => {
             if (n > 0) {
-                enc(n - 1, x >> 8);
+                enc(n - 1, Math.floor(x / 256));
                 this.emitbyte(x & 255);
             }
         };
diff --git a/tests/samples.bin b/tests/samples.bin
index a832fc3641c963bab153de5eac4017f63db9e813..dba2dcba2c7471031272ef842e24f53c36bf7294 100644
GIT binary patch
delta 47
ucmdmE_t0*`RB0vN%)AmKQv)d2vY90$wYX#x+Y*MUOg|aG<mO4ztC#_j@evaM

delta 12
UcmaE8x5sY7RO!vTq?a=T04W9qtN;K2

diff --git a/tests/samples.txt b/tests/samples.txt
index a7c21c5..e6450b8 100644
--- a/tests/samples.txt
+++ b/tests/samples.txt
@@ -101,6 +101,7 @@
   int65535: <Test #x"a200ffff" 65535>
   int65536: <Test #x"a2010000" 65536>
   int131072: <Test #x"a2020000" 131072>
+  int2500000000: <Test #x"a4009502f900" 2500000000>
   list0: <Test #x"b584" []>
   list4: <Test #x"b59192939484" [1 2 3 4]>
   list4a: <Test #x"b59192939484" [1, 2, 3, 4]>