urbit-ob

commit f960ef2d16084aee693e96dfd49fc3c251e86a91
parent 144d4c8cf6d606357a13e43822f0cf1028435b91
Author: Jared Tobin <jared@jtobin.io>
Date:   Wed, 10 Oct 2018 19:16:33 +1300

Preserve leading zeros for hex -> patq.

This mimics the behaviour of Node's 'Buffer', which preserves leading
zeros when moving to and from hex.

Diffstat:
M
package.json
 | 
2
+-
M
src/index.js
 | 
40
+++++++++++++++++++++++++++++++++++++---

2 files changed, 38 insertions(+), 4 deletions(-)
diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ob-js",
-  "version": "1.4.0",
+  "version": "1.4.1",
   "description": "Utilities for Hoon-style atom printing and conversion",
   "main": "dist/index.js",
   "scripts": {
diff --git a/src/index.js b/src/index.js
@@ -386,6 +386,8 @@ const patp = (n) => {
     : loop(sxz, zero, ''))
 }
 
+
+
 // bignum patq
 const patq = (n) => {
   const buff = n.toArrayLike(Buffer)
@@ -415,9 +417,38 @@ const patq = (n) => {
     acc + (acc === '~' ? '' : '-') + alg(elem), '~')
 }
 
-hex2patq = hex => patq(new bnjs(hex, 'hex'))
 
-patq2hex = str => {
+
+/**
+ * Convert a hex-encoded string to @q.  Preserves leading zero bytes.
+ * @param  {string}  str a hex-encoded string
+ * @return  {string} a @q-encoded string
+ */
+const hex2patq = hex => {
+  const buf = Buffer.from(hex, 'hex')
+  const chunks =
+    isOdd(buf.length)
+    ? concat([[buf[0]]], chunk(buf.slice(1), 2))
+    : chunk(buf, 2)
+  const splat = map(chunks, chunk =>
+    isUndefined(chunk[1])
+    ? getPrefix(0) + getSuffix(chunk[0])
+    : getPrefix(chunk[0]) + getSuffix(chunk[1])
+  )
+  return hex.length === 0
+    ? '~zod'
+    : splat.reduce((acc, elem) =>
+        acc + (acc === '~' ? '' : '-') + elem, '~')
+}
+
+
+
+/**
+ * Convert a @q-encoded string to hexadecimal.  Preserves leading zero bytes.
+ * @param  {string}  str a @q-encoded string
+ * @return  {string} a hex-encoded string
+ */
+const patq2hex = str => {
   const chunks = split(str.slice(1), '-')
   const splat = map(chunks, chunk => {
     let syls = splitAt(3, chunk)
@@ -428,10 +459,13 @@ patq2hex = str => {
         dec2hex(getSuffixIndex(syls[1]))
     return hex
   })
-  return splat.join('')
+  return str.length === 0
+    ? '00'
+    : splat.join('')
 }
 
 
+
 /**
  * Remove all leading zero bytes from a hex-encoded string.
  * @param  {string}  str a hex encoded string