Merge pull request #16 from bitcoinjs/ext

Remove length limits

README.md

@@ -7,11 +7,22 @@ A [BIP173](https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki) compa
 
 ## Example
 ``` javascript
+let bech32 = require('bech32')
 
-
+bech32.decode('abcdef1qpzry9x8gf2tvdw0s3jn54khce6mua7lmqqqxw')
+// => {
+// 	 prefix: 'abcdef',
+// 	 words: [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31]
+// }
 ```
 
 
+### Advanced
+BIP173 enforces a limitation of 90 characters,  if extend the `LIMIT` parameter beyond this,  be aware that the [effectiveness of checksum decreases as the length increases](https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki#checksum-design).
+
+It is highly recommended **NOT** exceed 1023 characters, as the module could only guarantee detecting 1 error.
+
+
 ## Credits
 - [Peter Wuille](https://github.com/sipa/bech32) for the reference JavaScript implementation, and for authoring the Bech32 [BIP173](https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki).
 

index.js

@@ -37,9 +37,10 @@ function prefixChk (prefix) {
   return chk
 }
 
-function encode (prefix, words) {
-  // too long?
-  if ((prefix.length + 7 + words.length) > 90) throw new TypeError('Exceeds Bech32 maximum length')
+function encode (prefix, words, LIMIT) {
+  LIMIT = LIMIT || 90
+  if ((prefix.length + 7 + words.length) > LIMIT) throw new TypeError('Exceeds length limit')
+
   prefix = prefix.toLowerCase()
 
   // determine chk mod
@@ -66,9 +67,10 @@ function encode (prefix, words) {
   return result
 }
 
-function decode (str) {
+function decode (str, LIMIT) {
+  LIMIT = LIMIT || 90
   if (str.length < 8) throw new TypeError(str + ' too short')
-  if (str.length > 90) throw new TypeError(str + ' too long')
+  if (str.length > LIMIT) throw new TypeError('Exceeds length limit')
 
   // don't allow mixed case
   let lowered = str.toLowerCase()

test/fixtures.json

@@ -42,6 +42,13 @@
         "prefix": "split",
         "hex": "c5f38b70305f519bf66d85fb6cf03058f3dde463ecd7918f2dc743918f2d",
         "words": [24,23,25,24,22,28,1,16,11,29,8,25,23,29,19,13,16,23,29,22,25,28,1,16,11,3,25,29,27,25,3,3,29,19,11,25,3,3,25,13,24,29,1,25,3,3,25,13]
+      },
+      {
+        "string": "11qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq978ear",
+        "prefix": "1",
+        "hex": "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+        "words": [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
+        "limit": 300
       }
     ],
     "invalid": [
@@ -59,7 +66,7 @@
       },
       {
         "string": "an84characterslonghumanreadablepartthatcontainsthenumber1andtheexcludedcharactersbio1569pvx",
-        "exception": "an84characterslonghumanreadablepartthatcontainsthenumber1andtheexcludedcharactersbio1569pvx too long"
+        "exception": "Exceeds length limit"
       },
       {
         "string": "x1b4n0q5v",
@@ -89,12 +96,22 @@
       {
         "prefix": "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzfoobarfoobar",
         "words": [128],
-        "exception": "Exceeds Bech32 maximum length"
+        "exception": "Exceeds length limit"
       },
       {
         "prefix": "foobar",
         "words": [20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20],
-        "exception": "Exceeds Bech32 maximum length"
+        "exception": "Exceeds length limit"
+      },
+      {
+        "prefix": "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzfoobarfoobarfoobarfoobar",
+        "words": [128],
+        "limit": 104,
+        "exception": "Exceeds length limit"
+      },
+      {
+        "string": "11qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqc8247j",
+        "exception": "Exceeds length limit"
       },
       {
         "prefix": "abc\u00ff",

test/index.js

@@ -15,14 +15,12 @@ fixtures.bech32.valid.forEach((f) => {
 
   tape(`encode ${f.prefix} ${f.hex}`, (t) => {
     t.plan(1)
-
-    t.strictEqual(bech32.encode(f.prefix, f.words), f.string.toLowerCase())
+    t.strictEqual(bech32.encode(f.prefix, f.words, f.limit), f.string.toLowerCase())
   })
 
   tape(`decode ${f.string}`, (t) => {
     t.plan(1)
-
-    t.same(bech32.decode(f.string), {
+    t.same(bech32.decode(f.string, f.limit), {
       prefix: f.prefix.toLowerCase(),
       words: f.words
     })
@@ -35,7 +33,7 @@ fixtures.bech32.valid.forEach((f) => {
     buffer[f.string.lastIndexOf('1') + 1] ^= 0x1 // flip a bit, after the prefix
     let string = buffer.toString('utf8')
     t.throws(function () {
-      bech32.decode(string)
+      bech32.decode(string, f.limit)
     }, new RegExp('Invalid checksum|Unknown character'))
   })
 })