remove native code and use bignum package

gasteve · Jul 28, 2013 · 9a3ecbc · 9a3ecbc
1 parent b779bb8
commit 9a3ecbc
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Showing 4 changed files with 74 additions and 280 deletions.
diff --git a/base58.js b/base58.js
@@ -1,14 +1,69 @@
-var lib = require('bindings')('base58');
 var crypto = require('crypto');
+var bignum = require('bignum');
+
+var globalBuffer = new Buffer(1024);
+var zerobuf = new Buffer(0);
+var ALPHABET = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz';
+var ALPHABET_ZERO = ALPHABET[0];
+var ALPHABET_BUF = new Buffer(ALPHABET, 'ascii');
+var ALPHABET_INV = {};
+for(var i=0; i < ALPHABET.length; i++) {
+  ALPHABET_INV[ALPHABET[i]] = i;
+};
 
 // Vanilla Base58 Encoding
 var base58 = {
-  encode: lib.base58_encode,
-  decode: lib.base58_decode,
+  encode: function(buf) {
+    var str;
+    var x = bignum.fromBuffer(buf);
+    var r;
+
+    if(buf.length < 512) {
+      str = globalBuffer;
+    } else {
+      str = new Buffer(buf.length << 1);
+    }
+    var i = str.length - 1;
+    while(x.gt(0)) {
+      r = x.mod(58);
+      x = x.div(58);
+      str[i] = ALPHABET_BUF[r.toNumber()];
+      i--;
+    }
+
+    // deal with leading zeros
+    var j=0;
+    while(buf[j] == 0) {
+      str[i] = ALPHABET_BUF[0];
+      j++; i--;
+    }
+
+    return str.slice(i+1,str.length).toString('ascii');
+  },
+
+  decode: function(str) {
+    if(str.length == 0) return zerobuf;
+    var answer = bignum(0);
+    for(var i=0; i<str.length; i++) {
+    answer.mul(58)
+      answer = answer.mul(58);
+      answer = answer.add(ALPHABET_INV[str[i]]);
+    };
+    var i = 0;
+    while(i < str.length && str[i] == ALPHABET_ZERO) {
+      i++;
+    }
+    if(i > 0) {
+      var zb = new Buffer(i);
+      zb.fill(0);
+      if(i == str.length) return zb;
+      answer = answer.toBuffer();
+      return Buffer.concat([zb, answer], i+answer.length);
+    } else {
+      return answer.toBuffer();
+    }
+  },
 };
-exports.base58 = base58;
-exports.encode = base58.encode;
-exports.decode = base58.decode;
 
 // Base58Check Encoding
 function sha256(data) {
@@ -19,7 +74,7 @@ function doubleSHA256(data) {
   return sha256(sha256(data));
 };
 
-exports.base58Check = {
+var base58Check = {
   encode: function(buf) {
     var checkedBuf = new Buffer(buf.length + 4);
     var hash = doubleSHA256(buf);
@@ -47,3 +102,15 @@ exports.base58Check = {
     return data;
   },
 };
+
+// if you frequently do base58 encodings with data larger
+// than 512 bytes, you can use this method to expand the
+// size of the reusable buffer
+exports.setBuffer = function(buf) {
+  globalBuffer = buf;
+};
+
+exports.base58 = base58;
+exports.base58Check = base58Check;
+exports.encode = base58.encode;
+exports.decode = base58.decode;
diff --git a/binding.gyp b/binding.gyp
diff --git a/src/base58.cc b/src/base58.cc
diff --git a/src/common.h b/src/common.h