From a9d3af88214b37ea61394b0b5abee6d380f9a5f0 Mon Sep 17 00:00:00 2001
From: Doug Huff <mith@jrbobdobbs.org>
Date: Mon, 6 Jun 2011 12:47:19 -0500
Subject: Demystify a few magic numbers.

---
 src/base58.h | 2 ++
 src/bignum.h | 3 +++
 2 files changed, 5 insertions(+)

(limited to 'src')

diff --git a/src/base58.h b/src/base58.h
index 580bd3fc63..c2729d4770 100644
--- a/src/base58.h
+++ b/src/base58.h
@@ -38,6 +38,8 @@ inline std::string EncodeBase58(const unsigned char* pbegin, const unsigned char
 
     // Convert bignum to std::string
     std::string str;
+    // Expected size increase from base58 conversion is approximately 137%
+    // use 138% to be safe
     str.reserve((pend - pbegin) * 138 / 100 + 1);
     CBigNum dv;
     CBigNum rem;
diff --git a/src/bignum.h b/src/bignum.h
index 5b4c78e7fa..5eaa4028b7 100644
--- a/src/bignum.h
+++ b/src/bignum.h
@@ -228,10 +228,13 @@ public:
     {
         std::vector<unsigned char> vch2(vch.size() + 4);
         unsigned int nSize = vch.size();
+        // BIGNUM's byte stream format expects 4 bytes of
+        // big endian size data info at the front
         vch2[0] = (nSize >> 24) & 0xff;
         vch2[1] = (nSize >> 16) & 0xff;
         vch2[2] = (nSize >> 8) & 0xff;
         vch2[3] = (nSize >> 0) & 0xff;
+        // swap data to big endian
         reverse_copy(vch.begin(), vch.end(), vch2.begin() + 4);
         BN_mpi2bn(&vch2[0], vch2.size(), this);
     }
-- 
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