9 files changed, 45 insertions, 20 deletions
diff --git a/src/lib/codec/base64/base64.cpp b/src/lib/codec/base64/base64.cpp
index 1b1767aa1..a63d2b373 100644
--- a/src/lib/codec/base64/base64.cpp
+++ b/src/lib/codec/base64/base64.cpp
@@ -78,9 +78,7 @@ size_t base64_encode(char out[],
 std::string base64_encode(const byte input[],
                           size_t input_length)
    {
-   const size_t output_length = (input_length == 0)
-           ? 0
-           : (round_up<size_t>(input_length, 3) / 3) * 4;
+   const size_t output_length = (round_up(input_length, 3) / 3) * 4;
    std::string output(output_length, 0);
 
    size_t consumed = 0;
@@ -231,10 +229,8 @@ size_t base64_decode(byte output[],
 secure_vector<byte> base64_decode(const char input[],
                                  size_t input_length,
                                  bool ignore_ws)
-   { 
-   const size_t output_length = (input_length == 0)
-           ? 0
-           : (round_up<size_t>(input_length, 4) * 3) / 4;
+   {
+   const size_t output_length = (round_up(input_length, 4) * 3) / 4;
    secure_vector<byte> bin(output_length);
 
    size_t written = base64_decode(bin.data(),
diff --git a/src/lib/math/bigint/bigint.cpp b/src/lib/math/bigint/bigint.cpp
index b5a8e0dd5..c9aa1d981 100644
--- a/src/lib/math/bigint/bigint.cpp
+++ b/src/lib/math/bigint/bigint.cpp
@@ -34,7 +34,7 @@ BigInt::BigInt(u64bit n)
 */
 BigInt::BigInt(Sign s, size_t size)
    {
-   m_reg.resize(round_up<size_t>(size, 8));
+   m_reg.resize(round_up(size, 8));
    m_signedness = s;
    }
 
@@ -271,7 +271,7 @@ void BigInt::binary_decode(const byte buf[], size_t length)
    const size_t WORD_BYTES = sizeof(word);
 
    clear();
-   m_reg.resize(round_up<size_t>((length / WORD_BYTES) + 1, 8));
+   m_reg.resize(round_up((length / WORD_BYTES) + 1, 8));
 
    for(size_t i = 0; i != length / WORD_BYTES; ++i)
       {
diff --git a/src/lib/math/numbertheory/mp_numth.cpp b/src/lib/math/numbertheory/mp_numth.cpp
index fafc6b03f..6eb938286 100644
--- a/src/lib/math/numbertheory/mp_numth.cpp
+++ b/src/lib/math/numbertheory/mp_numth.cpp
@@ -19,7 +19,7 @@ BigInt square(const BigInt& x)
    {
    const size_t x_sw = x.sig_words();
 
-   BigInt z(BigInt::Positive, round_up<size_t>(2*x_sw, 16));
+   BigInt z(BigInt::Positive, round_up(2*x_sw, 16));
    secure_vector<word> workspace(z.size());
 
    bigint_sqr(z.mutable_data(), z.size(),
diff --git a/src/lib/modes/cbc/cbc.cpp b/src/lib/modes/cbc/cbc.cpp
index 27f2bce4a..dd6550fce 100644
--- a/src/lib/modes/cbc/cbc.cpp
+++ b/src/lib/modes/cbc/cbc.cpp
@@ -105,6 +105,7 @@ size_t CBC_Encryption::minimum_final_size() const
 
 size_t CBC_Encryption::output_length(size_t input_length) const
    {
+   BOTAN_ASSERT(input_length != 0, "CBC_Encryption::output_length() call");
    return round_up(input_length, cipher().block_size());
    }
 
diff --git a/src/lib/modes/ecb/ecb.cpp b/src/lib/modes/ecb/ecb.cpp
index 73a241394..6de00f18a 100644
--- a/src/lib/modes/ecb/ecb.cpp
+++ b/src/lib/modes/ecb/ecb.cpp
@@ -83,6 +83,7 @@ size_t ECB_Encryption::minimum_final_size() const
 
 size_t ECB_Encryption::output_length(size_t input_length) const
    {
+   BOTAN_ASSERT(input_length != 0, "ECB_Encryption::output_length() call");
    return round_up(input_length, cipher().block_size());
    }
 
diff --git a/src/lib/modes/xts/xts.cpp b/src/lib/modes/xts/xts.cpp
index cc0e6d54c..4eaf03fe5 100644
--- a/src/lib/modes/xts/xts.cpp
+++ b/src/lib/modes/xts/xts.cpp
@@ -135,6 +135,7 @@ void XTS_Mode::update_tweak(size_t which)
 
 size_t XTS_Encryption::output_length(size_t input_length) const
    {
+   BOTAN_ASSERT(input_length != 0, "XTS_Encryption::output_length() call");
    return round_up(input_length, cipher().block_size());
    }
 
diff --git a/src/lib/utils/calendar.cpp b/src/lib/utils/calendar.cpp
index 3ce5170fc..b578f6be9 100644
--- a/src/lib/utils/calendar.cpp
+++ b/src/lib/utils/calendar.cpp
@@ -33,9 +33,30 @@ std::tm do_gmtime(std::time_t time_val)
 
 }
 
-/*
-* Convert a time_point to a calendar_point
-*/
+std::chrono::system_clock::time_point calendar_point::to_std_timepoint()
+   {
+   if (year < 1900)
+      throw Invalid_Argument("calendar_point::to_std_timepoint() does not support years before 1990.");
+
+   std::tm tm;
+   tm.tm_sec   = seconds;
+   tm.tm_min   = minutes;
+   tm.tm_hour  = hour;
+   tm.tm_mday  = day;
+   tm.tm_mon   = month - 1;
+   tm.tm_year  = year - 1900;
+
+   // Convert std::tm to std::time_t
+   // http://stackoverflow.com/questions/16647819/timegm-cross-platform
+   #if defined(BOTAN_TARGET_OS_IS_WINDOWS)
+   #define timegm _mkgmtime
+   #endif
+   std::time_t tt = timegm(&tm);
+
+   return std::chrono::system_clock::from_time_t(tt);
+   }
+
+
 calendar_point calendar_value(
    const std::chrono::system_clock::time_point& time_point)
    {
diff --git a/src/lib/utils/calendar.h b/src/lib/utils/calendar.h
index 4efff0edc..4f882e49f 100644
--- a/src/lib/utils/calendar.h
+++ b/src/lib/utils/calendar.h
@@ -49,9 +49,15 @@ struct BOTAN_DLL calendar_point
    */
    calendar_point(u32bit y, byte mon, byte d, byte h, byte min, byte sec) :
       year(y), month(mon), day(d), hour(h), minutes(min), seconds(sec) {}
+
+   /**
+   * Returns an STL timepoint object
+   */
+   std::chrono::system_clock::time_point to_std_timepoint();
    };
 
-/*
+/**
+* Convert a time_point to a calendar_point
 * @param time_point a time point from the system clock
 * @return calendar_point object representing this time point
 */
diff --git a/src/lib/utils/rounding.h b/src/lib/utils/rounding.h
index 02edb1929..8ad324225 100644
--- a/src/lib/utils/rounding.h
+++ b/src/lib/utils/rounding.h
@@ -9,22 +9,21 @@
 #define BOTAN_ROUNDING_H__
 
 #include <botan/types.h>
+#include <botan/assert.h>
 
 namespace Botan {
 
 /**
 * Round up
-* @param n an integer
+* @param n a non-negative integer
 * @param align_to the alignment boundary
 * @return n rounded up to a multiple of align_to
 */
-template<typename T>
-inline T round_up(T n, T align_to)
+inline size_t round_up(size_t n, size_t align_to)
    {
-   if(align_to == 0)
-      return n;
+   BOTAN_ASSERT(align_to != 0, "align_to must not be 0");
 
-   if(n % align_to || n == 0)
+   if(n % align_to)
       n += align_to - (n % align_to);
    return n;
    }