Remove to_string, replacing with std::to_string

Convert to_u32bit to use the new C++0x library func stoul instead of
hand-written code.

33 files changed, 107 insertions, 147 deletions

diff --git a/src/asn1/asn1_int.cpp b/src/asn1/asn1_int.cpp
index 5e18f3961..af01d8fa3 100644
--- a/src/asn1/asn1_int.cpp
+++ b/src/asn1/asn1_int.cpp
@@ -20,11 +20,11 @@ BER_Decoding_Error::BER_Decoding_Error(const std::string& str) :
    Decoding_Error("BER: " + str) {}
 
 BER_Bad_Tag::BER_Bad_Tag(const std::string& str, ASN1_Tag tag) :
-      BER_Decoding_Error(str + ": " + to_string(tag)) {}
+      BER_Decoding_Error(str + ": " + std::to_string(tag)) {}
 
 BER_Bad_Tag::BER_Bad_Tag(const std::string& str,
                          ASN1_Tag tag1, ASN1_Tag tag2) :
-   BER_Decoding_Error(str + ": " + to_string(tag1) + "/" + to_string(tag2)) {}
+   BER_Decoding_Error(str + ": " + std::to_string(tag1) + "/" + std::to_string(tag2)) {}
 
 namespace ASN1 {
 
diff --git a/src/asn1/asn1_oid.cpp b/src/asn1/asn1_oid.cpp
index 531ceb9b2..c72ee7a1a 100644
--- a/src/asn1/asn1_oid.cpp
+++ b/src/asn1/asn1_oid.cpp
@@ -44,7 +44,7 @@ std::string OID::as_string() const
    std::string oid_str;
    for(u32bit j = 0; j != id.size(); ++j)
       {
-      oid_str += to_string(id[j]);
+      oid_str += std::to_string(id[j]);
       if(j != id.size() - 1)
          oid_str += '.';
       }
diff --git a/src/asn1/asn1_str.cpp b/src/asn1/asn1_str.cpp
index 25782e239..892a44472 100644
--- a/src/asn1/asn1_str.cpp
+++ b/src/asn1/asn1_str.cpp
@@ -89,7 +89,7 @@ ASN1_String::ASN1_String(const std::string& str, ASN1_Tag t) : tag(t)
       tag != UTF8_STRING &&
       tag != BMP_STRING)
       throw Invalid_Argument("ASN1_String: Unknown string type " +
-                             to_string(tag));
+                             std::to_string(tag));
    }
 
 /*
diff --git a/src/asn1/asn1_tm.cpp b/src/asn1/asn1_tm.cpp
index c57d1bc73..9df10f4a3 100644
--- a/src/asn1/asn1_tm.cpp
+++ b/src/asn1/asn1_tm.cpp
@@ -103,11 +103,13 @@ void X509_Time::set_to(const std::string& time_str)
 void X509_Time::set_to(const std::string& t_spec, ASN1_Tag tag)
    {
    if(tag != GENERALIZED_TIME && tag != UTC_TIME)
-      throw Invalid_Argument("X509_Time: Invalid tag " + to_string(tag));
+      throw Invalid_Argument("X509_Time: Invalid tag " + std::to_string(tag));
+
    if(tag == GENERALIZED_TIME && t_spec.size() != 13 && t_spec.size() != 15)
       throw Invalid_Argument("Invalid GeneralizedTime: " + t_spec);
    if(tag == UTC_TIME && t_spec.size() != 11 && t_spec.size() != 13)
       throw Invalid_Argument("Invalid UTCTime: " + t_spec);
+
    if(t_spec[t_spec.size()-1] != 'Z')
       throw Invalid_Argument("Invalid time encoding: " + t_spec);
 
@@ -179,21 +181,30 @@ std::string X509_Time::as_string() const
    if(time_is_set() == false)
       throw Invalid_State("X509_Time::as_string: No time set");
 
-   std::string asn1rep;
-   if(tag == GENERALIZED_TIME)
-      asn1rep = to_string(year, 4);
-   else
+   u32bit full_year = year;
+
+   if(tag == UTC_TIME)
       {
       if(year < 1950 || year >= 2050)
          throw Encoding_Error("X509_Time: The time " + readable_string() +
                               " cannot be encoded as a UTCTime");
-      u32bit asn1year = (year >= 2000) ? (year - 2000) : (year - 1900);
-      asn1rep = to_string(asn1year, 2);
+
+      full_year = (year >= 2000) ? (year - 2000) : (year - 1900);
       }
-   asn1rep += to_string(month, 2) + to_string(day, 2);
-   asn1rep += to_string(hour, 2) + to_string(minute, 2) + to_string(second, 2);
-   asn1rep += "Z";
-   return asn1rep;
+
+   std::string repr = std::to_string(full_year*10000000000 +
+                                     month*100000000 +
+                                     day*1000000 +
+                                     hour*10000 +
+                                     minute*100 +
+                                     second) + "Z";
+
+   u32bit desired_size = (tag == UTC_TIME) ? 13 : 15;
+
+   while(repr.size() < desired_size)
+      repr = "0" + repr;
+
+   return repr;
    }
 
 /*
@@ -212,14 +223,12 @@ std::string X509_Time::readable_string() const
    if(time_is_set() == false)
       throw Invalid_State("X509_Time::readable_string: No time set");
 
-   std::string readable;
-   readable += to_string(year,   4) + "/";
-   readable += to_string(month    ) + "/";
-   readable += to_string(day      ) + " ";
-   readable += to_string(hour     ) + ":";
-   readable += to_string(minute, 2) + ":";
-   readable += to_string(second, 2) + " UTC";
-   return readable;
+   std::string output(24, 0);
+
+   std::sprintf(&output[0], "%04d/%02d/%02d %02d:%02d:%02d UTC",
+                year, month, day, hour, minute, second);
+
+   return output;
    }
 
 /*
diff --git a/src/asn1/der_enc.cpp b/src/asn1/der_enc.cpp
index bee269431..1863e400d 100644
--- a/src/asn1/der_enc.cpp
+++ b/src/asn1/der_enc.cpp
@@ -24,7 +24,7 @@ SecureVector<byte> encode_tag(ASN1_Tag type_tag, ASN1_Tag class_tag)
    {
    if((class_tag | 0xE0) != 0xE0)
       throw Encoding_Error("DER_Encoder: Invalid class tag " +
-                           to_string(class_tag));
+                           std::to_string(class_tag));
 
    SecureVector<byte> encoded_tag;
    if(type_tag <= 30)
diff --git a/src/block/lion/lion.cpp b/src/block/lion/lion.cpp
index d8822b9f2..81252f5e3 100644
--- a/src/block/lion/lion.cpp
+++ b/src/block/lion/lion.cpp
@@ -81,7 +81,7 @@ std::string Lion::name() const
    {
    return "Lion(" + hash->name() + "," +
                     cipher->name() + "," +
-                    to_string(BLOCK_SIZE) + ")";
+                    std::to_string(BLOCK_SIZE) + ")";
    }
 
 /*
diff --git a/src/block/misty1/misty1.cpp b/src/block/misty1/misty1.cpp
index 8a92824cc..56cd7446c 100644
--- a/src/block/misty1/misty1.cpp
+++ b/src/block/misty1/misty1.cpp
@@ -255,7 +255,7 @@ MISTY1::MISTY1(u32bit rounds) : BlockCipher(8, 16)
    {
    if(rounds != 8)
       throw Invalid_Argument("MISTY1: Invalid number of rounds: "
-                             + to_string(rounds));
+                             + std::to_string(rounds));
    }
 
 }
diff --git a/src/block/rc5/rc5.cpp b/src/block/rc5/rc5.cpp
index 0bd596b10..1b71de85a 100644
--- a/src/block/rc5/rc5.cpp
+++ b/src/block/rc5/rc5.cpp
@@ -99,7 +99,7 @@ void RC5::key_schedule(const byte key[], u32bit length)
 */
 std::string RC5::name() const
    {
-   return "RC5(" + to_string(ROUNDS) + ")";
+   return "RC5(" + std::to_string(ROUNDS) + ")";
    }
 
 /*
diff --git a/src/block/safer/safer_sk.cpp b/src/block/safer/safer_sk.cpp
index eb5c22fc9..fcbe84c8b 100644
--- a/src/block/safer/safer_sk.cpp
+++ b/src/block/safer/safer_sk.cpp
@@ -112,7 +112,7 @@ void SAFER_SK::key_schedule(const byte key[], u32bit)
 */
 std::string SAFER_SK::name() const
    {
-   return "SAFER-SK(" + to_string(ROUNDS) + ")";
+   return "SAFER-SK(" + std::to_string(ROUNDS) + ")";
    }
 
 /*
diff --git a/src/cert/cvc/asn1_eac_tm.cpp b/src/cert/cvc/asn1_eac_tm.cpp
index f361e6098..b0238ac4d 100644
--- a/src/cert/cvc/asn1_eac_tm.cpp
+++ b/src/cert/cvc/asn1_eac_tm.cpp
@@ -1,7 +1,7 @@
 /*
 * EAC Time Types
 * (C) 2007 FlexSecure GmbH
-*     2008 Jack Lloyd
+*     2008-2009 Jack Lloyd
 *
 * Distributed under the terms of the Botan license
 */
@@ -22,7 +22,7 @@ SecureVector<byte> enc_two_digit(u32bit in)
    {
    SecureVector<byte> result;
    in %= 100;
-   if (in < 10)
+   if(in < 10)
       result.append(0x00);
    else
       {
@@ -84,7 +84,7 @@ EAC_Time::EAC_Time(u32bit y, u32bit m, u32bit d, ASN1_Tag t)
 */
 void EAC_Time::set_to(const std::string& time_str)
    {
-   if (time_str == "")
+   if(time_str == "")
       {
       year = month = day = 0;
       return;
@@ -93,28 +93,28 @@ void EAC_Time::set_to(const std::string& time_str)
    std::vector<std::string> params;
    std::string current;
 
-   for (u32bit j = 0; j != time_str.size(); ++j)
+   for(u32bit j = 0; j != time_str.size(); ++j)
       {
-      if (Charset::is_digit(time_str[j]))
+      if(Charset::is_digit(time_str[j]))
          current += time_str[j];
       else
          {
-         if (current != "")
+         if(current != "")
             params.push_back(current);
          current.clear();
          }
       }
-   if (current != "")
+   if(current != "")
       params.push_back(current);
 
-   if (params.size() != 3)
+   if(params.size() != 3)
       throw Invalid_Argument("Invalid time specification " + time_str);
 
    year   = to_u32bit(params[0]);
    month  = to_u32bit(params[1]);
    day    = to_u32bit(params[2]);
 
-   if (!passes_sanity_check())
+   if(!passes_sanity_check())
       throw Invalid_Argument("Invalid time specification " + time_str);
    }
 
@@ -133,15 +133,10 @@ void EAC_Time::encode_into(DER_Encoder& der) const
 */
 std::string EAC_Time::as_string() const
    {
-   if (time_is_set() == false)
+   if(time_is_set() == false)
       throw Invalid_State("EAC_Time::as_string: No time set");
 
-   std::string asn1rep;
-   asn1rep = to_string(year, 2);
-
-   asn1rep += to_string(month, 2) + to_string(day, 2);
-
-   return asn1rep;
+   return std::to_string(year * 10000 + month * 100 + day);
    }
 
 /*
@@ -157,15 +152,14 @@ bool EAC_Time::time_is_set() const
 */
 std::string EAC_Time::readable_string() const
    {
-   if (time_is_set() == false)
+   if(time_is_set() == false)
       throw Invalid_State("EAC_Time::readable_string: No time set");
 
-   std::string readable;
-   readable += to_string(year,     2) + "/";
-   readable += to_string(month,    2) + "/";
-   readable += to_string(day,      2) + " ";
+   std::string output(11, 0);
+
+   std::sprintf(&output[0], "%04d/%02d/%02d", year, month, day);
 
-   return readable;
+   return output;
    }
 
 /*
@@ -173,11 +167,11 @@ std::string EAC_Time::readable_string() const
 */
 bool EAC_Time::passes_sanity_check() const
    {
-   if (year < 2000 || year > 2099)
+   if(year < 2000 || year > 2099)
       return false;
-   if (month == 0 || month > 12)
+   if(month == 0 || month > 12)
       return false;
-   if (day == 0 || day > 31)
+   if(day == 0 || day > 31)
       return false;
 
    return true;
@@ -186,11 +180,11 @@ bool EAC_Time::passes_sanity_check() const
 /******************************************
 * modification functions
 ******************************************/
-
 void EAC_Time::add_years(u32bit years)
    {
    year += years;
    }
+
 void EAC_Time::add_months(u32bit months)
    {
    year += months/12;
@@ -202,23 +196,22 @@ void EAC_Time::add_months(u32bit months)
       }
    }
 
-
 /*
 * Compare this time against another
 */
 s32bit EAC_Time::cmp(const EAC_Time& other) const
    {
-   if (time_is_set() == false)
+   if(time_is_set() == false)
       throw Invalid_State("EAC_Time::cmp: No time set");
 
    const s32bit EARLIER = -1, LATER = 1, SAME_TIME = 0;
 
-   if (year < other.year)     return EARLIER;
-   if (year > other.year)     return LATER;
-   if (month < other.month)   return EARLIER;
-   if (month > other.month)   return LATER;
-   if (day < other.day)       return EARLIER;
-   if (day > other.day)       return LATER;
+   if(year < other.year)     return EARLIER;
+   if(year > other.year)     return LATER;
+   if(month < other.month)   return EARLIER;
+   if(month > other.month)   return LATER;
+   if(day < other.day)       return EARLIER;
+   if(day > other.day)       return LATER;
 
    return SAME_TIME;
    }
@@ -230,22 +223,27 @@ bool operator==(const EAC_Time& t1, const EAC_Time& t2)
    {
    return (t1.cmp(t2) == 0);
    }
+
 bool operator!=(const EAC_Time& t1, const EAC_Time& t2)
    {
    return (t1.cmp(t2) != 0);
    }
+
 bool operator<=(const EAC_Time& t1, const EAC_Time& t2)
    {
    return (t1.cmp(t2) <= 0);
    }
+
 bool operator>=(const EAC_Time& t1, const EAC_Time& t2)
    {
    return (t1.cmp(t2) >= 0);
    }
+
 bool operator>(const EAC_Time& t1, const EAC_Time& t2)
    {
    return (t1.cmp(t2) > 0);
    }
+
 bool operator<(const EAC_Time& t1, const EAC_Time& t2)
    {
    return (t1.cmp(t2) < 0);
diff --git a/src/cert/x509/pkcs10.cpp b/src/cert/x509/pkcs10.cpp
index 5617cece4..5645552a0 100644
--- a/src/cert/x509/pkcs10.cpp
+++ b/src/cert/x509/pkcs10.cpp
@@ -45,7 +45,7 @@ void PKCS10_Request::force_decode()
    cert_req_info.decode(version);
    if(version != 0)
       throw Decoding_Error("Unknown version code in PKCS #10 request: " +
-                           to_string(version));
+                           std::to_string(version));
 
    X509_DN dn_subject;
    cert_req_info.decode(dn_subject);
diff --git a/src/cert/x509/x509_crl.cpp b/src/cert/x509/x509_crl.cpp
index f6a344dba..3613c1a91 100644
--- a/src/cert/x509/x509_crl.cpp
+++ b/src/cert/x509/x509_crl.cpp
@@ -44,7 +44,7 @@ void X509_CRL::force_decode()
 
    if(version != 0 && version != 1)
       throw X509_CRL_Error("Unknown X.509 CRL version " +
-                           to_string(version+1));
+                           std::to_string(version+1));
 
    AlgorithmIdentifier sig_algo_inner;
    tbs_crl.decode(sig_algo_inner);
diff --git a/src/cert/x509/x509cert.cpp b/src/cert/x509/x509cert.cpp
index 6a062b7ce..32c508a0c 100644
--- a/src/cert/x509/x509cert.cpp
+++ b/src/cert/x509/x509cert.cpp
@@ -80,7 +80,7 @@ void X509_Certificate::force_decode()
       .decode(dn_subject);
 
    if(version > 2)
-      throw Decoding_Error("Unknown X.509 cert version " + to_string(version));
+      throw Decoding_Error("Unknown X.509 cert version " + std::to_string(version));
    if(sig_algo != sig_algo_inner)
       throw Decoding_Error("Algorithm identifier mismatch");
 
diff --git a/src/engine/openssl/arc4_openssl.cpp b/src/engine/openssl/arc4_openssl.cpp
index 793e1faff..15bb8f98e 100644
--- a/src/engine/openssl/arc4_openssl.cpp
+++ b/src/engine/openssl/arc4_openssl.cpp
@@ -40,7 +40,7 @@ std::string ARC4_OpenSSL::name() const
    {
    if(SKIP == 0)   return "ARC4";
    if(SKIP == 256) return "MARK-4";
-   else            return "RC4_skip(" + to_string(SKIP) + ")";
+   else            return "RC4_skip(" + std::to_string(SKIP) + ")";
    }
 
 /*
diff --git a/src/filters/hex/hex.cpp b/src/filters/hex/hex.cpp
index 651899b73..56576a8a0 100644
--- a/src/filters/hex/hex.cpp
+++ b/src/filters/hex/hex.cpp
@@ -141,7 +141,7 @@ void Hex_Decoder::handle_bad_char(byte c)
       return;
 
    throw Decoding_Error("Hex_Decoder: Invalid hex character: " +
-                        to_string(c));
+                        std::to_string(c));
    }
 
 /*
diff --git a/src/filters/modes/cfb/cfb.cpp b/src/filters/modes/cfb/cfb.cpp
index a126bd995..672dbe7f5 100644
--- a/src/filters/modes/cfb/cfb.cpp
+++ b/src/filters/modes/cfb/cfb.cpp
@@ -22,7 +22,7 @@ void check_feedback(u32bit BLOCK_SIZE, u32bit FEEDBACK_SIZE, u32bit bits,
    {
    if(FEEDBACK_SIZE == 0 || FEEDBACK_SIZE > BLOCK_SIZE || bits % 8 != 0)
       throw Invalid_Argument(name + ": Invalid feedback size " +
-                             to_string(bits));
+                             std::to_string(bits));
    }
 
 }
diff --git a/src/filters/modes/eax/eax.cpp b/src/filters/modes/eax/eax.cpp
index e2ef178b6..4b712fa90 100644
--- a/src/filters/modes/eax/eax.cpp
+++ b/src/filters/modes/eax/eax.cpp
@@ -43,7 +43,7 @@ EAX_Base::EAX_Base(BlockCipher* ciph,
    mac = new CMAC(cipher->clone());
 
    if(tag_size % 8 != 0 || TAG_SIZE == 0 || TAG_SIZE > mac->OUTPUT_LENGTH)
-      throw Invalid_Argument(name() + ": Bad tag size " + to_string(tag_size));
+      throw Invalid_Argument(name() + ": Bad tag size " + std::to_string(tag_size));
 
    state.resize(BLOCK_SIZE);
    buffer.resize(BLOCK_SIZE);
diff --git a/src/filters/pipe.cpp b/src/filters/pipe.cpp
index d43868e3f..ae0f6996d 100644
--- a/src/filters/pipe.cpp
+++ b/src/filters/pipe.cpp
@@ -19,7 +19,7 @@ Pipe::Invalid_Message_Number::Invalid_Message_Number(const std::string& where,
                                                      message_id msg)
    {
    set_msg("Pipe::" + where + ": Invalid message number " +
-           to_string(msg));
+           std::to_string(msg));
    }
 
 namespace {
diff --git a/src/hash/skein/skein_512.cpp b/src/hash/skein/skein_512.cpp
index e1ca08c15..5ae09f621 100644
--- a/src/hash/skein/skein_512.cpp
+++ b/src/hash/skein/skein_512.cpp
@@ -175,7 +175,7 @@ Skein_512::Skein_512(u32bit arg_output_bits,
 
 std::string Skein_512::name() const
    {
-   return "Skein-512(" + to_string(output_bits) + ")";
+   return "Skein-512(" + std::to_string(output_bits) + ")";
    }
 
 HashFunction* Skein_512::clone() const
diff --git a/src/hash/tiger/tiger.cpp b/src/hash/tiger/tiger.cpp
index 4f4d4dc83..2d56aa1b3 100644
--- a/src/hash/tiger/tiger.cpp
+++ b/src/hash/tiger/tiger.cpp
@@ -143,7 +143,7 @@ void Tiger::clear()
 */
 std::string Tiger::name() const
    {
-   return "Tiger(" + to_string(OUTPUT_LENGTH) + "," + to_string(PASS) + ")";
+   return "Tiger(" + std::to_string(OUTPUT_LENGTH) + "," + std::to_string(PASS) + ")";
    }
 
 /*
@@ -154,10 +154,10 @@ Tiger::Tiger(u32bit hashlen, u32bit pass) :
    {
    if(OUTPUT_LENGTH != 16 && OUTPUT_LENGTH != 20 && OUTPUT_LENGTH != 24)
       throw Invalid_Argument("Tiger: Illegal hash output size: " +
-                             to_string(OUTPUT_LENGTH));
+                             std::to_string(OUTPUT_LENGTH));
    if(PASS < 3)
       throw Invalid_Argument("Tiger: Invalid number of passes: "
-                             + to_string(PASS));
+                             + std::to_string(PASS));
    clear();
    }
 
diff --git a/src/math/numbertheory/dsa_gen.cpp b/src/math/numbertheory/dsa_gen.cpp
index d5f6dc792..39a7cf5fa 100644
--- a/src/math/numbertheory/dsa_gen.cpp
+++ b/src/math/numbertheory/dsa_gen.cpp
@@ -47,15 +47,15 @@ bool generate_dsa_primes(RandomNumberGenerator& rng,
    if(!fips186_3_valid_size(pbits, qbits))
       throw Invalid_Argument(
          "FIPS 186-3 does not allow DSA domain parameters of " +
-         to_string(pbits) + "/" + to_string(qbits) + " bits long");
+         std::to_string(pbits) + "/" + std::to_string(qbits) + " bits long");
 
    if(seed_c.size() * 8 < qbits)
       throw Invalid_Argument(
-         "Generating a DSA parameter set with a " + to_string(qbits) +
+         "Generating a DSA parameter set with a " + std::to_string(qbits) +
          "long q requires a seed at least as many bits long");
 
    std::unique_ptr<HashFunction> hash(
-      af.make_hash_function("SHA-" + to_string(qbits)));
+      af.make_hash_function("SHA-" + std::to_string(qbits)));
 
    const u32bit HASH_SIZE = hash->OUTPUT_LENGTH;
 
diff --git a/src/math/numbertheory/make_prm.cpp b/src/math/numbertheory/make_prm.cpp
index b136b6d25..3eb01cd42 100644
--- a/src/math/numbertheory/make_prm.cpp
+++ b/src/math/numbertheory/make_prm.cpp
@@ -20,7 +20,7 @@ BigInt random_prime(RandomNumberGenerator& rng,
    {
    if(bits <= 1)
       throw Invalid_Argument("random_prime: Can't make a prime of " +
-                             to_string(bits) + " bits");
+                             std::to_string(bits) + " bits");
    else if(bits == 2)
       return ((rng.next_byte() % 2) ? 2 : 3);
    else if(bits == 3)
@@ -85,7 +85,7 @@ BigInt random_safe_prime(RandomNumberGenerator& rng, u32bit bits)
    {
    if(bits <= 64)
       throw Invalid_Argument("random_safe_prime: Can't make a prime of " +
-                             to_string(bits) + " bits");
+                             std::to_string(bits) + " bits");
 
    BigInt p;
    do
diff --git a/src/pubkey/dl_group/dl_group.cpp b/src/pubkey/dl_group/dl_group.cpp
index 13ea03016..1c18179e2 100644
--- a/src/pubkey/dl_group/dl_group.cpp
+++ b/src/pubkey/dl_group/dl_group.cpp
@@ -46,7 +46,7 @@ DL_Group::DL_Group(RandomNumberGenerator& rng,
                    PrimeType type, u32bit pbits, u32bit qbits)
    {
    if(pbits < 512)
-      throw Invalid_Argument("DL_Group: prime size " + to_string(pbits) +
+      throw Invalid_Argument("DL_Group: prime size " + std::to_string(pbits) +
                              " is too small");
 
    if(type == Strong)
@@ -237,7 +237,7 @@ SecureVector<byte> DL_Group::DER_encode(Format format) const
       .get_contents();
       }
 
-   throw Invalid_Argument("Unknown DL_Group encoding " + to_string(format));
+   throw Invalid_Argument("Unknown DL_Group encoding " + std::to_string(format));
    }
 
 /*
@@ -253,7 +253,7 @@ std::string DL_Group::PEM_encode(Format format) const
    else if(format == ANSI_X9_42)
       return PEM_Code::encode(encoding, "X942 DH PARAMETERS");
    else
-      throw Invalid_Argument("Unknown DL_Group encoding " + to_string(format));
+      throw Invalid_Argument("Unknown DL_Group encoding " + std::to_string(format));
    }
 
 /*
@@ -287,7 +287,7 @@ void DL_Group::BER_decode(DataSource& source, Format format)
          .discard_remaining();
       }
    else
-      throw Invalid_Argument("Unknown DL_Group encoding " + to_string(format));
+      throw Invalid_Argument("Unknown DL_Group encoding " + std::to_string(format));
 
    initialize(new_p, new_q, new_g);
    }
diff --git a/src/pubkey/pubkey.cpp b/src/pubkey/pubkey.cpp
index 4ddaa6fb6..5a5ca335e 100644
--- a/src/pubkey/pubkey.cpp
+++ b/src/pubkey/pubkey.cpp
@@ -216,7 +216,7 @@ SecureVector<byte> PK_Signer::signature(RandomNumberGenerator& rng)
       }
    else
       throw Encoding_Error("PK_Signer: Unknown signature format " +
-                           to_string(sig_format));
+                           std::to_string(sig_format));
    }
 
 /*
@@ -328,7 +328,7 @@ bool PK_Verifier::check_signature(const byte sig[], u32bit length)
          }
       else
          throw Decoding_Error("PK_Verifier: Unknown signature format " +
-                              to_string(sig_format));
+                              std::to_string(sig_format));
       }
    catch(Invalid_Argument) { return false; }
    catch(Decoding_Error) { return false; }
diff --git a/src/pubkey/rsa/rsa.cpp b/src/pubkey/rsa/rsa.cpp
index 83e6e1b17..38ea1eeca 100644
--- a/src/pubkey/rsa/rsa.cpp
+++ b/src/pubkey/rsa/rsa.cpp
@@ -60,7 +60,7 @@ RSA_PrivateKey::RSA_PrivateKey(RandomNumberGenerator& rng,
    {
    if(bits < 512)
       throw Invalid_Argument(algo_name() + ": Can't make a key that is only " +
-                             to_string(bits) + " bits long");
+                             std::to_string(bits) + " bits long");
    if(exp < 3 || exp % 2 == 0)
       throw Invalid_Argument(algo_name() + ": Invalid encryption exponent");
 
diff --git a/src/pubkey/rw/rw.cpp b/src/pubkey/rw/rw.cpp
index def0ae689..460c740ab 100644
--- a/src/pubkey/rw/rw.cpp
+++ b/src/pubkey/rw/rw.cpp
@@ -60,7 +60,7 @@ RW_PrivateKey::RW_PrivateKey(RandomNumberGenerator& rng,
    {
    if(bits < 512)
       throw Invalid_Argument(algo_name() + ": Can't make a key that is only " +
-                             to_string(bits) + " bits long");
+                             std::to_string(bits) + " bits long");
    if(exp < 2 || exp % 2 == 1)
       throw Invalid_Argument(algo_name() + ": Invalid encryption exponent");
 
diff --git a/src/stream/arc4/arc4.cpp b/src/stream/arc4/arc4.cpp
index 293a0a336..5d0c67d3e 100644
--- a/src/stream/arc4/arc4.cpp
+++ b/src/stream/arc4/arc4.cpp
@@ -81,7 +81,7 @@ std::string ARC4::name() const
    {
    if(SKIP == 0)   return "ARC4";
    if(SKIP == 256) return "MARK-4";
-   else            return "RC4_skip(" + to_string(SKIP) + ")";
+   else            return "RC4_skip(" + std::to_string(SKIP) + ")";
    }
 
 /*
diff --git a/src/utils/charset.cpp b/src/utils/charset.cpp
index 53125cad1..e98cf601e 100644
--- a/src/utils/charset.cpp
+++ b/src/utils/charset.cpp
@@ -119,7 +119,7 @@ std::string transcode(const std::string& str,
       return ucs2_to_latin1(str);
 
    throw Invalid_Argument("Unknown transcoding operation from " +
-                          to_string(from) + " to " + to_string(to));
+                          std::to_string(from) + " to " + std::to_string(to));
    }
 
 /*
diff --git a/src/utils/datastor/datastor.cpp b/src/utils/datastor/datastor.cpp
index 5e7c94634..634b72872 100644
--- a/src/utils/datastor/datastor.cpp
+++ b/src/utils/datastor/datastor.cpp
@@ -124,7 +124,7 @@ void Data_Store::add(const std::string& key, const std::string& val)
 */
 void Data_Store::add(const std::string& key, u32bit val)
    {
-   add(key, to_string(val));
+   add(key, std::to_string(val));
    }
 
 /*
diff --git a/src/utils/exceptn.cpp b/src/utils/exceptn.cpp
index 753d63424..2fa05f59d 100644
--- a/src/utils/exceptn.cpp
+++ b/src/utils/exceptn.cpp
@@ -15,7 +15,7 @@ namespace Botan {
 */
 Invalid_Key_Length::Invalid_Key_Length(const std::string& name, u32bit length)
    {
-   set_msg(name + " cannot accept a key of length " + to_string(length));
+   set_msg(name + " cannot accept a key of length " + std::to_string(length));
    }
 
 /*
@@ -32,7 +32,7 @@ Invalid_Block_Size::Invalid_Block_Size(const std::string& mode,
 */
 Invalid_IV_Length::Invalid_IV_Length(const std::string& mode, u32bit bad_len)
    {
-   set_msg("IV length " + to_string(bad_len) + " is invalid for " + mode);
+   set_msg("IV length " + std::to_string(bad_len) + " is invalid for " + mode);
    }
 
 /*
@@ -56,7 +56,7 @@ Invalid_Algorithm_Name::Invalid_Algorithm_Name(const std::string& name)
 */
 Config_Error::Config_Error(const std::string& err, u32bit line)
    {
-   set_msg("Config error at line " + to_string(line) + ": " + err);
+   set_msg("Config error at line " + std::to_string(line) + ": " + err);
    }
 
 }
diff --git a/src/utils/parsing.cpp b/src/utils/parsing.cpp
index 63dfce64f..3412cf02b 100644
--- a/src/utils/parsing.cpp
+++ b/src/utils/parsing.cpp
@@ -13,53 +13,6 @@
 namespace Botan {
 
 /*
-* Convert a string into an integer
-*/
-u32bit to_u32bit(const std::string& number)
-   {
-   u32bit n = 0;
-
-   for(auto i = number.begin(); i != number.end(); ++i)
-      {
-      const u32bit OVERFLOW_MARK = 0xFFFFFFFF / 10;
-
-      if(*i == ' ')
-         continue;
-
-      byte digit = Charset::char2digit(*i);
-
-      if((n > OVERFLOW_MARK) || (n == OVERFLOW_MARK && digit > 5))
-         throw Decoding_Error("to_u32bit: Integer overflow");
-      n *= 10;
-      n += digit;
-      }
-   return n;
-   }
-
-/*
-* Convert an integer into a string
-*/
-std::string to_string(u64bit n, u32bit min_len)
-   {
-   std::string lenstr;
-   if(n)
-      {
-      while(n > 0)
-         {
-         lenstr = Charset::digit2char(n % 10) + lenstr;
-         n /= 10;
-         }
-      }
-   else
-      lenstr = "0";
-
-   while(lenstr.size() < min_len)
-      lenstr = "0" + lenstr;
-
-   return lenstr;
-   }
-
-/*
 * Convert a string into a time duration
 */
 u32bit timespec_to_u32bit(const std::string& timespec)
@@ -282,7 +235,7 @@ std::string ipv4_to_string(u32bit ip)
       {
       if(i)
          str += ".";
-      str += to_string(get_byte(i, ip));
+      str += std::to_string(get_byte(i, ip));
       }
 
    return str;
diff --git a/src/utils/parsing.h b/src/utils/parsing.h
index 2c29d5b4d..cb8d61cee 100644
--- a/src/utils/parsing.h
+++ b/src/utils/parsing.h
@@ -23,10 +23,10 @@ BOTAN_DLL std::vector<u32bit> parse_asn1_oid(const std::string&);
 BOTAN_DLL bool x500_name_cmp(const std::string&, const std::string&);
 
 /*
-* String/Integer Conversions
+* Convert a string into an integer
 */
-BOTAN_DLL std::string to_string(u64bit, u32bit = 0);
-BOTAN_DLL u32bit to_u32bit(const std::string&);
+inline u32bit to_u32bit(const std::string& number)
+   { return stoul(number); }
 
 BOTAN_DLL u32bit timespec_to_u32bit(const std::string& timespec);
 
diff --git a/src/utils/version.cpp b/src/utils/version.cpp
index d540864b2..ef591b4d7 100644
--- a/src/utils/version.cpp
+++ b/src/utils/version.cpp
@@ -21,9 +21,9 @@ namespace Botan {
 */
 std::string version_string()
    {
-   return to_string(version_major()) + "." +
-          to_string(version_minor()) + "." +
-          to_string(version_patch());
+   return std::to_string(version_major()) + "." +
+          std::to_string(version_minor()) + "." +
+          std::to_string(version_patch());
    }
 
 /*