Add a standalone version of hex encoding and decoding, defining the filters

in terms of these calls.

The header for the hex filter is renamed hex_filt.h. This probably
won't affect people because filters.h (included by botan.h) already
included hex.h, and now just includes hex_filt.h instead.

8 files changed, 334 insertions, 137 deletions

diff --git a/src/codec/hex/hex.cpp b/src/codec/hex/hex.cpp
new file mode 100644
index 000000000..70e819906
--- /dev/null
+++ b/src/codec/hex/hex.cpp
@@ -0,0 +1,180 @@
+/*
+* Hex Encoding and Decoding
+* (C) 2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/hex.h>
+#include <botan/mem_ops.h>
+#include <stdexcept>
+
+namespace Botan {
+
+void hex_encode(char output[],
+                const byte input[],
+                u32bit input_length,
+                bool uppercase)
+   {
+   static const byte BIN_TO_HEX_UPPER[16] = {
+      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+      'A', 'B', 'C', 'D', 'E', 'F' };
+
+   static const byte BIN_TO_HEX_LOWER[16] = {
+      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+      'a', 'b', 'c', 'd', 'e', 'f' };
+
+   const byte* tbl = uppercase ? BIN_TO_HEX_UPPER : BIN_TO_HEX_LOWER;
+
+   for(u32bit i = 0; i != input_length; ++i)
+      {
+      byte x = input[i];
+      output[2*i  ] = tbl[(x >> 4) & 0x0F];
+      output[2*i+1] = tbl[(x     ) & 0x0F];
+      }
+   }
+
+std::string hex_encode(const byte input[],
+                       u32bit input_length,
+                       bool uppercase)
+   {
+   std::string output(2 * input_length, 0);
+   hex_encode(&output[0], input, input_length, uppercase);
+   return output;
+   }
+
+u32bit hex_decode(byte output[],
+                  const char input[],
+                  u32bit input_length,
+                  u32bit& input_consumed,
+                  bool ignore_ws)
+   {
+   /*
+   * Mapping of hex characters to either their binary equivalent
+   * or to an error code.
+   *  If valid hex (0-9 A-F a-f), the value.
+   *  If whitespace, then 0x80
+   *  Otherwise 0xFF
+   * Warning: this table assumes ASCII character encodings
+   */
+
+   static const byte HEX_TO_BIN[256] = {
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x80,
+      0x80, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0x80, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x01,
+      0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
+      0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x0A, 0x0B, 0x0C,
+      0x0D, 0x0E, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
+
+   byte* out_ptr = output;
+   bool top_nibble = true;
+
+   clear_mem(output, input_length / 2);
+
+   for(u32bit i = 0; i != input_length; ++i)
+      {
+      const byte bin = HEX_TO_BIN[(byte)input[i]];
+
+      if(bin >= 0x10)
+         {
+         if(bin == 0x80 && ignore_ws)
+            continue;
+
+         std::string bad_char(1, input[i]);
+         if(bad_char == "\t")
+           bad_char = "\\t";
+         else if(bad_char == "\n")
+           bad_char = "\\n";
+
+         throw std::invalid_argument(
+           std::string("hex_decode: invalid hex character '") +
+           bad_char + "'");
+         }
+
+      *out_ptr |= bin << (top_nibble*4);
+
+      top_nibble = !top_nibble;
+      if(top_nibble)
+         ++out_ptr;
+      }
+
+   input_consumed = input_length;
+   u32bit written = (out_ptr - output);
+
+   /*
+   * We only got half of a byte at the end; zap the half-written
+   * output and mark it as unread
+   */
+   if(!top_nibble)
+      {
+      *out_ptr = 0;
+      input_consumed -= 1;
+      }
+
+   return written;
+   }
+
+u32bit hex_decode(byte output[],
+                  const char input[],
+                  u32bit input_length,
+                  bool ignore_ws)
+   {
+   u32bit consumed = 0;
+   u32bit written = hex_decode(output, input, input_length,
+                               consumed, ignore_ws);
+
+   if(consumed != input_length)
+      throw std::invalid_argument("hex_decode: input did not have full bytes");
+
+   return written;
+   }
+
+u32bit hex_decode(byte output[],
+                  const std::string& input,
+                  bool ignore_ws)
+   {
+   return hex_decode(output, &input[0], input.length(), ignore_ws);
+   }
+
+SecureVector<byte> hex_decode(const char input[],
+                              u32bit input_length,
+                              bool ignore_ws)
+   {
+   SecureVector<byte> bin(input_length / 2);
+
+   u32bit written = hex_decode(&bin[0],
+                               input,
+                               input_length,
+                               ignore_ws);
+
+   bin.truncate(written);
+   return bin;
+   }
+
+SecureVector<byte> hex_decode(const std::string& input,
+                              bool ignore_ws)
+   {
+   return hex_decode(&input[0], input.size(), ignore_ws);
+   }
+
+}
diff --git a/src/codec/hex/hex.h b/src/codec/hex/hex.h
new file mode 100644
index 000000000..91a743b45
--- /dev/null
+++ b/src/codec/hex/hex.h
@@ -0,0 +1,108 @@
+/*
+* Hex Encoding and Decoding
+* (C) 2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_HEX_CODEC_H__
+#define BOTAN_HEX_CODEC_H__
+
+#include <botan/secmem.h>
+#include <string>
+
+namespace Botan {
+
+/**
+* Perform hex encoding
+* @param output an array of at least input_length*2 bytes
+* @param input is some binary data
+* @param input_length length of input in bytes
+* @param uppercase should output be upper or lower case?
+*/
+void BOTAN_DLL hex_encode(char output[],
+                          const byte input[],
+                          u32bit input_length,
+                          bool uppercase = true);
+
+/**
+* Perform hex encoding
+* @param input some input
+* @param input_length length of input in bytes
+* @param uppercase should output be upper or lower case?
+* @return hexadecimal representation of input
+*/
+std::string BOTAN_DLL hex_encode(const byte input[],
+                                 u32bit input_length,
+                                 bool uppercase = true);
+
+/**
+* Perform hex decoding
+* @param output an array of at least input_length/2 bytes
+* @param input some hex input
+* @param input_length length of input in bytes
+* @param input_consumed is an output parameter which says how many
+*        bytes of input were actually consumed. If less than
+*        input_length, then the range input[consumed:length]
+*        should be passed in later along with more input.
+* @param ignore_ws ignore whitespace on input; if false, throw an
+                   exception if whitespace is encountered
+* @return number of bytes written to output
+*/
+u32bit BOTAN_DLL hex_decode(byte output[],
+                            const char input[],
+                            u32bit input_length,
+                            u32bit& input_consumed,
+                            bool ignore_ws = true);
+
+/**
+* Perform hex decoding
+* @param output an array of at least input_length/2 bytes
+* @param input some hex input
+* @param input_length length of input in bytes
+* @param ignore_ws ignore whitespace on input; if false, throw an
+                   exception if whitespace is encountered
+* @return number of bytes written to output
+*/
+u32bit BOTAN_DLL hex_decode(byte output[],
+                            const char input[],
+                            u32bit input_length,
+                            bool ignore_ws = true);
+
+/**
+* Perform hex decoding
+* @param output an array of at least input_length/2 bytes
+* @param input some hex input
+* @param ignore_ws ignore whitespace on input; if false, throw an
+                   exception if whitespace is encountered
+* @return number of bytes written to output
+*/
+u32bit BOTAN_DLL hex_decode(byte output[],
+                            const std::string& input,
+                            bool ignore_ws = true);
+
+/**
+* Perform hex decoding
+* @param input some hex input
+* @param input_length the length of input in bytes
+* @param ignore_ws ignore whitespace on input; if false, throw an
+                   exception if whitespace is encountered
+* @return decoded hex output
+*/
+SecureVector<byte> BOTAN_DLL hex_decode(const char input[],
+                                        u32bit input_length,
+                                        bool ignore_ws = true);
+
+/**
+* Perform hex decoding
+* @param input some hex input
+* @param ignore_ws ignore whitespace on input; if false, throw an
+                   exception if whitespace is encountered
+* @return decoded hex output
+*/
+SecureVector<byte> BOTAN_DLL hex_decode(const std::string& input,
+                                        bool ignore_ws = true);
+
+}
+
+#endif
diff --git a/src/codec/hex/info.txt b/src/codec/hex/info.txt
new file mode 100644
index 000000000..c9eb8fb73
--- /dev/null
+++ b/src/codec/hex/info.txt
@@ -0,0 +1 @@
+define HEX_CODEC
diff --git a/src/filters/filters.h b/src/filters/filters.h
index e2c7cb5ec..51b4f00fe 100644
--- a/src/filters/filters.h
+++ b/src/filters/filters.h
@@ -24,8 +24,8 @@
   #include <botan/base64.h>
 #endif
 
-#if defined(BOTAN_HAS_HEX_CODEC)
-  #include <botan/hex.h>
+#if defined(BOTAN_HAS_HEX_FILTER)
+  #include <botan/hex_filt.h>
 #endif
 
 namespace Botan {
diff --git a/src/filters/hex/hex_char.cpp b/src/filters/hex/hex_char.cpp
deleted file mode 100644
index c28efc5f7..000000000
--- a/src/filters/hex/hex_char.cpp
+++ /dev/null
@@ -1,48 +0,0 @@
-/*
-* Hex Character Table
-* (C) 1999-2008 Jack Lloyd
-*
-* Distributed under the terms of the Botan license
-*/
-
-#include <botan/hex.h>
-
-namespace Botan {
-
-/*
-* Hex Encoder Lookup Tables
-*/
-const byte Hex_Encoder::BIN_TO_HEX_UPPER[16] = {
-0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x41, 0x42, 0x43,
-0x44, 0x45, 0x46 };
-
-const byte Hex_Encoder::BIN_TO_HEX_LOWER[16] = {
-0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x61, 0x62, 0x63,
-0x64, 0x65, 0x66 };
-
-/*
-* Hex Decoder Lookup Table
-*/
-const byte Hex_Decoder::HEX_TO_BIN[256] = {
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x00, 0x01, 0x02, 0x03,
-0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80 };
-
-}
diff --git a/src/filters/hex/hex.cpp b/src/filters/hex_filt/hex_filt.cpp
index 7191e1554..0f3daa464 100644
--- a/src/filters/hex/hex.cpp
+++ b/src/filters/hex_filt/hex_filt.cpp
@@ -5,6 +5,7 @@
 * Distributed under the terms of the Botan license
 */
 
+#include <botan/hex_filt.h>
 #include <botan/hex.h>
 #include <botan/parsing.h>
 #include <botan/charset.h>
@@ -40,24 +41,13 @@ Hex_Encoder::Hex_Encoder(Case c) : casing(c), line_length(0)
    }
 
 /*
-* Hex Encoding Operation
-*/
-void Hex_Encoder::encode(byte in, byte out[2], Hex_Encoder::Case casing)
-   {
-   const byte* BIN_TO_HEX = ((casing == Uppercase) ? BIN_TO_HEX_UPPER :
-                                                     BIN_TO_HEX_LOWER);
-
-   out[0] = BIN_TO_HEX[((in >> 4) & 0x0F)];
-   out[1] = BIN_TO_HEX[((in     ) & 0x0F)];
-   }
-
-/*
 * Encode and send a block
 */
 void Hex_Encoder::encode_and_send(const byte block[], u32bit length)
    {
-   for(u32bit j = 0; j != length; ++j)
-      encode(block[j], out + 2*j, casing);
+   hex_encode(reinterpret_cast<char*>(&out[0]),
+              block, length,
+              casing == Uppercase);
 
    if(line_length == 0)
       send(out, 2*length);
@@ -125,62 +115,35 @@ Hex_Decoder::Hex_Decoder(Decoder_Checking c) : checking(c)
    }
 
 /*
-* Check if a character is a valid hex char
-*/
-bool Hex_Decoder::is_valid(byte in)
-   {
-   return (HEX_TO_BIN[in] != 0x80);
-   }
-
-/*
-* Handle processing an invalid character
-*/
-void Hex_Decoder::handle_bad_char(byte c)
-   {
-   if(checking == NONE)
-      return;
-
-   if((checking == IGNORE_WS) && Charset::is_space(c))
-      return;
-
-   throw Decoding_Error("Hex_Decoder: Invalid hex character: " +
-                        to_string(c));
-   }
-
-/*
-* Hex Decoding Operation
-*/
-byte Hex_Decoder::decode(const byte hex[2])
-   {
-   return ((HEX_TO_BIN[hex[0]] << 4) | HEX_TO_BIN[hex[1]]);
-   }
-
-/*
-* Decode and send a block
-*/
-void Hex_Decoder::decode_and_send(const byte block[], u32bit length)
-   {
-   for(u32bit j = 0; j != length / 2; ++j)
-      out[j] = decode(block + 2*j);
-   send(out, length / 2);
-   }
-
-/*
 * Convert some data from hex format
 */
 void Hex_Decoder::write(const byte input[], u32bit length)
    {
-   for(u32bit j = 0; j != length; ++j)
+   while(length)
       {
-      if(is_valid(input[j]))
-         in[position++] = input[j];
-      else
-         handle_bad_char(input[j]);
-      if(position == in.size())
+      u32bit to_copy = std::min(length, in.size() - position);
+      copy_mem(&in[position], input, to_copy);
+      position += to_copy;
+
+      u32bit consumed = 0;
+      u32bit written = hex_decode(&out[0],
+                                  reinterpret_cast<const char*>(&in[0]),
+                                  position,
+                                  consumed,
+                                  checking != FULL_CHECK);
+
+      send(out, written);
+
+      if(consumed != position)
          {
-         decode_and_send(in, in.size());
-         position = 0;
+         copy_mem(&in[0], &in[consumed], position - consumed);
+         position = position - consumed;
          }
+      else
+         position = 0;
+
+      length -= to_copy;
+      input += to_copy;
       }
    }
 
@@ -189,8 +152,21 @@ void Hex_Decoder::write(const byte input[], u32bit length)
 */
 void Hex_Decoder::end_msg()
    {
-   decode_and_send(in, position);
+   u32bit consumed = 0;
+   u32bit written = hex_decode(&out[0],
+                               reinterpret_cast<const char*>(&in[0]),
+                               position,
+                               consumed,
+                               checking != FULL_CHECK);
+
+   send(out, written);
+
+   const bool not_full_bytes = consumed != position;
+
    position = 0;
+
+   if(not_full_bytes)
+      throw std::invalid_argument("Hex_Decoder: Input not full bytes");
    }
 
 }
diff --git a/src/filters/hex/hex.h b/src/filters/hex_filt/hex_filt.h
index 6698a61be..2a7300ddb 100644
--- a/src/filters/hex/hex.h
+++ b/src/filters/hex_filt/hex_filt.h
@@ -5,8 +5,8 @@
 * Distributed under the terms of the Botan license
 */
 
-#ifndef BOTAN_HEX_H__
-#define BOTAN_HEX_H__
+#ifndef BOTAN_HEX_FILTER_H__
+#define BOTAN_HEX_FILTER_H__
 
 #include <botan/filter.h>
 
@@ -50,8 +50,6 @@ class BOTAN_DLL Hex_Encoder : public Filter
                   Case the_case = Uppercase);
    private:
       void encode_and_send(const byte[], u32bit);
-      static const byte BIN_TO_HEX_UPPER[16];
-      static const byte BIN_TO_HEX_LOWER[16];
 
       const Case casing;
       const u32bit line_length;
@@ -65,20 +63,6 @@ class BOTAN_DLL Hex_Encoder : public Filter
 class BOTAN_DLL Hex_Decoder : public Filter
    {
    public:
-      /**
-      * Decode a pair of hex chars to a byte
-      * @param in an array of two hex chars
-      * @return byte formed by decoding in
-      */
-      static byte decode(const byte in[2]);
-
-      /**
-      * Check if this character is a valid hex input
-      * @param c a single character
-      * @return true iff c is a valid hex char
-      */
-      static bool is_valid(byte c);
-
       std::string name() const { return "Hex_Decoder"; }
 
       void write(const byte[], u32bit);
@@ -91,10 +75,6 @@ class BOTAN_DLL Hex_Decoder : public Filter
       */
       Hex_Decoder(Decoder_Checking checking = NONE);
    private:
-      void decode_and_send(const byte[], u32bit);
-      void handle_bad_char(byte);
-      static const byte HEX_TO_BIN[256];
-
       const Decoder_Checking checking;
       SecureVector<byte> in, out;
       u32bit position;
diff --git a/src/filters/hex/info.txt b/src/filters/hex_filt/info.txt
index 0a4205669..7f5f47fa1 100644
--- a/src/filters/hex/info.txt
+++ b/src/filters/hex_filt/info.txt
@@ -1,4 +1,4 @@
-define HEX_CODEC
+define HEX_FILTER
 
 <requires>
 filters