X-Git-Url: https://git.dogcows.com/gitweb?p=chaz%2Fyoink;a=blobdiff_plain;f=src%2Fstlplus%2Fstrings%2Fstring_inf.cpp;h=e1eb545e046b48359de84fba817bb894e70011d5;hp=1734335d492b3cb6976377cf88c325853dd3453c;hb=5846afb00833cc72fe72422ca896d2387c712cb4;hpb=a97500609dc3c1b11f9786d32bc458eb00de4c36

diff --git a/src/stlplus/strings/string_inf.cpp b/src/stlplus/strings/string_inf.cpp
index 1734335..e1eb545 100644
--- a/src/stlplus/strings/string_inf.cpp
+++ b/src/stlplus/strings/string_inf.cpp
@@ -1,536 +1,536 @@
-////////////////////////////////////////////////////////////////////////////////
-
-//   Author:    Andy Rushton
-//   Copyright: (c) Southampton University 1999-2004
-//              (c) Andy Rushton           2004-2009
-//   License:   BSD License, see ../docs/license.html
-
-//   String conversion functions for the infinite precision integer type inf
-
-////////////////////////////////////////////////////////////////////////////////
-
-// can be excluded from the build to break the dependency on the portability library
-#ifndef NO_STLPLUS_INF
-
-#include "string_inf.hpp"
-#include "string_basic.hpp"
-#include <ctype.h>
-
-////////////////////////////////////////////////////////////////////////////////
-
-namespace stlplus
-{
-
-  ////////////////////////////////////////////////////////////////////////////////
-
-  static char to_char [] = "0123456789abcdefghijklmnopqrstuvwxyz";
-  static int from_char [] = 
-  {
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-    0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
-    -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
-    25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, -1,
-    -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
-    25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, -1,
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
-  };
-
-  ////////////////////////////////////////////////////////////////////////////////
-
-  std::string inf_to_string(const stlplus::inf& data, unsigned radix, radix_display_t display, unsigned width)
-    throw(std::invalid_argument)
-  {
-    std::string result;
-    if (radix < 2 || radix > 36)
-      throw std::invalid_argument("invalid radix value");
-    inf local_i = data;
-    // untangle all the options
-    bool hashed = false;
-    bool binary = false;
-    bool octal = false;
-    bool hex = false;
-    switch(display)
-    {
-    case radix_none:
-      break;
-    case radix_hash_style:
-      hashed = radix != 10;
-      break;
-    case radix_hash_style_all:
-      hashed = true;
-      break;
-    case radix_c_style:
-      if (radix == 16)
-        hex = true;
-      else if (radix == 8)
-        octal = true;
-      else if (radix == 2)
-        binary = true;
-      break;
-    case radix_c_style_or_hash:
-      if (radix == 16)
-        hex = true;
-      else if (radix == 8)
-        octal = true;
-      else if (radix == 2)
-        binary = true;
-      else if (radix != 10)
-        hashed = true;
-      break;
-    default:
-      throw std::invalid_argument("invalid radix display value");
-    }
-    // create constants of the same type as the template parameter to avoid type mismatches
-    const inf t_zero(0);
-    const inf t_radix(radix);
-    // the C representations for binary, octal and hex use 2's-complement representation
-    // all other represenations use sign-magnitude
-    if (hex || octal || binary)
-    {
-      // bit-pattern representation
-      // this is the binary representation optionally shown in octal or hex
-      // first generate the binary by masking the bits
-      for (unsigned j = local_i.bits(); j--; )
-        result += (local_i.bit(j) ? '1' : '0');
-      // the result is now the full width of the type - e.g. int will give a 32-bit result
-      // now interpret this as either binary, octal or hex and add the prefix
-      if (binary)
-      {
-        // the result is already binary - but the width may be wrong
-        // if this is still smaller than the width field, sign extend
-        // otherwise trim down to either the width or the smallest string that preserves the value
-        while (result.size() < width)
-          result.insert((std::string::size_type)0, 1, result[0]);
-        while (result.size() > width)
-        {
-          // do not trim to less than 1 bit (sign only)
-          if (result.size() <= 1) break;
-          // only trim if it doesn't change the sign and therefore the value
-          if (result[0] != result[1]) break;
-          result.erase(0,1);
-        }
-        // add the prefix
-        result.insert((std::string::size_type)0, "0b");
-      }
-      else if (octal)
-      {
-        // the result is currently binary - but before converting get the width right
-        // the width is expressed in octal digits so make the binary 3 times this
-        // if this is still smaller than the width field, sign extend
-        // otherwise trim down to either the width or the smallest string that preserves the value
-        // also ensure that the binary is a multiple of 3 bits to make the conversion to octal easier
-        while (result.size() < 3*width)
-          result.insert((std::string::size_type)0, 1, result[0]);
-        while (result.size() > 3*width)
-        {
-          // do not trim to less than 2 bits (sign plus 1-bit magnitude)
-          if (result.size() <= 2) break;
-          // only trim if it doesn't change the sign and therefore the value
-          if (result[0] != result[1]) break;
-          result.erase(0,1);
-        }
-        while (result.size() % 3 != 0)
-          result.insert((std::string::size_type)0, 1, result[0]);
-        // now convert to octal
-        std::string octal_result;
-        for (unsigned i = 0; i < result.size()/3; i++)
-        {
-          // yuck - ugly or what?
-          if (result[i*3] == '0')
-          {
-            if (result[i*3+1] == '0')
-            {
-              if (result[i*3+2] == '0')
-                octal_result += '0';
-              else
-                octal_result += '1';
-            }
-            else
-            {
-              if (result[i*3+2] == '0')
-                octal_result += '2';
-              else
-                octal_result += '3';
-            }
-          }
-          else
-          {
-            if (result[i*3+1] == '0')
-            {
-              if (result[i*3+2] == '0')
-                octal_result += '4';
-              else
-                octal_result += '5';
-            }
-            else
-            {
-              if (result[i*3+2] == '0')
-                octal_result += '6';
-              else
-                octal_result += '7';
-            }
-          }
-        }
-        result = octal_result;
-        // add the prefix
-        result.insert((std::string::size_type)0, "0");
-      }
-      else
-      {
-        // similar to octal
-        while (result.size() < 4*width)
-          result.insert((std::string::size_type)0, 1, result[0]);
-        while (result.size() > 4*width)
-        {
-          // do not trim to less than 2 bits (sign plus 1-bit magnitude)
-          if (result.size() <= 2) break;
-          // only trim if it doesn't change the sign and therefore the value
-          if (result[0] != result[1]) break;
-          result.erase(0,1);
-        }
-        while (result.size() % 4 != 0)
-          result.insert((std::string::size_type)0, 1, result[0]);
-        // now convert to hex
-        std::string hex_result;
-        for (unsigned i = 0; i < result.size()/4; i++)
-        {
-          // yuck - ugly or what?
-          if (result[i*4] == '0')
-          {
-            if (result[i*4+1] == '0')
-            {
-              if (result[i*4+2] == '0')
-              {
-                if (result[i*4+3] == '0')
-                  hex_result += '0';
-                else
-                  hex_result += '1';
-              }
-              else
-              {
-                if (result[i*4+3] == '0')
-                  hex_result += '2';
-                else
-                  hex_result += '3';
-              }
-            }
-            else
-            {
-              if (result[i*4+2] == '0')
-              {
-                if (result[i*4+3] == '0')
-                  hex_result += '4';
-                else
-                  hex_result += '5';
-              }
-              else
-              {
-                if (result[i*4+3] == '0')
-                  hex_result += '6';
-                else
-                  hex_result += '7';
-              }
-            }
-          }
-          else
-          {
-            if (result[i*4+1] == '0')
-            {
-              if (result[i*4+2] == '0')
-              {
-                if (result[i*4+3] == '0')
-                  hex_result += '8';
-                else
-                  hex_result += '9';
-              }
-              else
-              {
-                if (result[i*4+3] == '0')
-                  hex_result += 'a';
-                else
-                  hex_result += 'b';
-              }
-            }
-            else
-            {
-              if (result[i*4+2] == '0')
-              {
-                if (result[i*4+3] == '0')
-                  hex_result += 'c';
-                else
-                  hex_result += 'd';
-              }
-              else
-              {
-                if (result[i*4+3] == '0')
-                  hex_result += 'e';
-                else
-                  hex_result += 'f';
-              }
-            }
-          }
-        }
-        result = hex_result;
-        // add the prefix
-        result.insert((std::string::size_type)0, "0x");
-      }
-    }
-    else
-    {
-      // convert to sign-magnitude
-      // the representation is:
-      // [radix#][sign]magnitude
-      bool negative = local_i.negative();
-      local_i.abs();
-      // create a representation of the magnitude by successive division
-      do
-      {
-        std::pair<inf,inf> divided = local_i.divide(t_radix);
-        unsigned remainder = divided.second.to_unsigned();
-        char digit = to_char[remainder];
-        result.insert((std::string::size_type)0, 1, digit);
-        local_i = divided.first;
-      }
-      while(!local_i.zero() || result.size() < width);
-      // add the prefixes
-      // add a sign only for negative values
-      if (negative)
-        result.insert((std::string::size_type)0, 1, '-');
-      // then prefix everything with the radix if the hashed representation was requested
-      if (hashed)
-        result.insert((std::string::size_type)0, unsigned_to_string(radix) + "#");
-    }
-    return result;
-  }
-
-  ////////////////////////////////////////////////////////////////////////////////
-  // Conversions FROM string
-
-  inf string_to_inf(const std::string& str, unsigned radix) throw(std::invalid_argument)
-  {
-    inf result;
-    if (radix != 0 && (radix < 2 || radix > 36))
-      throw std::invalid_argument("invalid radix value " + unsigned_to_string(radix));
-    unsigned i = 0;
-    // the radix passed as a parameter is just the default - it can be
-    // overridden by either the C prefix or the hash prefix
-    // Note: a leading zero is the C-style prefix for octal - I only make this
-    // override the default when the default radix is not specified
-    // first check for a C-style prefix
-    bool c_style = false;
-    if (i < str.size() && str[i] == '0')
-    {
-      // binary or hex
-      if (i+1 < str.size() && tolower(str[i+1]) == 'x')
-      {
-        c_style = true;
-        radix = 16;
-        i += 2;
-      }
-      else if (i+1 < str.size() && tolower(str[i+1]) == 'b')
-      {
-        c_style = true;
-        radix = 2;
-        i += 2;
-      }
-      else if (radix == 0)
-      {
-        c_style = true;
-        radix = 8;
-        i += 1;
-      }
-    }
-    // now check for a hash-style prefix if a C-style prefix was not found
-    if (i == 0)
-    {
-      // scan for the sequence {digits}#
-      bool hash_found = false;
-      unsigned j = i;
-      for (; j < str.size(); j++)
-      {
-        if (!isdigit(str[j]))
-        {
-          if (str[j] == '#')
-            hash_found = true;
-          break;
-        }
-      }
-      if (hash_found)
-      {
-        // use the hash prefix to define the radix
-        // i points to the start of the radix and j points to the # character
-        std::string slice = str.substr(i, j-i);
-        radix = string_to_unsigned(slice);
-        i = j+1;
-      }
-    }
-    if (radix == 0)
-      radix = 10;
-    if (radix < 2 || radix > 36)
-      throw std::invalid_argument("invalid radix value");
-    if (c_style)
-    {
-      // the C style formats are bit patterns not integer values - these need
-      // to be sign-extended to get the right value
-      std::string binary;
-      if (radix == 2)
-      {
-        for (unsigned j = i; j < str.size(); j++)
-        {
-          switch(str[j])
-          {
-          case '0':
-            binary += '0';
-            break;
-          case '1':
-            binary += '1';
-            break;
-          default:
-            throw std::invalid_argument("invalid binary character in string " + str);
-          }
-        }
-      }
-      else if (radix == 8)
-      {
-        for (unsigned j = i; j < str.size(); j++)
-        {
-          switch(str[j])
-          {
-          case '0':
-            binary += "000";
-            break;
-          case '1':
-            binary += "001";
-            break;
-          case '2':
-            binary += "010";
-            break;
-          case '3':
-            binary += "011";
-            break;
-          case '4':
-            binary += "100";
-            break;
-          case '5':
-            binary += "101";
-            break;
-          case '6':
-            binary += "110";
-            break;
-          case '7':
-            binary += "111";
-            break;
-          default:
-            throw std::invalid_argument("invalid octal character in string " + str);
-          }
-        }
-      }
-      else
-      {
-        for (unsigned j = i; j < str.size(); j++)
-        {
-          switch(tolower(str[j]))
-          {
-          case '0':
-            binary += "0000";
-            break;
-          case '1':
-            binary += "0001";
-            break;
-          case '2':
-            binary += "0010";
-            break;
-          case '3':
-            binary += "0011";
-            break;
-          case '4':
-            binary += "0100";
-            break;
-          case '5':
-            binary += "0101";
-            break;
-          case '6':
-            binary += "0110";
-            break;
-          case '7':
-            binary += "0111";
-            break;
-          case '8':
-            binary += "1000";
-            break;
-          case '9':
-            binary += "1001";
-            break;
-          case 'a':
-            binary += "1010";
-            break;
-          case 'b':
-            binary += "1011";
-            break;
-          case 'c':
-            binary += "1100";
-            break;
-          case 'd':
-            binary += "1101";
-            break;
-          case 'e':
-            binary += "1110";
-            break;
-          case 'f':
-            binary += "1111";
-            break;
-          default:
-            throw std::invalid_argument("invalid hex character in string " + str);
-          }
-        }
-      }
-      // now convert the value
-      result.resize(binary.size());
-      for (unsigned j = 0; j < binary.size(); j++)
-        result.preset(binary.size() - j - 1, binary[j] == '1');
-    }
-    else
-    {
-      // now scan for a sign and find whether this is a negative number
-      bool negative = false;
-      if (i < str.size())
-      {
-        switch (str[i])
-        {
-        case '-':
-          negative = true;
-          i++;
-          break;
-        case '+':
-          i++;
-          break;
-        }
-      }
-      for (; i < str.size(); i++)
-      {
-        result *= inf(radix);
-        int ch = from_char[(unsigned char)str[i]] ;
-        if (ch == -1)
-          throw std::invalid_argument("invalid character in string " + str + " for radix " + unsigned_to_string(radix));
-        result += inf(ch);
-      }
-      if (negative)
-        result.negate();
-    }
-    return result;
-  }
-
-////////////////////////////////////////////////////////////////////////////////
-
-} // end namespace stlplus
-
-#endif
+////////////////////////////////////////////////////////////////////////////////
+
+//   Author:    Andy Rushton
+//   Copyright: (c) Southampton University 1999-2004
+//              (c) Andy Rushton           2004-2009
+//   License:   BSD License, see ../docs/license.html
+
+//   String conversion functions for the infinite precision integer type inf
+
+////////////////////////////////////////////////////////////////////////////////
+
+// can be excluded from the build to break the dependency on the portability library
+#ifndef NO_STLPLUS_INF
+
+#include "string_inf.hpp"
+#include "string_basic.hpp"
+#include <ctype.h>
+
+////////////////////////////////////////////////////////////////////////////////
+
+namespace stlplus
+{
+
+  ////////////////////////////////////////////////////////////////////////////////
+
+  static char to_char [] = "0123456789abcdefghijklmnopqrstuvwxyz";
+  static int from_char [] = 
+  {
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
+    -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
+    25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, -1,
+    -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
+    25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
+  };
+
+  ////////////////////////////////////////////////////////////////////////////////
+
+  std::string inf_to_string(const stlplus::inf& data, unsigned radix, radix_display_t display, unsigned width)
+    throw(std::invalid_argument)
+  {
+    std::string result;
+    if (radix < 2 || radix > 36)
+      throw std::invalid_argument("invalid radix value");
+    inf local_i = data;
+    // untangle all the options
+    bool hashed = false;
+    bool binary = false;
+    bool octal = false;
+    bool hex = false;
+    switch(display)
+    {
+    case radix_none:
+      break;
+    case radix_hash_style:
+      hashed = radix != 10;
+      break;
+    case radix_hash_style_all:
+      hashed = true;
+      break;
+    case radix_c_style:
+      if (radix == 16)
+        hex = true;
+      else if (radix == 8)
+        octal = true;
+      else if (radix == 2)
+        binary = true;
+      break;
+    case radix_c_style_or_hash:
+      if (radix == 16)
+        hex = true;
+      else if (radix == 8)
+        octal = true;
+      else if (radix == 2)
+        binary = true;
+      else if (radix != 10)
+        hashed = true;
+      break;
+    default:
+      throw std::invalid_argument("invalid radix display value");
+    }
+    // create constants of the same type as the template parameter to avoid type mismatches
+    const inf t_zero(0);
+    const inf t_radix(radix);
+    // the C representations for binary, octal and hex use 2's-complement representation
+    // all other represenations use sign-magnitude
+    if (hex || octal || binary)
+    {
+      // bit-pattern representation
+      // this is the binary representation optionally shown in octal or hex
+      // first generate the binary by masking the bits
+      for (unsigned j = local_i.bits(); j--; )
+        result += (local_i.bit(j) ? '1' : '0');
+      // the result is now the full width of the type - e.g. int will give a 32-bit result
+      // now interpret this as either binary, octal or hex and add the prefix
+      if (binary)
+      {
+        // the result is already binary - but the width may be wrong
+        // if this is still smaller than the width field, sign extend
+        // otherwise trim down to either the width or the smallest string that preserves the value
+        while (result.size() < width)
+          result.insert((std::string::size_type)0, 1, result[0]);
+        while (result.size() > width)
+        {
+          // do not trim to less than 1 bit (sign only)
+          if (result.size() <= 1) break;
+          // only trim if it doesn't change the sign and therefore the value
+          if (result[0] != result[1]) break;
+          result.erase(0,1);
+        }
+        // add the prefix
+        result.insert((std::string::size_type)0, "0b");
+      }
+      else if (octal)
+      {
+        // the result is currently binary - but before converting get the width right
+        // the width is expressed in octal digits so make the binary 3 times this
+        // if this is still smaller than the width field, sign extend
+        // otherwise trim down to either the width or the smallest string that preserves the value
+        // also ensure that the binary is a multiple of 3 bits to make the conversion to octal easier
+        while (result.size() < 3*width)
+          result.insert((std::string::size_type)0, 1, result[0]);
+        while (result.size() > 3*width)
+        {
+          // do not trim to less than 2 bits (sign plus 1-bit magnitude)
+          if (result.size() <= 2) break;
+          // only trim if it doesn't change the sign and therefore the value
+          if (result[0] != result[1]) break;
+          result.erase(0,1);
+        }
+        while (result.size() % 3 != 0)
+          result.insert((std::string::size_type)0, 1, result[0]);
+        // now convert to octal
+        std::string octal_result;
+        for (unsigned i = 0; i < result.size()/3; i++)
+        {
+          // yuck - ugly or what?
+          if (result[i*3] == '0')
+          {
+            if (result[i*3+1] == '0')
+            {
+              if (result[i*3+2] == '0')
+                octal_result += '0';
+              else
+                octal_result += '1';
+            }
+            else
+            {
+              if (result[i*3+2] == '0')
+                octal_result += '2';
+              else
+                octal_result += '3';
+            }
+          }
+          else
+          {
+            if (result[i*3+1] == '0')
+            {
+              if (result[i*3+2] == '0')
+                octal_result += '4';
+              else
+                octal_result += '5';
+            }
+            else
+            {
+              if (result[i*3+2] == '0')
+                octal_result += '6';
+              else
+                octal_result += '7';
+            }
+          }
+        }
+        result = octal_result;
+        // add the prefix
+        result.insert((std::string::size_type)0, "0");
+      }
+      else
+      {
+        // similar to octal
+        while (result.size() < 4*width)
+          result.insert((std::string::size_type)0, 1, result[0]);
+        while (result.size() > 4*width)
+        {
+          // do not trim to less than 2 bits (sign plus 1-bit magnitude)
+          if (result.size() <= 2) break;
+          // only trim if it doesn't change the sign and therefore the value
+          if (result[0] != result[1]) break;
+          result.erase(0,1);
+        }
+        while (result.size() % 4 != 0)
+          result.insert((std::string::size_type)0, 1, result[0]);
+        // now convert to hex
+        std::string hex_result;
+        for (unsigned i = 0; i < result.size()/4; i++)
+        {
+          // yuck - ugly or what?
+          if (result[i*4] == '0')
+          {
+            if (result[i*4+1] == '0')
+            {
+              if (result[i*4+2] == '0')
+              {
+                if (result[i*4+3] == '0')
+                  hex_result += '0';
+                else
+                  hex_result += '1';
+              }
+              else
+              {
+                if (result[i*4+3] == '0')
+                  hex_result += '2';
+                else
+                  hex_result += '3';
+              }
+            }
+            else
+            {
+              if (result[i*4+2] == '0')
+              {
+                if (result[i*4+3] == '0')
+                  hex_result += '4';
+                else
+                  hex_result += '5';
+              }
+              else
+              {
+                if (result[i*4+3] == '0')
+                  hex_result += '6';
+                else
+                  hex_result += '7';
+              }
+            }
+          }
+          else
+          {
+            if (result[i*4+1] == '0')
+            {
+              if (result[i*4+2] == '0')
+              {
+                if (result[i*4+3] == '0')
+                  hex_result += '8';
+                else
+                  hex_result += '9';
+              }
+              else
+              {
+                if (result[i*4+3] == '0')
+                  hex_result += 'a';
+                else
+                  hex_result += 'b';
+              }
+            }
+            else
+            {
+              if (result[i*4+2] == '0')
+              {
+                if (result[i*4+3] == '0')
+                  hex_result += 'c';
+                else
+                  hex_result += 'd';
+              }
+              else
+              {
+                if (result[i*4+3] == '0')
+                  hex_result += 'e';
+                else
+                  hex_result += 'f';
+              }
+            }
+          }
+        }
+        result = hex_result;
+        // add the prefix
+        result.insert((std::string::size_type)0, "0x");
+      }
+    }
+    else
+    {
+      // convert to sign-magnitude
+      // the representation is:
+      // [radix#][sign]magnitude
+      bool negative = local_i.negative();
+      local_i.abs();
+      // create a representation of the magnitude by successive division
+      do
+      {
+        std::pair<inf,inf> divided = local_i.divide(t_radix);
+        unsigned remainder = divided.second.to_unsigned();
+        char digit = to_char[remainder];
+        result.insert((std::string::size_type)0, 1, digit);
+        local_i = divided.first;
+      }
+      while(!local_i.zero() || result.size() < width);
+      // add the prefixes
+      // add a sign only for negative values
+      if (negative)
+        result.insert((std::string::size_type)0, 1, '-');
+      // then prefix everything with the radix if the hashed representation was requested
+      if (hashed)
+        result.insert((std::string::size_type)0, unsigned_to_string(radix) + "#");
+    }
+    return result;
+  }
+
+  ////////////////////////////////////////////////////////////////////////////////
+  // Conversions FROM string
+
+  inf string_to_inf(const std::string& str, unsigned radix) throw(std::invalid_argument)
+  {
+    inf result;
+    if (radix != 0 && (radix < 2 || radix > 36))
+      throw std::invalid_argument("invalid radix value " + unsigned_to_string(radix));
+    unsigned i = 0;
+    // the radix passed as a parameter is just the default - it can be
+    // overridden by either the C prefix or the hash prefix
+    // Note: a leading zero is the C-style prefix for octal - I only make this
+    // override the default when the default radix is not specified
+    // first check for a C-style prefix
+    bool c_style = false;
+    if (i < str.size() && str[i] == '0')
+    {
+      // binary or hex
+      if (i+1 < str.size() && tolower(str[i+1]) == 'x')
+      {
+        c_style = true;
+        radix = 16;
+        i += 2;
+      }
+      else if (i+1 < str.size() && tolower(str[i+1]) == 'b')
+      {
+        c_style = true;
+        radix = 2;
+        i += 2;
+      }
+      else if (radix == 0)
+      {
+        c_style = true;
+        radix = 8;
+        i += 1;
+      }
+    }
+    // now check for a hash-style prefix if a C-style prefix was not found
+    if (i == 0)
+    {
+      // scan for the sequence {digits}#
+      bool hash_found = false;
+      unsigned j = i;
+      for (; j < str.size(); j++)
+      {
+        if (!isdigit(str[j]))
+        {
+          if (str[j] == '#')
+            hash_found = true;
+          break;
+        }
+      }
+      if (hash_found)
+      {
+        // use the hash prefix to define the radix
+        // i points to the start of the radix and j points to the # character
+        std::string slice = str.substr(i, j-i);
+        radix = string_to_unsigned(slice);
+        i = j+1;
+      }
+    }
+    if (radix == 0)
+      radix = 10;
+    if (radix < 2 || radix > 36)
+      throw std::invalid_argument("invalid radix value");
+    if (c_style)
+    {
+      // the C style formats are bit patterns not integer values - these need
+      // to be sign-extended to get the right value
+      std::string binary;
+      if (radix == 2)
+      {
+        for (unsigned j = i; j < str.size(); j++)
+        {
+          switch(str[j])
+          {
+          case '0':
+            binary += '0';
+            break;
+          case '1':
+            binary += '1';
+            break;
+          default:
+            throw std::invalid_argument("invalid binary character in string " + str);
+          }
+        }
+      }
+      else if (radix == 8)
+      {
+        for (unsigned j = i; j < str.size(); j++)
+        {
+          switch(str[j])
+          {
+          case '0':
+            binary += "000";
+            break;
+          case '1':
+            binary += "001";
+            break;
+          case '2':
+            binary += "010";
+            break;
+          case '3':
+            binary += "011";
+            break;
+          case '4':
+            binary += "100";
+            break;
+          case '5':
+            binary += "101";
+            break;
+          case '6':
+            binary += "110";
+            break;
+          case '7':
+            binary += "111";
+            break;
+          default:
+            throw std::invalid_argument("invalid octal character in string " + str);
+          }
+        }
+      }
+      else
+      {
+        for (unsigned j = i; j < str.size(); j++)
+        {
+          switch(tolower(str[j]))
+          {
+          case '0':
+            binary += "0000";
+            break;
+          case '1':
+            binary += "0001";
+            break;
+          case '2':
+            binary += "0010";
+            break;
+          case '3':
+            binary += "0011";
+            break;
+          case '4':
+            binary += "0100";
+            break;
+          case '5':
+            binary += "0101";
+            break;
+          case '6':
+            binary += "0110";
+            break;
+          case '7':
+            binary += "0111";
+            break;
+          case '8':
+            binary += "1000";
+            break;
+          case '9':
+            binary += "1001";
+            break;
+          case 'a':
+            binary += "1010";
+            break;
+          case 'b':
+            binary += "1011";
+            break;
+          case 'c':
+            binary += "1100";
+            break;
+          case 'd':
+            binary += "1101";
+            break;
+          case 'e':
+            binary += "1110";
+            break;
+          case 'f':
+            binary += "1111";
+            break;
+          default:
+            throw std::invalid_argument("invalid hex character in string " + str);
+          }
+        }
+      }
+      // now convert the value
+      result.resize(binary.size());
+      for (unsigned j = 0; j < binary.size(); j++)
+        result.preset(binary.size() - j - 1, binary[j] == '1');
+    }
+    else
+    {
+      // now scan for a sign and find whether this is a negative number
+      bool negative = false;
+      if (i < str.size())
+      {
+        switch (str[i])
+        {
+        case '-':
+          negative = true;
+          i++;
+          break;
+        case '+':
+          i++;
+          break;
+        }
+      }
+      for (; i < str.size(); i++)
+      {
+        result *= inf(radix);
+        int ch = from_char[(unsigned char)str[i]] ;
+        if (ch == -1)
+          throw std::invalid_argument("invalid character in string " + str + " for radix " + unsigned_to_string(radix));
+        result += inf(ch);
+      }
+      if (negative)
+        result.negate();
+    }
+    return result;
+  }
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // end namespace stlplus
+
+#endif