Merge pull request EOSIO#144 from EOSIO/efficient-name-symbol-asset-p…

…rinting

Efficient name and symbol_code printing (and to_string)

libraries/eosiolib/datastream.hpp

@@ -6,6 +6,7 @@
 #include <eosiolib/system.h>
 #include <eosiolib/memory.h>
 #include <eosiolib/symbol.hpp>
+#include <eosiolib/fixed_key.hpp>
 #include <eosiolib/ignore.hpp>
 #include <boost/container/flat_set.hpp>
 #include <boost/container/flat_map.hpp>
@@ -285,7 +286,7 @@ inline datastream<Stream>& operator<<(datastream<Stream>& ds, const std::optiona
 /**
  *  Deserialize an optional from a stream
  *
- *  @brief Deserialize an optional 
+ *  @brief Deserialize an optional
  *  @param ds - The stream to read
  *  @param opt - The destination for deserialized value
  *  @tparam Stream - Type of datastream buffer
@@ -372,7 +373,7 @@ inline datastream<Stream>& operator>>(datastream<Stream>& ds, eosio::symbol& sym
 /**
  *  Serialize an ignored_wrapper type into a stream
  *
- *  @brief Serialize ignored_wrapper<T>'s T value 
+ *  @brief Serialize ignored_wrapper<T>'s T value
  *  @param ds - The stream to write
  *  @param val - The value to serialize
  *  @tparam Stream - Type of datastream buffer

libraries/eosiolib/name.hpp

@@ -5,6 +5,7 @@
 #pragma once
 
 #include <eosiolib/system.h>
+#include <eosiolib/serialize.hpp>
 #include <string>
 #include <string_view>
 
@@ -131,21 +132,40 @@ namespace eosio {
 
       constexpr explicit operator bool()const { return value != 0; }
 
-      // keep in sync with name::operator string() in eosio source code definition for name
-      std::string to_string() const {
+      /**
+       *  Writes the name as a string to the provided char buffer
+       *
+       *
+       *  @brief Writes the name as a string to the provided char buffer
+       *  @pre Appropriate Size Precondition: (begin + 13) <= end and (begin + 13) does not overflow
+       *  @pre Valid Memory Region Precondition: The range [begin, end) must be a valid range of memory to write to.
+       *  @param begin - The start of the char buffer
+       *  @param end - Just past the end of the char buffer
+       *  @return char* - Just past the end of the last character written (returns begin if the Appropriate Size Precondition is not satisfied)
+       *  @post If the Appropriate Size Precondition is satisfied, the range [begin, returned pointer) contains the string representation of the name.
+       */
+      char* write_as_string( char* begin, char* end )const {
          static const char* charmap = ".12345abcdefghijklmnopqrstuvwxyz";
+         constexpr uint64_t mask = 0xF800000000000000ull;
 
-         std::string str(13,'.');
+         if( (begin + 13) < begin || (begin + 13) > end ) return begin;
 
-         uint64_t tmp = value;
-         for( uint32_t i = 0; i <= 12; ++i ) {
-            char c = charmap[tmp & (i == 0 ? 0x0f : 0x1f)];
-            str[12-i] = c;
-            tmp >>= (i == 0 ? 4 : 5);
+         auto v = value;
+         for( auto i = 0;   i < 13; ++i, v <<= 5 ) {
+            if( v == 0 ) return begin;
+
+            auto indx = (v & mask) >> (i == 12 ? 60 : 59);
+            *begin = charmap[indx];
+            ++begin;
          }
 
-         trim_right_dots( str );
-         return str;
+         return begin;
+      }
+
+      std::string to_string()const {
+         char buffer[13];
+         auto end = write_as_string( buffer, buffer + sizeof(buffer) );
+         return {buffer, end};
       }
 
       /**
@@ -181,13 +201,6 @@ namespace eosio {
       uint64_t value = 0;
 
       EOSLIB_SERIALIZE( name, (value) )
-
-   private:
-      static void trim_right_dots(std::string& str ) {
-         const auto last = str.find_last_not_of('.');
-         if (last != std::string::npos)
-            str = str.substr(0, last + 1);
-      }
    };
 
 } /// namespace eosio

libraries/eosiolib/print.hpp

@@ -5,6 +5,7 @@
 #pragma once
 #include <eosiolib/print.h>
 #include <eosiolib/name.hpp>
+#include <eosiolib/symbol.hpp>
 #include <eosiolib/fixed_key.hpp>
 #include <utility>
 #include <string>
@@ -176,6 +177,19 @@ namespace eosio {
       printn(name.value);
    }
 
+   /**
+    * Prints a symbol_code
+    *
+    * @brief Prints a symbol_code
+    * @param sym_code symbol code to be printed
+    */
+   inline void print( eosio::symbol_code sym_code ) {
+      char buffer[7];
+      auto end = sym_code.write_as_string( buffer, buffer + sizeof(buffer) );
+      if( buffer < end )
+         prints_l( buffer, (end-buffer) );
+   }
+
   /**
     * Prints bool
     *

libraries/eosiolib/symbol.hpp

@@ -4,9 +4,10 @@
  */
 #pragma once
 
-#include <eosiolib/serialize.hpp>
-#include <eosiolib/print.hpp>
 #include <eosiolib/system.h>
+#include <eosiolib/print.h>
+#include <eosiolib/name.hpp>
+#include <eosiolib/serialize.hpp>
 #include <tuple>
 #include <limits>
 #include <string_view>
@@ -94,18 +95,37 @@ namespace eosio {
       constexpr explicit operator bool()const { return value != 0; }
 
       /**
-       * %Print the symbol code
+       *  Writes the symbol_code as a string to the provided char buffer
+       *
        *
-       * @brief %Print the symbol code
+       *  @brief Writes the symbol_code as a string to the provided char buffer
+       *  @pre Appropriate Size Precondition: (begin + 7) <= end and (begin + 7) does not overflow
+       *  @pre Valid Memory Region Precondition: The range [begin, end) must be a valid range of memory to write to.
+       *  @param begin - The start of the char buffer
+       *  @param end - Just past the end of the char buffer
+       *  @return char* - Just past the end of the last character written (returns begin if the Appropriate Size Precondition is not satisfied)
+       *  @post If the Appropriate Size Precondition is satisfied, the range [begin, returned pointer) contains the string representation of the symbol_code.
        */
-      void print()const {
-         auto sym = value;
-         for( int i = 0; i < 7; ++i ) {
-            char c = (char)(sym & 0xff);
-            if( !c ) return;
-            prints_l(&c, 1 );
-            sym >>= 8;
+      char* write_as_string( char* begin, char* end )const {
+         constexpr uint64_t mask = 0xFFull;
+
+         if( (begin + 7) < begin || (begin + 7) > end ) return begin;
+
+         auto v = value;
+         for( auto i = 0; i < 7; ++i, v >>= 8 ) {
+            if( v == 0 ) return begin;
+
+            *begin = static_cast<char>(v & mask);
+            ++begin;
          }
+
+         return begin;
+      }
+
+      std::string to_string()const {
+         char buffer[7];
+         auto end = write_as_string( buffer, buffer + sizeof(buffer) );
+         return {buffer, end};
       }
 
       /**
@@ -185,10 +205,13 @@ namespace eosio {
        */
       void print( bool show_precision = true )const {
          if( show_precision ){
-            ::eosio::print( static_cast<uint64_t>(precision()) );
+            printui( static_cast<uint64_t>(precision()) );
             prints(",");
          }
-         code().print();
+         char buffer[7];
+         auto end = code().write_as_string( buffer, buffer + sizeof(buffer) );
+         if( buffer < end )
+            prints_l( buffer, (end-buffer) );
       }
 
       /**
@@ -244,8 +267,8 @@ namespace eosio {
        *
        * @brief %Print the extended symbol
        */
-      void print()const {
-         symbol.print();
+      void print( bool show_precision = true )const {
+         symbol.print( show_precision );
          prints("@");
          printn( contract.value );
       }