// util/hex.h

/*    Copyright 2009 10gen Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the GNU Affero General Public License in all respects
 *    for all of the code used other than as permitted herein. If you modify
 *    file(s) with this exception, you may extend this exception to your
 *    version of the file(s), but you are not obligated to do so. If you do not
 *    wish to do so, delete this exception statement from your version. If you
 *    delete this exception statement from all source files in the program,
 *    then also delete it in the license file.
 */

#pragma once

#include <string>

#include "mongo/base/string_data.h"
#include "mongo/bson/util/builder.h"

namespace mongo {
    //can't use hex namespace because it conflicts with hex iostream function
    inline int fromHex( char c ) {
        if ( '0' <= c && c <= '9' )
            return c - '0';
        if ( 'a' <= c && c <= 'f' )
            return c - 'a' + 10;
        if ( 'A' <= c && c <= 'F' )
            return c - 'A' + 10;
        verify( false );
        return 0xff;
    }
    inline char fromHex( const char *c ) {
        return (char)(( fromHex( c[ 0 ] ) << 4 ) | fromHex( c[ 1 ] ));
    }
    inline char fromHex( const StringData& c ) {
        return (char)(( fromHex( c[ 0 ] ) << 4 ) | fromHex( c[ 1 ] ));
    }

    inline std::string toHex(const void* inRaw, int len) {
        static const char hexchars[] = "0123456789ABCDEF";

        StringBuilder out;
        const char* in = reinterpret_cast<const char*>(inRaw);
        for (int i=0; i<len; ++i) {
            char c = in[i];
            char hi = hexchars[(c & 0xF0) >> 4];
            char lo = hexchars[(c & 0x0F)];

            out << hi << lo;
        }

        return out.str();
    }

    template <typename T> std::string integerToHex(T val);

    inline std::string toHexLower(const void* inRaw, int len) {
        static const char hexchars[] = "0123456789abcdef";

        StringBuilder out;
        const char* in = reinterpret_cast<const char*>(inRaw);
        for (int i=0; i<len; ++i) {
            char c = in[i];
            char hi = hexchars[(c & 0xF0) >> 4];
            char lo = hexchars[(c & 0x0F)];

            out << hi << lo;
        }

        return out.str();
    }
}
