hex.h

// util/hex.h

/*    Copyright 2009 10gen Inc.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

#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();
}
}