RetroShare/libretroshare/src/util/rsid.h
2012-08-15 20:08:18 +00:00

123 lines
3.5 KiB
C++

// This class aims at defining a generic ID type that is a list of bytes. It
// can be converted into a hexadecial string for printing, mainly) or for
// compatibility with old methods.
//
// To use this class, derive your own ID type from it. Examples include:
//
// class PGPIdType: public t_RsGenericIdType<8>
// {
// [..]
// };
//
// class PGPFingerprintType: public t_RsGenericIdType<20>
// {
// [..]
// };
//
// With this, there is no implicit conversion between subtypes, and therefore ID mixup
// is impossible.
//
// A simpler way to make ID types is to
// typedef t_RsGenericIdType<MySize> MyType ;
//
// ID Types with different lengths will be incompatible on compilation.
//
// Warning: never store references to a t_RsGenericIdType accross threads, since the
// cached string convertion is not thread safe.
//
#pragma once
#include <stdexcept>
#include <string>
#include <stdint.h>
template<uint32_t ID_SIZE_IN_BYTES> class t_RsGenericIdType
{
public:
t_RsGenericIdType() { memset(bytes,0,ID_SIZE_IN_BYTES) ;}
virtual ~t_RsGenericIdType() {}
// Explicit constructor from a hexadecimal string
//
explicit t_RsGenericIdType(const std::string& hex_string) ;
// Explicit constructor from a byte array. The array should have size at least ID_SIZE_IN_BYTES
//
explicit t_RsGenericIdType(const unsigned char bytes[]) ;
// Converts to a std::string using cached value.
//
std::string toStdString(bool upper_case = true) const ;
const unsigned char *toByteArray() const { return &bytes[0] ; }
static const uint32_t SIZE_IN_BYTES = ID_SIZE_IN_BYTES ;
bool operator==(const t_RsGenericIdType<ID_SIZE_IN_BYTES>& fp) const
{
for(uint32_t i=0;i<ID_SIZE_IN_BYTES;++i)
if(fp.bytes[i] != bytes[i])
return false ;
return true ;
}
bool operator!=(const t_RsGenericIdType<ID_SIZE_IN_BYTES>& fp) const
{
return !operator==(fp) ;
}
private:
unsigned char bytes[ID_SIZE_IN_BYTES] ;
};
template<uint32_t ID_SIZE_IN_BYTES> std::string t_RsGenericIdType<ID_SIZE_IN_BYTES>::toStdString(bool upper_case) const
{
static const char outh[16] = { '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F' } ;
static const char outl[16] = { '0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f' } ;
std::string res(ID_SIZE_IN_BYTES*2,' ') ;
for(uint32_t j = 0; j < ID_SIZE_IN_BYTES; j++)
if(upper_case)
{
res[2*j ] = outh[ (bytes[j]>>4) ] ;
res[2*j+1] = outh[ bytes[j] & 0xf ] ;
}
else
{
res[2*j ] = outl[ (bytes[j]>>4) ] ;
res[2*j+1] = outl[ bytes[j] & 0xf ] ;
}
return res ;
}
template<uint32_t ID_SIZE_IN_BYTES> t_RsGenericIdType<ID_SIZE_IN_BYTES>::t_RsGenericIdType(const std::string& s)
{
int n=0;
if(s.length() != ID_SIZE_IN_BYTES*2)
throw std::runtime_error("t_RsGenericIdType<>::t_RsGenericIdType(std::string&): supplied string in constructor has wrong size.") ;
for(uint32_t i = 0; i < ID_SIZE_IN_BYTES; ++i)
{
bytes[i] = 0 ;
for(int k=0;k<2;++k)
{
char b = s[n++] ;
if(b >= 'A' && b <= 'F')
bytes[i] += (b-'A'+10) << 4*(1-k) ;
else if(b >= 'a' && b <= 'f')
bytes[i] += (b-'a'+10) << 4*(1-k) ;
else if(b >= '0' && b <= '9')
bytes[i] += (b-'0') << 4*(1-k) ;
else
throw std::runtime_error("t_RsGenericIdType<>::t_RsGenericIdType(std::string&): supplied string is not purely hexadecimal") ;
}
}
}
template<uint32_t ID_SIZE_IN_BYTES> t_RsGenericIdType<ID_SIZE_IN_BYTES>::t_RsGenericIdType(const unsigned char *mem)
{
memcpy(bytes,mem,ID_SIZE_IN_BYTES) ;
}