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Add optional offset to partial_range

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This commit is contained in:
Kp 2014-04-19 21:54:35 +00:00
parent 20164b0639
commit 5c14cf870f
1 changed files with 37 additions and 10 deletions
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47
common/include/partial_range.h
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@ -5,7 +5,10 @@
* terms and a link to the Git history.
*/
#pragma once
#include <stdexcept>
#include <cstdio>
#include "dxxsconf.h"
#include "compiler-addressof.h"
#include "compiler-begin.h"
#include "compiler-type_traits.h"
@ -41,19 +44,43 @@ namespace boost
}
#endif
template <typename T, typename U>
typename tt::enable_if<!tt::is_unsigned<U>::value, void>::type partial_range(T &, U) DXX_CXX11_EXPLICIT_DELETE;
template <typename T>
struct partial_range_error_t : public std::out_of_range
{
partial_range_error_t(const std::string& s) :
std::out_of_range(s)
{
}
static void report(const char *desc, unsigned long expr, const T &t, unsigned long d)
{
char buf[84];
snprintf(buf, sizeof(buf), "%s %lu past %p end %lu", desc, expr, addressof(t), d);
throw partial_range_error_t<T>(buf);
}
};
template <typename T, typename U>
typename tt::enable_if<tt::is_unsigned<U>::value, partial_range_t<typename T::iterator>>::type partial_range(T &t, const U &l)
{
auto b = begin(t);
return partial_range_t<typename T::iterator>(b, b + l);
}
typename tt::enable_if<!tt::is_unsigned<U>::value, void>::type partial_range(T &, U, U = U()) DXX_CXX11_EXPLICIT_DELETE;
template <typename T, typename U>
typename tt::enable_if<tt::is_unsigned<U>::value, partial_range_t<typename T::const_iterator>>::type partial_range(const T &t, const U &l)
static inline typename tt::enable_if<tt::is_unsigned<U>::value, partial_range_t<typename tt::conditional<tt::is_const<T>::value, typename T::const_iterator, typename T::iterator>::type>>::type partial_range(T &t, const U l, const U o = 0)
{
auto b = begin(t);
return partial_range_t<typename T::const_iterator>(b, b + l);
using std::begin;
using std::end;
using std::advance;
using std::distance;
auto range_begin = begin(t), range_end = range_begin;
#define PARTIAL_RANGE_CHECK_BOUND(EXPR,S) \
if (EXPR > d) \
partial_range_error_t<const T>::report(S, EXPR, t, d)
size_t d = distance(range_begin, end(t));
PARTIAL_RANGE_CHECK_BOUND(o, "begin");
PARTIAL_RANGE_CHECK_BOUND(l, "end");
#undef PARTIAL_RANGE_CHECK_BOUND
if (o <= l)
{
advance(range_begin, o);
advance(range_end, l);
}
return partial_range_t<typename tt::conditional<tt::is_const<T>::value, typename T::const_iterator, typename T::iterator>::type>(range_begin, range_end);
}