ZRCola/lib/libZRCola/src/mapping.cpp

83 lines
2.5 KiB
C++

/*
Copyright 2015-2017 Amebis
This file is part of ZRCola.
ZRCola is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
ZRCola 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with ZRCola. If not, see <http://www.gnu.org/licenses/>.
*/
#include "stdafx.h"
size_t ZRCola::mapping_vector::to_src(_In_ size_t dst) const
{
if (empty()) {
// One-to-one mapping.
return dst;
}
for (size_type l = 0, r = size();;) {
if (l < r) {
size_type m = (l + r) / 2;
const mapping &el = (*this)[m];
if ( dst < el.dst) r = m;
else if (el.dst < dst) l = m + 1;
else {
// An exact match found.
return el.src;
}
} else if (l) {
// We found a map interval.
const mapping &el = (*this)[l - 1];
return el.src + (dst - el.dst);
} else {
// The destination character index is left of the first transformation.
const mapping &el = (*this)[0];
return std::min<size_t>(dst, el.src);
}
}
}
size_t ZRCola::mapping_vector::to_dst(_In_ size_t src) const
{
if (empty()) {
// One-to-one mapping.
return src;
}
for (size_type l = 0, r = size();;) {
if (l < r) {
size_type m = (l + r) / 2;
const mapping &el = (*this)[m];
if ( src < el.src) r = m;
else if (el.src < src) l = m + 1;
else {
// An exact match found.
return el.dst;
}
} else if (l) {
// We found a map interval.
const mapping &el = (*this)[l - 1];
return el.dst + (src - el.src);
} else {
// The source character index is left of the first transformation.
const mapping &el = (*this)[0];
return std::min<size_t>(src, el.dst);
}
}
}