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/*************************************************************************
** ToUnicodeMap.cpp **
** **
** This file is part of dvisvgm -- a fast DVI to SVG converter **
** Copyright (C) 2005-2023 Martin Gieseking <martin.gieseking@uos.de> **
** **
** This program 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. **
** **
** 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 General Public License for more details. **
** **
** You should have received a copy of the GNU General Public License **
** along with this program; if not, see <http://www.gnu.org/licenses/>. **
*************************************************************************/
#include <limits>
#include "ToUnicodeMap.hpp"
#include "Unicode.hpp"
using namespace std;
/** Adds valid but random mappings for all missing character indexes.
* If a font's cmap table doesn't provide Unicode mappings for some
* glyphs in the font, it's necessary to fill the gaps in order to
* handle all characters correctly. This functions assumes that the
* characters are numbered from 1 to maxIndex.
* @param[in] maxIndex largest character index to consider
* @return true on success */
bool ToUnicodeMap::addMissingMappings (uint32_t maxIndex) {
bool success=true;
// collect Unicode points already in assigned
NumericRanges<uint32_t> codepoints;
for (size_t i=0; i < numRanges() && success; i++)
codepoints.addRange(rangeAt(i).minval(), rangeAt(i).maxval());
// fill unmapped ranges
if (empty()) // no Unicode mapping present at all?
success = fillRange(1, maxIndex, 1, codepoints, true);
else { // (partial) Unicode mapping present?
success = fillRange(1, rangeAt(0).min()-1, rangeAt(0).minval()-1, codepoints, false);
for (size_t i=0; i < numRanges()-1 && success; i++)
success = fillRange(rangeAt(i).max()+1, rangeAt(i+1).min()-1, rangeAt(i).maxval()+1, codepoints, true);
if (success)
success = fillRange(rangeAt(numRanges()-1).max()+1, maxIndex, rangeAt(numRanges()-1).maxval()+1, codepoints, true);
}
return success;
}
/** Checks if a given codepoint is valid and unused. Otherwise, try to find an alternative.
* @param[in,out] ucp codepoint to fix
* @param[in] used_codepoints codepoints already in use
* @param[in] ascending if true, increase ucp to look for valid/unused codepoints
* @return true on success */
static bool fix_codepoint (uint32_t &ucp, const NumericRanges<uint32_t> &used_codepoints, bool ascending) {
uint32_t start = ucp;
while (!Unicode::isValidCodepoint(ucp) && used_codepoints.valueExists(ucp)) {
if (ascending)
ucp = (ucp == numeric_limits<uint32_t>::max()) ? 0 : ucp+1;
else
ucp = (ucp == 0) ? numeric_limits<uint32_t>::max() : ucp-1;
if (ucp == start) // no free Unicode point found
return false;
}
return true;
}
static bool is_less_or_equal (uint32_t a, uint32_t b) {return a <= b;}
static bool is_greater_or_equal (uint32_t a, uint32_t b) {return a >= b;}
/** Adds index to Unicode mappings for a given range of character indexes.
* @param[in] minIndex lower bound of range to fill
* @param[in] maxIndex upper bound of range to fill
* @param[in] ucp first Unicode point to add (if possible)
* @param[in,out] used_ucps Unicode points already in use
* @param[in] ascending if true, fill range from lower to upper bound
* @return true on success */
bool ToUnicodeMap::fillRange (uint32_t minIndex, uint32_t maxIndex, uint32_t ucp, NumericRanges<uint32_t> &used_ucps, bool ascending) {
if (minIndex <= maxIndex) {
uint32_t first=minIndex, last=maxIndex;
int inc=1;
bool (*cmp)(uint32_t, uint32_t) = is_less_or_equal;
if (!ascending) {
swap(first, last);
inc = -1;
cmp = is_greater_or_equal;
}
for (uint32_t i=first; cmp(i, last); i += inc) {
if (!fix_codepoint(ucp, used_ucps, ascending))
return false;
else {
addRange(i, i, ucp);
used_ucps.addRange(ucp);
ucp += inc; // preferred Unicode point for the next character of the current range
}
}
}
return true;
}
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