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| -rw-r--r-- | include/unotools/digitgroupingiterator.hxx | 194 |
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diff --git a/include/unotools/digitgroupingiterator.hxx b/include/unotools/digitgroupingiterator.hxx new file mode 100644 index 000000000..7206f72f1 --- /dev/null +++ b/include/unotools/digitgroupingiterator.hxx @@ -0,0 +1,194 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + * + * This file incorporates work covered by the following license notice: + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed + * with this work for additional information regarding copyright + * ownership. The ASF licenses this file to you 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 . + */ + +#ifndef INCLUDED_UNOTOOLS_DIGITGROUPINGITERATOR_HXX +#define INCLUDED_UNOTOOLS_DIGITGROUPINGITERATOR_HXX + +#include <com/sun/star/uno/Sequence.hxx> +#include <sal/log.hxx> + +namespace utl { + +/** Iterator to be used with a digit grouping as obtained through + LocaleDataWrapper::getDigitGrouping(). + + The iterator advances over the digit groupings, returning the number of + digits per group. If the last group was encountered the iterator will + always return the last grouping. + + Grouping values are sanitized to be >= 0, even if originally signed + sal_Int32. + + Usage example with a string buffer containing a decimal representation of + an integer number. Note that of course this loop could be optimized to not + count single characters but hunks of groups instead using the get() method, + this is just for illustrating usage. Anyway, for double values it is highly + more efficient to use ::rtl::math::doubleToString() and pass the grouping + sequence, instead of using this iterator and inserting characters into + strings. + + DigitGroupingIterator aGrouping(...) + sal_Int32 nCount = 0; + sal_Int32 n = aBuffer.getLength(); + // >1 because we don't want to insert a separator if there is no leading digit. + while (n-- > 1) + { + if (++nCount >= aGrouping.getPos()) + { + aBuffer.insert( n, cSeparator); + nGroupDigits = aGrouping.advance(); + } + } + + */ + +class DigitGroupingIterator +{ + const css::uno::Sequence< sal_Int32 > maGroupings; + + sal_Int32 mnGroup; // current active grouping + sal_Int32 mnDigits; // current active digits per group + sal_Int32 mnNextPos; // position (in digits) of next grouping + + void setInfinite() + { + mnGroup = maGroupings.getLength(); + } + + bool isInfinite() const + { + return mnGroup >= maGroupings.getLength(); + } + + sal_Int32 getGrouping() const + { + if (mnGroup < maGroupings.getLength()) + { + sal_Int32 n = maGroupings[mnGroup]; + SAL_WARN_IF( n < 0, "unotools.i18n", "DigitGroupingIterator::getGrouping: negative grouping"); + if (n < 0) + n = 0; // sanitize ... + return n; + } + return 0; + } + + void setPos() + { + // someone might be playing jokes on us, so check for overflow + if (mnNextPos <= SAL_MAX_INT32 - mnDigits) + mnNextPos += mnDigits; + } + + void setDigits() + { + sal_Int32 nPrev = mnDigits; + mnDigits = getGrouping(); + if (!mnDigits) + { + mnDigits = nPrev; + setInfinite(); + } + setPos(); + } + + void initGrouping() + { + mnDigits = 3; // just in case of constructed with empty grouping + mnGroup = 0; + mnNextPos = 0; + setDigits(); + } + + DigitGroupingIterator( const DigitGroupingIterator & ) = delete; + DigitGroupingIterator & operator=( const DigitGroupingIterator & ) = delete; + +public: + + explicit DigitGroupingIterator( const css::uno::Sequence< sal_Int32 > & rGroupings ) + : maGroupings( rGroupings) + { + initGrouping(); + } + + /** Advance iterator to next grouping. */ + DigitGroupingIterator & advance() + { + if (isInfinite()) + setPos(); + else + { + ++mnGroup; + setDigits(); + } + return *this; + } + + /** Obtain current grouping. Always > 0. */ + sal_Int32 get() const + { + return mnDigits; + } + + /** The next position (in integer digits) from the right where to insert a + group separator. */ + sal_Int32 getPos() const + { + return mnNextPos; + } + + /** Reset iterator to start again from the right beginning. */ + void reset() + { + initGrouping(); + } + + /** Create a sequence of bool values containing positions where to add a + separator when iterating forward over a string and copying digit per + digit. For example, for grouping in thousands and nIntegerDigits==7 the + sequence returned would be {1,0,0,1,0,0,0} so the caller would add a + separator after the 1st and the 4th digit. */ + static css::uno::Sequence< sal_Bool > createForwardSequence( + sal_Int32 nIntegerDigits, + const css::uno::Sequence< sal_Int32 > & rGroupings ) + { + if (nIntegerDigits <= 0) + return css::uno::Sequence< sal_Bool >(); + DigitGroupingIterator aIterator( rGroupings); + css::uno::Sequence< sal_Bool > aSeq( nIntegerDigits); + sal_Bool* pArr = aSeq.getArray(); + for (sal_Int32 j = 0; --nIntegerDigits >= 0; ++j) + { + if (j == aIterator.getPos()) + { + pArr[nIntegerDigits] = true; + aIterator.advance(); + } + else + pArr[nIntegerDigits] = false; + } + return aSeq; + } +}; + +} // namespace utl + +#endif // INCLUDED_UNOTOOLS_DIGITGROUPINGITERATOR_HXX + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |