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// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2015 Google Inc. All rights reserved.
// http://ceres-solver.org/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of Google Inc. nor the names of its contributors may be
// used to endorse or promote products derived from this software without
// specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// Author: keir@google.com (Keir Mierle)
#include "ceres/split.h"
#include <iterator>
#include <string>
#include <vector>
#include "ceres/internal/port.h"
namespace ceres {
namespace internal {
using std::string;
using std::vector;
// If we know how much to allocate for a vector of strings, we can allocate the
// vector<string> only once and directly to the right size. This saves in
// between 33-66 % of memory space needed for the result, and runs faster in the
// microbenchmarks.
//
// The reserve is only implemented for the single character delim.
//
// The implementation for counting is cut-and-pasted from
// SplitStringToIteratorUsing. I could have written my own counting iterator,
// and use the existing template function, but probably this is more clear and
// more sure to get optimized to reasonable code.
static int CalculateReserveForVector(const string& full, const char* delim) {
int count = 0;
if (delim[0] != '\0' && delim[1] == '\0') {
// Optimize the common case where delim is a single character.
char c = delim[0];
const char* p = full.data();
const char* end = p + full.size();
while (p != end) {
if (*p == c) { // This could be optimized with hasless(v,1) trick.
++p;
} else {
while (++p != end && *p != c) {
// Skip to the next occurence of the delimiter.
}
++count;
}
}
}
return count;
}
template <typename StringType, typename ITR>
static inline void SplitStringToIteratorUsing(const StringType& full,
const char* delim,
ITR& result) {
// Optimize the common case where delim is a single character.
if (delim[0] != '\0' && delim[1] == '\0') {
char c = delim[0];
const char* p = full.data();
const char* end = p + full.size();
while (p != end) {
if (*p == c) {
++p;
} else {
const char* start = p;
while (++p != end && *p != c) {
// Skip to the next occurence of the delimiter.
}
*result++ = StringType(start, p - start);
}
}
return;
}
string::size_type begin_index, end_index;
begin_index = full.find_first_not_of(delim);
while (begin_index != string::npos) {
end_index = full.find_first_of(delim, begin_index);
if (end_index == string::npos) {
*result++ = full.substr(begin_index);
return;
}
*result++ = full.substr(begin_index, (end_index - begin_index));
begin_index = full.find_first_not_of(delim, end_index);
}
}
void SplitStringUsing(const string& full,
const char* delim,
vector<string>* result) {
result->reserve(result->size() + CalculateReserveForVector(full, delim));
std::back_insert_iterator<vector<string>> it(*result);
SplitStringToIteratorUsing(full, delim, it);
}
} // namespace internal
} // namespace ceres
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