| // 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 |