ChunkDimensionStats.hpp

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#ifndef TATAMI_CHUNKED_CHUNK_DIMENSION_STATS_HPP
#define TATAMI_CHUNKED_CHUNK_DIMENSION_STATS_HPP
 
#include "sanisizer/sanisizer.hpp"
 
namespace tatami_chunked {
 
template<typename Index_>
Index_ integer_ceil(Index_ left, Index_ right) {
    if (right) {
        return left / right + (left % right > 0); // avoids overflow.
    } else {
        return 0;
    }
}
 
template<typename Index_>
struct ChunkDimensionStats {
    template<typename DimExtent_, typename ChunkLength_>
    ChunkDimensionStats(DimExtent_ dimension_extent, ChunkLength_ chunk_length) :
        dimension_extent(sanisizer::cast<Index_>(dimension_extent)),
        chunk_length(sanisizer::cast<Index_>(chunk_length)),
        num_chunks(integer_ceil(dimension_extent, chunk_length)),
        last_chunk_length(num_chunks ? (dimension_extent - (num_chunks - 1) * chunk_length) : 0)
    {}
 
    ChunkDimensionStats() : ChunkDimensionStats(0, 0) {}
 
    Index_ dimension_extent;
 
    Index_ chunk_length;
 
    Index_ num_chunks;
 
    Index_ last_chunk_length;
};
 
template<typename Index_>
Index_ get_chunk_length(const ChunkDimensionStats<Index_>& stats, Index_ i) {
    return (i + 1 == stats.num_chunks ? stats.last_chunk_length : stats.chunk_length);
}
 
}
 
#endif