comparison data/fileio/CSVStreamWriter.h @ 1453:4b496a258782

Merge from branch streaming-csv-writer

+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    This file copyright 2017 Queen Mary, University of London.
+    
+    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 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef SV_CSV_STREAM_WRITER_H
+#define SV_CSV_STREAM_WRITER_H
+
+#include "base/BaseTypes.h"
+#include "base/Selection.h"
+#include "base/ProgressReporter.h"
+#include "base/DataExportOptions.h"
+#include "data/model/Model.h"
+#include <QString>
+#include <algorithm>
+#include <numeric>
+
+namespace CSVStreamWriter
+{
+
+template <class OutStream>
+bool
+writeInChunks(OutStream& oss,
+              const Model& model,
+              const MultiSelection& regions,
+              ProgressReporter* reporter = nullptr,
+              QString delimiter = ",",
+              DataExportOptions options = DataExportDefaults,
+              const sv_frame_t blockSize = 16384)
+{
+    const auto selections = regions.getSelections();
+    if (blockSize <= 0 || selections.empty()) return false;
+
+    // TODO, some form of checking validity of selections?
+    const auto nFramesToWrite = std::accumulate(
+        selections.begin(),
+        selections.end(),
+        0,
+        [](sv_frame_t acc, const Selection& current) -> sv_frame_t {
+            return acc + (current.getEndFrame() - current.getStartFrame());
+        }
+    );
+    const auto finalFrameOfLastRegion = (*selections.crbegin()).getEndFrame();
+
+    const auto wasCancelled = [&reporter]() { 
+        return reporter && reporter->wasCancelled(); 
+    };
+
+    sv_frame_t nFramesWritten = 0;
+    int previousProgress = 0;
+
+    for (const auto& extents : selections) {
+        const auto startFrame = extents.getStartFrame();
+        const auto endFrame = extents.getEndFrame();
+        auto readPtr = startFrame;
+        while (readPtr < endFrame) {
+            if (wasCancelled()) return false;
+
+            const auto start = readPtr;
+            const auto end = std::min(start + blockSize, endFrame);
+            const auto data = model.toDelimitedDataStringSubsetWithOptions(
+                delimiter,
+                options,
+                start,
+                end
+            ).trimmed();
+
+            if ( data != "" ) {
+                oss << data << (end < finalFrameOfLastRegion ? "\n" : "");
+            }
+
+            nFramesWritten += end - start;
+            const auto currentProgress = 100 * nFramesWritten / nFramesToWrite;
+            const bool hasIncreased = currentProgress > previousProgress;
+            if (hasIncreased) {
+                if (reporter) reporter->setProgress(currentProgress);
+                previousProgress = currentProgress;
+            }
+            readPtr = end;
+        }
+    }
+    return !wasCancelled(); // setProgress could process event loop
+}
+
+template <class OutStream>
+bool 
+writeInChunks(OutStream& oss,
+              const Model& model,
+              const Selection& extents,
+              ProgressReporter* reporter = nullptr,
+              QString delimiter = ",",
+              DataExportOptions options = DataExportDefaults,
+              const sv_frame_t blockSize = 16384)
+{
+    const auto startFrame = extents.isEmpty() ?
+        model.getStartFrame() : extents.getStartFrame();
+    const auto endFrame = extents.isEmpty() ?
+        model.getEndFrame() : extents.getEndFrame();
+    const auto hasValidExtents = startFrame >= 0 && endFrame > startFrame;
+    if (!hasValidExtents) return false;
+    Selection all {
+        startFrame,
+        endFrame
+    };
+    MultiSelection regions;
+    regions.addSelection(all);
+    return CSVStreamWriter::writeInChunks(
+        oss,
+        model,
+        regions,
+        reporter,
+        delimiter,
+        options,
+        blockSize
+    );
+}
+
+template <class OutStream>
+bool 
+writeInChunks(OutStream& oss,
+              const Model& model,
+              ProgressReporter* reporter = nullptr,
+              QString delimiter = ",",
+              DataExportOptions options = DataExportDefaults,
+              const sv_frame_t blockSize = 16384)
+{
+    const Selection empty;
+    return CSVStreamWriter::writeInChunks(
+        oss,
+        model,
+        empty,
+        reporter,
+        delimiter,
+        options,
+        blockSize
+    );
+}
+} // namespace CSVStreamWriter
+#endif