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- /*
- * Copyright 2015 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #ifndef Stats_DEFINED
- #define Stats_DEFINED
- #include "include/core/SkString.h"
- #include "include/private/SkFloatingPoint.h"
- #include "src/core/SkTSort.h"
- #ifdef SK_BUILD_FOR_WIN
- static const char* kBars[] = { ".", "o", "O" };
- #else
- static const char* kBars[] = { "▁", "▂", "▃", "▄", "▅", "▆", "▇", "█" };
- #endif
- struct Stats {
- Stats(const SkTArray<double>& samples, bool want_plot) {
- int n = samples.count();
- if (!n) {
- min = max = mean = var = median = 0;
- return;
- }
- min = samples[0];
- max = samples[0];
- for (int i = 0; i < n; i++) {
- if (samples[i] < min) { min = samples[i]; }
- if (samples[i] > max) { max = samples[i]; }
- }
- double sum = 0.0;
- for (int i = 0 ; i < n; i++) {
- sum += samples[i];
- }
- mean = sum / n;
- double err = 0.0;
- for (int i = 0 ; i < n; i++) {
- err += (samples[i] - mean) * (samples[i] - mean);
- }
- var = sk_ieee_double_divide(err, n-1);
- SkAutoTMalloc<double> sorted(n);
- memcpy(sorted.get(), samples.begin(), n * sizeof(double));
- SkTQSort(sorted.get(), sorted.get() + n - 1);
- median = sorted[n/2];
- // Normalize samples to [min, max] in as many quanta as we have distinct bars to print.
- for (int i = 0; want_plot && i < n; i++) {
- if (min == max) {
- // All samples are the same value. Don't divide by zero.
- plot.append(kBars[0]);
- continue;
- }
- double s = samples[i];
- s -= min;
- s /= (max - min);
- s *= (SK_ARRAY_COUNT(kBars) - 1);
- const size_t bar = (size_t)(s + 0.5);
- SkASSERT_RELEASE(bar < SK_ARRAY_COUNT(kBars));
- plot.append(kBars[bar]);
- }
- }
- double min;
- double max;
- double mean; // Estimate of population mean.
- double var; // Estimate of population variance.
- double median;
- SkString plot; // A single-line bar chart (_not_ histogram) of the samples.
- };
- #endif//Stats_DEFINED
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