resample: add peaks resampler

spa/plugins/audioconvert/resample-peaks.h

@@ -0,0 +1,101 @@
+/* Spa
+ *
+ * Copyright © 2018 Wim Taymans
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <math.h>
+
+struct peaks_data {
+	unsigned o_count;
+	unsigned i_count;
+	float max_f[0];
+};
+
+static void impl_peaks_free(struct resample *r)
+{
+	if (r->data)
+		free(r->data);
+	r->data = NULL;
+}
+
+static void impl_peaks_update_rate(struct resample *r, double rate)
+{
+}
+
+static void impl_peaks_process(struct resample *r, int channel,
+			void *src, uint32_t *in_len, void *dst, uint32_t *out_len)
+{
+	struct peaks_data *pd = r->data;
+	float *s = src, *d = dst;
+	int i, o, end;
+
+	i = ((uint64_t) pd->o_count * r->i_rate) / r->o_rate;
+	i = i > pd->i_count ? i - pd->i_count : 0;
+	o = 0;
+
+	while (i < *in_len && o < *out_len) {
+	        end = ((uint64_t) (pd->o_count + 1) * r->i_rate) / r->o_rate;
+		end = end > pd->i_count ? end - pd->i_count : 0;
+
+		for (; i < end && i < *in_len; i++) {
+			float n = fabsf(s[i]);
+			if (n > pd->max_f[channel])
+				pd->max_f[channel] = n;
+		}
+
+		if (i == end) {
+			d[o++] = pd->max_f[channel];
+			pd->max_f[channel] = 0.0f;
+			pd->o_count++;
+		}
+	}
+	*out_len = o;
+	*in_len = i;
+	pd->i_count += i;
+
+	while (pd->i_count >= r->i_rate) {
+		pd->i_count -= r->i_rate;
+		pd->o_count -= r->o_rate;
+	}
+}
+
+static void impl_peaks_reset (struct resample *r)
+{
+	struct peaks_data *d = r->data;
+	d->i_count = d->o_count = 0;
+}
+
+static int impl_peaks_init(struct resample *r)
+{
+	struct peaks_data *d;
+
+	r->free = impl_peaks_free;
+	r->update_rate = impl_peaks_update_rate;
+	r->process = impl_peaks_process;
+	r->reset = impl_peaks_reset;
+	d = r->data = calloc(1, sizeof(struct peaks_data) * sizeof(float) * r->channels);
+	if (r->data == NULL)
+		return -ENOMEM;
+
+	d->i_count = d->o_count = 0;
+	return 0;
+}