From d8e3d3fc0fb6e4f88f3e3c789575e38a74a01299 Mon Sep 17 00:00:00 2001
From: XANTRONIX Development
Date: Mon, 31 Jan 2022 10:53:09 -0500
Subject: Add examples/

---
 examples/Makefile | 18 +++++++++++
 examples/test.c   | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 114 insertions(+)
 create mode 100644 examples/Makefile
 create mode 100644 examples/test.c

diff --git a/examples/Makefile b/examples/Makefile
new file mode 100644
index 0000000..52755fd
--- /dev/null
+++ b/examples/Makefile
@@ -0,0 +1,18 @@
+include ../mk/build.mk
+
+CC		= $(CROSS)cc
+
+INCLUDE_PATH	= ../include
+
+CFLAGS		+= -I$(INCLUDE_PATH)
+LDFLAGS		+= -L../src -lxas -lm
+
+EXAMPLES	= test
+
+all: $(EXAMPLES)
+
+$(EXAMPLES): %: %.c
+	$(CC) $(CFLAGS) -o $@ $< $(LDFLAGS)
+
+clean:
+	$(RM) -f $(EXAMPLES)
diff --git a/examples/test.c b/examples/test.c
new file mode 100644
index 0000000..ebc32fe
--- /dev/null
+++ b/examples/test.c
@@ -0,0 +1,96 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <sysexits.h>
+#include <fcntl.h>
+#include <math.h>
+
+#include <xas/audio.h>
+#include <xas/riff.h>
+
+#define SYNTH_STATUS_ON (1 << 0)
+
+typedef struct _synth_sine {
+    int flags;
+    float phase;
+
+    size_t sample_rate,
+           frequency;
+} synth_sine;
+
+static void usage(int argc, char **argv, const char *message, ...) {
+    va_list args;
+
+    va_start(args, message);
+
+    if (message) {
+        vfprintf(stderr, message, args);
+        fputc('\n', stderr);
+    }
+
+    va_end(args);
+
+    fprintf(stderr, "usage: %s output.wav\n", argv[0]);
+
+    exit(EX_USAGE);
+}
+
+static ssize_t synth_sine_fill(synth_sine *synth,
+                               int16_t *samples,
+                               size_t count,
+                               xas_audio_stream *stream) {
+    size_t i;
+
+    for (i=0; i<count; i++) {
+        if (synth->flags & SYNTH_STATUS_ON) {
+            samples[i] = (int16_t)roundf((INT16_MAX >> 2) * sinf(synth->phase));
+
+            synth->phase += (2.0f * M_PI) / (stream->sample_rate / synth->frequency);
+        } else {
+            samples[i] = 0;
+        }
+    }
+
+    return count;
+}
+
+int main(int argc, char **argv) {
+    xas_audio_stream *stream;
+
+    int duration_s  = 60,
+        frequency   = 220,
+        sample_rate = 44100;
+
+    int i;
+
+    if (argc != 2) {
+        usage(argc, argv, "No output file provided");
+    }
+
+    if ((stream = xas_riff_file_open(argv[1],
+                                       2,
+                                       sample_rate,
+                                       1,
+                                       O_WRONLY | O_CREAT | O_TRUNC)) == NULL) {
+        goto error_riff_file_open;
+    }
+
+    for (i=0; i < duration_s * frequency; i++) {
+        float phase;
+
+        for (phase = 0.0; phase < 2 * M_PI; phase += (2 * M_PI) / (sample_rate / frequency)) {
+            int16_t value = (int16_t)round((INT16_MAX >> 2) * sin(phase));
+
+            xas_audio_stream_write(stream, &value, 1);
+        }
+    }
+
+    xas_audio_stream_flush(stream);
+    xas_audio_stream_destroy(stream);
+
+    return EX_OK;
+
+error_riff_file_open:
+    return EX_OSERR;
+}
-- 
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