From 5317e1ce90f781458e3e75585a6f46ba2ea788f2 Mon Sep 17 00:00:00 2001
From: Taylor Holberton <taylorcholberton@gmail.com>
Date: Sun, 4 Dec 2016 13:17:53 -0800
Subject: Added examples for basic IO

Added an example of pcm_writei usage and an example of pcm_readi
usage. Both examples use a common file called 'audio.raw'.
---
 examples/pcm-readi.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 examples/pcm-readi.c

(limited to 'examples/pcm-readi.c')

diff --git a/examples/pcm-readi.c b/examples/pcm-readi.c
new file mode 100644
index 0000000..5b85ca6
--- /dev/null
+++ b/examples/pcm-readi.c
@@ -0,0 +1,83 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <tinyalsa/pcm.h>
+
+static size_t read_frames(void **frames)
+{
+    unsigned int card = 0;
+    unsigned int device = 0;
+    int flags = PCM_IN;
+
+    const struct pcm_config config = {
+        .channels = 2,
+        .rate = 48000,
+        .format = PCM_FORMAT_S32_LE,
+        .period_size = 1024,
+        .period_count = 2,
+        .start_threshold = 1024,
+        .silence_threshold = 1024 * 2,
+        .stop_threshold = 1024 * 2
+    };
+
+    struct pcm *pcm = pcm_open(card, device, flags, &config);
+    if (pcm == NULL) {
+        fprintf(stderr, "failed to allocate memory for PCM\n");
+        return EXIT_FAILURE;
+    } else if (!pcm_is_ready(pcm)){
+        pcm_close(pcm);
+        fprintf(stderr, "failed to open PCM\n");
+        return EXIT_FAILURE;
+    }
+
+    unsigned int frame_size = pcm_frames_to_bytes(pcm, 1);
+    unsigned int frames_per_sec = pcm_get_rate(pcm);
+
+    *frames = malloc(frame_size * frames_per_sec);
+    if (*frames == NULL) {
+        fprintf(stderr, "failed to allocate frames\n");
+        pcm_close(pcm);
+        return EXIT_FAILURE;
+    }
+
+    int read_count = pcm_readi(pcm, *frames, frames_per_sec);
+
+    size_t byte_count = pcm_frames_to_bytes(pcm, read_count);
+
+    pcm_close(pcm);
+
+    return byte_count;
+}
+
+static int write_file(const void *frames, size_t size)
+{
+    FILE *output_file = fopen("audio.raw", "wb");
+    if (output_file == NULL) {
+        perror("failed to open 'audio.raw' for writing");
+        return EXIT_FAILURE;
+    }
+    fwrite(frames, 1, size, output_file);
+    fclose(output_file);
+    return 0;
+}
+
+int main(void)
+{
+    void *frames;
+    size_t size;
+
+    size = read_frames(&frames);
+    if (size == 0) {
+        return EXIT_FAILURE;
+    }
+
+    if (write_file(frames, size) < 0) {
+        free(frames);
+        return EXIT_FAILURE;
+    }
+
+    free(frames);
+
+    return EXIT_SUCCESS;
+}
+
-- 
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