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-writei.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 examples/pcm-writei.c

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

diff --git a/examples/pcm-writei.c b/examples/pcm-writei.c
new file mode 100644
index 0000000..66280eb
--- /dev/null
+++ b/examples/pcm-writei.c
@@ -0,0 +1,100 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <tinyalsa/pcm.h>
+
+static long int file_size(FILE * file)
+{
+    if (fseek(file, 0, SEEK_END) < 0) {
+        return -1;
+    }
+    long int file_size = ftell(file);
+    if (fseek(file, 0, SEEK_SET) < 0) {
+        return -1;
+    }
+    return file_size;
+}
+
+static size_t read_file(void ** frames){
+
+    FILE * input_file = fopen("audio.raw", "rb");
+    if (input_file == NULL) {
+        perror("failed to open 'audio.raw' for writing");
+        return -1;
+    }
+
+    long int size = file_size(input_file);
+    if (size < 0) {
+        perror("failed to get file size of 'audio.raw'");
+        fclose(input_file);
+        return -1;
+    }
+
+    *frames = malloc(size);
+    if (*frames == NULL) {
+        fprintf(stderr, "failed to allocate frames\n");
+        fclose(input_file);
+        return -1;
+    }
+
+    size = fread(*frames, 1, size, input_file);
+
+    fclose(input_file);
+
+    return size;
+}
+
+static int write_frames(const void * frames, size_t byte_count){
+
+    unsigned int card = 0;
+    unsigned int device = 0;
+    int flags = PCM_OUT;
+
+    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 -1;
+    } else if (!pcm_is_ready(pcm)){
+        pcm_close(pcm);
+        fprintf(stderr, "failed to open PCM\n");
+        return -1;
+    }
+
+    unsigned int frame_count = pcm_bytes_to_frames(pcm, byte_count);
+
+    pcm_writei(pcm, frames, frame_count);
+
+    pcm_close(pcm);
+
+    return 0;
+}
+
+int main(void)
+{
+    void *frames;
+    size_t size;
+
+    size = read_file(&frames);
+    if (size == 0) {
+        return EXIT_FAILURE;
+    }
+
+    if (write_frames(frames, size) < 0) {
+        return EXIT_FAILURE;
+    }
+
+    free(frames);
+    return EXIT_SUCCESS;
+}
+
-- 
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