Add support for mot-encoder fifo

1 files changed, 53 insertions, 17 deletions

diff --git a/xpad.c b/xpad.c
index 472e40c..2960068 100644
--- a/xpad.c
+++ b/xpad.c
@@ -6,6 +6,7 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <assert.h>
+#include <errno.h>
 
 #include "xpad.h"
 
@@ -22,31 +23,66 @@ static int xpad_fd = 0;
    it generates
    */
 
-int xpad_len() {
-    if (xpad_fd == 0) {
-        xpad_fd = open("/home/bram/dab/mot-slideshow.file", O_RDONLY);
-        if (xpad_fd < 0) {
-            perror("Failed to open xpad file");
-            exit(1);
+/* Create and open the desired PAD input fifo
+ */
+int xpad_init(char* pad_fifo, int pad_len)
+{
+    if (mkfifo(pad_fifo, S_IWUSR | S_IRUSR | S_IRGRP | S_IROTH) != 0) {
+        if (errno != EEXIST) {
+            fprintf(stderr, "Can't create pad file: %d!\n", errno);
+            return -1;
         }
     }
-    return 1;
-}
 
-uint8_t xpad_byte(void) {
-    uint8_t dat;
+    xpad_fd = open(pad_fifo, O_RDONLY | O_NONBLOCK);
+    if (xpad_fd == -1) {
+        fprintf(stderr, "Can't open pad file!\n");
+        return -1;
+    }
+
+    int flags = fcntl(xpad_fd, F_GETFL, 0);
+    if (fcntl(xpad_fd, F_SETFL, flags | O_NONBLOCK)) {
+        fprintf(stderr, "Can't set non-blocking mode in pad file!\n");
+        return -1;
+    }
+
+    return 0;
+}
 
+int xpad_read_len(uint8_t* buf, int len)
+{
     assert(xpad_fd != 0);
-    ssize_t num_read = read(xpad_fd, &dat, 1);
 
-    if (num_read == 0) {
-        fprintf(stderr, "xpad rewind\n");
-        lseek(xpad_fd, 0, SEEK_SET);
-        num_read = read(xpad_fd, &dat, 1);
+    ssize_t num_read = 0;
+
+    while (num_read < len) {
+        ssize_t r = read(xpad_fd, buf, len);
+
+        if(r < 0) {
+            if (errno == EAGAIN) {
+                return 0;
+            }
+            else {
+                perror("PAD input read error");
+                return -1;
+            }
+        }
+        else if (r == 0) {
+            // reached end of data
+            return 0;
+        }
+
+        num_read += r;
+    }
 
-        assert(num_read == 1);
+#if XPAD_DEBUG
+    int i;
+    for (i = 0; i < len; i++) {
+        fprintf(stderr, "%02x ", buf[i]);
     }
+    fprintf(stderr, "\n");
+#endif
 
-    return dat;
+    return num_read;
 }