KEEN REFACTORING YES VERY MUCH THANK YOU MA'AM

src/kiss.c

@@ -92,19 +92,10 @@ error_io:
     return -1;
 }
 
-ssize_t patty_kiss_tnc_recv(patty_kiss_tnc *tnc, void **frame, int *port) {
+static ssize_t tnc_decode(patty_kiss_tnc *tnc, void *frame, size_t *len, int *port) {
     size_t i, b;
     int flags = KISS_NONE;
 
-    if (tnc_buffer(tnc) < 0) {
-        goto error_io;
-    }
-
-    /*
-     * Initialize the frame to be returned to the caller.
-     */
-    memset(tnc->frame, '\0', tnc->bufsz);
-
     /*
      * The default port is always zero, unless a command byte issued from the
      * TNC in the first byte of the frame body.
@@ -144,9 +135,9 @@ ssize_t patty_kiss_tnc_recv(patty_kiss_tnc *tnc, void **frame, int *port) {
 
         if (flags & KISS_ESCAPE) {
             if (c == PATTY_KISS_TFEND) {
-                ((unsigned char *)tnc->frame)[b++] = PATTY_KISS_FEND;
+                ((unsigned char *)frame)[b++] = PATTY_KISS_FEND;
             } else if (c == PATTY_KISS_TFESC) {
-                ((unsigned char *)tnc->frame)[b++] = PATTY_KISS_FESC;
+                ((unsigned char *)frame)[b++] = PATTY_KISS_FESC;
             } else {
                 errno = EIO;
 
@@ -167,7 +158,7 @@ ssize_t patty_kiss_tnc_recv(patty_kiss_tnc *tnc, void **frame, int *port) {
                 break;
             }
 
-            ((unsigned char *)tnc->frame)[b++] = c;
+            ((unsigned char *)frame)[b++] = c;
         }
     }
 
@@ -175,32 +166,61 @@ ssize_t patty_kiss_tnc_recv(patty_kiss_tnc *tnc, void **frame, int *port) {
      * Return empty-handed if we do not have a fully book-ended frame.
      */
     if ((flags & KISS_FRAME) == 0) {
-        *frame = NULL;
+        *len  = 0;
+        *port = 0;
 
         return 0;
     }
 
-    if (i) {
-        /*
-         * As we have indeed found a frame at this point, move everything from
-         * the buffer not processed up to this point, to the beginning of the
-         * buffer.
-         */
-        memmove(tnc->buf, ((unsigned char *)tnc->buf) + i, tnc->buflen - i);
+    *len = b;
 
-        /*
-         * And decrement the buffer length by the number of bytes already
-         * processed.
-         */
-        tnc->buflen -= i;
+    return i;
+
+error_io:
+    return -1;
+}
+
+static void tnc_flush(patty_kiss_tnc *tnc, size_t len) {
+    /*
+     * Move everything from the buffer not processed up to this point, to the
+     * beginning of the buffer.
+     */
+    memmove(tnc->buf, ((unsigned char *)tnc->buf) + len, tnc->buflen - len);
+
+    /*
+     * Then, decrement the buffer length by the number of bytes already
+     * processed.
+     */
+    tnc->buflen -= len;
+}
+
+ssize_t patty_kiss_tnc_recv(patty_kiss_tnc *tnc, void **frame, int *port) {
+    ssize_t decoded;
+     size_t framelen;
+
+    /*
+     * Fill the buffer with something to parse!
+     */
+    if (tnc_buffer(tnc) < 0) {
+        goto error_io;
     }
 
     /*
-     * Set the output parameter to the frame buffer.
+     * Initialize the frame to be returned to the caller.
      */
+    memset(tnc->frame, '\0', tnc->bufsz);
+
+    if ((decoded = tnc_decode(tnc, tnc->frame, &framelen, port)) < 0) {
+        goto error_io;
+    }
+
+    if (decoded) {
+        tnc_flush(tnc, decoded);
+    }
+
     *frame = tnc->frame;
 
-    return b;
+    return framelen;
 
 error_io:
     return -1;

src/test.c

@@ -0,0 +1,49 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <patty/kiss.h>
+
+static void usage(int argc, char **argv, const char *message, ...) {
+    if (message) {
+        va_list args;
+
+        va_start(args, message);
+        vfprintf(stderr, message, args);
+         fprintf(stderr, "\n");
+        va_end(args);
+    }
+
+    fprintf(stderr, "usage: %s kiss.cap\n", argv[0]);
+
+    exit(1);
+}
+
+int main(int argc, char **argv) {
+    patty_kiss_tnc *tnc;
+    ssize_t len;
+    void *frame;
+    int port;
+
+    if (argc != 2) {
+        usage(argc, argv, "No TNC device provided");
+    }
+
+    if ((tnc = patty_kiss_tnc_open(argv[1], 330)) == NULL) {
+        perror("Unable to open TNC");
+
+        exit(127);
+    }
+
+    while ((len = patty_kiss_tnc_recv(tnc, &frame, &port)) > 0) {
+        write(fileno(stdout), frame, len);
+
+        fprintf(stderr, "Got %ld byte frame\n", len);
+    }
+
+    patty_kiss_tnc_close(tnc);
+
+    return 0;
+}