libftdi: (tomj) limit ftdi_read buffer size to n*64 bytes, n != 0

[libftdi] / ftdi / ftdi.c

diff --git a/ftdi/ftdi.c b/ftdi/ftdi.c
index 01d8f1a..2ccc2b7 100644 (file)
--- a/ftdi/ftdi.c
+++ b/ftdi/ftdi.c
@@ -216,6 +216,11 @@ int ftdi_read_data(struct ftdi_context *ftdi, unsigned char *buf, int size) {
     int ret = 1;
     int offset = 0;
 
+    if (size != 0 && size % 64 != 0) {
+           ftdi->error_str = "Sorry, read buffer size must currently be a multiple (1x, 2x, 3x...) of 64";
+            return -2;
+    }
+
     while (offset < size && ret > 0) {
        ret = usb_bulk_read (ftdi->usb_dev, 0x81, readbuf, 64, ftdi->usb_timeout);
        // Skip FTDI status bytes