- char start[3], length[10];
- int len, tmp;
-
- /* Read the hashsign and length digit. */
- tmp = sr_scpi_read_data(scpi, start, 2);
- start[2] = '\0';
- if (tmp != 2) {
- sr_err("Failed to read first two bytes of data block header.");
- return -1;
+ struct sr_scpi_dev_inst *scpi = sdi->conn;
+ struct dev_context *devc = sdi->priv;
+ char *buf = (char *) devc->buffer;
+ size_t header_length;
+ int ret;
+
+ /* Try to read the hashsign and length digit. */
+ if (devc->num_header_bytes < 2) {
+ ret = sr_scpi_read_data(scpi, buf + devc->num_header_bytes,
+ 2 - devc->num_header_bytes);
+ if (ret < 0) {
+ sr_err("Read error while reading data header.");
+ return SR_ERR;
+ }
+ devc->num_header_bytes += ret;