&scpi_libgpib_dev,
#endif
#ifdef HAVE_LIBSERIALPORT
- &scpi_serial_dev, /* must be last as it matches any resource */
+ &scpi_serial_dev, /* Must be last as it matches any resource. */
#endif
};
SR_PRIV int sr_scpi_get_string(struct sr_scpi_dev_inst *scpi,
const char *command, char **scpi_response)
{
- char buf[256];
+ GString *response;
+ response = g_string_sized_new(1024);
+
+ if (sr_scpi_get_data(scpi, command, &response) != SR_OK) {
+ if (response)
+ g_string_free(response, TRUE);
+ return SR_ERR;
+ }
+
+ /* Get rid of trailing linefeed if present */
+ if (response->len >= 1 && response->str[response->len - 1] == '\n')
+ g_string_truncate(response, response->len - 1);
+
+ /* Get rid of trailing carriage return if present */
+ if (response->len >= 1 && response->str[response->len - 1] == '\r')
+ g_string_truncate(response, response->len - 1);
+
+ sr_spew("Got response: '%.70s', length %" G_GSIZE_FORMAT ".",
+ response->str, response->len);
+
+ *scpi_response = g_string_free(response, FALSE);
+
+ return SR_OK;
+}
+
+SR_PRIV int sr_scpi_get_data(struct sr_scpi_dev_inst *scpi,
+ const char *command, GString **scpi_response)
+{
int len;
GString *response;
gint64 laststart;
unsigned int elapsed_ms;
+ unsigned int offset;
+ int space;
- if (command)
+ /* Optionally send caller provided command. */
+ if (command) {
if (sr_scpi_send(scpi, command) != SR_OK)
return SR_ERR;
+ }
+ /* Initiate SCPI read operation. */
if (sr_scpi_read_begin(scpi) != SR_OK)
return SR_ERR;
+ /* Keep reading until completion or until timeout. */
laststart = g_get_monotonic_time();
- response = g_string_new("");
-
- *scpi_response = NULL;
+ response = *scpi_response;
+ offset = response->len;
while (!sr_scpi_read_complete(scpi)) {
- len = sr_scpi_read_data(scpi, buf, sizeof(buf));
+ /* Resize the buffer when free space drops below a threshold. */
+ space = response->allocated_len - response->len;
+ if (space < 128) {
+ g_string_set_size(response, response->len + 1024);
+ g_string_set_size(response, offset);
+ space = response->allocated_len - response->len;
+ }
+ /* Read another chunk of the response. */
+ len = sr_scpi_read_data(scpi, &response->str[offset], space);
if (len < 0) {
sr_err("Incompletely read SCPI response.");
- g_string_free(response, TRUE);
return SR_ERR;
} else if (len > 0) {
- laststart = g_get_monotonic_time();
+ laststart = g_get_monotonic_time();
}
- g_string_append_len(response, buf, len);
+ offset += len;
+ g_string_set_size(response, offset);
+ /* Quit reading after a period of time without receive data. */
elapsed_ms = (g_get_monotonic_time() - laststart) / 1000;
if (elapsed_ms >= scpi->read_timeout_ms) {
sr_err("Timed out waiting for SCPI response.");
- g_string_free(response, TRUE);
return SR_ERR;
}
}
- /* Get rid of trailing linefeed if present */
- if (response->len >= 1 && response->str[response->len - 1] == '\n')
- g_string_truncate(response, response->len - 1);
-
- /* Get rid of trailing carriage return if present */
- if (response->len >= 1 && response->str[response->len - 1] == '\r')
- g_string_truncate(response, response->len - 1);
-
- sr_spew("Got response: '%.70s', length %" G_GSIZE_FORMAT ".",
- response->str, response->len);
-
- *scpi_response = g_string_free(response, FALSE);
-
return SR_OK;
}
return ret;
}
+/**
+ * Send a SCPI command, read the reply, parse it as binary data with a
+ * "definite length block" header and store the as an result in scpi_response.
+ *
+ * @param scpi Previously initialised SCPI device structure.
+ * @param command The SCPI command to send to the device (can be NULL).
+ * @param scpi_response Pointer where to store the parsed result.
+ *
+ * @return SR_OK upon successfully parsing all values, SR_ERR* upon a parsing
+ * error or upon no response. The allocated response must be freed by
+ * the caller in the case of an SR_OK as well as in the case of
+ * parsing error.
+ */
+SR_PRIV int sr_scpi_get_block(struct sr_scpi_dev_inst *scpi,
+ const char *command, GByteArray **scpi_response)
+{
+ int ret;
+ GString* response;
+ char buf[10];
+ long llen;
+ long datalen;
+
+ /*
+ * Assume an initial maximum length, optionally gets adjusted below.
+ * Prepare a NULL return value for when error paths will be taken.
+ */
+ response = g_string_sized_new(1024);
+ *scpi_response = NULL;
+
+ /* Get (the first chunk of) the response. */
+ ret = sr_scpi_get_data(scpi, command, &response);
+ if (ret != SR_OK) {
+ g_string_free(response, TRUE);
+ return ret;
+ }
+
+ /*
+ * SCPI protocol data blocks are preceeded with a length spec.
+ * The length spec consists of a '#' marker, one digit which
+ * specifies the character count of the length spec, and the
+ * respective number of characters which specify the data block's
+ * length. Raw data bytes follow (thus one must no longer assume
+ * that the received input stream would be an ASCIIZ string).
+ *
+ * Get the data block length, and strip off the length spec from
+ * the input buffer, leaving just the data bytes.
+ */
+ if (response->str[0] != '#') {
+ g_string_free(response, TRUE);
+ return SR_ERR_DATA;
+ }
+ buf[0] = response->str[1];
+ buf[1] = '\0';
+ ret = sr_atol(buf, &llen);
+ if ((ret != SR_OK) || (llen == 0)) {
+ g_string_free(response, TRUE);
+ return ret;
+ }
+ memcpy(buf, &response->str[2], llen);
+ buf[llen] = '\0';
+ ret = sr_atol(buf, &datalen);
+ if ((ret != SR_OK) || (datalen == 0)) {
+ g_string_free(response, TRUE);
+ return ret;
+ }
+ g_string_erase(response, 0, 2 + llen);
+
+ /*
+ * If the initially assumed length does not cover the data block
+ * length, then re-allocate the buffer size to the now known
+ * length, and keep reading more chunks of response data.
+ */
+ if (response->len < (unsigned long)(datalen)) {
+ int oldlen = response->len;
+ g_string_set_size(response, datalen);
+ g_string_set_size(response, oldlen);
+ }
+ while (response->len < (unsigned long)(datalen)) {
+ ret = sr_scpi_get_data(scpi, NULL, &response);
+ if (ret != SR_OK) {
+ g_string_free(response, TRUE);
+ return ret;
+ }
+ }
+
+ /* Convert received data to byte array. */
+ *scpi_response = g_byte_array_new_take(
+ (guint8*)g_string_free(response, FALSE), datalen);
+
+ return ret;
+}
+
/**
* Send the *IDN? SCPI command, receive the reply, parse it and store the
* reply as a sr_scpi_hw_info structure in the supplied scpi_response pointer.