uint8_t *logic_samples;
const char *xlabel; /* Don't free: will point to a static string. */
const char *title; /* Don't free: will point into the driver struct. */
+
+ /* Input data constraints check. */
+ gboolean have_checked;
+ gboolean have_frames;
+ uint64_t pkt_snums;
};
/*
/* Some metadata */
if (ctx->header && !ctx->did_header) {
/* save_gnuplot knows how many lines we print. */
+ time_t secs;
+ secs = hdr->starttime.tv_sec;
g_string_append_printf(header,
"%s CSV generated by %s %s\n%s from %s on %s",
ctx->comment, PACKAGE_NAME,
sr_package_version_string_get(), ctx->comment,
- ctx->title, ctime(&hdr->starttime.tv_sec));
+ ctx->title, ctime(&secs));
/* Columns / channels */
channels = o->sdi ? o->sdi->channels : NULL;
} else {
sr_info("Dumping %u samples", ctx->num_samples);
- *out = g_string_sized_new(512);
+ if (!*out)
+ *out = g_string_sized_new(512);
num_channels =
ctx->num_logic_channels + ctx->num_analog_channels;
g_string_free(script, TRUE);
}
+static void check_input_constraints(struct context *ctx)
+{
+ size_t snum_count, snum_warn_limit;
+ size_t logic, analog;
+ gboolean has_frames, is_short, is_mixed, is_multi_analog;
+ gboolean do_warn;
+
+ /*
+ * Check and conditionally warn exactly once during execution
+ * of the output module on a set of input data.
+ */
+ if (ctx->have_checked)
+ return;
+ ctx->have_checked = TRUE;
+
+ /*
+ * This implementation of the CSV output module assumes some
+ * constraints which need not be met in reality. Emit warnings
+ * until a better version becomes available. Letting users know
+ * that their request may not get processed correctly is the
+ * only thing we can do for now except for complete refusal to
+ * process the input data.
+ *
+ * What the implementation appears to assume (unverified, this
+ * interpretation may be incorrect and/or incomplete):
+ * - Multi-channel analog data, or mixed signal input, always
+ * is enclosed in frame markers.
+ * - Data which gets received across several packets spans a
+ * consistent sample number range. All samples of one frame
+ * and channel number or data type fit into a single packet.
+ * Arbitrary chunking seems to not be supported.
+ * - A specific order of analog data packets is assumed.
+ *
+ * With these assumptions encoded in the implementation, and
+ * not being met at runtime, incorrect and unexpected results
+ * were seen for these configurations:
+ * - More than one analog channel.
+ * - The combination of logic and analog channel types.
+ *
+ * The condition of frames with large sample counts is a wild
+ * guess, the limit is a totally arbitrary choice. It assumes
+ * typical scope frames with at most a few thousand samples per
+ * frame, and assumes that a channel's data gets sent in large
+ * enough packets. The absence of a warning message does not
+ * necessarily translate to correct output, it's more of a rate
+ * limiting approach to not scare users too much.
+ */
+ snum_count = ctx->pkt_snums;
+ snum_warn_limit = 1 * 1000 * 1000;
+ logic = ctx->num_logic_channels;
+ analog = ctx->num_analog_channels;
+ has_frames = ctx->have_frames;
+ is_short = snum_count < snum_warn_limit;
+ is_mixed = logic && analog;
+ is_multi_analog = analog > 1;
+
+ if (has_frames && is_short) {
+ sr_info("Assuming consistent framed input data.");
+ return;
+ }
+
+ do_warn = FALSE;
+ if (has_frames) {
+ sr_warn("Untested configuration: large frame content.");
+ do_warn = TRUE;
+ }
+ if (is_mixed) {
+ sr_warn("Untested configuration: mixed signal input data.");
+ do_warn = TRUE;
+ }
+ if (is_multi_analog) {
+ sr_warn("Untested configuration: multi-channel analog data.");
+ do_warn = TRUE;
+ }
+ if (!do_warn)
+ return;
+ sr_warn("Resulting CSV output data may be incomplete or incorrect.");
+}
+
static int receive(const struct sr_output *o,
const struct sr_datafeed_packet *packet, GString **out)
{
struct context *ctx;
+ const struct sr_datafeed_logic *logic;
+ const struct sr_datafeed_analog *analog;
*out = NULL;
if (!o || !o->sdi)
sr_dbg("Got packet of type %d", packet->type);
switch (packet->type) {
case SR_DF_HEADER:
+ ctx->have_checked = FALSE;
+ ctx->have_frames = FALSE;
+ ctx->pkt_snums = FALSE;
*out = gen_header(o, packet->payload);
break;
case SR_DF_TRIGGER:
ctx->trigger = TRUE;
break;
case SR_DF_LOGIC:
- process_logic(ctx, packet->payload);
+ *out = g_string_sized_new(512);
+ logic = packet->payload;
+ ctx->pkt_snums = logic->length;
+ ctx->pkt_snums /= logic->length;
+ check_input_constraints(ctx);
+ process_logic(ctx, logic);
break;
case SR_DF_ANALOG:
- process_analog(ctx, packet->payload);
+ *out = g_string_sized_new(512);
+ analog = packet->payload;
+ ctx->pkt_snums = analog->num_samples;
+ ctx->pkt_snums /= g_slist_length(analog->meaning->channels);
+ check_input_constraints(ctx);
+ process_analog(ctx, analog);
break;
case SR_DF_FRAME_BEGIN:
+ ctx->have_frames = TRUE;
*out = g_string_new(ctx->frame);
/* Fallthrough */
case SR_DF_END:
projects / libsigrok.git / blobdiff