From: Gerhard Sittig <redacted>
Date: Fri, 24 Jul 2020 14:10:55 +0000 (+0200)
Subject: input/vcd: unbreak the logic which skips a user specified period
X-Git-Url: https://sigrok.org/gitaction?a=commitdiff_plain;h=dd8bec71c2bc82d3df2ff9e5be3bcfa25fddc709;p=libsigrok.git

input/vcd: unbreak the logic which skips a user specified period

Rephrase the default value for the 'skip' option and the detection of a
user specified value. This is tricky because: Sample numbers are kept in
64bit values. Skip and downsample are fed to formulae so we want them
both to be unsigned. Yet absence of a user spec as well as possible user
values 0 and positive must be told apart. Use all-ones for the default
of "-1" which translates to "first timestamp", users need not be able to
specify that negative value.

Make sure to only downsample 'skip' values when the user specified some.
Which avoids the undesired insertion of huge idle gaps at the start of
the capture. An earlier implementation had to check for -1, this recent
version uses an unsigned number in combination with a boolean flag to
achieve this.

Reword some diagnostics messages, and print the samples count between
timestamps while we are here. Add a check for successful text to number
conversion of timestamp values.

How to reproduce:

  $ pulseview -i file.vcd
  $ pulseview -i file.vcd -I vcd:downsample=5
  $ pulseview -i file.vcd -I vcd:skip=111381600

Example file:

  $timescale 1 ns $end
  $scope module top $end
  $var wire 1 ! d1 $end
  $upscope $end
  $enddefinitions $end
  #111381815
  0!
  #111381905
  1!
  #111381990
  0!
  #111382075
---

diff --git a/src/input/vcd.c b/src/input/vcd.c
index b71931ee..e1224be0 100644
--- a/src/input/vcd.c
+++ b/src/input/vcd.c
@@ -1250,7 +1250,7 @@ static int parse_textline(const struct sr_input *in, char *lines)
 	char *curr_word, *next_word, curr_first;
 	gboolean is_timestamp, is_section, is_real, is_multibit, is_singlebit;
 	uint64_t timestamp;
-	char *identifier;
+	char *identifier, *endptr;
 	size_t count;
 
 	inc = in->priv;
@@ -1344,7 +1344,13 @@ static int parse_textline(const struct sr_input *in, char *lines)
 		 */
 		is_timestamp = curr_first == '#' && g_ascii_isdigit(curr_word[1]);
 		if (is_timestamp) {
-			timestamp = strtoull(&curr_word[1], NULL, 10);
+			endptr = NULL;
+			timestamp = strtoull(&curr_word[1], &endptr, 10);
+			if (!endptr || *endptr) {
+				sr_err("Invalid timestamp: %s.", curr_word);
+				ret = SR_ERR_DATA;
+				break;
+			}
 			sr_spew("Got timestamp: %" PRIu64, timestamp);
 			if (inc->options.downsample > 1) {
 				timestamp /= inc->options.downsample;
@@ -1357,11 +1363,13 @@ static int parse_textline(const struct sr_input *in, char *lines)
 			 * Skip > 0 => skip until timestamp >= skip.
 			 */
 			if (inc->options.skip_specified && !inc->use_skip) {
-				sr_dbg("Seeding use of skip");
+				sr_dbg("Seeding skip from user spec %" PRIu64,
+					inc->options.skip_starttime);
+				inc->prev_timestamp = inc->options.skip_starttime;
 				inc->use_skip = TRUE;
 			}
 			if (!inc->use_skip) {
-				sr_dbg("First timestamp, and no skip used");
+				sr_dbg("Seeding skip from first timestamp");
 				inc->options.skip_starttime = timestamp;
 				inc->prev_timestamp = timestamp;
 				inc->use_skip = TRUE;
@@ -1400,8 +1408,8 @@ static int parse_textline(const struct sr_input *in, char *lines)
 			}
 
 			/* Generate samples from prev_timestamp up to timestamp - 1. */
-			sr_spew("Got a new timestamp, feeding samples");
 			count = timestamp - inc->prev_timestamp;
+			sr_spew("Got a new timestamp, feeding %zu samples", count);
 			add_samples(in, count, FALSE);
 			inc->prev_timestamp = timestamp;
 			inc->data_after_timestamp = FALSE;
@@ -1711,6 +1719,10 @@ static int init(struct sr_input *in, GHashTable *options)
 	if (data) {
 		inc->options.skip_specified = TRUE;
 		inc->options.skip_starttime = g_variant_get_uint64(data);
+		if (inc->options.skip_starttime == ~UINT64_C(0)) {
+			inc->options.skip_specified = FALSE;
+			inc->options.skip_starttime = 0;
+		}
 		inc->options.skip_starttime /= inc->options.downsample;
 	}
 
@@ -1865,7 +1877,7 @@ static const struct sr_option *get_options(void)
 	if (!options[0].def) {
 		options[OPT_NUM_CHANS].def = g_variant_ref_sink(g_variant_new_uint32(0));
 		options[OPT_DOWN_SAMPLE].def = g_variant_ref_sink(g_variant_new_uint64(1));
-		options[OPT_SKIP_COUNT].def = g_variant_ref_sink(g_variant_new_uint64(0));
+		options[OPT_SKIP_COUNT].def = g_variant_ref_sink(g_variant_new_uint64(~UINT64_C(0)));
 		options[OPT_COMPRESS].def = g_variant_ref_sink(g_variant_new_uint64(0));
 	}