+ sr_dbg("Second timestamp value %g in line %zu.", ts, inc->line_number);
+ ts -= inc->prev_timestamp;
+ sr_dbg("Timestamp difference %g in line %zu.",
+ ts, inc->line_number);
+ if (!ts) {
+ sr_warn("Zero timestamp difference in line %zu.",
+ inc->line_number);
+ inc->prev_timestamp = ts;
+ return SR_OK;
+ }
+ rate = 1.0 / ts;
+ rate += 0.5;
+ rate = (uint64_t)rate;
+ sr_dbg("Rate from timestamp %g in line %zu.", rate, inc->line_number);
+ inc->calc_samplerate = rate;
+ inc->prev_timestamp = 0.0;
+
+ return SR_OK;
+}
+
+/**
+ * Parse routine which ignores the input text.
+ *
+ * This routine exists to unify dispatch code paths, mapping input file
+ * columns' data types to their respective parse routines.
+ */
+static int parse_ignore(const char *column, struct context *inc,
+ const struct column_details *details)
+{
+ (void)column;
+ (void)inc;
+ (void)details;
+
+ return SR_OK;
+}
+
+typedef int (*col_parse_cb)(const char *column, struct context *inc,
+ const struct column_details *details);
+
+static const col_parse_cb col_parse_funcs[] = {
+ [FORMAT_NONE] = parse_ignore,
+ [FORMAT_BIN] = parse_logic,
+ [FORMAT_OCT] = parse_logic,
+ [FORMAT_HEX] = parse_logic,
+ [FORMAT_ANALOG] = parse_analog,
+ [FORMAT_TIME] = parse_timestamp,
+};
+
+/*
+ * BEWARE! Implementor's notes. Sync with feature set and default option
+ * values required during maintenance of the input module implementation.
+ *
+ * When applications invoke .format_match() routines, trying automatic
+ * determination of an input file's format handler, then no options are
+ * in effect. Because specifying options requires selection of an input
+ * module to pass the options to, which obsoletes the format-match check.
+ *
+ * Which means that we only need to deal with the default format here,
+ * which happens to be the simple multi-column format without header
+ * lines or leading garbage. Which means that the check can be rather
+ * strict, resulting in high levels of confidence upon match, never
+ * "accidently" winning for unreadable or unsupported-by-default formats.
+ *
+ * This .format_match() logic only needs to become more involved when
+ * default option values change, or when automatic detection of column
+ * data types improves. Then the supported-by-default types of input
+ * data must be considered acceptable here in the format-match check
+ * as well.
+ *
+ * Notice that the format check cannot re-use regular processing logic
+ * when their implementation assumes proper input data and wll generate
+ * diagnostics for unexpected input data. Failure to match the format is
+ * non-fatal here, mismatch must remain silent. It's up to applications
+ * how large a chunk of data gets passed here (start of the file's
+ * content). But inspection of the first few hundred bytes will usually
+ * be GoodEnough(TM) for the format-match purpose. Notice that filenames
+ * need not necessarily be available to the format-match routine.
+ *
+ * This implementation errs on the safe side. Users can always select
+ * the CSV input module when automatic format detection fails.
+ */
+static int format_match(GHashTable *metadata, unsigned int *confidence)
+{
+ const int match_confidence = 100;
+ const char *default_extension = ".csv";
+ const char *line_termination = "\n";
+ const char *comment_leader = ";";
+ const char *column_separator = ",";
+ const char *binary_charset = "01";
+
+ const char *fn;
+ GString *buf;
+ size_t fn_len;
+ GString *tmpbuf;
+ gboolean status;
+ size_t line_idx, col_idx;
+ char *rdptr, **lines, *line;
+ char **cols, *col;
+
+ /* Get the application provided input data properties. */
+ fn = g_hash_table_lookup(metadata, GINT_TO_POINTER(SR_INPUT_META_FILENAME));
+ buf = g_hash_table_lookup(metadata, GINT_TO_POINTER(SR_INPUT_META_HEADER));
+
+ /* Filenames are a strong hint. Use then when available. */
+ if (fn && *fn && (fn_len = strlen(fn)) >= strlen(default_extension)) {
+ if (strcasecmp(&fn[fn_len - strlen(default_extension)], default_extension) == 0) {
+ *confidence = 10;
+ return SR_OK;
+ }
+ }
+
+ /*
+ * Check file content for compatibility with the input module's
+ * default format. Which translates to:
+ * - Must be at least one text line worth of input data. Ignore
+ * incomplete lines at the end of the available buffer.
+ * - Must be LF terminated text lines, optional CR-LF sequence.
+ * (Drop CR-only for simplicity since that's rare and users
+ * can override the automatic detection.)
+ * - Strip comments and skip empty lines.
+ * - Data lines must be binary input (potentially multiple bits
+ * per column which then get ignored). Presence of comma is
+ * optional but then must be followed by another data column.
+ * - No other content is acceptable, there neither are ignored
+ * columns nor analog data nor timestamps in the default layout.
+ * (See the above "sync format match with default options"
+ * comment though during maintenance!)
+ * Run the check on a copy to not affect the caller's buffer.
+ */
+ if (!buf || !buf->len || !buf->str || !*buf->str)
+ return SR_ERR;
+ rdptr = g_strstr_len(buf->str, buf->len, line_termination);
+ if (!rdptr)
+ return SR_ERR;
+ tmpbuf = g_string_new_len(buf->str, rdptr + 1 - buf->str);
+ tmpbuf->str[tmpbuf->len - 1] = '\0';
+ status = TRUE;
+ *confidence = match_confidence;
+ lines = g_strsplit(tmpbuf->str, line_termination, 0);
+ for (line_idx = 0; status && (line = lines[line_idx]); line_idx++) {
+ rdptr = strstr(line, comment_leader);
+ if (rdptr)
+ *rdptr = '\0';
+ line = g_strstrip(line);
+ if (!line || !*line)
+ continue;
+ cols = g_strsplit(line, column_separator, 0);
+ if (!cols) {
+ status = FALSE;
+ break;
+ }
+ for (col_idx = 0; status && (col = cols[col_idx]); col_idx++) {
+ if (strspn(col, binary_charset) != strlen(col)) {
+ status = FALSE;
+ break;
+ }
+ }
+ g_strfreev(cols);
+ }
+ g_strfreev(lines);
+ g_string_free(tmpbuf, TRUE);
+
+ if (!status)
+ return SR_ERR;