static int
importer_dates_check (char **labels, BookFlag *pflags,
DATASET *newset, PRN *prn,
int *err)
{
int d, t;
char dstr[12];
char *s;
int ret = 0;
for (t=0; t<newset->n; t++) {
s = labels[t];
if (s == NULL || *s == '\0') {
fprintf(stderr, "importer_dates_check: got blank label\n");
return 0;
}
}
*err = dataset_allocate_obs_markers(newset);
if (*err) {
return 0;
}
for (t=0; t<newset->n && !*err; t++) {
s = labels[t];
if (*s == '"' || *s == '\'') s++;
if (*pflags & BOOK_NUMERIC_DATES) {
if (sscanf(s, "%d", &d)) {
MS_excel_date_string(dstr, d, 0, *pflags & BOOK_DATE_BASE_1904);
s = dstr;
} else {
pprintf(prn, "Bad date on row %d: '%s'\n", t+1, s);
*err = E_DATA;
}
}
strncat(newset->S[t], s, OBSLEN - 1);
}
if (!*err) {
int reversed = 0;
ret = test_markers_for_dates(newset, &reversed, NULL, prn);
if (reversed) {
*pflags |= BOOK_DATA_REVERSED;
}
}
if (newset->markers != DAILY_DATE_STRINGS) {
dataset_destroy_obs_markers(newset);
}
return ret;
}
static void xlsx_dates_check (DATASET *dset)
{
int t, maybe_dates = 1;
int date_min = 0, date_max = 0;
int d, delta_min = 0, delta_max = 0;
#if DATE_DEBUG
fprintf(stderr, "xlsx_dates_check: starting\n");
#endif
/* We're dealing here with the case where our prior heuristics
suggest we got an "observations" column, yet the values we
found there were numeric (and we converted them to strings).
Here we see if it might be reasonable to interpret the
labels as representing MS dates (days since Dec 31, 1899).
For this purpose we'll require that all the obs labels are
integer strings, and that the gap between successive values
should be constant, or variable to a degree that's consistent
with a sane time-series frequency.
We should bear in mind, however, that the numeric values that
we started with could be plain years rather than MS dates.
*/
for (t=0; t<dset->n && maybe_dates; t++) {
if (!integer_string(dset->S[t])) {
#if DATE_DEBUG
fprintf(stderr, "S[%d] = '%s', giving up\n", t, dset->S[t]);
#endif
maybe_dates = 0;
} else if (t == 0) {
if (!strcmp(dset->S[0], "1")) {
maybe_dates = 0;
} else {
date_min = date_max = atoi(dset->S[t]);
}
} else {
d = atoi(dset->S[t]);
if (d < date_min) {
date_min = d;
}
if (d > date_max) {
date_max = d;
}
d = atoi(dset->S[t]) - atoi(dset->S[t-1]);
if (t == 1) {
delta_min = delta_max = d;
} else if (d < delta_min) {
#if DATE_DEBUG
fprintf(stderr, " at t=%d, delta_min = %d - %d = %d\n",
t, atoi(dset->S[t]), atoi(dset->S[t-1]), d);
#endif
delta_min = d;
} else if (d > delta_max) {
delta_max = d;
}
}
}
#if DATE_DEBUG
fprintf(stderr, "after obs loop, maybe_dates=%d\n"
" (date_min=%d, date_max=%d, delta_min=%d, delta_max=%d)\n",
maybe_dates, date_min, date_max, delta_min, delta_max);
#endif
if (maybe_dates && delta_max < 0) {
/* allow for the possibility that time runs backwards */
int tmp = delta_min;
delta_min = -delta_max;
delta_max = -tmp;
fprintf(stderr, "xlsx_dates_check: diffmin=%d, diffmax=%d\n",
delta_min, delta_max);
}
if (maybe_dates) {
/* are these things in fact more plausibly years? */
if (delta_min == 1 && delta_max == 1 &&
date_min > 1749 && date_max < 2050) {
#if DATE_DEBUG
fprintf(stderr, "assuming these are years, not MS dates\n");
#endif
maybe_dates = 0;
}
}
if (maybe_dates) {
if (delta_min >= 364 && delta_max <= 365) {
; /* annual? */
} else if (delta_min >= 90 && delta_max <= 92) {
; /* quarterly? */
} else if (delta_min >= 28 && delta_max <= 31) {
; /* monthly? */
} else if (delta_min == 7 && delta_max == 7) {
; /* weekly? */
} else if (delta_min == 1 && delta_max <= 5) {
; /* daily? */
} else {
/* unsupported frequency or nonsensical */
#if DATE_DEBUG
fprintf(stderr, "delta_max = %d, delta_min = %d, unsupported\n",
delta_max, delta_min);
#endif
maybe_dates = 0;
}
}
#if DATE_DEBUG
fprintf(stderr, "xlsx_dates_check: maybe_dates = %d\n", maybe_dates);
#endif
if (maybe_dates) {
char datestr[OBSLEN];
for (t=0; t<dset->n; t++) {
/* FIXME detect use of 1904-based dates? */
MS_excel_date_string(datestr, atoi(dset->S[t]), 0, 0);
strcpy(dset->S[t], datestr);
}
}
}