datetime.c

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/*
    This file is part of darktable,
    Copyright (C) 2022 Aldric Renaudin.
    Copyright (C) 2022 HansBull.
    Copyright (C) 2022 Martin Bařinka.
    Copyright (C) 2022 Philippe Weyland.
    Copyright (C) 2024, 2026 Guillaume Stutin.
    
    darktable is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
    
    darktable is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
    
    You should have received a copy of the GNU General Public License
    along with darktable.  If not, see <http://www.gnu.org/licenses/>.
*/
 
#include "common/darktable.h"
#include "common/datetime.h"
 
#define DT_DATETIME_ORIGIN "0001-01-01 00:00:00.000"
#define DT_DATETIME_EPOCH "1970-01-01 00:00:00.000"
#define DT_DATETIME_EXIF_FORMAT "%Y:%m:%d %H:%M:%S"
 
void dt_datetime_init()
{
  darktable.utc_tz =  g_time_zone_new_utc();
  darktable.origin_gdt = g_date_time_new_from_iso8601(DT_DATETIME_ORIGIN, darktable.utc_tz);
}
 
gboolean _datetime_gdatetime_to_numbers(dt_datetime_t *dt, GDateTime *gdt)
{
  if(gdt)
  {
    dt->year = g_date_time_get_year(gdt);
    dt->month = g_date_time_get_month(gdt);
    dt->day = g_date_time_get_day_of_month(gdt);
    dt->hour = g_date_time_get_hour(gdt);
    dt->minute = g_date_time_get_minute(gdt);
    dt->second = g_date_time_get_second(gdt);
    dt->msec = g_date_time_get_microsecond(gdt) * 0.001;
    return TRUE;
  }
  return FALSE;
}
 
static char *_datetime_append_msec(char *exif, GDateTime *gdt)
{
  return g_strdup_printf("%s%s%03d", exif, ".", (int)(g_date_time_get_microsecond(gdt) * 0.001));
  }
 
static GTimeSpan _gdatetime_to_gtimespan(GDateTime *gdt)
{
  if(gdt)
  {
    GTimeSpan gts = g_date_time_difference(gdt, darktable.origin_gdt);
    g_date_time_unref(gdt);
    return gts;
  }
  return 0;
}
 
gboolean dt_datetime_exif_to_numbers(dt_datetime_t *dt, const char *exif)
{
  if(IS_NULL_PTR(exif) || !*exif || IS_NULL_PTR(dt)) return FALSE;
 
  // fast-path for ISO-8601 (handles timezone offsets and 'T' separator)
  GDateTime *gdt = g_date_time_new_from_iso8601(exif, darktable.utc_tz);
  if(gdt)
  {
    const gboolean res = _datetime_gdatetime_to_numbers(dt, gdt);
    g_date_time_unref(gdt);
    return res;
  }
 
  // fallback for EXIF-like formats (YYYY:MM:DD HH:MM:SS[.sss])
  // convert date separators to ISO form before parsing. Partial inputs (e.g. a bare
  // "YYYY:MM:DD" with no time part) are padded from the origin template so the missing
  // components default to the start of the period — g_date_time_new_from_iso8601 rejects
  // a date without a time. We memcpy (not g_strlcpy) so the copy does NOT drop a null
  // terminator over the template tail, which would defeat the padding. See #924 and the
  // matching logic in dt_string_to_datetime().
  char sdt[DT_DATETIME_LENGTH] = DT_DATETIME_ORIGIN;
  size_t len = strlen(exif);
  if(len > sizeof(sdt) - 1) len = sizeof(sdt) - 1;
  memcpy(sdt, exif, len);
  sdt[4] = sdt[7] = '-';
  gdt = g_date_time_new_from_iso8601(sdt, darktable.utc_tz);
  if(gdt)
  {
    const gboolean res = _datetime_gdatetime_to_numbers(dt, gdt);
    g_date_time_unref(gdt);
    return res;
  }
 
  return FALSE;
}
 
gboolean dt_datetime_exif_to_numbers_raw(dt_datetime_t *dt, const char *exif)
{
  if(exif && *exif && dt)
  {
    GMatchInfo *match_info;
    // we capture each date componenent
    GRegex *regex = g_regex_new(
        "^\\s*(\\d{4})?(?::(\\d{2}))?(?::(\\d{2}))?(?: (\\d{2}))?(?::(\\d{2}))?(?::(\\d{2}))?\\s*$", 0, 0, NULL);
    g_regex_match_full(regex, exif, -1, 0, 0, &match_info, NULL);
    int match_count = g_match_info_get_match_count(match_info);
    if(match_count == 7)
    {
      dt->year = atoi(g_match_info_fetch(match_info, 1));
      dt->month = atoi(g_match_info_fetch(match_info, 2));
      dt->day = atoi(g_match_info_fetch(match_info, 3));
      dt->hour = atoi(g_match_info_fetch(match_info, 4));
      dt->minute = atoi(g_match_info_fetch(match_info, 5));
      dt->second = atoi(g_match_info_fetch(match_info, 6));
      g_match_info_free(match_info);
      g_regex_unref(regex);
      return TRUE;
    }
    g_match_info_free(match_info);
    g_regex_unref(regex);
  }
  return FALSE;
}
 
gboolean dt_datetime_gdatetime_to_local(char *local, const size_t local_size,
                                        GDateTime *gdt, const gboolean msec, const gboolean tz)
{
  if(IS_NULL_PTR(local) || !local_size || IS_NULL_PTR(gdt)) return FALSE;
  local[0] = '\0';
  if(gdt)
  {
    char *sdt;
    if(tz)
    {
      GDateTime *lgdt = g_date_time_to_local(gdt);
      sdt = g_date_time_format(lgdt, "%a %x %X");
      g_date_time_unref(lgdt);
    }
    else
      sdt = g_date_time_format(gdt, "%a %x %X");
    if(sdt)
    {
      if(msec)
      { // add milliseconds
        char *sdt2 = _datetime_append_msec(sdt, gdt);
        dt_free(sdt);
        sdt = sdt2;
      }
      g_strlcpy(local, sdt, local_size);
      dt_free(sdt);
      return TRUE;
    }
  }
  return FALSE;
}
 
gboolean dt_datetime_gtimespan_to_local(char *local, const size_t local_size,
                                        const GTimeSpan gts, const gboolean msec, const gboolean tz)
{
  gboolean res = FALSE;
  if(IS_NULL_PTR(local) || !local_size) return FALSE;
  local[0] = '\0';
  GDateTime *gdt = g_date_time_add(darktable.origin_gdt, gts);
  if(gdt)
  {
    res = dt_datetime_gdatetime_to_local(local, local_size, gdt, msec, tz);
    g_date_time_unref(gdt);
  }
  return res;
}
 
gboolean dt_datetime_img_to_local(char *local, const size_t local_size,
                                  const dt_image_t *img, const gboolean msec)
{
  return dt_datetime_gtimespan_to_local(local, local_size, img->exif_datetime_taken, msec, FALSE);
}
 
gboolean dt_datetime_unix_to_img(dt_image_t *img, const time_t *unix)
{
  GDateTime *gdt = g_date_time_new_from_unix_local(*unix);
  if(gdt)
  {
    img->exif_datetime_taken = g_date_time_difference(gdt, darktable.origin_gdt);
    g_date_time_unref(gdt);
    return TRUE;
  }
  img->exif_datetime_taken = 0;
  return FALSE;
}
 
gboolean dt_datetime_unix_to_exif(char *exif, const size_t exif_size, const time_t *unix)
{
  GDateTime *gdt = g_date_time_new_from_unix_local(*unix);
  if(gdt)
  {
    const gboolean res = dt_datetime_gdatetime_to_exif(exif, exif_size, gdt);
    g_date_time_unref(gdt);
    return res;
  }
  return FALSE;
}
 
 
void dt_datetime_now_to_exif(char *exif)
{
  if(IS_NULL_PTR(exif)) return;
  exif[0] = '\0';
  GDateTime *gdt = g_date_time_new_now_local();
  if(gdt)
  {
    dt_datetime_gdatetime_to_exif(exif, DT_DATETIME_EXIF_LENGTH, gdt);
    g_date_time_unref(gdt);
  }
}
 
GTimeSpan dt_datetime_now_to_gtimespan()
{
  GDateTime *gdt = g_date_time_new_now_local();
  return _gdatetime_to_gtimespan(gdt);
}
 
void dt_datetime_exif_to_img(dt_image_t *img, const char *exif)
{
  if(IS_NULL_PTR(exif)) return;
  GDateTime *gdt = dt_datetime_exif_to_gdatetime(exif, darktable.utc_tz);
  if(gdt)
  {
    img->exif_datetime_taken = g_date_time_difference(gdt, darktable.origin_gdt);
    g_date_time_unref(gdt);
  }
  else img->exif_datetime_taken = 0;
}
 
gboolean dt_datetime_img_to_exif(char *exif, const size_t exif_size, const dt_image_t *img)
{
  return dt_datetime_gtimespan_to_exif(exif, exif_size, img->exif_datetime_taken);
}
 
GDateTime *dt_datetime_exif_to_gdatetime(const char *exif, const GTimeZone *tz)
{
  dt_datetime_t dt;
  if(dt_datetime_exif_to_numbers(&dt, exif))
  {
    GDateTime *gdt = g_date_time_new((GTimeZone *)tz, dt.year, dt.month, dt.day,
                                     dt.hour, dt.minute, dt.second);
    if(gdt)
    {
      if(dt.msec)
      {
        GDateTime *gdt2 = g_date_time_add(gdt, dt.msec * 1000);
        g_date_time_unref(gdt);
        return gdt2;
      }
    }
    return gdt;
  }
  return NULL;
}
 
gboolean dt_datetime_gdatetime_to_exif(char *exif, const size_t exif_size, GDateTime *gdt)
{
  if(IS_NULL_PTR(exif) || !exif_size || IS_NULL_PTR(gdt)) return FALSE;
  exif[0] = '\0';
  char *sdt = g_date_time_format(gdt, DT_DATETIME_EXIF_FORMAT);
  if(sdt)
  {
    if(exif_size == DT_DATETIME_LENGTH)
    {
      // the format %f seems not to be available in glib2.0  before version 2.70
      char *sdt2 = _datetime_append_msec(sdt, gdt);
      dt_free(sdt);
      sdt = sdt2;
    }
    g_strlcpy(exif, sdt, exif_size);
    dt_free(sdt);
    return TRUE;
  }
  return FALSE;
}
 
GDateTime *dt_datetime_img_to_gdatetime(const dt_image_t *img, const GTimeZone *tz)
{
  // GTimeSpan is UTC based. Therefore we have to cheat a little bit to get image datetime
  if(IS_NULL_PTR(tz)) return NULL;
  GDateTime *gdt = g_date_time_add(darktable.origin_gdt, img->exif_datetime_taken);
  if(gdt)
  {
    dt_datetime_t dt;
    if(_datetime_gdatetime_to_numbers(&dt, gdt))
    {
      g_date_time_unref(gdt);
      gdt = g_date_time_new((GTimeZone *)tz, dt.year, dt.month, dt.day,
                            dt.hour, dt.minute, (double)dt.second);
      return gdt;
    }
  }
  return NULL;
}
 
GDateTime *dt_string_to_datetime(const char *string)
{
  if(g_utf8_strlen(string, -1) > DT_DATETIME_LENGTH - 1)
    return FALSE;
 
  char idt[DT_DATETIME_LENGTH];
  g_strlcpy(idt, DT_DATETIME_ORIGIN, sizeof(idt));
  memcpy(idt, string, g_utf8_strlen(string, -1));
  idt[4] = idt[7] = '-';
  return g_date_time_new_from_iso8601(idt, darktable.utc_tz);  
}
 
gboolean dt_datetime_entry_to_exif(char *exif, const size_t exif_size, const char *entry)
{
  if(IS_NULL_PTR(exif) || !exif_size) return FALSE;
  exif[0] = '\0';
  GDateTime *gdt = dt_string_to_datetime(entry);
 
  if(gdt)
  {
    const gboolean res = dt_datetime_gdatetime_to_exif(exif, exif_size, gdt);
    g_date_time_unref(gdt);
    return res;
  }
  return FALSE;
}
 
gboolean dt_datetime_entry_to_exif_upper_bound(char *exif, const size_t exif_size, const char *entry)
{
  if(IS_NULL_PTR(exif) || !exif_size) return FALSE;
  exif[0] = '\0';
 
  const int len = strlen(entry);
  if(len > DT_DATETIME_LENGTH - 1)
    return FALSE;
  char idt[DT_DATETIME_LENGTH];
  g_strlcpy(idt, DT_DATETIME_ORIGIN, sizeof(idt));
  memcpy(idt, entry, strlen(entry));
  idt[4] = idt[7] = '-';
  GDateTime *gdt = g_date_time_new_from_iso8601(idt, darktable.utc_tz);
  if(gdt)
  {
    GDateTime *gdt2 = NULL;
    if(len < 7)
      gdt2 = g_date_time_add_years(gdt, 1);
    else if(len < 10)
      gdt2 = g_date_time_add_months(gdt, 1);
    else if(len < 13)
      gdt2 = g_date_time_add_days(gdt, 1);
    else if(len < 16)
      gdt2 = g_date_time_add_hours(gdt, 1);
    else if(len < 19)
      gdt2 = g_date_time_add_minutes(gdt, 1);
    else if(len < 23)
      gdt2 = g_date_time_add_seconds(gdt, 1);
    else
      gdt2 = g_date_time_add(gdt, 2);
    g_date_time_unref(gdt);
    if(gdt2)
    {
      GDateTime *gdt3 = g_date_time_add(gdt2, -1);
      g_date_time_unref(gdt2);
      gdt = gdt3;
      if(gdt)
      {
        const gboolean res = dt_datetime_gdatetime_to_exif(exif, exif_size, gdt);
        g_date_time_unref(gdt);
        return res;
      }
    }
  }
  return FALSE;
}
 
void dt_datetime_add_subsec_to_exif(char *exif, const size_t exif_size, const char*subsec)
{
  if(IS_NULL_PTR(exif) || exif_size < DT_DATETIME_EXIF_LENGTH + 1) return;
 
  g_strlcpy(&exif[DT_DATETIME_EXIF_LENGTH - 1], ".000000", exif_size - DT_DATETIME_EXIF_LENGTH + 1);
  for(int i = 0; i < 6 && subsec[i] != '\0' && (DT_DATETIME_EXIF_LENGTH + i < exif_size - 1); i++)
    exif[DT_DATETIME_EXIF_LENGTH + i] = subsec[i];
  exif[exif_size - 1] = '\0';
}
 
gboolean dt_datetime_gtimespan_to_exif(char *sdt, const size_t sdt_size, const GTimeSpan gts)
{
  if(IS_NULL_PTR(sdt) || !sdt_size) return FALSE;
  sdt[0] = '\0';
  if(!gts) return FALSE;
  GDateTime *gdt = g_date_time_add(darktable.origin_gdt, gts);
  if(gdt)
  {
    const gboolean res = dt_datetime_gdatetime_to_exif(sdt, sdt_size, gdt);
    g_date_time_unref(gdt);
    return res;
  }
  return FALSE;
}
 
GTimeSpan dt_datetime_exif_to_gtimespan(const char *sdt)
{
  GTimeSpan gts = 0;
  if(IS_NULL_PTR(sdt)) return gts;
  GDateTime *gdt = dt_datetime_exif_to_gdatetime(sdt, darktable.utc_tz);
  if(gdt)
  {
    gts = g_date_time_difference(gdt, darktable.origin_gdt);
    g_date_time_unref(gdt);
  }
  return gts;
}
 
gboolean dt_datetime_gtimespan_to_numbers(dt_datetime_t *dt, const GTimeSpan gts)
{
  GDateTime *gdt = g_date_time_add(darktable.origin_gdt, gts);
  if(gdt)
  {
    const gboolean res = _datetime_gdatetime_to_numbers(dt, gdt);
    g_date_time_unref(gdt);
    return res;
  }
  return FALSE;
}
 
GDateTime *dt_datetime_gtimespan_to_gdatetime(const GTimeSpan gts)
{
  return g_date_time_add(darktable.origin_gdt, gts);
}
 
GTimeSpan dt_datetime_numbers_to_gtimespan(const dt_datetime_t *dt)
{
  if(IS_NULL_PTR(dt)) return 0;
  GDateTime *gdt = g_date_time_new(darktable.utc_tz,
                                   dt->year, dt->month, dt->day,
                                   dt->hour, dt->minute, (double)dt->second);
  return _gdatetime_to_gtimespan(gdt);
}
 
GTimeSpan dt_datetime_gdatetime_to_gtimespan(GDateTime *gdt)
{
  if(gdt)
    return g_date_time_difference(gdt, darktable.origin_gdt);
  else
    return 0;
}
 
GDateTime *dt_datetime_gdatetime_add_numbers(GDateTime *dte, const dt_datetime_t numbers, const gboolean add)
{
  const int s = add ? 1 : -1;
 
  GDateTime *dt2 = g_date_time_add_years(dte, s * numbers.year);
  GDateTime *dt = g_date_time_add_months(dt2, s * numbers.month);
  g_date_time_unref(dt2);
  dt2 = g_date_time_add_days(dt, s * numbers.day);
  g_date_time_unref(dt);
  dt = g_date_time_add_hours(dt2, s * numbers.hour);
  g_date_time_unref(dt2);
  dt2 = g_date_time_add_minutes(dt, s * numbers.minute);
  g_date_time_unref(dt);
  dt = g_date_time_add_seconds(dt2, s * numbers.second);
  g_date_time_unref(dt2);
  return dt;
}
 
GTimeSpan dt_datetime_gtimespan_add_numbers(const GTimeSpan dt, const dt_datetime_t numbers, const gboolean add)
{
  GDateTime *dte = dt_datetime_gtimespan_to_gdatetime(dt);
  GDateTime *dt2 = dt_datetime_gdatetime_add_numbers(dte, numbers, add);
  GTimeSpan ret = dt_datetime_gdatetime_to_gtimespan(dt2);
  g_date_time_unref(dte);
  g_date_time_unref(dt2);
  return ret;
}
 
gboolean dt_datetime_exif_add_numbers(const gchar *exif, const dt_datetime_t numbers, const gboolean add,
                                      gchar **result)
{
  GDateTime *dte = dt_datetime_exif_to_gdatetime(exif, darktable.utc_tz);
  if(IS_NULL_PTR(dte)) return FALSE;
  GDateTime *dt2 = dt_datetime_gdatetime_add_numbers(dte, numbers, add);
  char txt[DT_DATETIME_EXIF_LENGTH];
  dt_datetime_gdatetime_to_exif(txt, DT_DATETIME_EXIF_LENGTH, dt2);
  g_date_time_unref(dte);
  g_date_time_unref(dt2);
  *result = g_strdup(txt);
  return TRUE;
}
 
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