@@ -30,8 +30,9 @@ timelib_rel_time *timelib_diff(timelib_time *one, timelib_time *two)
3030{
3131 timelib_rel_time * rt ;
3232 timelib_time * swp ;
33- timelib_sll dst_corr = 0 ,dst_h_corr = 0 , dst_m_corr = 0 ;
34- timelib_time one_backup , two_backup ;
33+ timelib_sll dst_corr = 0 , dst_h_corr = 0 , dst_m_corr = 0 ;
34+ timelib_time_offset * trans = NULL ;
35+
3536
3637 rt = timelib_rel_time_ctor ();
3738 rt -> invert = 0 ;
@@ -45,23 +46,10 @@ timelib_rel_time *timelib_diff(timelib_time *one, timelib_time *two)
4546 rt -> invert = 1 ;
4647 }
4748
48- /* Calculate correction for DST change over, but only if the TZ type is ID
49- * and it's the same */
50- if (one -> zone_type == 3 && two -> zone_type == 3
51- && (strcmp (one -> tz_info -> name , two -> tz_info -> name ) == 0 )
52- && (one -> z != two -> z ))
53- {
54- dst_corr = two -> z - one -> z ;
55- dst_h_corr = dst_corr / 3600 ;
56- dst_m_corr = (dst_corr % 3600 ) / 60 ;
57- }
58-
59- /* Save old TZ info */
60- memcpy (& one_backup , one , sizeof (one_backup ));
61- memcpy (& two_backup , two , sizeof (two_backup ));
62-
63- timelib_apply_localtime (one , 0 );
64- timelib_apply_localtime (two , 0 );
49+ /* Calculate correction for UTC offset changes between first and second SSE */
50+ dst_corr = two -> z - one -> z ;
51+ dst_h_corr = dst_corr / 3600 ;
52+ dst_m_corr = (dst_corr % 3600 ) / 60 ;
6553
6654 rt -> y = two -> y - one -> y ;
6755 rt -> m = two -> m - one -> m ;
@@ -70,29 +58,87 @@ timelib_rel_time *timelib_diff(timelib_time *one, timelib_time *two)
7058 rt -> i = two -> i - one -> i ;
7159 rt -> s = two -> s - one -> s ;
7260 rt -> us = two -> us - one -> us ;
73- if (one_backup .dst == 0 && two_backup .dst == 1 && two -> sse >= one -> sse + 86400 - dst_corr ) {
74- rt -> h += dst_h_corr ;
75- rt -> i += dst_m_corr ;
76- }
7761
7862 rt -> days = fabs (floor ((one -> sse - two -> sse - (dst_h_corr * 3600 ) - (dst_m_corr * 60 )) / 86400 ));
7963
64+ /* Fall Back: Cater for transition period, where rt->invert is 0, but there are negative numbers */
65+ if (one -> dst == 1 && two -> dst == 0 ) {
66+ /* First for two "Type 3" times */
67+ if (one -> zone_type == 3 && two -> zone_type == 3 ) {
68+ trans = timelib_get_time_zone_info (two -> sse , two -> tz_info );
69+ if (trans ) {
70+ if (one -> sse >= trans -> transition_time + dst_corr && one -> sse < trans -> transition_time ) {
71+ timelib_sll flipped = SECS_PER_HOUR + (rt -> i * 60 ) + (rt -> s );
72+ rt -> h = flipped / SECS_PER_HOUR ;
73+ rt -> i = (flipped - rt -> h * SECS_PER_HOUR ) / 60 ;
74+ rt -> s = flipped % 60 ;
75+ }
76+ timelib_time_offset_dtor (trans );
77+ trans = NULL ;
78+ }
79+ } else if (rt -> h == 0 && (rt -> i < 0 || rt -> s < 0 )) {
80+ /* Then for all the others */
81+ timelib_sll flipped = SECS_PER_HOUR + (rt -> i * 60 ) + (rt -> s );
82+ rt -> h = flipped / SECS_PER_HOUR ;
83+ rt -> i = (flipped - rt -> h * SECS_PER_HOUR ) / 60 ;
84+ rt -> s = flipped % 60 ;
85+ dst_corr += SECS_PER_HOUR ;
86+ dst_h_corr ++ ;
87+ }
88+ }
89+
8090 timelib_do_rel_normalize (rt -> invert ? one : two , rt );
8191
82- /* We need to do this after normalisation otherwise we can't get "24H" */
83- if (one_backup .dst == 1 && two_backup .dst == 0 && two -> sse >= one -> sse + 86400 ) {
84- if (two -> sse < one -> sse + 86400 - dst_corr ) {
85- rt -> d -- ;
86- rt -> h = 24 ;
87- } else {
88- rt -> h += dst_h_corr ;
89- rt -> i += dst_m_corr ;
92+ /* Do corrections for "Type 3" times */
93+ if (one -> zone_type == 3 && two -> zone_type == 3 ) {
94+ if (one -> dst == 1 && two -> dst == 0 ) { /* Fall Back */
95+ if (two -> tz_info ) {
96+ trans = timelib_get_time_zone_info (two -> sse , two -> tz_info );
97+
98+ if (
99+ trans &&
100+ two -> sse >= trans -> transition_time &&
101+ ((two -> sse - one -> sse + dst_corr ) % SECS_PER_DAY ) > (two -> sse - trans -> transition_time )
102+ ) {
103+ rt -> h -= dst_h_corr ;
104+ rt -> i -= dst_m_corr ;
105+ }
106+ }
107+ } else if (one -> dst == 0 && two -> dst == 1 ) { /* Spring Forward */
108+ if (two -> tz_info ) {
109+ trans = timelib_get_time_zone_info (two -> sse , two -> tz_info );
110+
111+ if (
112+ trans &&
113+ !((one -> sse + SECS_PER_DAY > trans -> transition_time ) && (one -> sse + SECS_PER_DAY <= (trans -> transition_time + dst_corr ))) &&
114+ two -> sse >= trans -> transition_time &&
115+ ((two -> sse - one -> sse + dst_corr ) % SECS_PER_DAY ) > (two -> sse - trans -> transition_time )
116+ ) {
117+ rt -> h -= dst_h_corr ;
118+ rt -> i -= dst_m_corr ;
119+ }
120+ }
121+ } else if (two -> sse - one -> sse >= SECS_PER_DAY ) {
122+ /* Check whether we're in the period to the next transition time */
123+ trans = timelib_get_time_zone_info (two -> sse - two -> z , two -> tz_info );
124+ dst_corr = one -> z - trans -> offset ;
125+
126+ if (two -> sse >= trans -> transition_time - dst_corr && two -> sse < trans -> transition_time ) {
127+ rt -> d -- ;
128+ rt -> h = 24 ;
129+ }
90130 }
131+ } else {
132+ /* Then for all the others */
133+ rt -> h -= dst_h_corr + (two -> dst - one -> dst );
134+ rt -> i -= dst_m_corr ;
135+
136+ timelib_do_rel_normalize (rt -> invert ? one : two , rt );
91137 }
92138
93- /* Restore old TZ info */
94- memcpy ( one , & one_backup , sizeof ( one_backup ) );
95- memcpy ( two , & two_backup , sizeof ( two_backup ));
139+ if ( trans ) {
140+ timelib_time_offset_dtor ( trans );
141+ }
96142
97143 return rt ;
98144}
@@ -122,13 +168,6 @@ timelib_time *timelib_add(timelib_time *old_time, timelib_rel_time *interval)
122168
123169 timelib_update_ts (t , NULL );
124170
125- // printf("%lld %lld %d\n", old_time->dst, t->dst, (t->sse - old_time->sse));
126- /* Adjust for backwards DST changeover */
127- if (old_time -> dst == 1 && t -> dst == 0 && !interval -> y && !interval -> m && !interval -> d ) {
128- t -> sse -= old_time -> z ;
129- t -> sse += t -> z ;
130- }
131-
132171 timelib_update_from_sse (t );
133172 t -> have_relative = 0 ;
134173
@@ -157,19 +196,86 @@ timelib_time *timelib_sub(timelib_time *old_time, timelib_rel_time *interval)
157196
158197 timelib_update_ts (t , NULL );
159198
160- /* Adjust for backwards DST changeover */
161- if (old_time -> dst == 1 && t -> dst == 0 && !interval -> y && !interval -> m && !interval -> d ) {
162- t -> sse -= old_time -> z ;
163- t -> sse += t -> z ;
164- }
165- /* Adjust for forwards DST changeover */
166- if (old_time -> dst == 0 && t -> dst == 1 && !interval -> y && !interval -> m && !interval -> d ) {
167- t -> sse -= old_time -> z ;
168- t -> sse += t -> z ;
199+ timelib_update_from_sse (t );
200+
201+ t -> have_relative = 0 ;
202+
203+ return t ;
204+ }
205+
206+ timelib_time * timelib_add_wall (timelib_time * old_time , timelib_rel_time * interval )
207+ {
208+ int bias = 1 ;
209+ timelib_time * t = timelib_time_clone (old_time );
210+
211+ t -> have_relative = 1 ;
212+ t -> sse_uptodate = 0 ;
213+
214+ if (interval -> have_weekday_relative || interval -> have_special_relative ) {
215+ memcpy (& t -> relative , interval , sizeof (timelib_rel_time ));
216+
217+ timelib_update_ts (t , NULL );
218+ } else {
219+ if (interval -> invert ) {
220+ bias = -1 ;
221+ }
222+ memset (& t -> relative , 0 , sizeof (timelib_rel_time ));
223+ t -> relative .y = interval -> y * bias ;
224+ t -> relative .m = interval -> m * bias ;
225+ t -> relative .d = interval -> d * bias ;
226+
227+ if (t -> relative .y || t -> relative .m || t -> relative .d ) {
228+ timelib_update_ts (t , NULL );
229+ }
230+
231+ t -> sse += bias * timelib_hms_to_seconds (interval -> h , interval -> i , interval -> s );
232+ t -> us += interval -> us * bias ;
233+ timelib_do_normalize (t );
169234 }
170235
171236 timelib_update_from_sse (t );
237+ if (t -> zone_type == TIMELIB_ZONETYPE_ID ) {
238+ timelib_set_timezone (t , t -> tz_info );
239+ }
240+ t -> have_relative = 0 ;
241+
242+ return t ;
243+ }
244+
245+ timelib_time * timelib_sub_wall (timelib_time * old_time , timelib_rel_time * interval )
246+ {
247+ int bias = 1 ;
248+ timelib_time * t = timelib_time_clone (old_time );
172249
250+ t -> have_relative = 1 ;
251+ t -> sse_uptodate = 0 ;
252+
253+ if (interval -> have_weekday_relative || interval -> have_special_relative ) {
254+ memcpy (& t -> relative , interval , sizeof (timelib_rel_time ));
255+
256+ timelib_update_ts (t , NULL );
257+ } else {
258+ if (interval -> invert ) {
259+ bias = -1 ;
260+ }
261+ memset (& t -> relative , 0 , sizeof (timelib_rel_time ));
262+ t -> relative .y = 0 - (interval -> y * bias );
263+ t -> relative .m = 0 - (interval -> m * bias );
264+ t -> relative .d = 0 - (interval -> d * bias );
265+
266+ if (t -> relative .y || t -> relative .m || t -> relative .d ) {
267+ timelib_update_ts (t , NULL );
268+ }
269+
270+ t -> sse -= bias * timelib_hms_to_seconds (interval -> h , interval -> i , interval -> s );
271+ t -> us -= interval -> us * bias ;
272+ timelib_do_normalize (t );
273+ }
274+
275+ timelib_update_from_sse (t );
276+ if (t -> zone_type == TIMELIB_ZONETYPE_ID ) {
277+ timelib_set_timezone (t , t -> tz_info );
278+ }
173279 t -> have_relative = 0 ;
174280
175281 return t ;
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