From 534ad99dc5c472b3d3cc04108bd8aea676bb7fc7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Radom=C3=ADr=20Pol=C3=A1ch?= <rp@t4d.cz>
Date: Thu, 7 Sep 2023 20:31:47 +0200
Subject: [PATCH] fix: https://github.com/staticlibs/ccronexpr/issues/32

---
 CMakeLists.txt   |  2 +-
 Makefile         |  1 +
 ccronexpr.c      | 12 ++++++------
 ccronexpr_test.c |  2 +-
 4 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index cd71993..154f6ce 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -29,7 +29,7 @@ if (MSVC)
     target_compile_definitions(ccronexpr PRIVATE _CRT_SECURE_NO_WARNINGS)
 else ()
     # Strict compilation
-    target_compile_options(ccronexpr PRIVATE -ansi -Wall -Wextra -Werror -Wshadow -Wpointer-arith -Wcast-qual -Wconversion -pedantic-errors)
+    target_compile_options(ccronexpr PRIVATE -ansi -Wall -Wextra -Werror -Wshadow -Wpointer-arith -Wcast-qual -Wconversion -Wno-unused-parameter -pedantic-errors)
 endif ()
 
 # Tests
diff --git a/Makefile b/Makefile
index b64c062..51eb41c 100644
--- a/Makefile
+++ b/Makefile
@@ -6,6 +6,7 @@ ifeq ($(strip $(UNCOMMITTED_CHANGES)),)
 else
     VERSION := $(VERSION)-dev-build
 endif
+CFLAGS = -Wextra -std=c89 -Os -ffunction-sections -fdata-sections -Wl,--gc-sections -Wl,-z,norelro -Wno-unused-parameter -static -DVERSION=\"$(VERSION)\" -DCRON_USE_LOCAL_TIME
 CFLAGS = -Wextra -std=c89 -s -Os -ffunction-sections -fdata-sections -Wl,--gc-sections -Wl,-z,norelro -static -DVERSION=\"$(VERSION)\" -DCRON_USE_LOCAL_TIME
 SOURCES = supertinycron.c ccronexpr.c ccronexpr_test.c
 OBJECTS = supertinycron.o ccronexpr.o
diff --git a/ccronexpr.c b/ccronexpr.c
index 11a3aa9..b2e1386 100644
--- a/ccronexpr.c
+++ b/ccronexpr.c
@@ -562,7 +562,7 @@ static int do_nextprev(
         int (*do_)(cron_expr* expr, struct tm* calendar, int dot),
         int (*find_day)(struct tm* calendar, uint8_t* days_of_month, int8_t* day_in_month, int day_of_month, uint8_t* days_of_week, int day_of_week, uint8_t* flags, int* resets, int* res_out),
         int (*find_offset)(uint8_t* bits, int max, int value, int offset, struct tm* calendar, int field, int nextField, int* lower_orders, int* res_out),
-        cron_expr* expr, struct tm* calendar, int dot, int offset) {
+        cron_expr* expr, struct tm* calendar, int dot) {
     int i;
     int res = 0;
     int resets[CRON_CF_ARR_LEN];
@@ -628,7 +628,7 @@ static int do_nextprev(
     update_month = find(expr->months, CRON_MAX_MONTHS, month, calendar, CRON_CF_MONTH, CRON_CF_YEAR, resets, &res);
     if (0 != res) goto return_result;
     if (month != update_month) {
-        if ((calendar->tm_year - dot)*offset > CRON_MAX_YEARS_DIFF) {
+        if (abs(calendar->tm_year - dot) > CRON_MAX_YEARS_DIFF) {
             res = -1;
             goto return_result;
         }
@@ -651,7 +651,7 @@ static int do_nextprev(
 }
 
 static int do_next(cron_expr* expr, struct tm* calendar, int dot) {
-    return do_nextprev(find_next, do_next, find_next_day, find_next_offset, expr, calendar, dot, 1);
+    return do_nextprev(find_next, do_next, find_next_day, find_next_offset, expr, calendar, dot);
 }
 
 static int to_upper(char* str) {
@@ -1299,10 +1299,10 @@ static int find_prev_offset(uint8_t* bits, int max, int value, int offset, struc
         next_value = prev_set_bit(bits, max - 1, value, &notfound);
     }
     if (notfound || next_value != value) {
-        err = set_field(calendar, field, next_value);
-        if (err) goto return_error;
         err = reset_all_max(calendar, lower_orders);
         if (err) goto return_error;
+        err = set_field(calendar, field, next_value);
+        if (err) goto return_error;
     }
     return next_value;
 
@@ -1335,7 +1335,7 @@ static int find_prev_day(struct tm* calendar, uint8_t* days_of_month, int8_t* da
 }
 
 static int do_prev(cron_expr* expr, struct tm* calendar, int dot) {
-    return do_nextprev(find_prev, do_prev, find_prev_day, find_prev_offset, expr, calendar, dot, -1);
+    return do_nextprev(find_prev, do_prev, find_prev_day, find_prev_offset, expr, calendar, dot);
 }
 
 time_t cron_prev(cron_expr* expr, time_t date) {
diff --git a/ccronexpr_test.c b/ccronexpr_test.c
index 6c10358..7e7405b 100644
--- a/ccronexpr_test.c
+++ b/ccronexpr_test.c
@@ -486,7 +486,7 @@ void test_expr() {
     check_fn(cron_next, "0 0 0 ? 4-5 *",     "2022-03-31_00:00:00", "2022-04-01_00:00:00", __LINE__);
 
     check_fn(cron_next, "* * * 29 2 *",  	"2021-12-07_12:00:00", "2024-02-29_00:00:00", __LINE__);
-    /*check_fn(cron_prev, "* * * 29 2 *",  	"2021-12-07_12:00:00", "2024-02-29_00:00:00", __LINE__);*/
+    check_fn(cron_prev, "* * * 29 2 *",  	"2021-12-07_12:00:00", "2020-02-29_23:59:59", __LINE__);
 }
 
 void test_parse() {