add timegm

3 files changed, 35 insertions, 0 deletions

diff --git a/src/date.h b/src/date.h
index d4b0680..bda32a0 100644
--- a/src/date.h
+++ b/src/date.h
@@ -27,4 +27,6 @@ struct tm *jd_opttm(Janet *argv, int32_t argc, int32_t n);
 struct tm *jd_maketm(void);
 JANET_CFUN(jd_mktime);
 JANET_CFUN(jd_mktime_inplace);
+JANET_CFUN(jd_timegm);
+JANET_CFUN(jd_timegm_inplace);
 JANET_CFUN(jd_strftime);
diff --git a/src/polyfill.h b/src/polyfill.h
index ecc3a0d..70ea4f5 100644
--- a/src/polyfill.h
+++ b/src/polyfill.h
@@ -1,5 +1,6 @@
 #pragma once
 #include <janet.h>
+#include <time.h>
 
 #if JANET_VERSION_MAJOR < 2 && JANET_VERSION_MINOR < 28
 #define POLYFILL_CBYTES
@@ -20,6 +21,14 @@ const char *janet_optcbytes(const Janet *argv, int32_t argc, int32_t n, const ch
 #endif // !defined(JANET_NO_SOURCEMAPS)
 #endif // JANET_VERSION_MAJOR < 2 && JANET_VERSION_MINOR < 28
 
+// timegm
+#ifdef _MSC_VER
+#define timegm _mkgmtime
+#else
+// since tm is a pointer, it should be ABI-compatible even if the true type is mismatched
+time_t timegm(struct tm *tm);
+#endif
+
 // ===
 
 // public domain code from
diff --git a/src/tm.c b/src/tm.c
index 9c2a91f..4d5d1d5 100644
--- a/src/tm.c
+++ b/src/tm.c
@@ -278,6 +278,28 @@ JANET_FN(jd_mktime_inplace,
 	return janet_wrap_abstract(time);
 }
 
+JANET_FN(jd_timegm,
+		"",
+		"") {
+	janet_fixarity(argc, 1);
+	struct tm *tm = jd_gettm(argv, 0);
+	struct tm *nw = jd_maketm();
+	*nw = *tm;
+	time_t *time = jd_maketime();
+	*time = timegm(nw);
+	return janet_wrap_abstract(time);
+}
+
+JANET_FN(jd_timegm_inplace,
+		"",
+		"") {
+	janet_fixarity(argc, 1);
+	struct tm *tm = jd_gettm(argv, 0);
+	time_t *time = jd_maketime();
+	*time = timegm(tm);
+	return janet_wrap_abstract(time);
+}
+
 // strftime
 struct strftime_format {
 	const char *keyword;
@@ -322,6 +344,8 @@ const JanetRegExt jd_tm_cfuns[] = {
 	JANET_REG("tm",       jd_tm),
 	JANET_REG("mktime",   jd_mktime),
 	JANET_REG("mktime!",  jd_mktime_inplace),
+	JANET_REG("timegm",   jd_timegm),
+	JANET_REG("timegm!",  jd_timegm_inplace),
 	JANET_REG("strftime", jd_strftime),
 	JANET_REG_END
 };