clock: Add -gmt option to format and scan

Signed-off-by: Steve Bennett <steveb@workware.net.au>

1 files changed, 108 insertions, 35 deletions

diff --git a/jim-clock.c b/jim-clock.c
index 69fb966..979b13f 100644
--- a/jim-clock.c
+++ b/jim-clock.c
@@ -4,46 +4,88 @@
  * Implements the clock command
  */
 
-/* For strptime() */
+#include "jimautoconf.h"
+
+/* For strptime() - currently nothing sets this */
+#ifdef STRPTIME_NEEDS_XOPEN_SOURCE
 #ifndef _XOPEN_SOURCE
 #define _XOPEN_SOURCE 500
 #endif
+#endif
+
+/* For timegm() */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 #include <time.h>
 
-#include "jimautoconf.h"
 #include <jim-subcmd.h>
 
 #ifdef HAVE_SYS_TIME_H
 #include <sys/time.h>
 #endif
 
+struct clock_options {
+    int gmt;
+    const char *format;
+};
+
+/* Parses the options ?-format string? ?-gmt boolean? and fills in *opts.
+ * Any options not present are not set.
+ * argc must be even.
+ *
+ * Returns JIM_OK or JIM_ERR and sets an error result.
+ */
+static int parse_clock_options(Jim_Interp *interp, int argc, Jim_Obj *const *argv, struct clock_options *opts)
+{
+    static const char * const options[] = { "-gmt", "-format", NULL };
+    enum { OPT_GMT, OPT_FORMAT, };
+    int i;
+
+    for (i = 0; i < argc; i += 2) {
+        int option;
+        if (Jim_GetEnum(interp, argv[i], options, &option, NULL, JIM_ERRMSG | JIM_ENUM_ABBREV) != JIM_OK) {
+            return JIM_ERR;
+        }
+        switch (option) {
+            case OPT_GMT:
+                if (Jim_GetBoolean(interp, argv[i + 1], &opts->gmt) != JIM_OK) {
+                    return JIM_ERR;
+                }
+                break;
+            case OPT_FORMAT:
+                opts->format = Jim_String(argv[i + 1]);
+                break;
+        }
+    }
+    return JIM_OK;
+}
+
 static int clock_cmd_format(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 {
     /* How big is big enough? */
     char buf[100];
     time_t t;
-    long seconds;
+    jim_wide seconds;
+    struct clock_options options = { 0, "%a %b %d %H:%M:%S %Z %Y" };
 
-    const char *format = "%a %b %d %H:%M:%S %Z %Y";
-
-    if (argc == 2 || (argc == 3 && !Jim_CompareStringImmediate(interp, argv[1], "-format"))) {
-        return -1;
+    if (Jim_GetWide(interp, argv[0], &seconds) != JIM_OK) {
+        return JIM_ERR;
     }
+    t = seconds;
 
-    if (argc == 3) {
-        format = Jim_String(argv[2]);
+    if (argc % 2 == 0) {
+        return -1;
     }
-
-    if (Jim_GetLong(interp, argv[0], &seconds) != JIM_OK) {
+    if (parse_clock_options(interp, argc - 1, argv + 1, &options) == JIM_ERR) {
         return JIM_ERR;
     }
-    t = seconds;
 
-    if (strftime(buf, sizeof(buf), format, localtime(&t)) == 0) {
+    if (strftime(buf, sizeof(buf), options.format, options.gmt ? gmtime(&t) : localtime(&t)) == 0) {
         Jim_SetResultString(interp, "format string too long", -1);
         return JIM_ERR;
     }
@@ -54,27 +96,58 @@ static int clock_cmd_format(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 }
 
 #ifdef HAVE_STRPTIME
+#ifndef HAVE_TIMEGM
+/* Implement a basic timegm() for system's that don't have it */
+static time_t timegm(struct tm *tm)
+{
+    time_t t;
+    const char *tz = getenv("TZ");
+    setenv("TZ", "", 1);
+    tzset();
+    t = mktime(tm);
+    if (tz) {
+        setenv("TZ", tz, 1);
+    }
+    else {
+        unsetenv("TZ");
+    }
+    tzset();
+    return t;
+}
+#endif
+
 static int clock_cmd_scan(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 {
     char *pt;
     struct tm tm;
-    time_t now = time(0);
+    /*time_t now = time(NULL);*/
+    /* No default format */
+    struct clock_options options = { 0, NULL };
+
+    if (argc % 2 == 0) {
+        return -1;
+    }
 
-    if (!Jim_CompareStringImmediate(interp, argv[1], "-format")) {
+    if (parse_clock_options(interp, argc - 1, argv + 1, &options) == JIM_ERR) {
+        return JIM_ERR;
+    }
+    if (options.format == NULL) {
         return -1;
     }
 
-    /* Initialise with the current date/time */
-    localtime_r(&now, &tm);
+    /* Set unspecified fields to 0, e.g. HH:MM becomes 00:00 */
+    memset(&tm, 0, sizeof(tm));
+    /* But this is 1-based */
+    tm.tm_mday = 1;
 
-    pt = strptime(Jim_String(argv[0]), Jim_String(argv[2]), &tm);
+    pt = strptime(Jim_String(argv[0]), options.format, &tm);
     if (pt == 0 || *pt != 0) {
         Jim_SetResultString(interp, "Failed to parse time according to format", -1);
         return JIM_ERR;
     }
 
     /* Now convert into a time_t */
-    Jim_SetResultInt(interp, mktime(&tm));
+    Jim_SetResultInt(interp, options.gmt ? timegm(&tm) : mktime(&tm));
 
     return JIM_OK;
 }
@@ -110,13 +183,6 @@ static int clock_cmd_millis(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 }
 
 static const jim_subcmd_type clock_command_table[] = {
-    {   "seconds",
-        NULL,
-        clock_cmd_seconds,
-        0,
-        0,
-        /* Description: Returns the current time as seconds since the epoch */
-    },
     {   "clicks",
         NULL,
         clock_cmd_micros,
@@ -124,6 +190,13 @@ static const jim_subcmd_type clock_command_table[] = {
         0,
         /* Description: Returns the current time in 'clicks' */
     },
+    {   "format",
+        "seconds ?-format string? ?-gmt boolean?",
+        clock_cmd_format,
+        1,
+        5,
+        /* Description: Format the given time */
+    },
     {   "microseconds",
         NULL,
         clock_cmd_micros,
@@ -138,22 +211,22 @@ static const jim_subcmd_type clock_command_table[] = {
         0,
         /* Description: Returns the current time in milliseconds */
     },
-    {   "format",
-        "seconds ?-format format?",
-        clock_cmd_format,
-        1,
-        3,
-        /* Description: Format the given time */
-    },
 #ifdef HAVE_STRPTIME
     {   "scan",
-        "str -format format",
+        "str -format format ?-gmt boolean?",
         clock_cmd_scan,
         3,
-        3,
+        5,
         /* Description: Determine the time according to the given format */
     },
 #endif
+    {   "seconds",
+        NULL,
+        clock_cmd_seconds,
+        0,
+        0,
+        /* Description: Returns the current time as seconds since the epoch */
+    },
     { NULL }
 };