getdate replacement code. smaller, slicker, faster.

lib/parsedate.c

+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2004, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * $Id$
+ ***************************************************************************/
+/*
+  RFC 2616 3.3.1
+
+  Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123
+  Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
+  Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format
+
+  we support dates without week day name:
+
+  06 Nov 1994 08:49:37 GMT
+  06-Nov-94 08:49:37 GMT
+  Nov  6 08:49:37 1994
+
+  and without the time zone (we always assume GMT):
+
+  06 Nov 1994 08:49:37
+  06-Nov-94 08:49:37
+
+  or even in weird order:
+
+  1994 Nov 6 08:49:37  (curl_getdate() and GNU date fails)
+  08:49:37 06-Nov-94
+  94 6 Nov 08:49:37    (curl_getdate() and GNU date fails)
+
+*/
+#include "setup.h"
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h> /* for strtol() */
+#endif
+
+#include <curl/curl.h>
+
+
+#include "parsedate.h"
+
+static const char *wkday[] = {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};
+static const char *weekday[] = { "Monday", "Tuesday", "Wednesday", "Thursday",
+                                 "Friday", "Saturday", "Sunday" };
+static const char *month[]= { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul",
+                              "Aug", "Sep", "Oct", "Nov", "Dec" };
+
+static const char *tz[]= { "GMT", "UTC" };
+
+/* returns:
+   -1 no day
+   0 monday - 6 sunday
+*/
+
+static int checkday(char *check, size_t len)
+{
+  int i;
+  const char **what;
+  bool found= FALSE;
+  if(len > 3)
+    what = &weekday[0];
+  else
+    what = &wkday[0];
+  for(i=0; i<7; i++) {
+    if(curl_strequal(check, what[0])) {
+      found=TRUE;
+      break;
+    }
+    what++;
+  }
+  return found?i:-1;
+}
+
+static int checkmonth(char *check)
+{
+  int i;
+  const char **what;
+  bool found= FALSE;
+
+  what = &month[0];
+  for(i=0; i<12; i++) {
+    if(curl_strequal(check, what[0])) {
+      found=TRUE;
+      break;
+    }
+    what++;
+  }
+  return found?i:-1;
+}
+
+static int checktz(char *check)
+{
+  int i;
+  const char **what;
+  bool found= FALSE;
+
+  what = &tz[0];
+  for(i=0; i<2; i++) {
+    if(curl_strequal(check, what[0])) {
+      found=TRUE;
+      break;
+    }
+    what++;
+  }
+  return found?i:-1;
+}
+
+static void skip(const char **date)
+{
+  /* skip everything that aren't letters or digits */
+  while(**date && !isalnum((int)**date))
+    (*date)++;
+}
+
+#define TM_YEAR_ORIGIN 1900
+
+/* Yield A - B, measured in seconds. (from getdate.y)  */
+static long
+difftm (struct tm *a, struct tm *b)
+{
+  int ay = a->tm_year + (TM_YEAR_ORIGIN - 1);
+  int by = b->tm_year + (TM_YEAR_ORIGIN - 1);
+  long days = (
+  /* difference in day of year */
+		a->tm_yday - b->tm_yday
+  /* + intervening leap days */
+		+ ((ay >> 2) - (by >> 2))
+		- (ay / 100 - by / 100)
+		+ ((ay / 100 >> 2) - (by / 100 >> 2))
+  /* + difference in years * 365 */
+		+ (long) (ay - by) * 365
+  );
+  return (60 * (60 * (24 * days + (a->tm_hour - b->tm_hour))
+		+ (a->tm_min - b->tm_min))
+	  + (a->tm_sec - b->tm_sec));
+}
+
+enum assume {
+  DATE_MDAY,
+  DATE_YEAR,
+  DATE_TIME
+};
+
+time_t Curl_parsedate(const char *date)
+{
+  time_t t = 0;
+  int wdaynum=-1;  /* day of the week number, 0-6 (mon-sun) */
+  int monnum=-1;   /* month of the year number, 0-11 */
+  long mdaynum=-1; /* day of month, 1 - 31 */
+  int hournum=-1;
+  int minnum=-1;
+  int secnum=-1;
+  long yearnum=-1;
+  int tznum=-1;
+  struct tm tm;
+  enum assume dignext = DATE_MDAY;
+
+  int part = 0; /* max 6 parts */
+
+  while(part < 6) {
+    bool found=FALSE;
+
+    skip(&date);
+
+    if(isalpha((int)*date)) {
+      /* a name coming up */
+      char buf[32]="";
+      size_t len;
+      sscanf(date, "%31[^ ,\n\t-]", buf);
+      len = strlen(buf);
+
+      if(wdaynum == -1) {
+        wdaynum = checkday(buf, len);
+        if(wdaynum != -1)
+          found = TRUE;
+      }
+      if(!found && (monnum == -1)) {
+        monnum = checkmonth(buf);
+        if(monnum != -1)
+          found = TRUE;
+      }
+
+      if(!found && (tznum == -1)) {
+        /* this just must be a time zone string */
+        tznum = checktz(buf);
+        if(tznum != -1)
+          found = TRUE;
+      }
+
+      if(!found)
+        return -1; /* bad string */
+
+      date += len;
+    }
+    else if(isdigit((int)*date)) {
+      /* a digit */
+      long val;
+      char *end;
+      if((secnum == -1) &&
+         (3 == sscanf(date, "%02d:%02d:%02d", &hournum, &minnum, &secnum))) {
+        /* time stamp! */
+        date += 8;
+        found = TRUE;
+      }
+      else {
+        val = strtol(date, &end, 10);
+
+        if((dignext == DATE_MDAY) && (mdaynum == -1)) {
+          if((val > 0) && (val<32)) {
+            mdaynum = val;
+            found = TRUE;
+          }
+          dignext = DATE_YEAR;
+        }
+
+        if(!found && (dignext == DATE_YEAR) && (yearnum == -1)) {
+          yearnum = val;
+          found = TRUE;
+          if(yearnum < 1900) {
+            if (yearnum > 70)
+              yearnum += 1900;
+            else
+              yearnum += 2000;
+          }
+          if(mdaynum == -1)
+            dignext = DATE_MDAY;
+        }
+
+        if(!found)
+          return -1;
+
+        date = end;
+      }
+    }
+
+    part++;
+  }
+
+  tm.tm_sec = secnum;
+  tm.tm_min = minnum;
+  tm.tm_hour = hournum;
+  tm.tm_mday = mdaynum;
+  tm.tm_mon = monnum;
+  tm.tm_year = yearnum - 1900;
+  tm.tm_wday = 0;
+  tm.tm_yday = 0;
+  tm.tm_isdst = 0;
+
+  t = mktime(&tm);
+
+  /* We have the time-stamp now, but in our local time zone, we must now
+     adjust it to GMT. */
+  {
+    struct tm *gmt;
+    long delta;
+#ifdef HAVE_GMTIME_R
+    /* thread-safe version */
+    struct tm keeptime2;
+    gmt = (struct tm *)gmtime_r(&t, &keeptime2);
+#else
+    gmt = gmtime(&t); /* use gmtime_r() if available */
+#endif
+    delta = difftm(&tm, gmt);
+
+    if(t + delta < t)
+      return -1; /* time_t overflow */
+
+    t += delta;
+  }
+
+  return t;
+}
+
+time_t curl_getdate(const char *p, const time_t *now)
+{
+  (void)now;
+  return Curl_parsedate(p);
+}
+
+#ifdef TESTIT
+
+int main(void)
+{
+  char buffer[1024];
+  char cmd[1024];
+  time_t t;
+
+  while(fgets(buffer, sizeof(buffer), stdin)) {
+    size_t len = strlen(buffer);
+
+    buffer[len-1]=0; /* cut off newline */
+
+    t = curl_getdate(buffer, NULL);
+
+    printf("curl_getdate(): %d\n", t);
+
+    sprintf(cmd, "date -d \"%s\" +%%s", buffer);
+
+    printf("GNU date:\n");
+    system(cmd);
+
+    t = parse_a_date(buffer);
+    printf("parse_a_date: %d\n===================\n\n", t);
+  }
+
+  return 0;
+}
+
+#endif

lib/parsedate.h

+#ifndef __PARSEDATE_H
+#define __PARSEDATE_H
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2004, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * $Id$
+ ***************************************************************************/
+
+time_t Curl_parsedate(const char *date);
+
+#endif