add scan_iso8601+test

scan.h

@@ -8,6 +8,8 @@
 #include <stdint.h>
 /* for time_t: */
 #include <sys/types.h>
+/* for struct timespec: */
+#include <time.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -103,6 +105,10 @@ size_t scan_noncharsetnskip(const char *in,const char *charset,size_t limit) __p
  */
 size_t scan_httpdate(const char *in,time_t *t) __pure__;
 
+/* try to parse ASCII ISO-8601 date; does not understand time zones. */
+/* example date: "2014-05-27T19:22:16Z" */
+size_t scan_iso8601(const char* in,struct timespec* t) __pure__;
+
 /* some variable length encodings for integers */
 size_t scan_utf8(const char* in,size_t len,uint32_t* n) __pure__;
 size_t scan_asn1derlength(const char* in,size_t len,unsigned long long* n) __pure__;

scan/scan_iso8601.c

@@ -0,0 +1,75 @@
+#define _GNU_SOURCE
+#define __deprecated__
+#include "scan.h"
+#include "byte.h"
+#include "case.h"
+#include <time.h>
+#include <stdlib.h>
+
+#ifdef sgi
+extern char** environ;
+#endif
+
+/* "2014-05-27T19:22:16Z" */
+size_t scan_iso8601(const char* in,struct timespec* t) {
+  struct tm x;
+  const char* c;
+  unsigned long tmp;
+  if (!(c=in)) return 0;
+  if (scan_ulong(c,&tmp)!=4 || c[4]!='-') return 0; c+=5; x.tm_year=(int)(tmp-1900);
+  if (scan_ulong(c,&tmp)!=2 || c[2]!='-') return 0; c+=3; x.tm_mon=(int)(tmp-1);
+  if (scan_ulong(c,&tmp)!=2 || c[2]!='T') return 0; c+=3; x.tm_mday=(int)tmp;
+  if (scan_ulong(c,&tmp)!=2 || c[2]!=':') return 0; c+=3; x.tm_hour=(int)tmp;
+  if (scan_ulong(c,&tmp)!=2 || c[2]!=':') return 0; c+=3; x.tm_min=(int)tmp;
+  if (scan_ulong(c,&tmp)!=2) return 0; c+=2; x.tm_sec=(int)tmp;
+  if (*c=='.') {
+    size_t i;
+    ++c;
+    i=scan_ulong(c,&tmp);
+    c+=i;
+    if (i<1 || i>9)
+      t->tv_nsec=0;
+    else {
+      while (i<9) {
+	++i;
+	tmp*=10;
+      }
+      t->tv_nsec=tmp;
+    }
+  }
+
+  x.tm_wday=x.tm_yday=x.tm_isdst=0;
+#if defined(__dietlibc__) || defined(__GLIBC__)
+  t->tv_sec=timegm(&x);
+#elif defined(__MINGW32__)
+  t->tv_sec=mktime(&x);
+#else
+  {
+#ifdef sgi
+    char** old=environ;
+    char** newenv={0};
+    environ=newenv;
+    t->tv_sec=mktime(&x);
+    environ=old;
+#else
+    char* old=getenv("TZ");
+    unsetenv("TZ");
+    t->tv_sec=mktime(&x);
+    if (old) setenv("TZ",old,1);
+#endif
+  }
+#endif
+
+  if (*c=='+' || *c=='-') {
+    int signum = (*c=='+') - (*c=='-');
+    unsigned int val;
+    ++c;
+    if (scan_ulong(c,&tmp)!=2 || c[2]!=':') return 0; c+=3; val=tmp*60;
+    if (scan_ulong(c,&tmp)!=2) return 0; c+=2; val+=tmp;
+    t->tv_sec+=signum*val;
+  } else if (*c=='Z')
+    ++c;
+  else
+    return 0;
+  return (size_t)(c-in);
+}

test/fmt_iso8691.c

@@ -1,10 +1,13 @@
 #include <fmt.h>
+#include <scan.h>
 #include <assert.h>
 #include <unistd.h>
 
 int main() {
   char buf[1024];
-  write(1,buf,fmt_iso8601(buf,0));
+  buf[fmt_iso8601(buf,1431551843)]=0;	// Wed May 13 14:17:23 PDT 2015
-  write(1,"\n",1);
+  assert(!strcmp(buf,"2015-05-13T21:17:23Z"));
+  struct timespec t;
+  assert(scan_iso8601("2015-05-13T21:17:23Z",&t)==20 && t.tv_sec==1431551843);
   return 0;
 }