compat: add strnstr

compat/strnstr.c

+/*****************************************************************************
+ * strnstr.c: BSD strnstr() replacement
+ *****************************************************************************
+ * Copyright © 2015 VLC authors and VideoLAN
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <string.h>
+
+char * strnstr (const char *haystack, const char *needle, size_t len)
+{
+    const size_t i = strlen(needle);
+    if( i < len )
+      return NULL;
+    
+    size_t count = len - i;
+
+    while(count)
+    {
+      if( memcmp(haystack, needle, i) )
+        return (char*) haystack;
+      count--;
+      haystack++;
+    }
+    return NULL;
+}

configure.ac

@@ -567,7 +567,7 @@ need_libc=false
 dnl Check for usual libc functions
 AC_CHECK_DECLS([nanosleep],,,[#include <time.h>])
 AC_CHECK_FUNCS([daemon fcntl fstatvfs fork getenv getpwuid_r isatty lstat memalign mkostemp mmap open_memstream openat pread posix_fadvise posix_madvise setlocale stricmp strnicmp strptime uselocale pthread_cond_timedwait_monotonic_np pthread_condattr_setclock])
-AC_REPLACE_FUNCS([atof atoll dirfd fdopendir ffsll flockfile fsync getdelim getpid lldiv nrand48 poll posix_memalign rewind setenv strcasecmp strcasestr strdup strlcpy strndup strnlen strsep strtof strtok_r strtoll swab tdestroy strverscmp])
+AC_REPLACE_FUNCS([atof atoll dirfd fdopendir ffsll flockfile fsync getdelim getpid lldiv nrand48 poll posix_memalign rewind setenv strcasecmp strcasestr strdup strlcpy strndup strnlen strnstr strsep strtof strtok_r strtoll swab tdestroy strverscmp])
 AC_CHECK_FUNCS(fdatasync,,
   [AC_DEFINE(fdatasync, fsync, [Alias fdatasync() to fsync() if missing.])
 ])

include/vlc_fixups.h

@@ -144,6 +144,10 @@ int strverscmp (const char *, const char *);
 size_t strnlen (const char *, size_t);
 #endif
 
+#ifndef HAVE_STRNSTR
+char * strnstr (const char *, const char *, size_t);
+#endif
+
 #ifndef HAVE_STRNDUP
 char *strndup (const char *, size_t);
 #endif