add strstr functions

Signed-off-by: Mattias Andrée <maandree@operamail.com>

7 files changed, 715 insertions, 12 deletions

diff --git a/include/string.h b/include/string.h
index f1cc0c1..8034973 100644
--- a/include/string.h
+++ b/include/string.h
@@ -848,6 +848,131 @@ char* strrchr(const char*, int)
 /* TODO Add case insensitive character searching functions. */
 
 
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case sensitive.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+char* strstr(const char*, const char*)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull)));
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case insensitive.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+char* strcasestr(const char*, const char*)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull)));
+
+#if defined(_SLIBC_SOURCE) && !defined(__PORTABLE)
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case sensitive.
+ * 
+ * This is a slibc extension added for because it was useful
+ * in implementing slibc itself.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @param   maxlen    The maximum number of character to search.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+char* strnstr(const char*, const char*, size_t)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull)));
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case insensitive.
+ * 
+ * This is a slibc extension added for completeness.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @param   maxlen    The maximum number of character to search.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+char* strncasestr(const char*, const char*, size_t)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull)));
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case sensitive.
+ * It must already be known that such a substring exists.
+ * 
+ * This is a slibc extension.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the substring.
+ */
+char* rawstrstr(const char*, const char*)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull, returns_nonnull)));
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case insensitive.
+ * It must already be known that such a substring exists.
+ * 
+ * This is a slibc extension.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the substring.
+ */
+char* rawstrcasestr(const char*, const char*)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull, returns_nonnull)));
+
+/**
+ * Finds the first occurrence of a substring
+ * This search is case insensitive.
+ * 
+ * This is a slibc extension added because it was useful
+ * in implementing slibc itself.
+ * 
+ * @param   haystack         The string to search.
+ * @param   haystack_length  The number of character to search.
+ * @param   needle           The sought after substring.
+ * @param   needle_length    The length of `needle`.
+ * @return                   Pointer to the first occurrence of
+ *                           the substring, `NULL` if not found.
+ */
+void* memcasemem(const void*, size_t, const void*, size_t)
+  __GCC_ONLY(__attribute__((warn_unused_result)));
+#endif
+
+#if (defined(_GNU_SOURCE) || defined(_SLIBC_SOURCE)) && !defined(__PORTABLE)
+/**
+ * Finds the first occurrence of a substring
+ * This search is case sensitive.
+ * 
+ * This is a GNU-compliant slibc extension. It was useful
+ * in implementing slibc itself.
+ * 
+ * @param   haystack         The string to search.
+ * @param   haystack_length  The number of character to search.
+ * @param   needle           The sought after substring.
+ * @param   needle_length    The length of `needle`.
+ * @return                   Pointer to the first occurrence of
+ *                           the substring, `NULL` if not found.
+ */
+void* memmem(const void*, size_t, const void*, size_t)
+  __GCC_ONLY(__attribute__((warn_unused_result)));
+#endif
+
+
+/* TODO Add case right-to-left substring searching functions. */
+
+
 
 #endif
 
diff --git a/include/wchar.h b/include/wchar.h
index 66c4127..16644c8 100644
--- a/include/wchar.h
+++ b/include/wchar.h
@@ -804,6 +804,140 @@ wchar_t* wcsrchr(const wchar_t*, wchar_t)
 /* TODO Add case insensitive character searching functions. */
 
 
+/**
+ * This function is identical to `wcsstr`.
+ */
+wchar_t* wcswcs(const wchar_t*, const wchar_t*)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull)))
+  __deprecated("Use 'wcsstr' instead.");
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case sensitive.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+wchar_t* wcsstr(const wchar_t*, const wchar_t*)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull)));
+
+#if defined(_SLIBC_SOURCE) && !defined(__PORTABLE)
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case insensitive.
+ * 
+ * This is a slibc extension.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+wchar_t* wcscasestr(const wchar_t*, const wchar_t*)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull)));
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case sensitive.
+ * 
+ * This is a slibc extension added for because it was useful
+ * in implementing slibc itself.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @param   maxlen    The maximum number of character to search.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+wchar_t* wcsnstr(const wchar_t*, const wchar_t*, size_t)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull)));
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case insensitive.
+ * 
+ * This is a slibc extension added for completeness.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @param   maxlen    The maximum number of character to search.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+wchar_t* wcsncasestr(const wchar_t*, const wchar_t*, size_t)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull)));
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case sensitive.
+ * It must already be known that such a substring exists.
+ * 
+ * This is a slibc extension.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the substring.
+ */
+wchar_t* rawwcsstr(const wchar_t*, const wchar_t*)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull, returns_nonnull)));
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case insensitive.
+ * It must already be known that such a substring exists.
+ * 
+ * This is a slibc extension.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the substring.
+ */
+wchar_t* rawwcscasestr(const wchar_t*, const wchar_t*)
+  __GCC_ONLY(__attribute__((warn_unused_result, nonnull, returns_nonnull)));
+
+/**
+ * Finds the first occurrence of a substring
+ * This search is case insensitive.
+ * 
+ * This is a slibc extension added because it was useful
+ * in implementing slibc itself.
+ * 
+ * @param   haystack         The string to search.
+ * @param   haystack_length  The number of character to search.
+ * @param   needle           The sought after substring.
+ * @param   needle_length    The length of `needle`.
+ * @return                   Pointer to the first occurrence of
+ *                           the substring, `NULL` if not found.
+ */
+wchar_t* wmemcasemem(const wchar_t*, size_t, const wchar_t*, size_t);
+#endif
+
+#if (defined(_GNU_SOURCE) || defined(_SLIBC_SOURCE)) && !defined(__PORTABLE)
+/**
+ * Finds the first occurrence of a substring
+ * This search is case sensitive.
+ * 
+ * This is a slibc extension added for completeness,
+ * and because it was it was useful in implementing
+ * slibc itself.
+ * 
+ * @param   haystack         The string to search.
+ * @param   haystack_length  The number of character to search.
+ * @param   needle           The sought after substring.
+ * @param   needle_length    The length of `needle`.
+ * @return                   Pointer to the first occurrence of
+ *                           the substring, `NULL` if not found.
+ */
+wchar_t* wmemmem(const wchar_t*, size_t, const wchar_t*, size_t)
+  __GCC_ONLY(__attribute__((warn_unused_result)));
+#endif
+
+
+/* TODO Add case right-to-left substring searching functions. */
+
+
 
 #endif
 #endif
diff --git a/src/string/strchr.c b/src/string/strchr.c
index 6a25f78..21345d4 100644
--- a/src/string/strchr.c
+++ b/src/string/strchr.c
@@ -93,10 +93,11 @@ void* memrchr(const void* segment, int c, size_t size)
  */
 char* strchr(const char* string, int c)
 {
-  while (; *string; string++)
+  for (;;)
     if (*string == c)
       return string;
-  return NULL;
+    else if (!*string++)
+      return NULL;
 }
 /* TODO Ensure that `s = strchr(s, 0)` is faster than `s = s + strlen(s)`. */
 
@@ -117,10 +118,11 @@ char* strchr(const char* string, int c)
  */
 char* strchrnul(const char* string, int c)
 {
-  while (; *string; string++)
+  for (;; string++)
     if (*string == c)
       return string;
-  return string;
+    else if (!*string)
+      return string;
 }
 
 
@@ -141,9 +143,10 @@ char* strchrnul(const char* string, int c)
 char* strrchr(const char* string, int c)
 {
   char* r = NULL;
-  while (; *string; string++)
+  for (;;)
     if (*string == c)
       r = string;
-  return r;
+    else if (!*string++)
+      return r;
 }
 
diff --git a/src/string/strstr.c b/src/string/strstr.c
new file mode 100644
index 0000000..a7e490a
--- /dev/null
+++ b/src/string/strstr.c
@@ -0,0 +1,179 @@
+/**
+ * slibc — Yet another C library
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <string.h>
+#include <stddef.h>
+#include <inttypes.h>
+
+
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case sensitive.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+char* strstr(const char* haystack, const char* needle)
+{
+  return memmem(haystack, strlen(haystack), needle, strlen(needle));
+}
+
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case insensitive.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+char* strcasestr(const char* haystack, const char* needle)
+{
+  return memcasemem(haystack, strlen(haystack), needle, strlen(needle));
+}
+
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case sensitive.
+ * 
+ * This is a slibc extension added for because it was useful
+ * in implementing slibc itself.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @param   maxlen    The maximum number of character to search.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+char* strnstr(const char* haystack, const char* needle, size_t maxlen)
+{
+  return memmem(haystack, strnlen(haystack, maxlen), needle, strlen(needle));
+}
+
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case insensitive.
+ * 
+ * This is a slibc extension added for completeness.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @param   maxlen    The maximum number of character to search.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+char* strncasestr(const char* haystack, const char* needle, size_t maxlen)
+{
+  return memcasemem(haystack, strnlen(haystack, maxlen), needle, strlen(needle));
+}
+
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case sensitive.
+ * It must already be known that such a substring exists.
+ * 
+ * This is a slibc extension.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the substring.
+ */
+char* rawstrstr(const char* haystack, const char* needle)
+{
+  return memmem(haystack, SIZE_MAX, needle, strlen(needle));
+}
+
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case insensitive.
+ * It must already be known that such a substring exists.
+ * 
+ * This is a slibc extension.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the substring.
+ */
+char* rawstrcasestr(const char* haystack, const char* needle)
+{
+  return memcasemem(haystack, SIZE_MAX, needle, strlen(needle));
+}
+
+
+/**
+ * Finds the first occurrence of a substring
+ * This search is case sensitive.
+ * 
+ * This is a GNU-compliant slibc extension. It was useful
+ * in implementing slibc itself.
+ * 
+ * @param   haystack         The string to search.
+ * @param   haystack_length  The number of character to search.
+ * @param   needle           The sought after substring.
+ * @param   needle_length    The length of `needle`.
+ * @return                   Pointer to the first occurrence of
+ *                           the substring, `NULL` if not found.
+ */
+void* memmem(const void* __haystack, size_t haystack_length,
+	     const void* __needle, size_t needle_length)
+{
+  const char* haystack = __haystack;
+  const char* needle = __needle;
+  if (haystack_length < needle_length)
+    return NULL;
+  if (haystack_length == needle_length)
+    return !memcmp(haystack, haystack_length, haystack_length) ? haystack : NULL;
+#include "substring.h"
+}
+
+
+/**
+ * Finds the first occurrence of a substring
+ * This search is case insensitive.
+ * 
+ * This is a slibc extension added because it was useful
+ * in implementing slibc itself.
+ * 
+ * @param   haystack         The string to search.
+ * @param   haystack_length  The number of character to search.
+ * @param   needle           The sought after substring.
+ * @param   needle_length    The length of `needle`.
+ * @return                   Pointer to the first occurrence of
+ *                           the substring, `NULL` if not found.
+ */
+void* memcasemem(const void* __haystack, size_t haystack_length,
+		 const void* __needle, size_t needle_length)
+{
+  const char* haystack = __haystack;
+  const char* needle = __needle;
+  if (haystack_length < needle_length)
+    return NULL;
+  if (haystack_length == needle_length)
+    return !memcasecmp(haystack, haystack_length, haystack_length) ? haystack : NULL;
+#define CASE
+#include "substring.h"
+#undef CASE
+}
+
diff --git a/src/string/substring.h b/src/string/substring.h
new file mode 100644
index 0000000..10e4a7d
--- /dev/null
+++ b/src/string/substring.h
@@ -0,0 +1,70 @@
+/**
+ * slibc — Yet another C library
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+/* This file is intended to be included inside a
+ * [w]mem[r][case]mem function. `haystack` and
+ * `needle` shall be defined the same pointer type,
+ * but not as `void*`. `haystack_length` and
+ * `needle_length` shall be defined in the `size_t`
+ * type. CASE shall be defined iff case insensitive
+ * search shall be used. RIGHT shall be defined iff
+ * the last occurrence shall be find. WIDE shall be
+ * defined iff wide characters are used. It is assumed
+ * that `needle_length` <= `haystack_length` */
+
+
+/* The Knuth–Morris–Pratt algorithm. */
+
+
+#if !defined(CASE)
+# define CHREQ(a, b)  (a == b)
+#elif !defined(WIDE)
+# define CHREQ(a, b)  ((islower(a) ? tolower(a) : (a)) == tolower(b))
+#else
+# define CHREQ(a, b)  ((iswlower(a) ? towlower(a) : (a)) == towlower(b))
+#endif
+
+
+/* TODO add support for RIGHT */
+
+
+{
+  ssize_t* next_map = alloca((needle_length + 1) * sizeof(ssize_t));
+  ssize_t hay, ned, skp;
+  
+  ned = 0, skp = next_map[0] = -1;
+  while (ned < needle_length)
+    {
+      while ((skp > -1) && !CHREQ(needle[ned], needle[skp]))
+	skp = next_map[skp];
+      ned++, skp++;
+      next_map[ned] = CHREQ(needle[ned], needle[skp]) ? next_map[skp] : skp;
+    }
+  
+  hay = ned = 0;
+  while (hay < haystack_length)
+    {
+      while ((ned > -1) && !CHREQ(haystack[hay], needle[ned]))
+	ned = next_map[ned];
+      hay++, ned++;
+      if (ned >= needle_length)
+	return needle + (hay - ned);
+    }
+  
+  return NULL;
+}
+
diff --git a/src/wchar/wcschr.c b/src/wchar/wcschr.c
index e96a90a..493f0a7 100644
--- a/src/wchar/wcschr.c
+++ b/src/wchar/wcschr.c
@@ -95,10 +95,11 @@ wchar_t* wmemrchr(const wchar_t* segment, wchar_t c, size_t size)
  */
 wchar_t* wcschr(const wchar_t* string, wchar_t c)
 {
-  while (; *string; string++)
+  for (;;)
     if (*string == c)
       return string;
-  return NULL;
+    else if (!*string++)
+      return NULL;
 }
 
 
@@ -119,10 +120,11 @@ wchar_t* wcschr(const wchar_t* string, wchar_t c)
  */
 wchar_t* wcschrnul(const wchar_t* string, wchar_t c)
 {
-  while (; *string; string++)
+  for (;; string++)
     if (*string == c)
       return string;
-  return string;
+    else if (!*string)
+      return string;
 }
 
 
@@ -143,9 +145,10 @@ wchar_t* wcschrnul(const wchar_t* string, wchar_t c)
 wchar_t* wcsrchr(const wchar_t* string, wchar_t c)
 {
   wchar_t* r = NULL;
-  while (; *string; string++)
+  for (;;)
     if (*string == c)
       r = string;
-  return r;
+    else if (!*string++)
+      return r;
 }
 
diff --git a/src/wchar/wcsstr.c b/src/wchar/wcsstr.c
new file mode 100644
index 0000000..bba7d96
--- /dev/null
+++ b/src/wchar/wcsstr.c
@@ -0,0 +1,189 @@
+/**
+ * slibc — Yet another C library
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <wchar.h>
+#include <stddef.h>
+#include <inttypes.h>
+
+#define WIDE
+
+
+
+/**
+ * This function is identical to `wcsstr`.
+ */
+wchar_t* wcswcs(const wchar_t* haystack, const wchar_t* needle)
+{
+  return wcsstr(haystack, needle);
+}
+
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case sensitive.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+wchar_t* wcsstr(const wchar_t* haystack, const wchar_t* needle)
+{
+  return wmemmem(haystack, wcslen(haystack), needle, wcslen(needle));
+}
+
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case insensitive.
+ * 
+ * This is a slibc extension.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+wchar_t* wcscasestr(const wchar_t* haystack, const wchar_t* needle)
+{
+  return wmemcasemem(haystack, wcslen(haystack), needle, wcslen(needle));
+}
+
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case sensitive.
+ * 
+ * This is a slibc extension added for because it was useful
+ * in implementing slibc itself.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @param   maxlen    The maximum number of character to search.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+wchar_t* wcsnstr(const wchar_t* haystack, const wchar_t* needle, size_t maxlen)
+{
+  return wmemmem(haystack, wcsnlen(haystack, maxlen), needle, wcslen(needle));
+}
+
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case insensitive.
+ * 
+ * This is a slibc extension added for completeness.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @param   maxlen    The maximum number of character to search.
+ * @return            Pointer to the first occurrence of the
+ *                    substring, `NULL` if not found.
+ */
+wchar_t* wcsncasestr(const wchar_t* haystack, const wchar_t* needle, size_t maxlen)
+{
+  return wmemcasemem(haystack, wcsnlen(haystack, maxlen), needle, wcslen(needle));
+}
+
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case sensitive.
+ * It must already be known that such a substring exists.
+ * 
+ * This is a slibc extension.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the substring.
+ */
+wchar_t* rawwcsstr(const wchar_t* haystack, const wchar_t* needle)
+{
+  return wmemmem(haystack, SIZE_MAX, needle, wcslen(needle));
+}
+
+
+/**
+ * Finds the first occurrence of a substring.
+ * This search is case insensitive.
+ * It must already be known that such a substring exists.
+ * 
+ * This is a slibc extension.
+ * 
+ * @param   haystack  The string to search.
+ * @param   needle    The sought after substring.
+ * @return            Pointer to the first occurrence of the substring.
+ */
+wchar_t* rawwcscasestr(const wchar_t* haystack, const wchar_t* needle)
+{
+  return wmemcasemem(haystack, SIZE_MAX, needle, wcslen(needle));
+}
+
+
+/**
+ * Finds the first occurrence of a substring
+ * This search is case sensitive.
+ * 
+ * This is a slibc extension added for completeness,
+ * and because it was it was useful in implementing
+ * slibc itself.
+ * 
+ * @param   haystack         The string to search.
+ * @param   haystack_length  The number of character to search.
+ * @param   needle           The sought after substring.
+ * @param   needle_length    The length of `needle`.
+ * @return                   Pointer to the first occurrence of
+ *                           the substring, `NULL` if not found.
+ */
+wchar_t* wmemmem(const wchar_t* haystack, size_t haystack_length,
+		 const wchar_t* needle, size_t needle_length)
+{
+  if (haystack_length < needle_length)
+    return NULL;
+  if (haystack_length == needle_length)
+    return !wmemcmp(haystack, haystack_length, haystack_length) ? haystack : NULL;
+#include "../string/substring.h"
+}
+
+
+/**
+ * Finds the first occurrence of a substring
+ * This search is case insensitive.
+ * 
+ * This is a slibc extension added because it was useful
+ * in implementing slibc itself.
+ * 
+ * @param   haystack         The string to search.
+ * @param   haystack_length  The number of character to search.
+ * @param   needle           The sought after substring.
+ * @param   needle_length    The length of `needle`.
+ * @return                   Pointer to the first occurrence of
+ *                           the substring, `NULL` if not found.
+ */
+wchar_t* wmemcasemem(const wchar_t* haystack, size_t haystack_length,
+		     const wchar_t* needle, size_t needle_length)
+{
+  if (haystack_length < needle_length)
+    return NULL;
+  if (haystack_length == needle_length)
+    return !wmemcasecmp(haystack, haystack_length, haystack_length) ? haystack : NULL;
+#define CASE
+#include "../string/substring.h"
+#undef CASE
+}
+