rearrange files

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

16 files changed, 736 insertions, 0 deletions

diff --git a/src/string/mem/memcasecmp.c b/src/string/mem/memcasecmp.c
new file mode 100644
index 0000000..d8ea014
--- /dev/null
+++ b/src/string/mem/memcasecmp.c
@@ -0,0 +1,50 @@
+/**
+ * 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 <ctype.h>
+
+
+
+/**
+ * Compare two memory segments alphabetically in a case insensitive manner.
+ * 
+ * This is a slibc extension added because it was useful
+ * in implementing slibc itself.
+ * 
+ * @param   a     A negative value is returned if this is the lesser.
+ * @param   b     A positive value is returned if this is the lesser.
+ * @param   size  The size of the segments.
+ * @return        Zero is returned if `a` and `b` are equal, otherwise,
+ *                see the specifications for `a` and `b`.
+ */
+int memcasecmp(const void* a, const void* b, size_t size)
+{
+  const signed char* s1 = a;
+  const signed char* s2 = b;
+  int c1, c2;
+  for (; size--; s1++, s2++)
+    if (*s1 != *s2)
+      {
+	c1 = isalpha(*s1) ? tolower(*s1) : (int)*s1;
+	c2 = isalpha(*s2) ? tolower(*s2) : (int)*s2;
+	if ((c1 -= c2))
+	  return c1;
+      }
+  return 0;
+}
+
diff --git a/src/string/mem/memcasemem.c b/src/string/mem/memcasemem.c
new file mode 100644
index 0000000..3fb24dc
--- /dev/null
+++ b/src/string/mem/memcasemem.c
@@ -0,0 +1,55 @@
+/**
+ * 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 <unistd.h>
+#include <alloca.h>
+#include <ctype.h>
+
+
+# pragma GCC diagnostic ignored "-Wdiscarded-qualifiers"
+
+
+
+/**
+ * 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, needle, haystack_length) ? haystack : NULL;
+#define CASE
+#include "substring.h"
+#undef CASE
+}
+
diff --git a/src/string/mem/memccpy.c b/src/string/mem/memccpy.c
new file mode 100644
index 0000000..18e423d
--- /dev/null
+++ b/src/string/mem/memccpy.c
@@ -0,0 +1,45 @@
+/**
+ * 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>
+
+
+
+/**
+ * Copy a memory segment to another, non-overlapping, segment,
+ * but stop if a specific byte is encountered.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @param   c        The byte to stop at if encountered.
+ * @param   size     The maximum number of bytes to copy.
+ * @return           `NULL` if `c` was not encountered, otherwise
+ *                   the possition of `c` translated to `whither`,
+ *                   that is, the address of `whither` plus the
+ *                   number of copied characters; the address of
+ *                   one character passed the last written character.
+ */
+void* (memccpy)(void* restrict whither, const void* restrict whence, int c, size_t size)
+{
+  char* stop = (memchr)(whence, c, size);
+  void* r = NULL;
+  if (stop != NULL)
+    size = (size_t)(stop - (const char*)whence), r = whither + size;
+  memcpy(whither, whence, size);
+  return r;
+}
+
diff --git a/src/string/mem/memchr.c b/src/string/mem/memchr.c
new file mode 100644
index 0000000..380fa0f
--- /dev/null
+++ b/src/string/mem/memchr.c
@@ -0,0 +1,42 @@
+/**
+ * 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>
+
+
+# pragma GCC diagnostic ignored "-Wdiscarded-qualifiers"
+
+
+
+/**
+ * Find the first occurrence of a byte in a memory segment.
+ * 
+ * @param   segment  The memory segment to search.
+ * @param   c        The sought after character.
+ * @param   size     The size of the memory segment.
+ * @return           Pointer to the first occurrence of `c`,
+ *                   `NULL` if none were found.
+ */
+void* (memchr)(const void* segment, int c, size_t size)
+{
+  char* s = segment;
+  while (size--)
+    if (*s++ == c)
+      return s - 1;
+  return NULL;
+}
+
diff --git a/src/string/mem/memcmove.c b/src/string/mem/memcmove.c
new file mode 100644
index 0000000..50ed1f9
--- /dev/null
+++ b/src/string/mem/memcmove.c
@@ -0,0 +1,47 @@
+/**
+ * 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>
+
+
+
+/**
+ * Copy a memory segment to another, possibly overlapping, segment,
+ * but stop if a specific byte is encountered.
+ * 
+ * This is a slibc extension added for completeness.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @param   c        The byte to stop at if encountered.
+ * @param   size     The maximum number of bytes to copy.
+ * @return           `NULL` if `c` was not encountered, otherwise
+ *                   the possition of `c` translated to `whither`,
+ *                   that is, the address of `whither` plus the
+ *                   number of copied characters; the address of
+ *                   one character passed the last written character.
+ */
+void* (memcmove)(void* whither, const void* whence, int c, size_t size)
+{
+  char* stop = (memchr)(whence, c, size);
+  void* r = NULL;
+  if (stop != NULL)
+    size = (size_t)(stop - (const char*)whence), r = whither + size;
+  memmove(whither, whence, size);
+  return r;
+}
+
diff --git a/src/string/mem/memcmp.c b/src/string/mem/memcmp.c
new file mode 100644
index 0000000..112cdd1
--- /dev/null
+++ b/src/string/mem/memcmp.c
@@ -0,0 +1,42 @@
+/**
+ * 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>
+
+
+
+/**
+ * Compare two memory segments alphabetically in a case sensitive manner.
+ * 
+ * @param   a     A negative value is returned if this is the lesser.
+ * @param   b     A positive value is returned if this is the lesser.
+ * @param   size  The size of the segments.
+ * @return        Zero is returned if `a` and `b` are equal, otherwise,
+ *                see the specifications for `a` and `b`.
+ */
+int memcmp(const void* a, const void* b, size_t size)
+{
+  const signed char* s1 = a;
+  const signed char* s2 = b;
+  while (size--)
+    if (*s1 == *s2)
+      s1++, s2++;
+    else
+      return (int)(*s1 - *s2);
+  return 0;
+}
+
diff --git a/src/string/mem/memcpy.c b/src/string/mem/memcpy.c
new file mode 100644
index 0000000..fcda29d
--- /dev/null
+++ b/src/string/mem/memcpy.c
@@ -0,0 +1,38 @@
+/**
+ * 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>
+
+
+
+/**
+ * Copy a memory segment to another, non-overlapping, segment.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @param   size     The number of bytes to copy.
+ * @return           `whither` is returned.
+ */
+void* memcpy(void* restrict whither, const void* restrict whence, size_t size)
+{
+  char* d = whither;
+  const char* s = whence;
+  while (size--)
+    *d++ = *s++;
+  return whither;
+}
+
diff --git a/src/string/mem/memdup.c b/src/string/mem/memdup.c
new file mode 100644
index 0000000..3b301dc
--- /dev/null
+++ b/src/string/mem/memdup.c
@@ -0,0 +1,40 @@
+/**
+ * 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 <stdlib.h>
+
+
+
+/**
+ * Duplicate a memory segment.
+ * 
+ * This is a slibc extension.
+ * 
+ * @param   segment  The memory segment to duplicate.
+ * @param   size     The size of the memory segment.
+ * @return           The new segment. `NULL` is returned on error
+ *                   and `errno` is set to indicate the error.
+ * 
+ * @throws  ENOMEM  The process could not allocate sufficient amount of memory.
+ */
+void* memdup(const void* segment, size_t size)
+{
+  void* r = malloc(size);
+  return r == NULL ? NULL : memcpy(r, segment, size);
+}
+
diff --git a/src/string/mem/memmem.c b/src/string/mem/memmem.c
new file mode 100644
index 0000000..62739d4
--- /dev/null
+++ b/src/string/mem/memmem.c
@@ -0,0 +1,52 @@
+/**
+ * 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 <unistd.h>
+#include <alloca.h>
+
+
+# pragma GCC diagnostic ignored "-Wdiscarded-qualifiers"
+
+
+
+/**
+ * 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, needle, haystack_length) ? haystack : NULL;
+#include "substring.h"
+}
+
diff --git a/src/string/mem/memmove.c b/src/string/mem/memmove.c
new file mode 100644
index 0000000..41871c6
--- /dev/null
+++ b/src/string/mem/memmove.c
@@ -0,0 +1,42 @@
+/**
+ * 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>
+
+
+
+/**
+ * Copy a memory segment to another, possibly overlapping, segment.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @param   size     The number of bytes to copy.
+ * @return           `whither` is returned.
+ */
+void* memmove(void* whither, const void* whence, size_t size)
+{
+  char* d = whither;
+  const char* s = whence;
+  if ((size_t)(d - s) < size)
+    while (size--)
+      d[size] = s[size];
+  else
+    while (size--)
+      *d++ = *s++;
+  return whither;
+}
+
diff --git a/src/string/mem/mempcpy.c b/src/string/mem/mempcpy.c
new file mode 100644
index 0000000..2072dc3
--- /dev/null
+++ b/src/string/mem/mempcpy.c
@@ -0,0 +1,36 @@
+/**
+ * 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>
+
+
+
+/**
+ * Copy a memory segment to another, non-overlapping, segment.
+ * 
+ * This is a GNU extension.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @param   size     The number of bytes to copy.
+ * @return           `whither + size` is returned.
+ */
+void* mempcpy(void* restrict whither, const void* restrict whence, size_t size)
+{
+  return (char*)memcpy(whither, whence, size) + size;
+}
+
diff --git a/src/string/mem/mempmove.c b/src/string/mem/mempmove.c
new file mode 100644
index 0000000..f837032
--- /dev/null
+++ b/src/string/mem/mempmove.c
@@ -0,0 +1,37 @@
+/**
+ * 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>
+
+
+
+/**
+ * Copy a memory segment to another, possibly overlapping, segment.
+ * 
+ * This is a slibc extension added for completeness.
+ * It is only available if GNU extensions are available.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @param   size     The number of bytes to copy.
+ * @return           `whither + size` is returned.
+ */
+void* mempmove(void* whither, const void* whence, size_t size)
+{
+  return (char*)memmove(whither, whence, size) + size;
+}
+
diff --git a/src/string/mem/memrchr.c b/src/string/mem/memrchr.c
new file mode 100644
index 0000000..7325049
--- /dev/null
+++ b/src/string/mem/memrchr.c
@@ -0,0 +1,46 @@
+/**
+ * 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>
+
+
+# pragma GCC diagnostic ignored "-Wdiscarded-qualifiers"
+
+
+
+/**
+ * Find the last occurrence of a byte in a memory segment.
+ * 
+ * For improved performace, use this function instead
+ * of `strrchr` if you already know the length of the
+ * string.
+ * 
+ * @param   segment  The memory segment to search.
+ * @param   c        The sought after character.
+ * @param   size     The size of the memory segment.
+ * @return           Pointer to the last occurrence of `c`,
+ *                   `NULL` if none were found.
+ */
+void* (memrchr)(const void* segment, int c, size_t size)
+{
+  char* s = segment;
+  while (size--)
+    if (s[size] == c)
+      return s + size;
+  return NULL;
+}
+
diff --git a/src/string/mem/memset.c b/src/string/mem/memset.c
new file mode 100644
index 0000000..df36052
--- /dev/null
+++ b/src/string/mem/memset.c
@@ -0,0 +1,37 @@
+/**
+ * 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>
+
+
+
+/**
+ * Override a memory segment with a repeated character.
+ * 
+ * @param   segment  The beginning of the memory segment.
+ * @param   c        The character (8 bits wide.)
+ * @param   size     The size of the memory segment.
+ * @return           `segment` is returned.
+ */
+void* memset(void* segment, int c, size_t size)
+{
+  char* s = segment;
+  while (size--)
+    *s++ = (char)c;
+  return segment;
+}
+
diff --git a/src/string/mem/rawmemchr.c b/src/string/mem/rawmemchr.c
new file mode 100644
index 0000000..8f5c03e
--- /dev/null
+++ b/src/string/mem/rawmemchr.c
@@ -0,0 +1,42 @@
+/**
+ * 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>
+
+
+# pragma GCC diagnostic ignored "-Wdiscarded-qualifiers"
+
+
+
+/**
+ * Find the first occurrence of a byte in a memory segment.
+ * The memory segment must be known to contain the sought after byte.
+ * 
+ * This is a GNU-compliant slibc extension.
+ * 
+ * @param   segment  The memory segment to search.
+ * @param   c        The sought after character.
+ * @return           Pointer to the first occurrence of `c`.
+ */
+void* (rawmemchr)(const void* segment, int c)
+{
+  char* s = segment;
+  for (;;)
+    if (*s++ == c)
+      return s - 1;
+}
+
diff --git a/src/string/mem/substring.h b/src/string/mem/substring.h
new file mode 100644
index 0000000..05ef7cc
--- /dev/null
+++ b/src/string/mem/substring.h
@@ -0,0 +1,85 @@
+/**
+ * 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. */
+
+
+/**
+ * Test whether to characters are equal.
+ * Case-sensitivity depends on `CASE` being defined.
+ * 
+ * @param   a  One of the characters.
+ * @param   b  The other character.
+ * @return     1 if `a` and `b` or equal, 0 otherwise.
+ *             The comparison is case-insensitive if
+ *             `CASE` is defined.
+ */
+#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 */
+
+
+/* The implementation of the algorithm, read
+ * elsewhere for documentation/explanation. */
+{
+  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 < (ssize_t)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 < (ssize_t)haystack_length)
+    {
+      while ((ned > -1) && !CHREQ(haystack[hay], needle[ned]))
+	ned = next_map[ned];
+      hay++, ned++;
+      if (ned >= (ssize_t)needle_length)
+	return needle + (hay - ned);
+    }
+  
+  return NULL;
+}
+
+
+#undef CHREQ
+