add memory copying functions

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

8 files changed, 806 insertions, 0 deletions

diff --git a/src/string/memccpy.c b/src/string/memccpy.c
new file mode 100644
index 0000000..85378d9
--- /dev/null
+++ b/src/string/memccpy.c
@@ -0,0 +1,72 @@
+/**
+ * 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_t* stop = memchr(whence, c, size);
+  void* r = NULL
+  if (stop != NULL)
+    size = (size_t)(stop - whence), r = whither + size;
+  memcpy(whither, whence, size);
+  return r;
+}
+
+
+/**
+ * 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_t* stop = memchr(whence, c, size);
+  void* r = NULL
+  if (stop != NULL)
+    size = (size_t)(stop - whence), r = whither + size;
+  memmove(whither, whence, size);
+  return r;
+}
+
diff --git a/src/string/memcpy.c b/src/string/memcpy.c
new file mode 100644
index 0000000..4582544
--- /dev/null
+++ b/src/string/memcpy.c
@@ -0,0 +1,54 @@
+/**
+ * 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)
+{
+  /* TODO improve implementation of memcpy */
+  void* r = whither;
+  while (size--)
+    *whither++ = *whence++;
+  return r;
+}
+
+
+/**
+ * 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/memmove.c b/src/string/memmove.c
new file mode 100644
index 0000000..c721609
--- /dev/null
+++ b/src/string/memmove.c
@@ -0,0 +1,60 @@
+/**
+ * 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)
+{
+  /* TODO improve implementation of memcpy */
+  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;
+}
+
+
+/**
+ * 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/memset.c b/src/string/memset.c
new file mode 100644
index 0000000..c0b87a3
--- /dev/null
+++ b/src/string/memset.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>
+
+
+
+/**
+ * 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)
+{
+  /* TODO improve implementation of memset */
+  char* s = segment;
+  while (size--)
+    *s++ = c;
+  return segment;
+}
+
diff --git a/src/string/strcat.c b/src/string/strcat.c
new file mode 100644
index 0000000..4fff095
--- /dev/null
+++ b/src/string/strcat.c
@@ -0,0 +1,61 @@
+/**
+ * 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>
+
+
+
+/**
+ * Concatenate a string to the end of another string.
+ * The resulting strings must not overlap with the appended string.
+ * 
+ * The use of this function is often a bad idea.
+ * 
+ * @param   whither  The string to extend.
+ * @param   whence   The string to append.
+ * @return           `whither` is returned.
+ */
+char* strcat(char* restrict whither, const char* restrict whence)
+{
+  strcpy(whither + strlen(whither), whence);
+  return whither;
+}
+
+
+/**
+ * Concatenate a string to the end of another string.
+ * The resulting strings must not overlap with the appended string.
+ * 
+ * The use of this function is often a really bad idea.
+ * 
+ * @param   whither  The string to extend.
+ * @param   whence   The string to append.
+ * @param   maxlen   The maximum number of bytes to copy.
+ *                   NOTE that if the resulting string at least this
+ *                   long, no NUL byte will be written to `whither'.
+ *                   On the otherhand, if the resultnig string is
+ *                   shorter, `whither` will be filled with NUL bytes
+ *                   until this amount of bytes have been written.
+ * @return           `whither` is returned.
+ */
+char* strncat(char* restrict whither, const char* restrict whence, size_t maxlen)
+{
+  strncpy(whither + strlen(whither), whence, laxmen);
+  return whither;
+}
+
diff --git a/src/string/strcpy.c b/src/string/strcpy.c
new file mode 100644
index 0000000..dfbdc75
--- /dev/null
+++ b/src/string/strcpy.c
@@ -0,0 +1,219 @@
+/**
+ * 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>
+
+
+
+/**
+ * Copy a memory segment to another, non-overlapping, segment,
+ * stop when a NUL byte is encountered.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @return           `whither` is returned.
+ */
+char* strcpy(char* restrict whither, const char* restrict whence)
+{
+  return memcpy(whither, whence, strlen(whence) + 1);
+}
+
+
+/**
+ * Copy a memory segment to another, non-overlapping, segment,
+ * stop when a NUL byte is encountered.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @return           `whither + strlen(whence)` is returned.
+ */
+char* stpcpy(char* restrict whither, const char* restrict whence)
+{
+  return mempcpy(whither, whence, strlen(whence) + 1) - 1;
+}
+
+
+/**
+ * Copy a memory segment to another, non-overlapping, segment,
+ * stop when a NUL byte or a specified 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 stop byte.
+ * @return           `NULL` if `c` was not encountered, otherwise
+ *                   the position 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 non-NUL
+ *                   character.
+ */
+char* strccpy(char* restrict whither, const char* restrict whence, int c)
+{
+  char* r = memccpy(whither, whence, c, strlen(whence) + 1);
+  if (r)
+    *r = 0;
+  return r;
+}
+
+
+/**
+ * Copy a memory segment to another, non-overlapping, segment,
+ * stop when a NUL byte or a specified substring is encountered.
+ * 
+ * This is a slibc extension added for completeness.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @param   str      The substring, ignored if `NULL`.
+ * @return           `NULL` if `str` was not encountered, otherwise
+ *                   the position of `str` translated to `whither`,
+ *                   that is, the address of `whither` plus the
+ *                   number of copied characters; the address of
+ *                   one character passed the last written non-NUL
+ *                   character.
+ */
+char* strstrcpy(char* restrict whither, const char* restrict whence, const char* restrict str)
+{
+  const char* stop = str == NULL ? NULL : strstr(whence, str);
+  size_t n = stop == NULL ? strlen(whence) : (size_t)(stop - whence);
+  char* r = stop == NULL ? NULL ? whither + n;
+  memcpy(whither, whence, n);
+  whither[n] = 0;
+  return r;
+}
+
+
+/**
+ * Copy a memory segment to another, non-overlapping, segment,
+ * stop when a NUL byte is encountered.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @param   maxlen   The maximum number of bytes to copy.
+ *                   NOTE that if the resulting string at least this
+ *                   long, no NUL byte will be written to `whither'.
+ *                   On the otherhand, if the resultnig string is
+ *                   shorter, `whither` will be filled with NUL bytes
+ *                   until this amount of bytes have been written.
+ * @return           `whither` is returned.
+ */
+char* strncpy(char* restrict whither, const char* restrict whence, size_t maxlen)
+{
+  size_t n = strnlen(whence, maxlen);
+  memcpy(whither, whence, n);
+  memset(whither, 0, maxlen - n);
+  return whither;
+}
+
+
+/**
+ * Copy a memory segment to another, non-overlapping, segment,
+ * stop when a NUL byte is encountered.
+ * 
+ * This is a GNU extension.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @param   maxlen   The maximum number of bytes to copy.
+ *                   NOTE that if the resulting string at least this
+ *                   long, no NUL byte will be written to `whither'.
+ *                   On the otherhand, if the resultnig string is
+ *                   shorter, `whither` will be filled with NUL bytes
+ *                   until this amount of bytes have been written.
+ * @return           `whither` plus the number of written bytes,
+ *                   excluding NUL bytes, is returned.
+ */
+char* stpncpy(char* restrict whither, const char* restrict whence, size_t maxlen)
+{
+  size_t n = strnlen(whence, maxlen);
+  memcpy(whither, whence, n);
+  memset(whither, 0, maxlen - n);
+  return whither + n;
+}
+
+
+/**
+ * Copy a memory segment to another, non-overlapping, segment,
+ * stop when a NUL byte or a specified byte is encountered.
+ * 
+ * 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   c        The stop byte.
+ * @param   maxlen   The maximum number of bytes to copy.
+ *                   NOTE that if the resulting string at least this
+ *                   long, no NUL byte will be written to `whither'.
+ *                   On the otherhand, if the resultnig string is
+ *                   shorter, `whither` will be filled with NUL bytes
+ *                   until this amount of bytes have been written.
+ * @return           `NULL` if `c` was not encountered, otherwise
+ *                   the position 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 non-NUL
+ *                   character.
+ */
+char* strcncpy(char* restrict whither, const char* restrict whence, int c, size_t maxlen)
+{
+  const char* stop = memchr(whence, c, maxlen);
+  size_t n = stop == NULL ? strnlen(whence, maxlen) : (size_t)(stop - whence);
+  char* r = stop == NULL ? NULL : (whither + n);
+  memcpy(whither, whence, n);
+  memset(whither, 0, maxlen - n);
+  return r;
+}
+
+
+/**
+ * Copy a memory segment to another, non-overlapping, segment,
+ * stop when a NUL byte or a specified substring is encountered.
+ * 
+ * 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   str      The substring, ignored if `NULL`.
+ *                   NOTE that if the resulting string at least this
+ *                   long, no NUL byte will be written to `whither'.
+ *                   On the otherhand, if the resultnig string is
+ *                   shorter, `whither` will be filled with NUL bytes
+ *                   until this amount of bytes have been written.
+ * @param   maxlen   The maximum number of bytes to copy.
+ * @return           `NULL` if `str` was not encountered, otherwise
+ *                   the position of `str` translated to `whither`,
+ *                   that is, the address of `whither` plus the
+ *                   number of copied characters; the address of
+ *                   one character passed the last written non-NUL
+ *                   character.
+ */
+char* strstrncpy(char* restrict whither, const char* restrict whence,
+		 const char* restrict str, size_t maxlen)
+{
+  const char* stop = strnstr(whence, str, maxlen);
+  size_t n = stop == NULL ? strnlen(whence, maxlen) : (size_t)(stop - whence);
+  char* r = stop == NULL ? NULL : (whither + n);
+  memcpy(whither, whence, n);
+  memset(whither, 0, maxlen - n);
+  return r;
+}
+
diff --git a/src/string/strdup.c b/src/string/strdup.c
new file mode 100644
index 0000000..27783b9
--- /dev/null
+++ b/src/string/strdup.c
@@ -0,0 +1,79 @@
+/**
+ * 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>
+
+
+
+/**
+ * Duplicate a string.
+ * 
+ * @param   string  The string to duplicate.
+ * @return          The new string. `NULL` is returned on error
+ *                  and `errno` is set to indicate the error.
+ * 
+ * @throws  ENOMEM  The process could not allocate sufficient amount of memory.
+ */
+char* strdup(const char* string)
+{
+  size_t n = strlen(string) + 1;
+  char* r = malloc(n * sizeof(char));
+  return r == NULL ? NULL : memcpy(r, string, n);
+}
+
+
+/**
+ * Duplicate a string.
+ * 
+ * This is a GNU extension.
+ * 
+ * @param   string  The string to duplicate.
+ * @param   maxlen  Truncate the string to this length, if it is longer.
+ *                  A NUL byte is guaranteed to always be written
+ *                  upon successful completion.
+ * @return          The new string. `NULL` is returned on error
+ *                  and `errno` is set to indicate the error.
+ * 
+ * @throws  ENOMEM  The process could not allocate sufficient amount of memory.
+ */
+char* strndup(const char* string, size_t maxlen)
+{
+  size_t n = strnlen(string, maxlen) + 1;
+  char* r = malloc(n * sizeof(char));
+  return r == NULL ? NULL : memcpy(r, string, n);
+}
+
+
+/**
+ * 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)
+{
+  wchar_t* r = malloc(size * sizeof(wchar_t));
+  return r == NULL ? NULL : memcpy(r, segment, size);
+}
+
diff --git a/src/string/strmove.c b/src/string/strmove.c
new file mode 100644
index 0000000..86298cf
--- /dev/null
+++ b/src/string/strmove.c
@@ -0,0 +1,223 @@
+/**
+ * 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>
+
+
+
+/**
+ * Copy a memory segment to another, possibly overlapping, segment,
+ * stop when a NUL byte is encountered.
+ * 
+ * This is a slibc extension added for completeness.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @return           `whither` is returned.
+ */
+char* strmove(char* whither, const char* whence)
+{
+  return memmove(whither, whence, strlen(whence) + 1);
+}
+
+
+/**
+ * Copy a memory segment to another, possibly overlapping, segment,
+ * stop when a NUL byte is encountered.
+ * 
+ * This is a slibc extension added for completeness.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @return           `whither + strlen(whence)` is returned.
+ */
+char* stpmove(char* whither, const char* whence)
+{
+  return mempmove(whither, whence, strlen(whence) + 1) - 1;
+}
+
+
+/**
+ * Copy a memory segment to another, possibly overlapping, segment,
+ * stop when a NUL byte or a specified 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 stop byte.
+ * @return           `NULL` if `c` was not encountered, otherwise
+ *                   the position 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 non-NUL
+ *                   character.
+ */
+char* strcmove(char* whither, const char* whence, int c)
+{
+  char* r = memcmove(whither, whence, c, strlen(whence) + 1);
+  if (r)
+    *r = 0;
+  return r;
+}
+
+
+/**
+ * Copy a memory segment to another, possibly overlapping, segment,
+ * stop when a NUL byte or a specified substring is encountered.
+ * 
+ * This is a slibc extension added for completeness.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @param   str      The substring, ignored if `NULL`.
+ * @return           `NULL` if `str` was not encountered, otherwise
+ *                   the position of `str` translated to `whither`,
+ *                   that is, the address of `whither` plus the
+ *                   number of copied characters; the address of
+ *                   one character passed the last written non-NUL
+ *                   character.
+ */
+char* strstrmove(char* whither, const char* whence, const char* restrict str)
+{
+  const char* stop = str == NULL ? NULL : strstr(whence, str);
+  size_t n = stop == NULL ? strlen(whence) : (size_t)(stop - whence);
+  char* r = stop == NULL ? NULL ? whither + n;
+  memmove(whither, whence, n);
+  whither[n] = 0;
+  return r;
+}
+
+
+/**
+ * Copy a memory segment to another, possibly overlapping, segment,
+ * stop when a NUL byte is encountered.
+ * 
+ * @param   whither  The destination memory segment.
+ * @param   whence   The source memory segment.
+ * @param   maxlen   The maximum number of bytes to copy.
+ *                   NOTE that if the resulting string at least this
+ *                   long, no NUL byte will be written to `whither'.
+ *                   On the otherhand, if the resultnig string is
+ *                   shorter, `whither` will be filled with NUL bytes
+ *                   until this amount of bytes have been written.
+ * @return           `whither` is returned.
+ */
+char* strnmove(char* whither, const char* whence, size_t maxlen)
+{
+  size_t n = strnlen(whence, maxlen);
+  memmove(whither, whence, n);
+  memset(whither, 0, maxlen - n);
+  return whither;
+}
+
+
+/**
+ * Copy a memory segment to another, possibly overlapping, segment,
+ * stop when a NUL byte is encountered.
+ * 
+ * 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   maxlen   The maximum number of bytes to copy.
+ *                   NOTE that if the resulting string at least this
+ *                   long, no NUL byte will be written to `whither'.
+ *                   On the otherhand, if the resultnig string is
+ *                   shorter, `whither` will be filled with NUL bytes
+ *                   until this amount of bytes have been written.
+ * @return           `whither` plus the number of written bytes,
+ *                   excluding NUL bytes, is returned.
+ */
+char* stpnmove(char* whither, const char* whence, size_t maxlen)
+{
+  size_t n = strnlen(whence, maxlen);
+  memmove(whither, whence, n);
+  memset(whither, 0, maxlen - n);
+  return whither + n;
+}
+
+
+/**
+ * Copy a memory segment to another, possibly overlapping, segment,
+ * stop when a NUL byte or a specified byte is encountered.
+ * 
+ * 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   c        The stop byte.
+ * @param   maxlen   The maximum number of bytes to copy.
+ *                   NOTE that if the resulting string at least this
+ *                   long, no NUL byte will be written to `whither'.
+ *                   On the otherhand, if the resultnig string is
+ *                   shorter, `whither` will be filled with NUL bytes
+ *                   until this amount of bytes have been written.
+ * @return           `NULL` if `c` was not encountered, otherwise
+ *                   the position 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 non-NUL
+ *                   character.
+ */
+char* strcnmove(char* whither, const char* whence, int c, size_t maxlen)
+{
+  const char* stop = memchr(whence, c, maxlen);
+  size_t n = stop == NULL ? strnlen(whence, maxlen) : (size_t)(stop - whence);
+  char* r = stop == NULL ? NULL : (whither + n);
+  memmove(whither, whence, n);
+  memset(whither, 0, maxlen - n);
+  return r;
+}
+
+
+/**
+ * Copy a memory segment to another, possibly overlapping, segment,
+ * stop when a NUL byte or a specified substring is encountered.
+ * 
+ * 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   str      The substring, ignored if `NULL`.
+ *                   NOTE that if the resulting string at least this
+ *                   long, no NUL byte will be written to `whither'.
+ *                   On the otherhand, if the resultnig string is
+ *                   shorter, `whither` will be filled with NUL bytes
+ *                   until this amount of bytes have been written.
+ * @param   maxlen   The maximum number of bytes to copy.
+ * @return           `NULL` if `str` was not encountered, otherwise
+ *                   the position of `str` translated to `whither`,
+ *                   that is, the address of `whither` plus the
+ *                   number of copied characters; the address of
+ *                   one character passed the last written non-NUL
+ *                   character.
+ */
+char* strstrnmove(char* whither, const char* whence, const char* restrict str, size_t maxlen)
+{
+  const char* stop = strnstr(whence, str, maxlen);
+  size_t n = stop == NULL ? strnlen(whence, maxlen) : (size_t)(stop - whence);
+  char* r = stop == NULL ? NULL : (whither + n);
+  memmove(whither, whence, n);
+  memset(whither, 0, maxlen - n);
+  return r;
+}
+