add memory copying functions

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

4 files changed, 224 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;
+}
+