add strtok functions

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

1 files changed, 112 insertions, 0 deletions

diff --git a/src/string/strtok.c b/src/string/strtok.c
new file mode 100644
index 0000000..04668fc
--- /dev/null
+++ b/src/string/strtok.c
@@ -0,0 +1,112 @@
+/**
+ * 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>
+
+
+
+/**
+ * Tokenise a string.
+ * 
+ * @param   string      The string to tokenise on the first,
+ *                      `NULL` on subsequent calls.
+ *                      All bytes found in `delimiters` will
+ *                      be overriden with NUL bytes.
+ * @param   delimiters  Delimiting bytes (not characters).
+ * @return              The next non-empty string that does not
+ *                      contain a byte from `delimiters`. The
+ *                      returned string will be as long as possible.
+ *                      `NULL` is returned the search as reached
+ *                      the end of the string, and there therefore
+ *                      are no more tokens.
+ */
+char* strtok(char* restrict string, const char* restrict delimiters)
+{
+  static char* state = NULL;
+  if (string == NULL)
+    state = NULL;
+  return strtok_r(string, delimiters, &state);
+}
+
+
+/**
+ * Tokenise a string.
+ * 
+ * @param   string      The string to tokenise on the first,
+ *                      `NULL` on subsequent calls.
+ *                      All bytes found in `delimiters` will
+ *                      be overriden with NUL bytes.
+ * @param   delimiters  Delimiting bytes (not characters).
+ * @param   state       Pointer to a `char*` that the function
+ *                      can use to keep track of its state.
+ *                      It is reasonable to make it point to `NULL`
+ *                      on the first call.
+ * @return              The next non-empty string that does not
+ *                      contain a byte from `delimiters`. The
+ *                      returned string will be as long as possible.
+ *                      `NULL` is returned the search as reached
+ *                      the end of the string, and there therefore
+ *                      are no more tokens.
+ */
+char* strtok_r(char* restrict string, const char* restrict delimiters,
+	       char** restrict state)
+{
+  char* r;
+  if (string == NULL)
+    *state = string;
+  for (;;)
+    {
+      r = strsep(state, delimiters);
+      if (r == NULL)
+	return NULL;
+      if (*r)
+	return r;
+    }
+}
+
+
+/**
+ * Tokenise a string.
+ * 
+ * @param   string      Pointer to the string to tokenise on the first call,
+ *                      will be updated to keep track of the state.
+ *                      All bytes found in `delimiters` will
+ *                      be overriden with NUL bytes.
+ * @param   delimiters  Delimiting bytes (not characters).
+ * @return              The next, possibly empty, string that does
+ *                      not contain a byte from `delimiters`. The
+ *                      returned string will be as long as possible.
+ *                      `NULL` is returned the search as reached
+ *                      the end of the string, and there therefore
+ *                      are no more tokens.
+ */
+char* strsep(char** restrict string, const char* restrict delimiters)
+{
+  char* r = *string;
+  char* next;
+  if (r == NULL)
+    return NULL;
+  
+  next = stpbrk(string, delimiters);
+  if (next != NULL)
+    *next++ = 0;
+  *string = next;
+  
+  return r;
+}
+