split atoi

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

1 files changed, 56 insertions, 0 deletions

diff --git a/src/stdlib/atol.c b/src/stdlib/atol.c
new file mode 100644
index 0000000..b4170e1
--- /dev/null
+++ b/src/stdlib/atol.c
@@ -0,0 +1,56 @@
+/**
+ * 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 <stdlib.h>
+#include <ctype.h>
+
+
+
+/**
+ * Convert a string to an integer,
+ * without checking for errors.
+ * 
+ * The string may being with an arbitrary number
+ * of whitespace characters. Convertion will end
+ * when a character is encountered that is not a
+ * decimal digit, and is not an absolutely leading
+ * '-' or '+'.
+ * 
+ * @param   string  The string to convert.
+ * @return          The integer encoded by the string.
+ */
+long int atol(const char* string)
+{
+  long int rc = 0;
+  int neg = 0;
+  
+  while (isspace(*string))
+    string++;
+  
+  switch (*string)
+    {
+    case '-': neg = 1;
+    case '+': string++;
+    default:  break;
+    }
+  
+  while (isdigit(*string))
+    rc = rc * 10 - (*string++ & 15);
+  
+  return neg ? rc : -rc;
+}
+