stdlib: add atoi, atol and atoll

CMakeLists.txt

@@ -99,6 +99,9 @@ set(SOURCES
   src/libc/stdio/printf.c
   # stdlib
   src/libc/stdlib/abs.c
+  src/libc/stdlib/atoi.c
+  src/libc/stdlib/atol.c
+  src/libc/stdlib/atoll.c
   src/libc/stdlib/calloc.c
   src/libc/stdlib/div.c
   src/libc/stdlib/labs.c

STATUS

@@ -98,7 +98,7 @@ DONE:       Function/symbol/macro is defined, builds, links, and is tested
 
 7.20 <stdlib.h>
      7.20.1.1  atof: TODO
-     7.20.1.2  atoi, atol, atoll: TODO
+     7.20.1.2  atoi, atol, atoll: DONE
      7.20.1.3  strtod, strtof, strtold: TODO
      7.20.1.4  strtol, strtoul, strtoll, strtoull: DONE
      7.20.2  Pseudo-random sequence generation functions: TODO

include/stdlib.h

@@ -63,6 +63,17 @@ div_t div(int __num, int __denom);
 ldiv_t ldiv(long int __num, long int __denom);
 lldiv_t lldiv(long long int __num, long long int __denom);
 
+/* Simplified numeric conversion functions. */
+
+/* ASCII to int. */
+extern int atoi(char const *__ptr);
+
+/* ASCII to long int. */
+extern long int atol(char const *__ptr);
+
+/* ASCII to long long int. */
+extern long long int atoll(char const *__ptr);
+
 /* Numeric conversion functions. */
 
 /* Parse a long int from a string. */

src/libc/stdlib/atoi.c

@@ -0,0 +1,6 @@
+#include <stdlib.h>
+
+int atoi(char const *ptr)
+{
+	return (int)strtol(ptr, NULL, 10);
+}

src/libc/stdlib/atol.c

@@ -0,0 +1,6 @@
+#include <stdlib.h>
+
+long int atol(char const *ptr)
+{
+	return strtol(ptr, NULL, 10);
+}

src/libc/stdlib/atoll.c

@@ -0,0 +1,6 @@
+#include <stdlib.h>
+
+long long int atoll(char const *ptr)
+{
+	return strtoll(ptr, NULL, 10);
+}