stdlib: add a test strtol, strtoul, strtoll (DONE)

The presumed bug where the value computed without the sign overflows
even though the negative result can be represented is not actually a
problem, because this only happens with signed results and the temporary
value is computed as unsigned (thus with extra range).

CMakeLists.txt

@@ -107,6 +107,9 @@ set(SOURCES
   src/libc/stdlib/lldiv.c
   src/libc/stdlib/reallocarray.c
   src/libc/stdlib/strto_int.c
+  src/libc/stdlib/strtol.c
+  src/libc/stdlib/strtoll.c
+  src/libc/stdlib/strtoul.c
   src/libc/stdlib/strtoull.c
   # string
   src/libc/string/strchr.c

STATUS

@@ -100,8 +100,7 @@ DONE:       Function/symbol/macro is defined, builds, links, and is tested
      7.20.1.1  atof: TODO
      7.20.1.2  atoi, atol, atoll: TODO
      7.20.1.3  strtod, strtof, strtold: TODO
-     7.20.1.4  strtol, strtoul, strtoll: TODO
+     7.20.1.4  strtol, strtoul, strtoll, strtoull: DONE
-               strtoull: DONE
      7.20.2  Pseudo-random sequence generation functions: TODO
      7.20.3  Memory management functions: TODO (check existing code first)
      7.20.4  Communication with the environment: TODO

src/libc/stdlib/stdlib_p.h

@@ -1,7 +1,7 @@
 #ifndef __STDLIB_P_H__
 # define __STDLIB_P_H__
 
-#include <stddef.h>
+#include <stdlib.h>
 #include <stdbool.h>
 
 /* Parse an integer from a string. This is the base function for strtol,

src/libc/stdlib/strto_int.c

@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include <ctype.h>
 #include <errno.h>
+#include <limits.h>
 
 /* Parse an integer from a string. Base function for strtol, strtoul, strtoll,
    and strtoull. This function:
@@ -55,12 +56,6 @@ int strto_int(char const * restrict ptr, char ** restrict endptr, int base,
 		valid = true;
 
 		/* (x = base*x + v) but with overflow checks */
-
-		/*
-		** TODO FIXME: There is a bug with overflows if the unsigned
-		** value cannot be represented but the signed value can (which
-		** is the case only for LONG_MIN and LLONG_MIN)
-		*/
 		if(outl) {
 			if(__builtin_umull_overflow(xl, base, &xl))
 				errno_value = ERANGE;
@@ -77,7 +72,7 @@ int strto_int(char const * restrict ptr, char ** restrict endptr, int base,
 		ptr++;
 	}
 
-	/* Handle the sign */
+	/* Handle sign and range */
 	if(negative) {
 		/* Only -0 can be represented as unsigned */
 		if(outl && use_unsigned && xl != 0)
@@ -85,9 +80,21 @@ int strto_int(char const * restrict ptr, char ** restrict endptr, int base,
 		if(outll && use_unsigned && xll != 0)
 			errno_value = ERANGE;
 
+		/* Handle signed range. Don't use -[L]LONG_MIN, it overflows */
+		if(outl && !use_unsigned && xl > LONG_MAX * 1ul + 1)
+			errno_value = ERANGE;
+		if(outll && !use_unsigned && xll > LLONG_MAX * 1ull + 1)
+			errno_value = ERANGE;
+
 		xl = -xl;
 		xll = -xll;
 	}
+	else {
+		if(outl && !use_unsigned && xl > LONG_MAX * 1ul)
+			errno_value = ERANGE;
+		if(outll && !use_unsigned && xll > LLONG_MAX * 1ull)
+			errno_value = ERANGE;
+	}
 
 	if(outl) *outl = xl;
 	if(outll) *outll = xll;

src/libc/stdlib/strtol.c

@@ -0,0 +1,10 @@
+#include "stdlib_p.h"
+#include <errno.h>
+
+long int strtol(char const * restrict ptr, char ** restrict endptr, int base)
+{
+	long n = 0;
+	int err = strto_int(ptr, endptr, base, &n, NULL, false);
+	if(err != 0) errno = err;
+	return n;
+}

src/libc/stdlib/strtoll.c

@@ -0,0 +1,11 @@
+#include "stdlib_p.h"
+#include <errno.h>
+
+long long int strtoll(char const * restrict ptr, char ** restrict endptr,
+	int base)
+{
+	long long n = 0;
+	int err = strto_int(ptr, endptr, base, NULL, &n, false);
+	if(err != 0) errno = err;
+	return n;
+}

src/libc/stdlib/strtoul.c

@@ -0,0 +1,11 @@
+#include "stdlib_p.h"
+#include <errno.h>
+
+unsigned long int strtoul(char const * restrict ptr, char ** restrict endptr,
+	int base)
+{
+	unsigned long n = 0;
+	int err = strto_int(ptr, endptr, base, (long *)&n, NULL, true);
+	if(err != 0) errno = err;
+	return n;
+}