Use cstdint types in integral_types.h

Include stdint.i in s2.i to get SWIG mappings.

Author: jmr

src/python/s2.i

@@ -1,15 +1,12 @@
 %include "std_vector.i"
 %include "std_string.i"
+%include "stdint.i"
 
-%template() std::vector<unsigned long long>;
 %template() std::vector<S2CellId>;
 %template() std::vector<S2Point>;
 %template() std::vector<S2LatLng>;
 
-%apply int {int32};
-%apply unsigned long long {uint64};
 %apply std::string {string};
-%apply std::vector<unsigned long long> const & {std::vector<uint64> const &};
 
 // Standard Google convention is to ignore all functions and methods, and
 // selectively add back those for which wrapping is both required and

src/s2/base/integral_types.h

@@ -16,16 +16,22 @@
 #ifndef S2_BASE_INTEGRAL_TYPES_H_
 #define S2_BASE_INTEGRAL_TYPES_H_
 
-using int8 = signed char;
-using int16 = short;
-using int32 = int;
-using int64 = long long;
+#include <cstdint>
+#include <type_traits>
 
-using uint8 = unsigned char;
-using uint16 = unsigned short;
-using uint32 = unsigned int;
-using uint64 = unsigned long long;
+using int8 = int8_t;
+using int16 = int16_t;
+using int32 = int32_t;
+using int64 = int64_t;
 
-using uword_t = unsigned long;
+using uint8 = uint8_t;
+using uint16 = uint16_t;
+using uint32 = uint32_t;
+using uint64 = uint64_t;
+
+static_assert(sizeof(void *) == 8 || sizeof(void *) == 4,
+              "void * must be 32 or 64 bits.");
+using uword_t =
+    std::conditional<sizeof(void *) == 8, uint64_t, uint32_t>::type;
 
 #endif  // S2_BASE_INTEGRAL_TYPES_H_