// Copyright 2008 Google Inc. All Rights Reserved.

//

// Architecture-neutral plug compatible replacements for strtol() friends.

//

// Long's have different lengths on ILP-32 and LP-64 platforms, and so overflow

// behavior across the two varies when strtol() and similar are used to parse

// 32-bit integers.  Similar problems exist with atoi(), because although it

// has an all-integer interface, it uses strtol() internally, and so suffers

// from the same narrowing problems on assignments to int.

//

// Examples:

//   errno = 0;

//   i = strtol("3147483647", NULL, 10);

//   printf("%d, errno %d\n", i, errno);

//   //   32-bit platform: 2147483647, errno 34

//   //   64-bit platform: -1147483649, errno 0

//

//   printf("%d\n", atoi("3147483647"));

//   //   32-bit platform: 2147483647

//   //   64-bit platform: -1147483649

//

// A way round this is to define local replacements for these, and use them

// instead of the standard libc functions.

//

// In most 32-bit cases the replacements can be inlined away to a call to the

// libc function.  In a couple of 64-bit cases, however, adapters are required,

// to provide the right overflow and errno behavior.

//

#pragma once

#include <stdlib.h> // For strtol* functions.

#include <string>

using std::string;

#include "gutil/integral_types.h"

#include "butil/macros.h"

// Adapter functions for handling overflow and errno.

int32 strto32_adapter(const char* nptr, char** endptr, int base);

uint32 strtou32_adapter(const char* nptr, char** endptr, int base);

// Conversions to a 32-bit integer can pass the call to strto[u]l on 32-bit

// platforms, but need a little extra work on 64-bit platforms.

inline int32 strto32(const char* nptr, char** endptr, int base) {

    if (sizeof(int32) == sizeof(long))

        return static_cast<int32>(strtol(nptr, endptr, base));

    else

        return strto32_adapter(nptr, endptr, base);

}

inline uint32 strtou32(const char* nptr, char** endptr, int base) {

    if (sizeof(uint32) == sizeof(unsigned long))

        return static_cast<uint32>(strtoul(nptr, endptr, base));

    else

        return strtou32_adapter(nptr, endptr, base);

}

// For now, long long is 64-bit on all the platforms we care about, so these

// functions can simply pass the call to strto[u]ll.

inline int64 strto64(const char* nptr, char** endptr, int base) {

    COMPILE_ASSERT(sizeof(int64) == sizeof(long long), sizeof_int64_is_not_sizeof_long_long);

    return strtoll(nptr, endptr, base);

}

inline uint64 strtou64(const char* nptr, char** endptr, int base) {

    COMPILE_ASSERT(sizeof(uint64) == sizeof(unsigned long long),

                   sizeof_uint64_is_not_sizeof_long_long);

    return strtoull(nptr, endptr, base);

}

// Although it returns an int, atoi() is implemented in terms of strtol, and

// so has differing overflow and underflow behavior.  atol is the same.

inline int32 atoi32(const char* nptr) {

    return strto32(nptr, NULL, 10);

}

inline int64 atoi64(const char* nptr) {

    return strto64(nptr, NULL, 10);

}

// Convenience versions of the above that take a string argument.

inline int32 atoi32(const string& s) {

    return atoi32(s.c_str());

}

inline int64 atoi64(const string& s) {

    return atoi64(s.c_str());

}