// bdls_filesystemutil_unixplatform.h -*-C++-*-
#ifndef INCLUDED_BDLS_FILESYSTEMUTIL_UNIXPLATFORM
#define INCLUDED_BDLS_FILESYSTEMUTIL_UNIXPLATFORM
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
//@PURPOSE: Provide Unix timstamp and offset type width detection macros.
//
//@MACROS:
// BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF: 1 if 'off_t' is 64 bits, else
// BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF64: 1 if 'off64_t' exists, else
// BDLS_FILESYSTEMUTIL_UNIXPLATFORM_32_BIT_OFF: 1 ('off_t' is 32 bits)
//
// BDLS_FILESYSTEMUTIL_UNIXPLATFORM_STAT_NS_MEMBER: The 'stat' nanosecond
// member name
//
//@SEE_ALSO: bdls_filesystemutil, bdls_filesystemutil_unixplatform,
// bdls_filesystemutil_transitionalunixplatform
//
//@DESCRIPTION: This subordinate component to 'bdls_filesystemutil' provides:
//
// a) a set of macros for detecting the most appropriate type to use for byte
// quantities, and most appropriate set of functions to use for file
// operations, on Unix platforms, and
//
// b) a macro which specifies the name of the member variable, within a 'stat'
// structure, that holds the nanosecond part of the file timestamp.
//
///Nanosecond Support Macros
///-------------------------
// This component defines the following Macros if the 'stat' structure defined
// in 'sys/stat.h' contains the 'st_mtim.tv_nsec' member. This is determined
// by the feature tests specified in POSIX.1-2008 - see
// https://linux.die.net/man/2/fstat.
//
//: 'BDLS_FILESYSTEMUTIL_UNIXPLATFORM_STAT_NS_MEMBER': This macro is defined to
//: be the name of the member of the 'stat' structure that contains the
//: nanosecond part of the timestamp value.
//
///Byte Quantity Macros
///--------------------
// This component defines exactly 1 of 3 macros depending on the current
// platform configuration, which are used to determine which offset type and
// associated set of file-system functions a program should use on Unix. These
// macros are:
//
//: 'BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF': The presence of this macro
//: definition indicates that the platform natively supports large (64-bit)
//: file operations, and that the 'off_t' type provided by the 'sys/types.h'
//: header is 64-bit.
//:
//: 'BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF64': The presence of this macro
//: definition indicates that the platform *does* *not* natively support large
//: (64-bit) file operations, but that it does support the
//: "transitional-compilation environment" that provides non-standard large
//: file types and operations. Specifically, this indicates that the platform
//: supports a 64-bit 'off64_t' type, and provides associated 'xxx64' file
//: operations. For more information about the transitional-complation
//: environment, see the component documentation of
//: {'bdls_filesystemutil_transitionaluniximputil'}.
//:
//: 'BDLS_FILESYSTEMUTIL_UNIXPLATFORM_32_BIT_OFF': The presence of this macro
//: definition indicates that the platform does not natively support large
//: (64-bit) file operations, nor is it configured to provide the
//: transitional-compilation environment. Specifically, this indicates that
//: the platform provides a 32-bit 'off_t' type and associated 32-bit file
//: operations. If this macro is defined, a program may be unable to operate
//: on files larger than approximately 2 Gigabytes.
//
///Byte Quantity Macro Selection
///-----------------------------
// Which of the 3 macros this component defines depends upon the capabilities
// of the platform's configuration. There are 4 criteria used to determine
// which macro is defined, and they are
//
//: o the operating system,
//: o whether the cpu is 32 or 64-bit,
//: o whether a '_FILE_OFFSET_BITS' macro is defined to '64', and
//: o whether the transitional-compilation environment is enabled
//
// The set of possible combinations of these critera, and consequently which
// macros are defined, is specified in the table below. The legend for this
// table is the following:
//
//: 'OS':
//: Short for "Operating System". This column lists the operating system
//: associated with the platform.
//:
//: 'Mode':
//: Either '32' or '64'. This column lists the number of bits in a machine
//: word associated with the platform. A program compiled for an x86
//: processor would be '32', and one compiled for an x86_64 processor would
//: be '64', for example.
//:
//: 'FOB=64':
//: Short for "File-Offset Bits == 64". This column lists whether or not the
//: '_FILE_OFFSET_BITS' macro is defined to the value '64', or is otherwise
//: defined to another value or undefined. A value of 'Yes' indicates
//: '_FILE_OFFSET_BITS' is defined to '64', and a value of 'No' indicates
//: that it is not. Note that this macro is not a part of any Unix standard,
//: but nevertheless is supported by several Unixes. On most Unix platforms,
//: defining '_FILE_OFFSET_BITS' to a value other than '64' has no meaning.
//:
//: 'LF':
//: Short for 'Large File Source'. This column lists whether or not a macro
//: is defined that indicates the current program is compiled in the
//: "Transitional-Compilation Environment." A value of 'Yes' indicates the
//: transitional-compilation environment is enabled, and a value of 'No'
//: indicates that it is not. Different macros enable this environment on
//: different Unixes, if they support it. This environment is enabled on AIX
//: if the '_LARGE_FILE' macro is defined, and it is enabled on Linux,
//: Solaris, and SunOS if the '_LARGEFILE64_SOURCE' macro is defined.
//: Neither Cygwin, Darwin, nor FreeBSD support this environment, because
//: they natively support large (64-bit) file operations in all compilation
//: modes.
//:
//: 'Off Type':
//: Short for "Offset Type". This column lists the type that a program
//: should use to represent file offsets on Unix platforms. The offset type
//: should be 'off_t' (64-bit) if the program natively supports large
//: (64-bit) file operations, 'off64_t' if the program does not natively
//: support these operations, but provides the transitional-compilation
//: environment, and 'off_t' (32-bit) if the program neither natively support
//: large (64-bit) file operations nor provides the transitional-compilation
//: environment. Note that a 32-bit 'off_t' is used as a "last resort" when
//: no 64-bit offset type is available on the platform. A program may be
//: unable to operate on files larger than approximately 2 Gigabytes if a
//: 32-bit 'off_t' is used.
//:
//: 'Off Bits':
//: This column lists the number of bits used in the offset type to represent
//: a byte quantity. A value of '64' indicates that the offset type has 64
//: bits, and a value of '32' indicates that the offset type has 32 bits.
//:
//: 'Macro Defined':
//: This column lists which macro provided by this component is defined, in
//: order to indicate the offset type and set of file-system functions that a
//: program should use on Unix. A value of '*_32_BIT_OFF' indicates that the
//: 'BDLS_FILESYSTEMUTIL_UNIXPLATFORM_32_BIT_OFF' macro is defined, and that
//: a program should use the 'off_t' offset type and associated file-system
//: functions, a value of "*_64_BIT_OFF" indicates that the
//: 'BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF' macro is defined, and that
//: a program should use the 'off_t' offset type and associated file-system
//: tunctions, and a value of '*_64_BIT_OFF64' indicates that the
//: 'BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF64' macro is defined, and
//: that a program should use the 'off64_t' offset type, and associated
//: file-system functions from the transitional-compilation environment.
//
// The table follows. Note that a value of 'N/A' in any cell of the table
// indicates that the value of that cell does affect the determination of the
// value of the associated 'Off Type', 'Off-Type Bits' and 'Macro Defined'
// cells.
//
//..
// |---------|------|--------|-----|----------|----------|---------------|
// | OS | Mode | FOB=64 | LF | Off Type | Off Bits | Macro Defined |
// |=========+======+========+=====+==========+==========+===============|
// | AIX | 32 | N/A | No | 'off64_t'| 64 | *_64_BIT_OFF64|
// | AIX | 32 | N/A | Yes | 'off_t' | 64 | *_64_BIT_OFF |
// | AIX | 64 | N/A | N/A | 'off_t' | 64 | *_64_BIT_OFF |
// | Cygiwn | N/A | N/A | N/A | 'off_t' | 64 | *_64_BIT_OFF |
// | Darwin | N/A | N/A | N/A | 'off_t' | 64 | *_64_BIT_OFF |
// | FreeBSD | N/A | N/A | N/A | 'off_t' | 64 | *_64_BIT_OFF |
// | Linux | 32 | No | No | 'off_t' | 32 | *_32_BIT_OFF |
// | Linux | 32 | No | Yes | 'off64_t'| 64 | *_64_BIT_OFF64|
// | Linux | 32 | Yes | N/A | 'off_t' | 64 | *_64_BIT_OFF |
// | Linux | 64 | N/A | N/A | 'off_t' | 64 | *_64_BIT_OFF |
// | SunOS | 32 | No | No | 'off_t' | 32 | *_32_BIT_OFF |
// | SunOS | 32 | No | Yes | 'off64_t'| 64 | *_64_BIT_OFF64|
// | SunOS | 32 | Yes | N/A | 'off_t' | 64 | *_64_BIT_OFF |
// | SunOS | 64 | N/A | N/A | 'off_t' | 64 | *_64_BIT_OFF |
// | Solaris | 32 | No | No | 'off_t' | 32 | *_32_BIT_OFF |
// | Solaris | 32 | No | Yes | 'off64_t'| 64 | *_64_BIT_OFF64|
// | Solaris | 32 | Yes | N/A | 'off_t' | 64 | *_64_BIT_OFF |
// | Solaris | 64 | N/A | N/A | 'off_t' | 64 | *_64_BIT_OFF |
// |---------+------+--------+-----+----------+----------+---------------+
//..
#include <bsls_platform.h>
#if defined(BSLS_PLATFORM_OS_UNIX)
#include <unistd.h>
// 32-Bit AIX with '_LARGE_FILE'
#if defined(BSLS_PLATFORM_OS_AIX) \
&& defined(BSLS_PLATFORM_CPU_32_BIT) \
&& defined(_LARGE_FILE)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF 1
// 32-Bit AIX
#elif defined(BSLS_PLATFORM_OS_AIX) \
&& defined(BSLS_PLATFORM_CPU_32_BIT)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF64 1
// 64-Bit AIX
#elif defined(BSLS_PLATFORM_OS_AIX) \
&& defined(BSLS_PLATFORM_CPU_64_BIT)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF 1
// Cygwin
#elif defined(BSLS_PLATFORM_OS_CYGWIN)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF 1
// Darwin
#elif defined(BSLS_PLATFORM_OS_DARWIN)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF 1
// FreeBSD
#elif defined(BSLS_PLATFORM_OS_FREEBSD)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF 1
// 32-Bit Linux with '_FILE_OFFSET_BITS = 64'
#elif defined(BSLS_PLATFORM_OS_LINUX) \
&& defined(BSLS_PLATFORM_CPU_32_BIT) \
&& defined(_FILE_OFFSET_BITS) \
&& _FILE_OFFSET_BITS == 64
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF 1
// 32-Bit Linux with '_LARGEFILE64_SOURCE'
#elif defined(BSLS_PLATFORM_OS_LINUX) \
&& defined(BSLS_PLATFORM_CPU_32_BIT) \
&& defined(_LARGEFILE64_SOURCE)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF64 1
// 32-Bit Linux
#elif defined(BSLS_PLATFORM_OS_LINUX) \
&& defined(BSLS_PLATFORM_CPU_32_BIT)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_32_BIT_OFF 1
// 64-Bit Linux
#elif defined(BSLS_PLATFORM_OS_LINUX) \
&& defined(BSLS_PLATFORM_CPU_64_BIT)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF 1
// 32-Bit SunOS with '_FILE_OFFSET_BITS = 64'
#elif defined(BSLS_PLATFORM_OS_SUNOS) \
&& defined(BSLS_PLATFORM_CPU_32_BIT) \
&& defined(_FILE_OFFSET_BITS) \
&& _FILE_OFFSET_BITS == 64
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF 1
// 32-Bit SunOS with '_LARGEFILE64_SOURCE'
#elif defined(BSLS_PLATFORM_OS_SUNOS) \
&& defined(BSLS_PLATFORM_CPU_32_BIT) \
&& defined(_LARGEFILE64_SOURCE)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF64 1
// 32-Bit SunOS
#elif defined(BSLS_PLATFORM_OS_SUNOS) \
&& defined(BSLS_PLATFORM_CPU_32_BIT)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_32_BIT_OFF 1
// 64-Bit SunOS
#elif defined(BSLS_PLATFORM_OS_SUNOS) \
&& defined(BSLS_PLATFORM_CPU_64_BIT)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF 1
// 32-Bit Solaris with '_FILE_OFFSET_BITS = 64'
#elif defined(BSLS_PLATFORM_OS_SOLARIS) \
&& defined(BSLS_PLATFORM_CPU_32_BIT) \
&& defined(_FILE_OFFSET_BITS) \
&& _FILE_OFFSET_BITS == 64
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF 1
// 32-Bit Solaris with '_LARGEFILE64_SOURCE'
#elif defined(BSLS_PLATFORM_OS_SOLARIS) \
&& defined(BSLS_PLATFORM_CPU_32_BIT) \
&& defined(_LARGEFILE64_SOURCE)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF64 1
// 32-Bit Solaris
#elif defined(BSLS_PLATFORM_OS_SOLARIS) \
&& defined(BSLS_PLATFORM_CPU_32_BIT)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_32_BIT_OFF 1
// 64-Bit Solaris
#elif defined(BSLS_PLATFORM_OS_SOLARIS) \
&& defined(BSLS_PLATFORM_CPU_64_BIT)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_64_BIT_OFF 1
#else
#error "'bdls_filesystemutil_unixplatform.h' does not support this Unix."
#endif
#if defined(BSLS_PLATFORM_OS_SOLARIS) || \
defined(BSLS_PLATFORM_OS_AIX) || \
defined(BSLS_PLATFORM_OS_LINUX)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_STAT_NS_MEMBER st_mtim.tv_nsec
#elif defined(BSLS_PLATFORM_OS_DARWIN)
#define BDLS_FILESYSTEMUTIL_UNIXPLATFORM_STAT_NS_MEMBER st_mtimespec.tv_nsec
#endif
#endif
#endif
// ----------------------------------------------------------------------------
// Copyright 2020 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------