root / lab4 / .minix-src / include / lzma / hardware.h @ 13
History | View | Annotate | Download (2.54 KB)
| 1 | 13 | up20180614 | /**
|
|---|---|---|---|
| 2 | * \file lzma/hardware.h
|
||
| 3 | * \brief Hardware information
|
||
| 4 | *
|
||
| 5 | * Since liblzma can consume a lot of system resources, it also provides
|
||
| 6 | * ways to limit the resource usage. Applications linking against liblzma
|
||
| 7 | * need to do the actual decisions how much resources to let liblzma to use.
|
||
| 8 | * To ease making these decisions, liblzma provides functions to find out
|
||
| 9 | * the relevant capabilities of the underlaying hardware. Currently there
|
||
| 10 | * is only a function to find out the amount of RAM, but in the future there
|
||
| 11 | * will be also a function to detect how many concurrent threads the system
|
||
| 12 | * can run.
|
||
| 13 | *
|
||
| 14 | * \note On some operating systems, these function may temporarily
|
||
| 15 | * load a shared library or open file descriptor(s) to find out
|
||
| 16 | * the requested hardware information. Unless the application
|
||
| 17 | * assumes that specific file descriptors are not touched by
|
||
| 18 | * other threads, this should have no effect on thread safety.
|
||
| 19 | * Possible operations involving file descriptors will restart
|
||
| 20 | * the syscalls if they return EINTR.
|
||
| 21 | */
|
||
| 22 | |||
| 23 | /*
|
||
| 24 | * Author: Lasse Collin
|
||
| 25 | *
|
||
| 26 | * This file has been put into the public domain.
|
||
| 27 | * You can do whatever you want with this file.
|
||
| 28 | *
|
||
| 29 | * See ../lzma.h for information about liblzma as a whole.
|
||
| 30 | */
|
||
| 31 | |||
| 32 | #ifndef LZMA_H_INTERNAL
|
||
| 33 | # error Never include this file directly. Use <lzma.h> instead.
|
||
| 34 | #endif
|
||
| 35 | |||
| 36 | |||
| 37 | /**
|
||
| 38 | * \brief Get the total amount of physical memory (RAM) in bytes
|
||
| 39 | *
|
||
| 40 | * This function may be useful when determining a reasonable memory
|
||
| 41 | * usage limit for decompressing or how much memory it is OK to use
|
||
| 42 | * for compressing.
|
||
| 43 | *
|
||
| 44 | * \return On success, the total amount of physical memory in bytes
|
||
| 45 | * is returned. If the amount of RAM cannot be determined,
|
||
| 46 | * zero is returned. This can happen if an error occurs
|
||
| 47 | * or if there is no code in liblzma to detect the amount
|
||
| 48 | * of RAM on the specific operating system.
|
||
| 49 | */
|
||
| 50 | extern LZMA_API(uint64_t) lzma_physmem(void) lzma_nothrow; |
||
| 51 | |||
| 52 | |||
| 53 | /**
|
||
| 54 | * \brief Get the number of processor cores or threads
|
||
| 55 | *
|
||
| 56 | * This function may be useful when determining how many threads to use.
|
||
| 57 | * If the hardware supports more than one thread per CPU core, the number
|
||
| 58 | * of hardware threads is returned if that information is available.
|
||
| 59 | *
|
||
| 60 | * \brief On success, the number of available CPU threads or cores is
|
||
| 61 | * returned. If this information isn't available or an error
|
||
| 62 | * occurs, zero is returned.
|
||
| 63 | */
|
||
| 64 | extern LZMA_API(uint32_t) lzma_cputhreads(void) lzma_nothrow; |