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