114 lines
3.0 KiB
C
114 lines
3.0 KiB
C
/*
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* Copyright (c) 2011, 2012, 2014 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* string/memcpy.c
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* Copy memory between non-overlapping regions.
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*/
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#include <stdint.h>
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#include <string.h>
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inline static
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void* memcpy_slow(void* restrict dst_ptr,
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const void* restrict src_ptr,
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size_t size)
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{
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unsigned char* restrict dst = (unsigned char* restrict) dst_ptr;
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const unsigned char* restrict src = (const unsigned char* restrict) src_ptr;
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for ( size_t i = 0; i < size; i++ )
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dst[i] = src[i];
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return dst_ptr;
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}
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void* memcpy(void* restrict dst_ptr,
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const void* restrict src_ptr,
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size_t size)
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{
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#if 8 < __SIZEOF_LONG__
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#warning "you should add support for your unexpectedly large unsigned long."
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return memcpy_slow(dst_ptr, src_ptr, size);
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#else
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unsigned long unalign_mask = sizeof(unsigned long) - 1;
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unsigned long src_unalign = (unsigned long) src_ptr & unalign_mask;
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unsigned long dst_unalign = (unsigned long) dst_ptr & unalign_mask;
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if ( src_unalign != dst_unalign )
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return memcpy_slow(dst_ptr, src_ptr, size);
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union
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{
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unsigned long srcval;
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const unsigned char* restrict src8;
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const uint16_t* restrict src16;
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const uint32_t* restrict src32;
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const uint64_t* restrict src64;
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const unsigned long* restrict srcul;
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} su;
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su.srcval = (unsigned long) src_ptr;
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union
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{
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unsigned long dstval;
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unsigned char* restrict dst8;
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uint16_t* restrict dst16;
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uint32_t* restrict dst32;
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uint64_t* restrict dst64;
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unsigned long* restrict dstul;
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} du;
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du.dstval = (unsigned long) dst_ptr;
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if ( dst_unalign )
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{
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if ( 1 <= size && !(du.dstval & (1-1)) && (du.dstval & (2-1)) )
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*du.dst8++ = *su.src8++,
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size -= 1;
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if ( 2 <= size && !(du.dstval & (2-1)) && (du.dstval & (4-1)) )
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*du.dst16++ = *su.src16++,
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size -= 2;
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#if 8 <= __SIZEOF_LONG__
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if ( 4 <= size && !(du.dstval & (4-1)) && (du.dstval & (8-1)) )
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*du.dst32++ = *su.src32++,
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size -= 4;
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#endif
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}
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size_t num_copies = size / sizeof(unsigned long);
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for ( size_t i = 0; i < num_copies; i++ )
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*du.dstul++ = *su.srcul++;
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size -= num_copies * sizeof(unsigned long);
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if ( size )
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{
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#if 8 <= __SIZEOF_LONG__
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if ( 4 <= size )
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*du.dst32++ = *su.src32++,
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size -= 4;
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#endif
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if ( 2 <= size )
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*du.dst16++ = *su.src16++,
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size -= 2;
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if ( 1 <= size )
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*du.dst8++ = *su.src8++,
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size -= 1;
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}
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return dst_ptr;
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#endif
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}
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