112 lines
1.8 KiB
C
112 lines
1.8 KiB
C
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#include <u.h>
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#include <libc.h>
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#include <bin.h>
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enum
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{
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StructAlign = sizeof(union {vlong vl; double d; ulong p; void *v;
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struct{vlong v;}vs; struct{double d;}ds; struct{ulong p;}ss; struct{void *v;}xs;})
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};
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enum
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{
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BinSize = 8*1024
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};
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struct Bin
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{
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Bin *next;
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ulong total; /* total bytes allocated in can->next */
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uintptr pos;
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uintptr end;
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uintptr v; /* last value allocated */
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uchar body[BinSize];
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};
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/*
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* allocator which allows an entire set to be freed at one time
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*/
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static Bin*
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mkbin(Bin *bin, ulong size)
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{
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Bin *b;
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size = ((size << 1) + (BinSize - 1)) & ~(BinSize - 1);
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b = malloc(sizeof(Bin) + size - BinSize);
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if(b == nil)
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return nil;
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b->next = bin;
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b->total = 0;
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if(bin != nil)
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b->total = bin->total + bin->pos - (uintptr)bin->body;
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b->pos = (uintptr)b->body;
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b->end = b->pos + size;
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return b;
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}
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void*
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binalloc(Bin **bin, ulong size, int zero)
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{
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Bin *b;
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uintptr p;
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if(size == 0)
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size = 1;
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b = *bin;
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if(b == nil){
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b = mkbin(nil, size);
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if(b == nil)
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return nil;
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*bin = b;
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}
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p = b->pos;
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p = (p + (StructAlign - 1)) & ~(StructAlign - 1);
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if(p + size > b->end){
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b = mkbin(b, size);
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if(b == nil)
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return nil;
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*bin = b;
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p = b->pos;
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}
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b->pos = p + size;
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b->v = p;
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if(zero)
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memset((void*)p, 0, size);
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return (void*)p;
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}
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void*
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bingrow(Bin **bin, void *op, ulong osize, ulong size, int zero)
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{
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Bin *b;
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void *np;
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uintptr p;
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p = (uintptr)op;
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b = *bin;
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if(b != nil && p == b->v && p + size <= b->end){
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b->pos = p + size;
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if(zero)
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memset((char*)p + osize, 0, size - osize);
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return op;
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}
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np = binalloc(bin, size, zero);
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if(np == nil)
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return nil;
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memmove(np, op, osize);
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return np;
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}
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void
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binfree(Bin **bin)
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{
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Bin *last;
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while(*bin != nil){
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last = *bin;
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*bin = (*bin)->next;
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last->pos = (uintptr)last->body;
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free(last);
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}
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}
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