libgo/runtime/mfixalloc.c

   1 // Copyright 2009 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 // Fixed-size object allocator.  Returned memory is not zeroed.
   6 //
   7 // See malloc.h for overview.
   8
   9 #include "runtime.h"
  10 #include "arch.h"
  11 #include "malloc.h"
  12
  13 // Initialize f to allocate objects of the given size,
  14 // using the allocator to obtain chunks of memory.
  15 void
  16 runtime_FixAlloc_Init(FixAlloc *f, uintptr size, void *(*alloc)(uintptr), void (*first)(void*, byte*), void *arg)
  17 {
  18         f->size = size;
  19         f->alloc = alloc;
  20         f->first = first;
  21         f->arg = arg;
  22         f->list = nil;
  23         f->chunk = nil;
  24         f->nchunk = 0;
  25         f->inuse = 0;
  26         f->sys = 0;
  27 }
  28
  29 void*
  30 runtime_FixAlloc_Alloc(FixAlloc *f)
  31 {
  32         void *v;
  33
  34         if(f->list) {
  35                 v = f->list;
  36                 f->list = *(void**)f->list;
  37                 f->inuse += f->size;
  38                 return v;
  39         }
  40         if(f->nchunk < f->size) {
  41                 f->sys += FixAllocChunk;
  42                 f->chunk = f->alloc(FixAllocChunk);
  43                 if(f->chunk == nil)
  44                         runtime_throw("out of memory (FixAlloc)");
  45                 f->nchunk = FixAllocChunk;
  46         }
  47         v = f->chunk;
  48         if(f->first)
  49                 f->first(f->arg, v);
  50         f->chunk += f->size;
  51         f->nchunk -= f->size;
  52         f->inuse += f->size;
  53         return v;
  54 }
  55
  56 void
  57 runtime_FixAlloc_Free(FixAlloc *f, void *p)
  58 {
  59         f->inuse -= f->size;
  60         *(void**)p = f->list;
  61         f->list = p;
  62 }
  63