dynarray.cpp

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/* Copyright (c) 2010 Wildfire Games
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/*
 * dynamic (expandable) array
 */

#include "precompiled.h"
#include "lib/allocators/dynarray.h"

#include "lib/alignment.h"
#include "lib/sysdep/vm.h"


static Status validate_da(DynArray* da)
{
    if(!da)
        WARN_RETURN(ERR::INVALID_POINTER);
//  u8* const base           = da->base;
    const size_t max_size_pa = da->max_size_pa;
    const size_t cur_size    = da->cur_size;
    const size_t pos         = da->pos;

    // note: this happens if max_size == 0
//  if(debug_IsPointerBogus(base))
//      WARN_RETURN(ERR::_1);
    // note: don't check if base is page-aligned -
    // might not be true for 'wrapped' mem regions.
    if(!IsAligned(max_size_pa, pageSize))
        WARN_RETURN(ERR::_3);
    if(cur_size > max_size_pa)
        WARN_RETURN(ERR::_4);
    if(pos > cur_size || pos > max_size_pa)
        WARN_RETURN(ERR::_5);

    return INFO::OK;
}

#define CHECK_DA(da) RETURN_STATUS_IF_ERR(validate_da(da))


Status da_alloc(DynArray* da, size_t max_size)
{
    ENSURE(max_size != 0);
    const size_t max_size_pa = Align<pageSize>(max_size);

    u8* p = (u8*)vm::ReserveAddressSpace(max_size_pa);
    if(!p)
        return ERR::NO_MEM; // NOWARN (already done in vm)

    da->base        = p;
    da->max_size_pa = max_size_pa;
    da->cur_size    = 0;
    da->cur_size_pa = 0;
    da->pos         = 0;
    CHECK_DA(da);
    return INFO::OK;
}


Status da_free(DynArray* da)
{
    CHECK_DA(da);

    vm::ReleaseAddressSpace(da->base, da->max_size_pa);

    // wipe out the DynArray for safety
    memset(da, 0, sizeof(*da));

    return INFO::OK;
}


Status da_set_size(DynArray* da, size_t new_size)
{
    CHECK_DA(da);

    // determine how much to add/remove
    const size_t cur_size_pa = Align<pageSize>(da->cur_size);
    const size_t new_size_pa = Align<pageSize>(new_size);
    const ssize_t size_delta_pa = (ssize_t)new_size_pa - (ssize_t)cur_size_pa;

    // not enough memory to satisfy this expand request: abort.
    // note: do not complain - some allocators (e.g. file_cache)
    // legitimately use up all available space.
    if(new_size_pa > da->max_size_pa)
        return ERR::LIMIT;  // NOWARN

    u8* end = da->base + cur_size_pa;
    bool ok = true;
    // expanding
    if(size_delta_pa > 0)
    {
        ok = vm::Commit(uintptr_t(end), size_delta_pa);
        if(!ok)
            debug_printf(L"Commit failed (%p %lld)\n", end, (long long)size_delta_pa);
    }
    // shrinking
    else if(size_delta_pa < 0)
        ok = vm::Decommit(uintptr_t(end+size_delta_pa), -size_delta_pa);
    // else: no change in page count, e.g. if going from size=1 to 2
    // (we don't want mem_* to have to handle size=0)

    da->cur_size = new_size;
    da->cur_size_pa = new_size_pa;
    CHECK_DA(da);
    return ok? INFO::OK : ERR::FAIL;
}


Status da_reserve(DynArray* da, size_t size)
{
    if(da->pos+size > da->cur_size_pa)
        RETURN_STATUS_IF_ERR(da_set_size(da, da->cur_size_pa+size));
    da->cur_size = std::max(da->cur_size, da->pos+size);
    return INFO::OK;
}


Status da_append(DynArray* da, const void* data, size_t size)
{
    RETURN_STATUS_IF_ERR(da_reserve(da, size));
    memcpy(da->base+da->pos, data, size);
    da->pos += size;
    return INFO::OK;
}