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//+build windows
//+private
package mem_virtual
foreign import Kernel32 "system:Kernel32.lib"
LPSYSTEM_INFO :: ^SYSTEM_INFO
SYSTEM_INFO :: struct {
using DUMMYUNIONNAME: struct #raw_union {
dwOemId: u32,
using DUMMYSTRUCTNAME:struct {
wProcessorArchitecture: u16,
wReserved: u16,
},
},
dwPageSize: u32,
lpMinimumApplicationAddress: rawptr,
lpMaximumApplicationAddress: rawptr,
dwActiveProcessorMask: uint,
dwNumberOfProcessors: u32,
dwProcessorType: u32,
dwAllocationGranularity: u32,
wProcessorLevel: u16,
wProcessorRevision: u16,
}
MEM_COMMIT :: 0x00001000
MEM_RESERVE :: 0x00002000
MEM_RESET :: 0x00080000
MEM_RESET_UNDO :: 0x01000000
MEM_LARGE_PAGES :: 0x20000000
MEM_PHYSICAL :: 0x00400000
MEM_TOP_DOWN :: 0x00100000
MEM_WRITE_WATCH :: 0x00200000
MEM_DECOMMIT :: 0x00004000
MEM_RELEASE :: 0x00008000
MEM_COALESCE_PLACEHOLDERS :: 0x00000001
MEM_PRESERVE_PLACEHOLDER :: 0x00000002
PAGE_EXECUTE :: 0x10
PAGE_EXECUTE_READ :: 0x20
PAGE_EXECUTE_READWRITE :: 0x40
PAGE_EXECUTE_WRITECOPY :: 0x80
PAGE_NOACCESS :: 0x01
PAGE_READONLY :: 0x02
PAGE_READWRITE :: 0x04
PAGE_WRITECOPY :: 0x08
PAGE_TARGETS_INVALID :: 0x40000000
PAGE_TARGETS_NO_UPDATE :: 0x40000000
ERROR_INVALID_ADDRESS :: 487
@(default_calling_convention="stdcall")
foreign Kernel32 {
GetSystemInfo :: proc(lpSystemInfo: LPSYSTEM_INFO) ---
VirtualAlloc :: proc(lpAddress: rawptr, dwSize: uint, flAllocationType: u32, flProtect: u32) -> rawptr ---
VirtualFree :: proc(lpAddress: rawptr, dwSize: uint, dwFreeType: u32) -> b32 ---
VirtualProtect :: proc(lpAddress: rawptr, dwSize: uint, flNewProtect: u32, lpflOldProtect: ^u32) -> b32 ---
GetLastError :: proc() -> u32 ---
}
_reserve :: proc "contextless" (size: uint) -> (data: []byte, err: Allocator_Error) {
result := VirtualAlloc(nil, size, MEM_RESERVE, PAGE_READWRITE)
if result == nil {
err = .Out_Of_Memory
return
}
data = ([^]byte)(result)[:size]
return
}
_commit :: proc "contextless" (data: rawptr, size: uint) -> Allocator_Error {
result := VirtualAlloc(data, size, MEM_COMMIT, PAGE_READWRITE)
if result == nil {
switch err := GetLastError(); err {
case ERROR_INVALID_ADDRESS:
return .Out_Of_Memory
}
// TODO(bill): Handle errors correctly
return .Invalid_Argument
}
return nil
}
_decommit :: proc "contextless" (data: rawptr, size: uint) {
VirtualFree(data, size, MEM_DECOMMIT)
}
_release :: proc "contextless" (data: rawptr, size: uint) {
VirtualFree(data, 0, MEM_RELEASE)
}
_protect :: proc "contextless" (data: rawptr, size: uint, flags: Protect_Flags) -> bool {
pflags: u32
pflags = PAGE_NOACCESS
switch flags {
case {}: pflags = PAGE_NOACCESS
case {.Read}: pflags = PAGE_READONLY
case {.Read, .Write}: pflags = PAGE_READWRITE
case {.Write}: pflags = PAGE_WRITECOPY
case {.Execute}: pflags = PAGE_EXECUTE
case {.Execute, .Read}: pflags = PAGE_EXECUTE_READ
case {.Execute, .Read, .Write}: pflags = PAGE_EXECUTE_READWRITE
case {.Execute, .Write}: pflags = PAGE_EXECUTE_WRITECOPY
case:
return false
}
old_protect: u32
ok := VirtualProtect(data, size, pflags, &old_protect)
return bool(ok)
}
_platform_memory_init :: proc() {
sys_info: SYSTEM_INFO
GetSystemInfo(&sys_info)
DEFAULT_PAGE_SIZE = max(DEFAULT_PAGE_SIZE, uint(sys_info.dwPageSize))
// is power of two
assert(DEFAULT_PAGE_SIZE != 0 && (DEFAULT_PAGE_SIZE & (DEFAULT_PAGE_SIZE-1)) == 0)
}
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