Merge pull request #977 from EXetoC/alloc-overloads

Allocation overloads

lib/system.nim

@@ -1164,6 +1164,14 @@ when not defined(nimrodVM):
       ## from it before writing to it is undefined behaviour!
       ## The allocated memory belongs to its allocating thread!
       ## Use `allocShared` to allocate from a shared heap.
+    proc alloc*(T: typedesc, size = 1): ptr T {.inline.} =
+      ## allocates a new memory block with at least ``T.sizeof * size``
+      ## bytes. The block has to be freed with ``realloc(block, 0)`` or
+      ## ``dealloc(block)``. The block is not initialized, so reading
+      ## from it before writing to it is undefined behaviour!
+      ## The allocated memory belongs to its allocating thread!
+      ## Use `allocShared` to allocate from a shared heap.
+      cast[ptr T](alloc(T.sizeof * size))
     proc alloc0*(size: int): pointer {.noconv, rtl, tags: [].}
       ## allocates a new memory block with at least ``size`` bytes. The
       ## block has to be freed with ``realloc(block, 0)`` or
@@ -1171,14 +1179,31 @@ when not defined(nimrodVM):
       ## containing zero, so it is somewhat safer than ``alloc``.
       ## The allocated memory belongs to its allocating thread!
       ## Use `allocShared0` to allocate from a shared heap.
-    proc realloc*(p: pointer, newsize: int): pointer {.noconv, rtl, tags: [].}
+    proc alloc0*(T: typedesc, size = 1): ptr T {.inline.} =
+      ## allocates a new memory block with at least ``T.sizeof * size``
+      ## bytes. The block has to be freed with ``realloc(block, 0)`` or
+      ## ``dealloc(block)``. The block is initialized with all bytes
+      ## containing zero, so it is somewhat safer than ``alloc``.
+      ## The allocated memory belongs to its allocating thread!
+      ## Use `allocShared0` to allocate from a shared heap.
+      cast[ptr T](alloc0(T.sizeof * size))
+    proc realloc*(p: pointer, newSize: int): pointer {.noconv, rtl, tags: [].}
       ## grows or shrinks a given memory block. If p is **nil** then a new
       ## memory block is returned. In either way the block has at least
-      ## ``newsize`` bytes. If ``newsize == 0`` and p is not **nil**
+      ## ``newSize`` bytes. If ``newSize == 0`` and p is not **nil**
       ## ``realloc`` calls ``dealloc(p)``. In other cases the block has to
       ## be freed with ``dealloc``.
       ## The allocated memory belongs to its allocating thread!
       ## Use `reallocShared` to reallocate from a shared heap.
+    proc reallocType*[T](p: ptr T, newSize: int): ptr T {.inline.} =
+      ## grows or shrinks a given memory block. If p is **nil** then a new
+      ## memory block is returned. In either way the block has at least
+      ## ``T.sizeof * newSize`` bytes. If ``newSize == 0`` and p is not
+      ## **nil** ``realloc`` calls ``dealloc(p)``. In other cases the block
+      ## has to be freed with ``dealloc``. The allocated memory belongs to
+      ## its allocating thread!
+      ## Use `reallocShared` to reallocate from a shared heap.
+      cast[ptr T](realloc(p, T.sizeof * newSize))
     proc dealloc*(p: pointer) {.noconv, rtl, tags: [].}
       ## frees the memory allocated with ``alloc``, ``alloc0`` or
       ## ``realloc``. This procedure is dangerous! If one forgets to
@@ -1187,25 +1212,45 @@ when not defined(nimrodVM):
       ## or other memory may be corrupted. 
       ## The freed memory must belong to its allocating thread!
       ## Use `deallocShared` to deallocate from a shared heap.
-
     proc allocShared*(size: int): pointer {.noconv, rtl.}
       ## allocates a new memory block on the shared heap with at
       ## least ``size`` bytes. The block has to be freed with
       ## ``reallocShared(block, 0)`` or ``deallocShared(block)``. The block
       ## is not initialized, so reading from it before writing to it is 
       ## undefined behaviour!
+    proc allocShared*(T: typedesc, size: int): ptr T {.inline.} =
+      ## allocates a new memory block on the shared heap with at
+      ## least ``T.sizeof * size`` bytes. The block has to be freed with
+      ## ``reallocShared(block, 0)`` or ``deallocShared(block)``. The block
+      ## is not initialized, so reading from it before writing to it is 
+      ## undefined behaviour!
+      cast[ptr T](allocShared(T.sizeof * size))
     proc allocShared0*(size: int): pointer {.noconv, rtl.}
       ## allocates a new memory block on the shared heap with at 
       ## least ``size`` bytes. The block has to be freed with
       ## ``reallocShared(block, 0)`` or ``deallocShared(block)``.
       ## The block is initialized with all bytes
       ## containing zero, so it is somewhat safer than ``allocShared``.
-    proc reallocShared*(p: pointer, newsize: int): pointer {.noconv, rtl.}
+    proc allocShared0*(T: typedesc, size: int): ptr T {.inline.} =
+      ## allocates a new memory block on the shared heap with at 
+      ## least ``T.sizeof * size`` bytes. The block has to be freed with
+      ## ``reallocShared(block, 0)`` or ``deallocShared(block)``.
+      ## The block is initialized with all bytes
+      ## containing zero, so it is somewhat safer than ``allocShared``.
+      cast[ptr T](allocShared(T.sizeof * size))
+    proc reallocShared*(p: pointer, newSize: int): pointer {.noconv, rtl.}
       ## grows or shrinks a given memory block on the heap. If p is **nil**
-      ## then a new memory block is returned. In either way the block has at least
-      ## ``newsize`` bytes. If ``newsize == 0`` and p is not **nil**
+      ## then a new memory block is returned. In either way the block has at
+      ## least ``newSize`` bytes. If ``newSize == 0`` and p is not **nil**
       ## ``reallocShared`` calls ``deallocShared(p)``. In other cases the
       ## block has to be freed with ``deallocShared``.
+    proc reallocSharedType*[T](p: ptr T, newSize: int): ptr T {.inline.} =
+      ## grows or shrinks a given memory block on the heap. If p is **nil**
+      ## then a new memory block is returned. In either way the block has at
+      ## least ``T.sizeof * newSize`` bytes. If ``newSize == 0`` and p is
+      ## not **nil** ``reallocShared`` calls ``deallocShared(p)``. In other
+      ## cases the block has to be freed with ``deallocShared``.
+      cast[ptr T](reallocShared(p, T.sizeof * newSize))
     proc deallocShared*(p: pointer) {.noconv, rtl.}
       ## frees the memory allocated with ``allocShared``, ``allocShared0`` or
       ## ``reallocShared``. This procedure is dangerous! If one forgets to

tests/system/alloc.nim

@@ -0,0 +1,45 @@
+var x: ptr int
+
+x = cast[ptr int](alloc(7))
+assert x != nil
+
+x = alloc(int, 3)
+assert x != nil
+x.dealloc()
+
+x = alloc0(int, 4)
+assert cast[ptr array[4, int]](x)[0] == 0
+assert cast[ptr array[4, int]](x)[1] == 0
+assert cast[ptr array[4, int]](x)[2] == 0
+assert cast[ptr array[4, int]](x)[3] == 0
+
+x = cast[ptr int](x.realloc(2))
+assert x != nil
+
+x = x.reallocType(4)
+assert x != nil
+x.dealloc()
+
+x = cast[ptr int](allocShared(100))
+assert x != nil
+deallocShared(x)
+
+x = allocShared(int, 3)
+assert x != nil
+x.deallocShared()
+
+x = allocShared0(int, 3)
+assert x != nil
+assert cast[ptr array[3, int]](x)[0] == 0
+assert cast[ptr array[3, int]](x)[1] == 0
+assert cast[ptr array[3, int]](x)[2] == 0
+
+x = cast[ptr int](reallocShared(x, 2))
+assert x != nil
+
+x = reallocType(x, 12)
+assert x != nil
+
+x = reallocSharedType(x, 1)
+assert x != nil
+x.deallocShared()