Move memory utilities to common

src/common/mem_utils/mem_utils.c

@@ -0,0 +1,115 @@
+#include "mem_utils.h"
+#include "aliases.h"
+#include "platform.h"
+#include <assert.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if defined(WAPP_PLATFORM_WINDOWS)
+#define WIN32_LEAN_AND_MEAN
+#include <Windows.h>
+#include <memoryapi.h>
+
+internal const i32 access_types[] = {
+    [WAPP_MEM_ACCESS_NONE] = PAGE_NOACCESS,
+    [WAPP_MEM_ACCESS_READ_ONLY] = PAGE_READONLY,
+    [WAPP_MEM_ACCESS_EXEC_ONLY] = PAGE_EXECUTE,
+    [WAPP_MEM_ACCESS_READ_WRITE] = PAGE_READWRITE,
+    [WAPP_MEM_ACCESS_READ_EXEC] = PAGE_EXECUTE_READ,
+    [WAPP_MEM_ACCESS_READ_WRITE_EXEC] = PAGE_EXECUTE_READWRITE,
+};
+
+internal inline void *alloc_windows(void *addr, u64 size, MemAccess access,
+                                    MemAllocFlags flags);
+#elif defined(WAPP_PLATFORM_POSIX)
+#include <sys/mman.h>
+
+internal const i32 access_types[] = {
+    [WAPP_MEM_ACCESS_NONE] = PROT_NONE,
+    [WAPP_MEM_ACCESS_READ_ONLY] = PROT_READ,
+    [WAPP_MEM_ACCESS_EXEC_ONLY] = PROT_EXEC,
+    [WAPP_MEM_ACCESS_READ_WRITE] = PROT_READ | PROT_WRITE,
+    [WAPP_MEM_ACCESS_READ_EXEC] = PROT_READ | PROT_EXEC,
+    [WAPP_MEM_ACCESS_READ_WRITE_EXEC] = PROT_READ | PROT_WRITE | PROT_EXEC,
+};
+
+internal inline void *alloc_posix(void *addr, u64 size, MemAccess access,
+                                  MemAllocFlags flags);
+#else
+#error "Unrecognised platform"
+#endif
+
+internal bool is_power_of_two(u64 num) { return (num & (num - 1)) == 0; }
+
+void *wapp_mem_util_align_forward(void *ptr, u64 alignment) {
+  if (!ptr) {
+    return NULL;
+  }
+
+  assert(is_power_of_two(alignment));
+
+  uptr p = (uptr)ptr;
+  uptr align = (uptr)alignment;
+
+  // Similar to p % align, but it's a faster implementation that works fine
+  // because align is guaranteed to be a power of 2
+  uptr modulo = p & (align - 1);
+
+  if (modulo != 0) {
+    p += align - modulo;
+  }
+
+  return (void *)p;
+}
+
+void *wapp_mem_util_alloc(void *addr, u64 size, MemAccess access,
+                          MemAllocFlags flags, MemInitType type) {
+#if defined(WAPP_PLATFORM_WINDOWS)
+  // Ensure memory is committed if it's meant to be initialised
+  if (type == WAPP_MEM_INIT_INITIALISED) {
+    flags |= WAPP_MEM_ALLOC_COMMIT;
+  }
+
+  void *output = alloc_windows(addr, size, access, flags);
+#elif defined(WAPP_PLATFORM_POSIX)
+  void *output = alloc_posix(addr, size, access, flags);
+#else
+  return NULL;
+#endif
+
+  if (type == WAPP_MEM_INIT_INITIALISED) {
+    memset(output, 0, size);
+  }
+
+  return output;
+}
+
+void wapp_mem_util_free(void *ptr, u64 size) {
+#if defined(WAPP_PLATFORM_WINDOWS)
+  VirtualFree(ptr, size, MEM_RELEASE);
+#elif defined(WAPP_PLATFORM_POSIX)
+  munmap(ptr, size);
+#endif
+}
+
+#ifdef WAPP_PLATFORM_WINDOWS
+internal inline void *alloc_windows(void *addr, u64 size, MemAccess access,
+                                    MemAllocFlags flags) {
+  return VirtualAlloc(addr, (SIZE_T)size, flags, access_types[access]);
+}
+#endif
+
+#if defined(WAPP_PLATFORM_POSIX)
+internal inline void *alloc_posix(void *addr, u64 size, MemAccess access,
+                                  MemAllocFlags flags) {
+  i32 alloc_flags = flags | MAP_ANON | MAP_PRIVATE;
+
+#if defined(WAPP_PLATFORM_LINUX) || defined(WAPP_PLATFORM_GNU) ||              \
+    defined(WAPP_PLATFORM_NET_BSD)
+  alloc_flags |= MAP_NORESERVE;
+#endif
+
+  return mmap(addr, size, access_types[access], alloc_flags, -1, 0);
+}
+#endif