fix comments; nicer strdup/strndup

include/mimalloc/prim.h

@@ -14,17 +14,17 @@ terms of the MIT license. A copy of the license can be found in the file
 // Each OS/host needs to implement these primitives, see `src/prim`
 // for implementations on Window, macOS, WASI, and Linux/Unix.
 //
-// note: on all primitive functions, we always have result parameters != NUL, and:
+// note: on all primitive functions, we always have result parameters != NULL, and:
 //  addr != NULL and page aligned
 //  size > 0     and page aligned
-//  return value is an error code an int where 0 is success.
+//  the return value is an error code as an `int` where 0 is success
 // --------------------------------------------------------------------------
 
 // OS memory configuration
 typedef struct mi_os_mem_config_s {
-  size_t  page_size;            // 4KiB
-  size_t  large_page_size;      // 2MiB
-  size_t  alloc_granularity;    // smallest allocation size (on Windows 64KiB)
+  size_t  page_size;            // default to 4KiB
+  size_t  large_page_size;      // 0 if not supported, usually 2MiB (4MiB on Windows)
+  size_t  alloc_granularity;    // smallest allocation size (usually 4KiB, on Windows 64KiB)
   bool    has_overcommit;       // can we reserve more memory than can be actually committed?
   bool    must_free_whole;      // must allocated blocks be freed as a whole (false for mmap, true for VirtualAlloc)
   bool    has_virtual_reserve;  // supports virtual address space reservation? (if true we can reserve virtual address space without using commit or physical memory)

src/alloc.c

@@ -329,11 +329,11 @@ mi_decl_nodiscard void* mi_recalloc(void* p, size_t count, size_t size) mi_attr_
 // `strdup` using mi_malloc
 mi_decl_nodiscard mi_decl_restrict char* mi_heap_strdup(mi_heap_t* heap, const char* s) mi_attr_noexcept {
   if (s == NULL) return NULL;
-  size_t n = strlen(s);
-  char* t = (char*)mi_heap_malloc(heap,n+1);
+  size_t len = _mi_strlen(s);
+  char* t = (char*)mi_heap_malloc(heap,len+1);
   if (t == NULL) return NULL;
-  _mi_memcpy(t, s, n);
-  t[n] = 0;
+  _mi_memcpy(t, s, len);
+  t[len] = 0;
   return t;
 }
 
@@ -344,13 +344,11 @@ mi_decl_nodiscard mi_decl_restrict char* mi_strdup(const char* s) mi_attr_noexce
 // `strndup` using mi_malloc
 mi_decl_nodiscard mi_decl_restrict char* mi_heap_strndup(mi_heap_t* heap, const char* s, size_t n) mi_attr_noexcept {
   if (s == NULL) return NULL;
-  const char* end = (const char*)memchr(s, 0, n);  // find end of string in the first `n` characters (returns NULL if not found)
-  const size_t m = (end != NULL ? (size_t)(end - s) : n);  // `m` is the minimum of `n` or the end-of-string
-  mi_assert_internal(m <= n);
-  char* t = (char*)mi_heap_malloc(heap, m+1);
+  const size_t len = _mi_strnlen(s,n);  // len <= n
+  char* t = (char*)mi_heap_malloc(heap, len+1);
   if (t == NULL) return NULL;
-  _mi_memcpy(t, s, m);
-  t[m] = 0;
+  _mi_memcpy(t, s, len);
+  t[len] = 0;
   return t;
 }
 

src/prim/windows/prim.c

@@ -482,7 +482,7 @@ void _mi_prim_out_stderr( const char* msg )
   // on windows with redirection, the C runtime cannot handle locale dependent output
   // after the main thread closes so we use direct console output.
   if (!_mi_preloading()) {
-    // _cputs(msg);  // _cputs cannot be used at is aborts if it fails to lock the console
+    // _cputs(msg);  // _cputs cannot be used as it aborts when failing to lock the console
     static HANDLE hcon = INVALID_HANDLE_VALUE;
     static bool hconIsConsole;
     if (hcon == INVALID_HANDLE_VALUE) {