Initial import

libc/alg/arraylist.h

@@ -0,0 +1,48 @@
+#ifndef COSMOPOLITAN_LIBC_ALG_ARRAYLIST_H_
+#define COSMOPOLITAN_LIBC_ALG_ARRAYLIST_H_
+#include "libc/bits/bits.h"
+#include "libc/mem/mem.h"
+#include "libc/str/str.h"
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+#if 0
+/**
+ * @fileoverview Cosmopolitan Array List.
+ *
+ * This is a generically-typed ArrayList<T> template which follows a
+ * duck-typing philosophy like Python, exporting an interface paradigm
+ * similar to Go, that's implicitly defined by way of macros like Lisp.
+ *
+ *     struct MyArrayList {
+ *       size_t i;  // current item count
+ *       size_t n;  // current item capacity
+ *       T *p;      // pointer to array (initially NULL)
+ *     };
+ *
+ * Any struct with those fields can be used. It's also very important
+ * that other data structures, which reference items in an arraylist, do
+ * so using indices rather than pointers, since realloc() can relocate.
+ *     
+ * @see libc/mem/grow.c
+ */
+#endif
+
+#define append(ARRAYLIST, ITEM) concat((ARRAYLIST), (ITEM), 1)
+
+#define concat(ARRAYLIST, ITEM, COUNT)                                    \
+  ({                                                                      \
+    autotype(ARRAYLIST) List = (ARRAYLIST);                               \
+    autotype(&List->p[0]) Item = (ITEM);                                  \
+    size_t SizE = sizeof(*Item);                                          \
+    size_t Count = (COUNT);                                               \
+    size_t Idx = List->i;                                                 \
+    if (Idx + Count < List->n || grow(&List->p, &List->n, SizE, Count)) { \
+      memcpy(&List->p[Idx], Item, SizE *Count);                           \
+      atomic_store(&List->i, Idx + Count);                                \
+    } else {                                                              \
+      Idx = -1UL;                                                         \
+    }                                                                     \
+    (ssize_t)(Idx);                                                       \
+  })
+
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_LIBC_ALG_ARRAYLIST_H_ */