py/objdeque: Expand implementation to be doubly-ended and support iter.

Add `pop()`, `appendleft()`, and `extend()` methods, support iteration
and indexing, and initializing from an existing sequence.

Iteration and indexing (subscription) have independent configuration flags
to enable them.  They are enabled by default at the same level that
collections.deque is enabled (the extra features level).

Also add tests for checking new behavior.

Signed-off-by: Damien George <damien@micropython.org>

ports/windows/mpconfigport.h

@@ -117,6 +117,8 @@
 #define MICROPY_PY_SYS_STDFILES     (1)
 #define MICROPY_PY_SYS_EXC_INFO     (1)
 #define MICROPY_PY_COLLECTIONS_DEQUE (1)
+#define MICROPY_PY_COLLECTIONS_DEQUE_ITER (1)
+#define MICROPY_PY_COLLECTIONS_DEQUE_SUBSCR (1)
 #define MICROPY_PY_COLLECTIONS_ORDEREDDICT (1)
 #ifndef MICROPY_PY_MATH_SPECIAL_FUNCTIONS
 #define MICROPY_PY_MATH_SPECIAL_FUNCTIONS (1)

py/mpconfig.h

@@ -1303,6 +1303,16 @@ typedef double mp_float_t;
 #define MICROPY_PY_COLLECTIONS_DEQUE (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_EXTRA_FEATURES)
 #endif
 
+// Whether "collections.deque" supports iteration
+#ifndef MICROPY_PY_COLLECTIONS_DEQUE_ITER
+#define MICROPY_PY_COLLECTIONS_DEQUE_ITER (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_EXTRA_FEATURES)
+#endif
+
+// Whether "collections.deque" supports subscription
+#ifndef MICROPY_PY_COLLECTIONS_DEQUE_SUBSCR
+#define MICROPY_PY_COLLECTIONS_DEQUE_SUBSCR (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_EXTRA_FEATURES)
+#endif
+
 // Whether to provide "collections.OrderedDict" type
 #ifndef MICROPY_PY_COLLECTIONS_ORDEREDDICT
 #define MICROPY_PY_COLLECTIONS_ORDEREDDICT (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_EXTRA_FEATURES)

py/objdeque.c

@@ -25,13 +25,11 @@
  */
 
 #include <unistd.h> // for ssize_t
-#include <string.h>
-
-#include "py/mpconfig.h"
-#if MICROPY_PY_COLLECTIONS_DEQUE
 
 #include "py/runtime.h"
 
+#if MICROPY_PY_COLLECTIONS_DEQUE
+
 typedef struct _mp_obj_deque_t {
     mp_obj_base_t base;
     size_t alloc;
@@ -42,15 +40,15 @@ typedef struct _mp_obj_deque_t {
     #define FLAG_CHECK_OVERFLOW 1
 } mp_obj_deque_t;
 
+static mp_obj_t mp_obj_deque_append(mp_obj_t self_in, mp_obj_t arg);
+static mp_obj_t mp_obj_deque_extend(mp_obj_t self_in, mp_obj_t arg_in);
+#if MICROPY_PY_COLLECTIONS_DEQUE_ITER
+static mp_obj_t mp_obj_new_deque_it(mp_obj_t deque, mp_obj_iter_buf_t *iter_buf);
+#endif
+
 static mp_obj_t deque_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 2, 3, false);
 
-    /* Initialization from existing sequence is not supported, so an empty
-       tuple must be passed as such. */
-    if (args[0] != mp_const_empty_tuple) {
-        mp_raise_ValueError(NULL);
-    }
-
     // Protect against -1 leading to zero-length allocation and bad array access
     mp_int_t maxlen = mp_obj_get_int(args[1]);
     if (maxlen < 0) {
@@ -66,21 +64,27 @@ static mp_obj_t deque_make_new(const mp_obj_type_t *type, size_t n_args, size_t
         o->flags = mp_obj_get_int(args[2]);
     }
 
+    mp_obj_deque_extend(MP_OBJ_FROM_PTR(o), args[0]);
+
     return MP_OBJ_FROM_PTR(o);
 }
 
+static size_t deque_len(mp_obj_deque_t *self) {
+    ssize_t len = self->i_put - self->i_get;
+    if (len < 0) {
+        len += self->alloc;
+    }
+    return len;
+}
+
 static mp_obj_t deque_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
     mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
     switch (op) {
         case MP_UNARY_OP_BOOL:
             return mp_obj_new_bool(self->i_get != self->i_put);
-        case MP_UNARY_OP_LEN: {
-            ssize_t len = self->i_put - self->i_get;
-            if (len < 0) {
-                len += self->alloc;
-            }
-            return MP_OBJ_NEW_SMALL_INT(len);
-        }
+        case MP_UNARY_OP_LEN:
+            return MP_OBJ_NEW_SMALL_INT(deque_len(self));
+
         #if MICROPY_PY_SYS_GETSIZEOF
         case MP_UNARY_OP_SIZEOF: {
             size_t sz = sizeof(*self) + sizeof(mp_obj_t) * self->alloc;
@@ -117,6 +121,45 @@ static mp_obj_t mp_obj_deque_append(mp_obj_t self_in, mp_obj_t arg) {
 }
 static MP_DEFINE_CONST_FUN_OBJ_2(deque_append_obj, mp_obj_deque_append);
 
+static mp_obj_t mp_obj_deque_appendleft(mp_obj_t self_in, mp_obj_t arg) {
+    mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
+
+    size_t new_i_get = self->i_get - 1;
+    if (self->i_get == 0) {
+        new_i_get = self->alloc - 1;
+    }
+
+    if (self->flags & FLAG_CHECK_OVERFLOW && new_i_get == self->i_put) {
+        mp_raise_msg(&mp_type_IndexError, MP_ERROR_TEXT("full"));
+    }
+
+    self->i_get = new_i_get;
+    self->items[self->i_get] = arg;
+
+    // overwriting first element in deque
+    if (self->i_put == new_i_get) {
+        if (self->i_put == 0) {
+            self->i_put = self->alloc - 1;
+        } else {
+            self->i_put--;
+        }
+    }
+
+    return mp_const_none;
+}
+static MP_DEFINE_CONST_FUN_OBJ_2(deque_appendleft_obj, mp_obj_deque_appendleft);
+
+static mp_obj_t mp_obj_deque_extend(mp_obj_t self_in, mp_obj_t arg_in) {
+    mp_obj_iter_buf_t iter_buf;
+    mp_obj_t iter = mp_getiter(arg_in, &iter_buf);
+    mp_obj_t item;
+    while ((item = mp_iternext(iter)) != MP_OBJ_STOP_ITERATION) {
+        mp_obj_deque_append(self_in, item);
+    }
+    return mp_const_none;
+}
+static MP_DEFINE_CONST_FUN_OBJ_2(deque_extend_obj, mp_obj_deque_extend);
+
 static mp_obj_t deque_popleft(mp_obj_t self_in) {
     mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
 
@@ -135,6 +178,51 @@ static mp_obj_t deque_popleft(mp_obj_t self_in) {
 }
 static MP_DEFINE_CONST_FUN_OBJ_1(deque_popleft_obj, deque_popleft);
 
+static mp_obj_t deque_pop(mp_obj_t self_in) {
+    mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
+
+    if (self->i_get == self->i_put) {
+        mp_raise_msg(&mp_type_IndexError, MP_ERROR_TEXT("empty"));
+    }
+
+    if (self->i_put == 0) {
+        self->i_put = self->alloc - 1;
+    } else {
+        self->i_put--;
+    }
+
+    mp_obj_t ret = self->items[self->i_put];
+    self->items[self->i_put] = MP_OBJ_NULL;
+
+    return ret;
+}
+static MP_DEFINE_CONST_FUN_OBJ_1(deque_pop_obj, deque_pop);
+
+#if MICROPY_PY_COLLECTIONS_DEQUE_SUBSCR
+static mp_obj_t deque_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
+    if (value == MP_OBJ_NULL) {
+        // delete not supported, fall back to mp_obj_subscr() error message
+        return MP_OBJ_NULL;
+    }
+    mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
+
+    size_t offset = mp_get_index(self->base.type, deque_len(self), index, false);
+    size_t index_val = self->i_get + offset;
+    if (index_val > self->alloc) {
+        index_val -= self->alloc;
+    }
+
+    if (value == MP_OBJ_SENTINEL) {
+        // load
+        return self->items[index_val];
+    } else {
+        // store into deque
+        self->items[index_val] = value;
+        return mp_const_none;
+    }
+}
+#endif
+
 #if 0
 static mp_obj_t deque_clear(mp_obj_t self_in) {
     mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
@@ -147,21 +235,80 @@ static MP_DEFINE_CONST_FUN_OBJ_1(deque_clear_obj, deque_clear);
 
 static const mp_rom_map_elem_t deque_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_append), MP_ROM_PTR(&deque_append_obj) },
+    { MP_ROM_QSTR(MP_QSTR_appendleft), MP_ROM_PTR(&deque_appendleft_obj) },
+    { MP_ROM_QSTR(MP_QSTR_extend), MP_ROM_PTR(&deque_extend_obj) },
     #if 0
     { MP_ROM_QSTR(MP_QSTR_clear), MP_ROM_PTR(&deque_clear_obj) },
     #endif
+    { MP_ROM_QSTR(MP_QSTR_pop), MP_ROM_PTR(&deque_pop_obj) },
     { MP_ROM_QSTR(MP_QSTR_popleft), MP_ROM_PTR(&deque_popleft_obj) },
 };
 
 static MP_DEFINE_CONST_DICT(deque_locals_dict, deque_locals_dict_table);
 
+#if MICROPY_PY_COLLECTIONS_DEQUE_ITER
+#define DEQUE_TYPE_FLAGS MP_TYPE_FLAG_ITER_IS_GETITER
+#define DEQUE_TYPE_ITER iter, mp_obj_new_deque_it,
+#else
+#define DEQUE_TYPE_FLAGS MP_TYPE_FLAG_NONE
+#define DEQUE_TYPE_ITER
+#endif
+
+#if MICROPY_PY_COLLECTIONS_DEQUE_SUBSCR
+#define DEQUE_TYPE_SUBSCR subscr, deque_subscr,
+#else
+#define DEQUE_TYPE_SUBSCR
+#endif
+
 MP_DEFINE_CONST_OBJ_TYPE(
     mp_type_deque,
     MP_QSTR_deque,
-    MP_TYPE_FLAG_NONE,
+    MP_TYPE_FLAG_ITER_IS_GETITER,
     make_new, deque_make_new,
     unary_op, deque_unary_op,
+    DEQUE_TYPE_SUBSCR
+    DEQUE_TYPE_ITER
     locals_dict, &deque_locals_dict
     );
 
+/******************************************************************************/
+/* deque iterator                                                             */
+
+#if MICROPY_PY_COLLECTIONS_DEQUE_ITER
+
+typedef struct _mp_obj_deque_it_t {
+    mp_obj_base_t base;
+    mp_fun_1_t iternext;
+    mp_obj_t deque;
+    size_t cur;
+} mp_obj_deque_it_t;
+
+static mp_obj_t deque_it_iternext(mp_obj_t self_in) {
+    mp_obj_deque_it_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_obj_deque_t *deque = MP_OBJ_TO_PTR(self->deque);
+    if (self->cur != deque->i_put) {
+        mp_obj_t o_out = deque->items[self->cur];
+        if (++self->cur == deque->alloc) {
+            self->cur = 0;
+        }
+        return o_out;
+    } else {
+        return MP_OBJ_STOP_ITERATION;
+    }
+}
+
+static mp_obj_t mp_obj_new_deque_it(mp_obj_t deque, mp_obj_iter_buf_t *iter_buf) {
+    mp_obj_deque_t *deque_ = MP_OBJ_TO_PTR(deque);
+    size_t i_get = deque_->i_get;
+    assert(sizeof(mp_obj_deque_it_t) <= sizeof(mp_obj_iter_buf_t));
+    mp_obj_deque_it_t *o = (mp_obj_deque_it_t *)iter_buf;
+    o->base.type = &mp_type_polymorph_iter;
+    o->iternext = deque_it_iternext;
+    o->deque = deque;
+    o->cur = i_get;
+    return MP_OBJ_FROM_PTR(o);
+}
+
+#endif
+
 #endif // MICROPY_PY_COLLECTIONS_DEQUE

tests/basics/deque1.py

@@ -63,3 +63,52 @@ try:
     ~d
 except TypeError:
     print("TypeError")
+
+
+# Same tests, but now with pop() and appendleft()
+
+d = deque((), 2)
+print(len(d))
+print(bool(d))
+
+try:
+    d.popleft()
+except IndexError:
+    print("IndexError")
+
+print(d.append(1))
+print(len(d))
+print(bool(d))
+print(d.popleft())
+print(len(d))
+
+d.append(2)
+print(d.popleft())
+
+d.append(3)
+d.append(4)
+print(len(d))
+print(d.popleft(), d.popleft())
+try:
+    d.popleft()
+except IndexError:
+    print("IndexError")
+
+d.append(5)
+d.append(6)
+d.append(7)
+print(len(d))
+print(d.popleft(), d.popleft())
+print(len(d))
+try:
+    d.popleft()
+except IndexError:
+    print("IndexError")
+
+d = deque((), 2)
+d.appendleft(1)
+d.appendleft(2)
+d.appendleft(3)
+d.appendleft(4)
+d.appendleft(5)
+print(d.pop(), d.pop())

tests/basics/deque2.py

@@ -6,18 +6,50 @@ except ImportError:
     print("SKIP")
     raise SystemExit
 
+# Initial sequence is supported
+d = deque([1, 2, 3], 10)
+
+# iteration over sequence
+for x in d:
+    print(x)
+
+# Iterables larger than maxlen have the beginnings removed, also tests
+# iteration through conversion to list
+d = deque([1, 2, 3, 4, 5], 3)
+print(list(d))
+
+# Empty iterables are also supported
+deque([], 10)
+
+# Extending deques with iterables
+d.extend([6, 7])
+print(list(d))
+
+# Accessing queue elements via index
+d = deque((0, 1, 2, 3), 5)
+print(d[0], d[1], d[-1])
+
+# Writing queue elements via index
+d[3] = 5
+print(d[3])
+
+# Accessing indices out of bounds raises IndexError
+try:
+    d[4]
+except IndexError:
+    print("IndexError")
 
-# Initial sequence is not supported
 try:
-    deque([1, 2, 3], 10)
-except ValueError:
-    print("ValueError")
+    d[4] = 0
+except IndexError:
+    print("IndexError")
 
-# Not even empty list, only empty tuple
+# Removing elements with del is not supported, fall back on mp_obj_subscr() error message
 try:
-    deque([], 10)
-except ValueError:
-    print("ValueError")
+    del d[0]
+except TypeError:
+    print("TypeError")
+
 
 # Only fixed-size deques are supported, so length arg is mandatory
 try:
@@ -32,6 +64,11 @@ try:
 except IndexError:
     print("IndexError")
 
+try:
+    d.pop()
+except IndexError:
+    print("IndexError")
+
 print(d.append(1))
 print(d.popleft())
 
@@ -46,6 +83,11 @@ try:
 except IndexError as e:
     print(repr(e))
 
+try:
+    d.pop()
+except IndexError as e:
+    print(repr(e))
+
 d.append(5)
 d.append(6)
 print(len(d))
@@ -53,6 +95,12 @@ try:
     d.append(7)
 except IndexError as e:
     print(repr(e))
+
+try:
+    d.appendleft(8)
+except IndexError as e:
+    print(repr(e))
+
 print(len(d))
 
 print(d.popleft(), d.popleft())

tests/basics/deque2.py.exp

@@ -1,14 +1,25 @@
-ValueError
-ValueError
+1
+2
+3
+[3, 4, 5]
+[5, 6, 7]
+0 1 3
+5
+IndexError
+IndexError
 TypeError
+TypeError
+IndexError
 IndexError
 None
 1
 2
 3 4
 IndexError('empty',)
+IndexError('empty',)
 2
 IndexError('full',)
+IndexError('full',)
 2
 5 6
 0

tests/basics/deque_slice.py

@@ -0,0 +1,29 @@
+try:
+    from collections import deque
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+d = deque((), 10)
+
+d.append(1)
+d.append(2)
+d.append(3)
+
+# Index slicing for reads is not supported in CPython
+try:
+    d[0:1]
+except TypeError:
+    print("TypeError")
+
+# Index slicing for writes is not supported in CPython
+try:
+    d[0:1] = (-1, -2)
+except TypeError:
+    print("TypeError")
+
+# Index slicing for writes is not supported in CPython
+try:
+    del d[0:1]
+except TypeError:
+    print("TypeError")