Changeset 4056ad0 in mainline for uspace/app/bithenge/transform.c

Timestamp:

2012-07-28T01:57:31Z (12 years ago)

Author:

Sean Bartell <wingedtachikoma@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

32eb01b

Parents:

03cad47

Message:

Bithenge: basic parameter passing (integer literals only)

File:

• uspace/app/bithenge/transform.c (modified) (4 diffs)

uspace/app/bithenge/transform.c

@@ -47 +47 @@
  * transform will get its own context with parameters, probably provided by a
  * param_wrapper. If this is zero, the existing outer context will be used with
- * whatever parameters it has.
+ * whatever parameters it has, so they can be passed to any param_wrappers
+ * within.
  * @return EOK or an error code from errno.h. */
 int bithenge_init_transform(bithenge_transform_t *self,
@@ -64 +65 @@
 {
         assert(false);
+}
+
+typedef struct {
+        bithenge_transform_t base;
+        bithenge_transform_t *transform;
+} param_transform_t;
+
+static inline param_transform_t *transform_as_param(
+    bithenge_transform_t *base)
+{
+        return (param_transform_t *)base;
+}
+
+static inline bithenge_transform_t *param_as_transform(
+    param_transform_t *self)
+{
+        return &self->base;
+}
+
+static int param_transform_apply(bithenge_transform_t *base,
+    bithenge_scope_t *scope, bithenge_node_t *in, bithenge_node_t **out)
+{
+        param_transform_t *self = transform_as_param(base);
+        return bithenge_transform_apply(self->transform, scope, in, out);
+}
+
+static int param_transform_prefix_length(bithenge_transform_t *base,
+    bithenge_scope_t *scope, bithenge_blob_t *in, aoff64_t *out)
+{
+        param_transform_t *self = transform_as_param(base);
+        return bithenge_transform_prefix_length(self->transform, scope, in,
+            out);
+}
+
+static void param_transform_destroy(bithenge_transform_t *base)
+{
+        param_transform_t *self = transform_as_param(base);
+        bithenge_transform_dec_ref(self->transform);
+        free(self);
+}
+
+static const bithenge_transform_ops_t param_transform_ops = {
+        .apply = param_transform_apply,
+        .prefix_length = param_transform_prefix_length,
+        .destroy = param_transform_destroy,
+};
+
+/** Create a wrapper transform with a different number of parameters. Takes a
+ * reference to @a transform, which it will use for all operations.
+ * @param[out] out Holds the created transform.
+ * @param transform The transform to wrap.
+ * @param num_params The number of parameters to require.
+ * @return EOK on success or an error code from errno.h. */
+int bithenge_new_param_transform(bithenge_transform_t **out,
+    bithenge_transform_t *transform, int num_params)
+{
+        assert(transform);
+        assert(bithenge_transform_num_params(transform) == 0);
+        assert(num_params != 0);
+
+        int rc;
+        param_transform_t *self = malloc(sizeof(*self));
+        if (!self) {
+                rc = ENOMEM;
+                goto error;
+        }
+        rc = bithenge_init_transform(param_as_transform(self),
+            &param_transform_ops, num_params);
+        if (rc != EOK)
+                goto error;
+        self->transform = transform;
+        *out = param_as_transform(self);
+        return EOK;
+error:
+        bithenge_transform_dec_ref(transform);
+        free(self);
+        return rc;
 }
 
@@ -105 +183 @@
 bithenge_transform_t bithenge_ascii_transform = {
         &ascii_ops, 1, 0
+};
+
+static int known_length_apply(bithenge_transform_t *self,
+    bithenge_scope_t *scope, bithenge_node_t *in, bithenge_node_t **out)
+{
+        bithenge_node_t *length_node;
+        int rc = bithenge_scope_get_param(scope, 0, &length_node);
+        if (rc != EOK)
+                return rc;
+        if (bithenge_node_type(length_node) != BITHENGE_NODE_INTEGER) {
+                bithenge_node_dec_ref(length_node);
+                return EINVAL;
+        }
+        bithenge_int_t length = bithenge_integer_node_value(length_node);
+        bithenge_node_dec_ref(length_node);
+
+        if (bithenge_node_type(in) != BITHENGE_NODE_BLOB)
+                return EINVAL;
+        aoff64_t size;
+        rc = bithenge_blob_size(bithenge_node_as_blob(in), &size);
+        if (rc != EOK)
+                return rc;
+        if (length != (bithenge_int_t)size)
+                return EINVAL;
+
+        bithenge_node_inc_ref(in);
+        *out = in;
+        return EOK;
+}
+
+static int known_length_prefix_length(bithenge_transform_t *self,
+    bithenge_scope_t *scope, bithenge_blob_t *in, aoff64_t *out)
+{
+        bithenge_node_t *length_node;
+        int rc = bithenge_scope_get_param(scope, 0, &length_node);
+        if (rc != EOK)
+                return rc;
+        if (bithenge_node_type(length_node) != BITHENGE_NODE_INTEGER) {
+                bithenge_node_dec_ref(length_node);
+                return EINVAL;
+        }
+        bithenge_int_t length = bithenge_integer_node_value(length_node);
+        bithenge_node_dec_ref(length_node);
+
+        *out = (aoff64_t)length;
+        return EOK;
+}
+
+static const bithenge_transform_ops_t known_length_ops = {
+        .apply = known_length_apply,
+        .prefix_length = known_length_prefix_length,
+        .destroy = transform_indestructible,
+};
+
+/** Pass through a blob, but require its length to equal the first argument. */
+bithenge_transform_t bithenge_known_length_transform = {
+        &known_length_ops, 1, 1
 };
 
@@ -232 +367 @@
 static bithenge_named_transform_t primitive_transforms[] = {
         {"ascii", &bithenge_ascii_transform},
+        {"known_length", &bithenge_known_length_transform},
         {"uint8", &bithenge_uint8_transform},
         {"uint16le", &bithenge_uint16le_transform},