Changeset 600f5d1 in mainline for uspace/app/bithenge/transform.c

Timestamp:

2012-06-27T20:10:30Z (13 years ago)

Author:

Sean Bartell <wingedtachikoma@…>

Branches:

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

Children:

02dcb20

Parents:

978ccaf1

Message:

Bithenge: add composition, ascii, and zero_terminated

File:

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

uspace/app/bithenge/transform.c

@@ -61 +61 @@
 }
 
+static int ascii_apply(bithenge_transform_t *self,
+    bithenge_node_t *in, bithenge_node_t **out)
+{
+        int rc;
+        if (bithenge_node_type(in) != BITHENGE_NODE_BLOB)
+                return EINVAL;
+        bithenge_blob_t *blob = bithenge_node_as_blob(in);
+        aoff64_t size;
+        rc = bithenge_blob_size(blob, &size);
+        if (rc != EOK)
+                return rc;
+
+        char *buffer = malloc(size + 1);
+        if (!buffer)
+                return ENOMEM;
+        aoff64_t size_read = size;
+        rc = bithenge_blob_read(blob, 0, buffer, &size_read);
+        if (rc != EOK) {
+                free(buffer);
+                return rc;
+        }
+        if (size_read != size) {
+                free(buffer);
+                return EINVAL;
+        }
+        buffer[size] = '\0';
+
+        /* TODO: what if the OS encoding is incompatible with ASCII? */
+        return bithenge_new_string_node(out, buffer, true);
+}
+
+static const bithenge_transform_ops_t ascii_ops = {
+        .apply = ascii_apply,
+        .destroy = transform_indestructible,
+};
+
+/** The ASCII text transform. */
+bithenge_transform_t bithenge_ascii_transform = {
+        &ascii_ops, 1
+};
+
 static int uint32le_apply(bithenge_transform_t *self, bithenge_node_t *in,
     bithenge_node_t **out)
@@ -130 +171 @@
 };
 
+static int zero_terminated_apply(bithenge_transform_t *self,
+    bithenge_node_t *in, bithenge_node_t **out)
+{
+        int rc;
+        if (bithenge_node_type(in) != BITHENGE_NODE_BLOB)
+                return EINVAL;
+        bithenge_blob_t *blob = bithenge_node_as_blob(in);
+        aoff64_t size;
+        rc = bithenge_blob_size(blob, &size);
+        if (rc != EOK)
+                return rc;
+        if (size < 1)
+                return EINVAL;
+        char ch;
+        aoff64_t size_read = 1;
+        rc = bithenge_blob_read(blob, size - 1, &ch, &size_read);
+        if (rc != EOK)
+                return rc;
+        if (size_read != 1 || ch != '\0')
+                return EINVAL;
+        bithenge_blob_inc_ref(blob);
+        return bithenge_new_subblob(out, blob, 0, size - 1);
+}
+
+static int zero_terminated_prefix_length(bithenge_transform_t *self,
+    bithenge_blob_t *blob, aoff64_t *out)
+{
+        int rc;
+        char buffer[4096];
+        aoff64_t offset = 0, size_read = sizeof(buffer);
+        do {
+                rc = bithenge_blob_read(blob, offset, buffer, &size_read);
+                if (rc != EOK)
+                        return rc;
+                char *found = memchr(buffer, '\0', size_read);
+                if (found) {
+                        *out = found - buffer + offset + 1;
+                        return EOK;
+                }
+                offset += size_read;
+        } while (size_read == sizeof(buffer));
+        return EINVAL;
+}
+
+static const bithenge_transform_ops_t zero_terminated_ops = {
+        .apply = zero_terminated_apply,
+        .prefix_length = zero_terminated_prefix_length,
+        .destroy = transform_indestructible,
+};
+
+/** The zero-terminated data transform. */
+bithenge_transform_t bithenge_zero_terminated_transform = {
+        &zero_terminated_ops, 1
+};
+
 static bithenge_named_transform_t primitive_transforms[] = {
+        {"ascii", &bithenge_ascii_transform},
         {"uint32le", &bithenge_uint32le_transform},
         {"uint32be", &bithenge_uint32be_transform},
+        {"zero_terminated", &bithenge_zero_terminated_transform},
         {NULL, NULL}
 };
@@ -367 +465 @@
 {
         int rc;
-        struct_transform_t *self =
-            malloc(sizeof(*self));
+        struct_transform_t *self = malloc(sizeof(*self));
         if (!self) {
                 rc = ENOMEM;
@@ -386 +483 @@
 }
 
+typedef struct {
+        bithenge_transform_t base;
+        bithenge_transform_t **xforms;
+        size_t num;
+} compose_transform_t;
+
+static bithenge_transform_t *compose_as_transform(compose_transform_t *xform)
+{
+        return &xform->base;
+}
+
+static compose_transform_t *transform_as_compose(bithenge_transform_t *xform)
+{
+        return (compose_transform_t *)xform;
+}
+
+static int compose_apply(bithenge_transform_t *base, bithenge_node_t *in,
+    bithenge_node_t **out)
+{
+        int rc;
+        compose_transform_t *self = transform_as_compose(base);
+        bithenge_node_inc_ref(in);
+
+        /* i ranges from (self->num - 1) to 0 inside the loop. */
+        for (size_t i = self->num; i--; ) {
+                bithenge_node_t *tmp;
+                rc = bithenge_transform_apply(self->xforms[i], in, &tmp);
+                bithenge_node_dec_ref(in);
+                if (rc != EOK)
+                        return rc;
+                in = tmp;
+        }
+
+        *out = in;
+        return rc;
+}
+
+static int compose_prefix_length(bithenge_transform_t *base,
+    bithenge_blob_t *blob, aoff64_t *out)
+{
+        compose_transform_t *self = transform_as_compose(base);
+        return bithenge_transform_prefix_length(self->xforms[self->num - 1],
+            blob, out);
+}
+
+static void compose_destroy(bithenge_transform_t *base)
+{
+        compose_transform_t *self = transform_as_compose(base);
+        for (size_t i = 0; i < self->num; i++)
+                bithenge_transform_dec_ref(self->xforms[i]);
+        free(self->xforms);
+        free(self);
+}
+
+static const bithenge_transform_ops_t compose_transform_ops = {
+        .apply = compose_apply,
+        .prefix_length = compose_prefix_length,
+        .destroy = compose_destroy,
+};
+
+/** Create a composition of multiple transforms. When the result is applied to a
+ * node, each transform is applied in turn, with the last transform applied
+ * first. @a xforms may contain any number of transforms or no transforms at
+ * all. This function takes ownership of @a xforms and the references therein.
+ * @param[out] out Holds the result.
+ * @param[in] xforms The transforms to apply.
+ * @param num The number of transforms.
+ * @return EOK on success or an error code from errno.h. */
+int bithenge_new_composed_transform(bithenge_transform_t **out,
+    bithenge_transform_t **xforms, size_t num)
+{
+        if (num == 0) {
+                /* TODO: optimize */
+        } else if (num == 1) {
+                *out = xforms[0];
+                free(xforms);
+                return EOK;
+        }
+
+        int rc;
+        compose_transform_t *self = malloc(sizeof(*self));
+        if (!self) {
+                rc = ENOMEM;
+                goto error;
+        }
+        rc = bithenge_init_transform(compose_as_transform(self),
+            &compose_transform_ops);
+        if (rc != EOK)
+                goto error;
+        self->xforms = xforms;
+        self->num = num;
+        *out = compose_as_transform(self);
+        return EOK;
+error:
+        for (size_t i = 0; i < num; i++)
+                bithenge_transform_dec_ref(xforms[i]);
+        free(xforms);
+        free(self);
+        return rc;
+}
+
 /** @}
  */