source: mainline/uspace/app/bithenge/transform.c@ 43788b2

/*
 * Copyright (c) 2012 Sean Bartell
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup bithenge
 * @{
 */
/**
 * @file
 * Transforms.
 */

#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include "blob.h"
#include "transform.h"

/** Initialize a new transform.
 * @param[out] self Transform to initialize.
 * @param[in] ops Operations provided by the transform.
 * @return EOK or an error code from errno.h. */
int bithenge_init_transform(bithenge_transform_t *self,
    const bithenge_transform_ops_t *ops)
{
        assert(ops);
        assert(ops->apply);
        assert(ops->destroy);
        self->ops = ops;
        self->refs = 1;
        return EOK;
}

static void transform_indestructible(bithenge_transform_t *self)
{
        assert(false);
}

static int ascii_apply(bithenge_transform_t *self,
    bithenge_transform_context_t *context, 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 prefix_length_1(bithenge_transform_t *self,
    bithenge_transform_context_t *context, bithenge_blob_t *blob,
    aoff64_t *out)
{
        *out = 1;
        return EOK;
}

static int prefix_length_2(bithenge_transform_t *self,
    bithenge_transform_context_t *context, bithenge_blob_t *blob,
    aoff64_t *out)
{
        *out = 2;
        return EOK;
}

static int prefix_length_4(bithenge_transform_t *self,
    bithenge_transform_context_t *context, bithenge_blob_t *blob,
    aoff64_t *out)
{
        *out = 4;
        return EOK;
}

static int prefix_length_8(bithenge_transform_t *self,
    bithenge_transform_context_t *context, bithenge_blob_t *blob,
    aoff64_t *out)
{
        *out = 8;
        return EOK;
}

#define MAKE_UINT_TRANSFORM(NAME, TYPE, ENDIAN, PREFIX_LENGTH_FUNC)            \
        static int NAME##_apply(bithenge_transform_t *self,                    \
            bithenge_transform_context_t *context, 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);             \
                                                                               \
                /* Read too many bytes; success means the blob is too long. */ \
                TYPE val[2];                                                   \
                aoff64_t size = sizeof(val[0]) + 1;                            \
                rc = bithenge_blob_read(blob, 0, (char *)val, &size);          \
                if (rc != EOK)                                                 \
                        return rc;                                             \
                if (size != sizeof(val[0]))                                    \
                        return EINVAL;                                         \
                                                                               \
                return bithenge_new_integer_node(out, ENDIAN(val[0]));         \
        }                                                                      \
                                                                               \
        static const bithenge_transform_ops_t NAME##_ops = {                   \
                .apply = NAME##_apply,                                         \
                .prefix_length = PREFIX_LENGTH_FUNC,                           \
                .destroy = transform_indestructible,                           \
        };                                                                     \
                                                                               \
        bithenge_transform_t bithenge_##NAME##_transform = {                   \
                &NAME##_ops, 1                                                 \
        }

MAKE_UINT_TRANSFORM(uint8   , uint8_t ,                 , prefix_length_1);
MAKE_UINT_TRANSFORM(uint16le, uint16_t, uint16_t_le2host, prefix_length_2);
MAKE_UINT_TRANSFORM(uint16be, uint16_t, uint16_t_be2host, prefix_length_2);
MAKE_UINT_TRANSFORM(uint32le, uint32_t, uint32_t_le2host, prefix_length_4);
MAKE_UINT_TRANSFORM(uint32be, uint32_t, uint32_t_be2host, prefix_length_4);
MAKE_UINT_TRANSFORM(uint64le, uint64_t, uint32_t_le2host, prefix_length_8);
MAKE_UINT_TRANSFORM(uint64be, uint64_t, uint32_t_be2host, prefix_length_8);

static int zero_terminated_apply(bithenge_transform_t *self,
    bithenge_transform_context_t *context, 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_transform_context_t *context, 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},
        {"uint8", &bithenge_uint8_transform},
        {"uint16le", &bithenge_uint16le_transform},
        {"uint16be", &bithenge_uint16be_transform},
        {"uint32le", &bithenge_uint32le_transform},
        {"uint32be", &bithenge_uint32be_transform},
        {"uint64le", &bithenge_uint64le_transform},
        {"uint64be", &bithenge_uint64be_transform},
        {"zero_terminated", &bithenge_zero_terminated_transform},
        {NULL, NULL}
};

/** An array of named built-in transforms. */
bithenge_named_transform_t *bithenge_primitive_transforms = primitive_transforms;

typedef struct {
        bithenge_node_t base;
        struct struct_transform *transform;
        bithenge_transform_context_t *context;
        bithenge_blob_t *blob;
} struct_node_t;

typedef struct struct_transform {
        bithenge_transform_t base;
        bithenge_named_transform_t *subtransforms;
} struct_transform_t;

static bithenge_node_t *struct_as_node(struct_node_t *node)
{
        return &node->base;
}

static struct_node_t *node_as_struct(bithenge_node_t *node)
{
        return (struct_node_t *)node;
}

static bithenge_transform_t *struct_as_transform(struct_transform_t *xform)
{
        return &xform->base;
}

static struct_transform_t *transform_as_struct(bithenge_transform_t *xform)
{
        return (struct_transform_t *)xform;
}

static int struct_node_for_one(const char *name,
    bithenge_transform_t *subxform, bithenge_transform_context_t *context,
    bithenge_blob_t **blob, bithenge_for_each_func_t func, void *data)
{
        int rc;
        bithenge_node_t *subxform_result = NULL;

        aoff64_t sub_size;
        rc = bithenge_transform_prefix_length(subxform, context, *blob,
            &sub_size);
        if (rc != EOK)
                goto error;

        bithenge_node_t *subblob_node;
        bithenge_blob_inc_ref(*blob);
        rc = bithenge_new_subblob(&subblob_node, *blob, 0, sub_size);
        if (rc != EOK)
                goto error;

        rc = bithenge_transform_apply(subxform, context, subblob_node,
            &subxform_result);
        bithenge_node_dec_ref(subblob_node);
        if (rc != EOK)
                goto error;

        if (name) {
                bithenge_node_t *name_node;
                rc = bithenge_new_string_node(&name_node, name, false);
                if (rc != EOK)
                        goto error;
                rc = func(name_node, subxform_result, data);
                subxform_result = NULL;
                if (rc != EOK)
                        goto error;
        } else {
                if (bithenge_node_type(subxform_result) !=
                    BITHENGE_NODE_INTERNAL) {
                        rc = EINVAL;
                        goto error;
                }
                rc = bithenge_node_for_each(subxform_result, func, data);
                if (rc != EOK)
                        goto error;
        }

        bithenge_node_t *blob_node;
        rc = bithenge_new_offset_blob(&blob_node, *blob, sub_size);
        *blob = NULL;
        if (rc != EOK)
                goto error;
        *blob = bithenge_node_as_blob(blob_node);

error:
        bithenge_node_dec_ref(subxform_result);
        return rc;
}

static int struct_node_for_each(bithenge_node_t *base,
    bithenge_for_each_func_t func, void *data)
{
        int rc = EOK;
        struct_node_t *struct_node = node_as_struct(base);
        bithenge_named_transform_t *subxforms =
            struct_node->transform->subtransforms;

        bithenge_node_t *blob_node = NULL;
        bithenge_blob_t *blob = NULL;
        bithenge_blob_inc_ref(struct_node->blob);
        rc = bithenge_new_offset_blob(&blob_node, struct_node->blob, 0);
        if (rc != EOK) {
                blob = NULL;
                goto error;
        }
        blob = bithenge_node_as_blob(blob_node);

        for (size_t i = 0; subxforms[i].transform; i++) {
                rc = struct_node_for_one(subxforms[i].name,
                    subxforms[i].transform, struct_node->context, &blob, func,
                    data);
                if (rc != EOK)
                        goto error;
        }

        aoff64_t remaining;
        rc = bithenge_blob_size(blob, &remaining);
        if (rc != EOK)
                goto error;
        if (remaining != 0) {
                rc = EINVAL;
                goto error;
        }

error:
        bithenge_blob_dec_ref(blob);
        return rc;
}

static void struct_node_destroy(bithenge_node_t *base)
{
        struct_node_t *node = node_as_struct(base);
        bithenge_transform_dec_ref(struct_as_transform(node->transform));
        bithenge_blob_dec_ref(node->blob);
        free(node);
}

static const bithenge_internal_node_ops_t struct_node_ops = {
        .for_each = struct_node_for_each,
        .destroy = struct_node_destroy,
};

static int struct_transform_apply(bithenge_transform_t *base,
    bithenge_transform_context_t *context, bithenge_node_t *in,
    bithenge_node_t **out)
{
        struct_transform_t *self = transform_as_struct(base);
        if (bithenge_node_type(in) != BITHENGE_NODE_BLOB)
                return EINVAL;
        struct_node_t *node = malloc(sizeof(*node));
        if (!node)
                return ENOMEM;
        int rc = bithenge_init_internal_node(struct_as_node(node),
            &struct_node_ops);
        if (rc != EOK) {
                free(node);
                return rc;
        }
        bithenge_transform_inc_ref(base);
        node->transform = self;
        bithenge_node_inc_ref(in);
        node->context = context;
        node->blob = bithenge_node_as_blob(in);
        *out = struct_as_node(node);
        return EOK;
}

static int struct_transform_prefix_length(bithenge_transform_t *base,
    bithenge_transform_context_t *context, bithenge_blob_t *blob,
    aoff64_t *out)
{
        struct_transform_t *self = transform_as_struct(base);
        int rc = EOK;
        bithenge_node_t *node;
        bithenge_blob_inc_ref(blob);
        rc = bithenge_new_offset_blob(&node, blob, 0);
        blob = NULL;
        if (rc != EOK)
                goto error;
        blob = bithenge_node_as_blob(node);
        *out = 0;
        for (size_t i = 0; self->subtransforms[i].transform; i++) {
                bithenge_transform_t *subxform =
                    self->subtransforms[i].transform;
                aoff64_t sub_size;
                rc = bithenge_transform_prefix_length(subxform, context, blob,
                    &sub_size);
                if (rc != EOK)
                        goto error;
                *out += sub_size;
                rc = bithenge_new_offset_blob(&node, blob, sub_size);
                blob = NULL;
                if (rc != EOK)
                        goto error;
                blob = bithenge_node_as_blob(node);
        }
error:
        bithenge_blob_dec_ref(blob);
        return EOK;
}

static void free_subtransforms(bithenge_named_transform_t *subtransforms)
{
        for (size_t i = 0; subtransforms[i].transform; i++) {
                free((void *)subtransforms[i].name);
                bithenge_transform_dec_ref(subtransforms[i].transform);
        }
        free(subtransforms);
}

static void struct_transform_destroy(bithenge_transform_t *base)
{
        struct_transform_t *self = transform_as_struct(base);
        free_subtransforms(self->subtransforms);
        free(self);
}

static bithenge_transform_ops_t struct_transform_ops = {
        .apply = struct_transform_apply,
        .prefix_length = struct_transform_prefix_length,
        .destroy = struct_transform_destroy,
};

/** Create a struct transform. The transform will apply its subtransforms
 * sequentially to a blob to create an internal node. Each result is either
 * given a key from @a subtransforms or, if the name is NULL, the result's keys
 * and values are merged into the struct transform's result. This function
 * takes ownership of @a subtransforms and the names and references therein.
 * @param[out] out Stores the created transform.
 * @param subtransforms The subtransforms and field names.
 * @return EOK on success or an error code from errno.h. */
int bithenge_new_struct(bithenge_transform_t **out,
    bithenge_named_transform_t *subtransforms)
{
        int rc;
        struct_transform_t *self = malloc(sizeof(*self));
        if (!self) {
                rc = ENOMEM;
                goto error;
        }
        rc = bithenge_init_transform(struct_as_transform(self),
            &struct_transform_ops);
        if (rc != EOK)
                goto error;
        self->subtransforms = subtransforms;
        *out = struct_as_transform(self);
        return EOK;
error:
        free_subtransforms(subtransforms);
        free(self);
        return rc;
}

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_transform_context_t *context, 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], context, 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_transform_context_t *context, 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],
            context, 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;
}

/** @}
 */