| 1 | /*
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| 2 | * Copyright (c) 2012 Sean Bartell
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | /** @addtogroup bithenge
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| 30 | * @{
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| 31 | */
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| 32 | /**
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| 33 | * @file
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| 34 | * Transforms.
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| 35 | */
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| 36 |
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| 37 | #ifndef BITHENGE_TRANSFORM_H_
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| 38 | #define BITHENGE_TRANSFORM_H_
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| 39 |
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| 40 | #include "blob.h"
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| 41 | #include "tree.h"
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| 42 |
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| 43 | /** A transform that creates a new tree from an old tree. */
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| 44 | typedef struct {
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| 45 | /** @privatesection */
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| 46 | const struct bithenge_transform_ops *ops;
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| 47 | unsigned int refs;
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| 48 | int num_params;
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| 49 | } bithenge_transform_t;
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| 50 |
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| 51 | /** Context and parameters used when applying transforms. */
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| 52 | typedef struct {
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| 53 | /** @privatesection */
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| 54 | int num_params;
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| 55 | bithenge_node_t **params;
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| 56 | bithenge_node_t *current_node;
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| 57 | } bithenge_scope_t;
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| 58 |
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| 59 | /** Operations that may be provided by a transform. All transforms must provide
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| 60 | * apply and/or prefix_apply. To be used in struct transforms and repeat
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| 61 | * transforms, transforms must provide prefix_length and/or prefix_apply. */
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| 62 | typedef struct bithenge_transform_ops {
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| 63 | /** @copydoc bithenge_transform_t::bithenge_transform_apply */
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| 64 | int (*apply)(bithenge_transform_t *self, bithenge_scope_t *scope,
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| 65 | bithenge_node_t *in, bithenge_node_t **out);
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| 66 | /** @copydoc bithenge_transform_t::bithenge_transform_prefix_length */
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| 67 | int (*prefix_length)(bithenge_transform_t *self,
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| 68 | bithenge_scope_t *scope, bithenge_blob_t *blob, aoff64_t *out);
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| 69 | /** @copydoc bithenge_transform_t::bithenge_transform_prefix_apply */
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| 70 | int (*prefix_apply)(bithenge_transform_t *self,
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| 71 | bithenge_scope_t *scope, bithenge_blob_t *blob,
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| 72 | bithenge_node_t **out_node, aoff64_t *out_size);
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| 73 | /** Destroy the transform.
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| 74 | * @param self The transform. */
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| 75 | void (*destroy)(bithenge_transform_t *self);
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| 76 | } bithenge_transform_ops_t;
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| 77 |
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| 78 | /** Get the number of parameters required by a transform. This number is used
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| 79 | * by the parser and param-wrapper. Takes ownership of nothing.
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| 80 | * @param self The transform.
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| 81 | * @return The number of parameters required. */
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| 82 | static inline int bithenge_transform_num_params(bithenge_transform_t *self)
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| 83 | {
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| 84 | assert(self);
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| 85 | return self->num_params;
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| 86 | }
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| 87 |
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| 88 | /** Increment a transform's reference count.
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| 89 | * @param self The transform to reference. */
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| 90 | static inline void bithenge_transform_inc_ref(bithenge_transform_t *self)
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| 91 | {
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| 92 | assert(self);
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| 93 | self->refs++;
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| 94 | }
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| 95 |
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| 96 | /** Decrement a transform's reference count and free it if appropriate.
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| 97 | * @param self The transform to dereference, or NULL. */
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| 98 | static inline void bithenge_transform_dec_ref(bithenge_transform_t *self)
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| 99 | {
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| 100 | if (!self)
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| 101 | return;
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| 102 | assert(self->ops);
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| 103 | if (--self->refs == 0)
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| 104 | self->ops->destroy(self);
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| 105 | }
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| 106 |
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| 107 | /** A transform with a name. */
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| 108 | typedef struct {
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| 109 | const char *name;
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| 110 | bithenge_transform_t *transform;
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| 111 | } bithenge_named_transform_t;
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| 112 |
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| 113 | extern bithenge_transform_t bithenge_ascii_transform;
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| 114 | extern bithenge_transform_t bithenge_invalid_transform;
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| 115 | extern bithenge_transform_t bithenge_known_length_transform;
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| 116 | extern bithenge_transform_t bithenge_nonzero_boolean_transform;
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| 117 | extern bithenge_transform_t bithenge_uint8_transform;
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| 118 | extern bithenge_transform_t bithenge_uint16le_transform;
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| 119 | extern bithenge_transform_t bithenge_uint16be_transform;
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| 120 | extern bithenge_transform_t bithenge_uint32le_transform;
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| 121 | extern bithenge_transform_t bithenge_uint32be_transform;
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| 122 | extern bithenge_transform_t bithenge_uint64le_transform;
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| 123 | extern bithenge_transform_t bithenge_uint64be_transform;
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| 124 | extern bithenge_transform_t bithenge_zero_terminated_transform;
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| 125 | extern bithenge_named_transform_t *bithenge_primitive_transforms;
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| 126 |
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| 127 | int bithenge_init_transform(bithenge_transform_t *,
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| 128 | const bithenge_transform_ops_t *, int);
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| 129 | int bithenge_transform_apply(bithenge_transform_t *, bithenge_scope_t *,
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| 130 | bithenge_node_t *, bithenge_node_t **);
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| 131 | int bithenge_transform_prefix_length(bithenge_transform_t *,
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| 132 | bithenge_scope_t *, bithenge_blob_t *, aoff64_t *);
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| 133 | int bithenge_transform_prefix_apply(bithenge_transform_t *, bithenge_scope_t *,
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| 134 | bithenge_blob_t *, bithenge_node_t **, aoff64_t *);
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| 135 | int bithenge_new_scope_transform(bithenge_transform_t **,
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| 136 | bithenge_transform_t *, int);
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| 137 | int bithenge_new_composed_transform(bithenge_transform_t **,
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| 138 | bithenge_transform_t **, size_t);
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| 139 |
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| 140 | void bithenge_scope_init(bithenge_scope_t *);
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| 141 | void bithenge_scope_destroy(bithenge_scope_t *);
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| 142 | int bithenge_scope_copy(bithenge_scope_t *, bithenge_scope_t *);
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| 143 | void bithenge_scope_set_current_node(bithenge_scope_t *, bithenge_node_t *);
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| 144 | bithenge_node_t *bithenge_scope_get_current_node(bithenge_scope_t *);
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| 145 | int bithenge_scope_alloc_params(bithenge_scope_t *, int);
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| 146 | int bithenge_scope_set_param(bithenge_scope_t *, int, bithenge_node_t *);
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| 147 | int bithenge_scope_get_param(bithenge_scope_t *, int, bithenge_node_t **);
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| 148 |
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| 149 | #endif
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| 150 |
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| 151 | /** @}
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| 152 | */
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