/* Copyright 2011-2020 David Robillard Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /// @file serd.h API for Serd, a lightweight RDF syntax library #ifndef SERD_SERD_H #define SERD_SERD_H #include #include #include #include #include #if defined(_WIN32) && !defined(SERD_STATIC) && defined(SERD_INTERNAL) # define SERD_API __declspec(dllexport) #elif defined(_WIN32) && !defined(SERD_STATIC) # define SERD_API __declspec(dllimport) #elif defined(__GNUC__) # define SERD_API __attribute__((visibility("default"))) #else # define SERD_API #endif #ifdef __GNUC__ # define SERD_PURE_FUNC __attribute__((pure)) # define SERD_CONST_FUNC __attribute__((const)) # define SERD_MALLOC_FUNC __attribute__((malloc)) #else # define SERD_PURE_FUNC # define SERD_CONST_FUNC # define SERD_MALLOC_FUNC #endif #if defined(__clang__) && __clang_major__ >= 7 # define SERD_NONNULL _Nonnull # define SERD_NULLABLE _Nullable # define SERD_ALLOCATED _Null_unspecified #else # define SERD_NONNULL # define SERD_NULLABLE # define SERD_ALLOCATED #endif #define SERD_PURE_API \ SERD_API \ SERD_PURE_FUNC #define SERD_CONST_API \ SERD_API \ SERD_CONST_FUNC #define SERD_MALLOC_API \ SERD_API \ SERD_MALLOC_FUNC #ifdef __cplusplus extern "C" { # if defined(__GNUC__) # pragma GCC diagnostic push # pragma GCC diagnostic ignored "-Wzero-as-null-pointer-constant" # endif #endif /** @defgroup serd Serd C API This is the complete public C API of serd. @{ */ /// Global library state typedef struct SerdWorldImpl SerdWorld; /// A subject, predicate, and object, with optional graph context typedef struct SerdStatementImpl SerdStatement; /// The origin of a statement in a document typedef struct SerdCursorImpl SerdCursor; /// Lexical environment for relative URIs or CURIEs (base URI and namespaces) typedef struct SerdEnvImpl SerdEnv; /// Streaming parser that reads a text stream and writes to a sink typedef struct SerdReaderImpl SerdReader; /// Streaming serialiser that writes a text stream as statements are pushed typedef struct SerdWriterImpl SerdWriter; /// An interface that receives a stream of RDF data typedef struct SerdSinkImpl SerdSink; /// Return status code typedef enum { SERD_SUCCESS, ///< No error SERD_FAILURE, ///< Non-fatal failure SERD_ERR_UNKNOWN, ///< Unknown error SERD_ERR_BAD_SYNTAX, ///< Invalid syntax SERD_ERR_BAD_ARG, ///< Invalid argument SERD_ERR_NOT_FOUND, ///< Not found SERD_ERR_ID_CLASH, ///< Encountered clashing blank node IDs SERD_ERR_BAD_CURIE, ///< Invalid CURIE (e.g. prefix does not exist) SERD_ERR_INTERNAL, ///< Unexpected internal error (should not happen) SERD_ERR_OVERFLOW ///< Stack overflow } SerdStatus; /// RDF syntax type typedef enum { SERD_TURTLE = 1, ///< Terse triples http://www.w3.org/TR/turtle SERD_NTRIPLES = 2, ///< Line-based triples http://www.w3.org/TR/n-triples/ SERD_NQUADS = 3, ///< Line-based quads http://www.w3.org/TR/n-quads/ SERD_TRIG = 4 ///< Terse quads http://www.w3.org/TR/trig/ } SerdSyntax; /// Flags indicating inline abbreviation information for a statement typedef enum { SERD_EMPTY_S = 1u << 1u, ///< Empty blank node subject SERD_EMPTY_O = 1u << 2u, ///< Empty blank node object SERD_ANON_S_BEGIN = 1u << 3u, ///< Start of anonymous subject SERD_ANON_O_BEGIN = 1u << 4u, ///< Start of anonymous object SERD_ANON_CONT = 1u << 5u, ///< Continuation of anonymous node SERD_LIST_S_BEGIN = 1u << 6u, ///< Start of list subject SERD_LIST_O_BEGIN = 1u << 7u, ///< Start of list object SERD_LIST_CONT = 1u << 8u ///< Continuation of list } SerdStatementFlag; /// Bitwise OR of SerdStatementFlag values typedef uint32_t SerdStatementFlags; /** Type of a node. An RDF node, in the abstract sense, can be either a resource, literal, or a blank. This type is more precise, because syntactically there are two ways to refer to a resource (by URI or CURIE). There are also two ways to refer to a blank node in syntax (by ID or anonymously), but this is handled by statement flags rather than distinct node types. */ typedef enum { /** Literal value. A literal optionally has either a language, or a datatype (not both). */ SERD_LITERAL = 1, /** URI (absolute or relative). Value is an unquoted URI string, which is either a relative reference with respect to the current base URI (e.g. "foo/bar"), or an absolute URI (e.g. "http://example.org/foo"). @see [RFC3986](http://tools.ietf.org/html/rfc3986) */ SERD_URI = 2, /** CURIE, a shortened URI. Value is an unquoted CURIE string relative to the current environment, e.g. "rdf:type". @see [CURIE Syntax 1.0](http://www.w3.org/TR/curie) */ SERD_CURIE = 3, /** A blank node. Value is a blank node ID without any syntactic prefix, like "id3", which is meaningful only within this serialisation. @see [RDF 1.1 Turtle](http://www.w3.org/TR/turtle/#grammar-production-BLANK_NODE_LABEL) */ SERD_BLANK = 4 } SerdNodeType; /// Flags indicating certain string properties relevant to serialisation typedef enum { SERD_HAS_NEWLINE = 1u << 0u, ///< Contains line breaks ('\\n' or '\\r') SERD_HAS_QUOTE = 1u << 1u, ///< Contains quotes ('"') SERD_HAS_DATATYPE = 1u << 2u, ///< Literal node has datatype SERD_HAS_LANGUAGE = 1u << 3u ///< Literal node has language } SerdNodeFlag; /// Bitwise OR of SerdNodeFlag values typedef uint32_t SerdNodeFlags; /// Index of a node in a statement typedef enum { SERD_SUBJECT = 0, ///< Subject SERD_PREDICATE = 1, ///< Predicate ("key") SERD_OBJECT = 2, ///< Object ("value") SERD_GRAPH = 3 ///< Graph ("context") } SerdField; /// A syntactic RDF node typedef struct SerdNodeImpl SerdNode; /// An unterminated immutable slice of a string typedef struct { const char* SERD_NULLABLE buf; ///< Start of chunk size_t len; ///< Length of chunk in bytes } SerdStringView; #ifdef __cplusplus # define SERD_EMPTY_STRING(str) \ SerdStringView { "", 0 } # define SERD_STATIC_STRING(str) \ SerdStringView { (str), sizeof(str) - 1 } # define SERD_MEASURE_STRING(str) \ SerdStringView { (str), (str) ? strlen(str) : 0 } # define SERD_STRING_VIEW(str, len) \ SerdStringView { (str), (len) } #else # define SERD_EMPTY_STRING(str) \ (SerdStringView) { "", 0 } # define SERD_STATIC_STRING(str) \ (SerdStringView) { (str), sizeof(str) - 1 } # define SERD_MEASURE_STRING(str) \ (SerdStringView) { (str), (str != NULL) ? strlen(str) : 0 } # define SERD_STRING_VIEW(str, len) \ (SerdStringView) { (str), (len) } #endif /// A mutable buffer in memory typedef struct { void* SERD_NULLABLE buf; ///< Buffer size_t len; ///< Size of buffer in bytes } SerdBuffer; /// An error description typedef struct { SerdStatus status; ///< Error code const SerdCursor* SERD_NULLABLE cursor; ///< Origin of error const char* SERD_NONNULL fmt; ///< Printf-style format string va_list* SERD_NONNULL args; ///< Arguments for fmt } SerdError; /** A parsed URI. This URI representation is designed for fast streaming, it allows creating relative URI references or resolving them into absolute URIs in-place without any string allocation. Each component refers to slices in other strings, so a URI view must outlive any strings it was parsed from. The components are not necessarily null-terminated. The scheme, authority, path, query, and fragment simply point to the string value of those components, not including any delimiters. The path_prefix is a special component for storing relative or resolved paths. If it points to a string (usually a base URI the URI was resolved against), then this string is prepended to the path. Otherwise, the length is interpret as the number of up-references ("../") that must be prepended to the path. */ typedef struct { SerdStringView scheme; ///< Scheme SerdStringView authority; ///< Authority SerdStringView path_prefix; ///< Path prefix for relative/resolved paths SerdStringView path; ///< Path suffix SerdStringView query; ///< Query SerdStringView fragment; ///< Fragment } SerdURIView; /** Writer style options. These flags allow more precise control of writer output style. Note that some options are only supported for some syntaxes, for example, NTriples does not support abbreviation and is always ASCII. */ typedef enum { SERD_WRITE_ABBREVIATED = 1u << 0u, ///< Abbreviate triples when possible SERD_WRITE_ASCII = 1u << 1u, ///< Escape all non-ASCII characters SERD_WRITE_RESOLVED = 1u << 2u, ///< Resolve URIs against base URI SERD_WRITE_CURIED = 1u << 3u, ///< Shorten URIs into CURIEs SERD_WRITE_BULK = 1u << 4u, ///< Write output in pages } SerdWriterFlag; /// Bitwise OR of SerdWriterFlag values typedef uint32_t SerdWriterFlags; /** Free memory allocated by Serd This function exists because some systems require memory allocated by a library to be freed by code in the same library. It is otherwise equivalent to the standard C free() function. */ SERD_API void serd_free(void* SERD_NULLABLE ptr); /** @defgroup serd_string String Utilities @{ */ /// Return a string describing a status code SERD_CONST_API const char* SERD_NONNULL serd_strerror(SerdStatus status); /** Measure a UTF-8 string. @return Length of `str` in bytes. @param str A null-terminated UTF-8 string. @param flags (Output) Set to the applicable flags. */ SERD_API size_t serd_strlen(const char* SERD_NONNULL str, SerdNodeFlags* SERD_NULLABLE flags); /** Decode a base64 string. This function can be used to deserialise a blob node created with serd_new_blob(). @param str Base64 string to decode. @param len The length of `str`. @param size Set to the size of the returned blob in bytes. @return A newly allocated blob which must be freed with serd_free(). */ SERD_API void* SERD_ALLOCATED serd_base64_decode(const char* SERD_NONNULL str, size_t len, size_t* SERD_NONNULL size); /** @} @defgroup serd_streams Byte Streams @{ */ /** Function to detect I/O stream errors. Identical semantics to `ferror`. @return Non-zero if `stream` has encountered an error. */ typedef int (*SerdStreamErrorFunc)(void* SERD_NONNULL stream); /** Source function for raw string input. Identical semantics to `fread`, but may set errno for more informative error reporting than supported by SerdStreamErrorFunc. @param buf Output buffer. @param size Size of a single element of data in bytes (always 1). @param nmemb Number of elements to read. @param stream Stream to read from (FILE* for fread). @return Number of elements (bytes) read, which is short on error. */ typedef size_t (*SerdReadFunc)(void* SERD_NONNULL buf, size_t size, size_t nmemb, void* SERD_NONNULL stream); /** Sink function for raw string output. Identical semantics to `fwrite`, but may set errno for more informative error reporting than supported by SerdStreamErrorFunc. @param buf Input buffer. @param size Size of a single element of data in bytes (always 1). @param nmemb Number of elements to read. @param stream Stream to write to (FILE* for fread). @return Number of elements (bytes) written, which is short on error. */ typedef size_t (*SerdWriteFunc)(const void* SERD_NONNULL buf, size_t size, size_t nmemb, void* SERD_NONNULL stream); /** @} @defgroup serd_syntax Syntax Utilities @{ */ /** Get a syntax by name. Case-insensitive, supports "Turtle", "NTriples", "NQuads", and "TriG". Zero is returned if the name is not recognized. */ SERD_PURE_API SerdSyntax serd_syntax_by_name(const char* SERD_NONNULL name); /** Guess a syntax from a filename. This uses the file extension to guess the syntax of a file. Zero is returned if the extension is not recognized. */ SERD_PURE_API SerdSyntax serd_guess_syntax(const char* SERD_NONNULL filename); /** Return whether a syntax can represent multiple graphs. @return True for SERD_NQUADS and SERD_TRIG, false otherwise. */ SERD_CONST_API bool serd_syntax_has_graphs(SerdSyntax syntax); /** @} @defgroup serd_uri URI @{ */ static const SerdURIView SERD_URI_NULL = {{NULL, 0}, {NULL, 0}, {NULL, 0}, {NULL, 0}, {NULL, 0}, {NULL, 0}}; /// Return true iff `string` starts with a valid URI scheme SERD_PURE_API bool serd_uri_string_has_scheme(const char* SERD_NONNULL string); /// Parse `string` and return a URI view that points into it SERD_API SerdURIView serd_parse_uri(const char* SERD_NONNULL string); /** Get the unescaped path and hostname from a file URI. The returned path and `*hostname` must be freed with serd_free(). @param uri A file URI. @param hostname If non-NULL, set to the hostname, if present. @return A filesystem path. */ SERD_API char* SERD_NULLABLE serd_parse_file_uri(const char* SERD_NONNULL uri, char* SERD_NONNULL* SERD_NULLABLE hostname); /** Return reference `r` resolved against `base`. This will make `r` an absolute URI if possible. @see [RFC3986 5.2.2](http://tools.ietf.org/html/rfc3986#section-5.2.2) @param r URI reference to make absolute, for example "child/path". @param base Base URI, for example "http://example.org/base/". @return An absolute URI, for example "http://example.org/base/child/path", or `r` if it is not a URI reference that can be resolved against `base`. */ SERD_API SerdURIView serd_resolve_uri(SerdURIView r, SerdURIView base); /** Return `r` as a reference relative to `base` if possible. @see [RFC3986 5.2.2](http://tools.ietf.org/html/rfc3986#section-5.2.2) @param r URI to make relative, for example "http://example.org/base/child/path". @param base Base URI, for example "http://example.org/base". @return A relative URI reference, for example "child/path", `r` if it can not be made relative to `base`, or a null URI if `r` could be made relative to base, but the path prefix is already being used (most likely because `r` was previously a relative URI reference that was resolved against some base). */ SERD_API SerdURIView serd_relative_uri(SerdURIView r, SerdURIView base); /** Return whether `r` can be written as a reference relative to `base`. For example, with `base` "http://example.org/base/", this returns true if `r` is also "http://example.org/base/", or something like "http://example.org/base/child" ("child") "http://example.org/base/child/grandchild#fragment" ("child/grandchild#fragment"), "http://example.org/base/child/grandchild?query" ("child/grandchild?query"), and so on. @return True if `r` and `base` are equal or if `r` is a child of `base`. */ SERD_API bool serd_uri_is_within(SerdURIView r, SerdURIView base); /** Write `uri` as a string to `sink`. This will call `sink` several times to emit the serialised URI. @param uri URI to write as a string. @param sink Sink to write string output to. @param stream Opaque user argument to pass to `sink`. @return The number of bytes written. */ SERD_API size_t serd_write_uri(SerdURIView uri, SerdWriteFunc SERD_NONNULL sink, void* SERD_NONNULL stream); /** @} @defgroup serd_node Node @{ */ /** Create a new "simple" node that is just a string. This can be used to create blank, CURIE, or URI nodes from an already measured string or slice of a buffer, which avoids a strlen compared to the friendly constructors. This may not be used for literals since those must be measured to set the SERD_HAS_NEWLINE and SERD_HAS_QUOTE flags. */ SERD_API SerdNode* SERD_ALLOCATED serd_new_simple_node(SerdNodeType type, SerdStringView string); /// Create a new plain literal string node from `str` SERD_API SerdNode* SERD_ALLOCATED serd_new_string(SerdStringView string); /** Create a new literal node from `str`. A plain literal has no datatype, but may have a language tag. The `lang` may be NULL, in which case this is equivalent to `serd_new_string()`. */ SERD_API SerdNode* SERD_ALLOCATED serd_new_plain_literal(SerdStringView str, SerdStringView lang); /** Create a new typed literal node from `str`. A typed literal has no language tag, but may have a datatype. The `datatype` may be NULL, in which case this is equivalent to `serd_new_string()`. */ SERD_API SerdNode* SERD_ALLOCATED serd_new_typed_literal(SerdStringView str, SerdStringView datatype_uri); /// Create a new blank node SERD_API SerdNode* SERD_ALLOCATED serd_new_blank(SerdStringView string); /// Create a new CURIE node SERD_API SerdNode* SERD_ALLOCATED serd_new_curie(SerdStringView string); /// Create a new URI from a string SERD_API SerdNode* SERD_ALLOCATED serd_new_uri(SerdStringView string); /// Create a new URI from a URI view SERD_API SerdNode* SERD_ALLOCATED serd_new_parsed_uri(SerdURIView uri); /** Create a new file URI node from a file system path and optional hostname. Backslashes in Windows paths will be converted, and other characters will be percent encoded as necessary. If `path` is relative, `hostname` is ignored. */ SERD_API SerdNode* SERD_ALLOCATED serd_new_file_uri(SerdStringView path, SerdStringView hostname); /// Create a new node by serialising `b` into an xsd:boolean string SERD_API SerdNode* SERD_ALLOCATED serd_new_boolean(bool b); /** Create a new node by serialising `d` into an xsd:decimal string The resulting node will always contain a `.', start with a digit, and end with a digit (a leading and/or trailing `0` will be added if necessary). It will never be in scientific notation. @param d The value for the new node. @param datatype Datatype of node, or NULL for xsd:decimal. */ SERD_API SerdNode* SERD_ALLOCATED serd_new_decimal(double d, const SerdNode* SERD_NULLABLE datatype); /** Create a new node by serialising `d` into a normalised xsd:double string. The returned node will always be in normalised scientific notation, like "1.23E4", except for NaN and negative/positive infinity, which are "NaN", "-INF", and "INF", respectively. Uses the shortest possible representation that precisely describes `d`, which has at most 17 significant digits (under 24 characters total). @param d Double value to serialise. @return A literal node with datatype xsd:double. */ SERD_API SerdNode* SERD_ALLOCATED serd_new_double(double d); /** Create a new node by serialising `f` into a normalised xsd:float string. Uses identical formatting to serd_new_double(), except with at most 9 significant digits (under 14 characters total). @param f Float value of literal. @return A literal node with datatype xsd:float. */ SERD_API SerdNode* SERD_ALLOCATED serd_new_float(float f); /** Create a new node by writing `i` as an xsd:integer string. @param i Integer value of literal. @param datatype Datatype of node, or NULL for xsd:integer. */ SERD_API SerdNode* SERD_ALLOCATED serd_new_integer(int64_t i, const SerdNode* SERD_NULLABLE datatype); /** Create a node by serialising `buf` into an xsd:base64Binary string This function can be used to make a serialisable node out of arbitrary binary data, which can be decoded using serd_base64_decode(). @param buf Raw binary input data. @param size Size of `buf`. @param datatype Datatype of node, or NULL for xsd:base64Binary. */ SERD_API SerdNode* SERD_ALLOCATED serd_new_blob(const void* SERD_NONNULL buf, size_t size, const SerdNode* SERD_NULLABLE datatype); /** Return the value of `node` as a boolean. This will work for booleans, and numbers of any datatype if they are 0 or 1. @return The value of `node` as a `bool`, or `false` on error. */ SERD_API bool serd_get_boolean(const SerdNode* SERD_NONNULL node); /** Return the value of `node` as a double. This will coerce numbers of any datatype to double, if the value fits. @return The value of `node` as a `double`, or NaN on error. */ SERD_API double serd_get_double(const SerdNode* SERD_NONNULL node); /** Return the value of `node` as a float. This will coerce numbers of any datatype to float, if the value fits. @return The value of `node` as a `float`, or NaN on error. */ SERD_API float serd_get_float(const SerdNode* SERD_NONNULL node); /** Return the value of `node` as a long (signed 64-bit integer). This will coerce numbers of any datatype to long, if the value fits. @return The value of `node` as a `int64_t`, or 0 on error. */ SERD_API int64_t serd_get_integer(const SerdNode* SERD_NONNULL node); /// Return a deep copy of `node` SERD_API SerdNode* SERD_ALLOCATED serd_node_copy(const SerdNode* SERD_NULLABLE node); /// Free any data owned by `node` SERD_API void serd_node_free(SerdNode* SERD_NULLABLE node); /// Return the type of a node (SERD_URI, SERD_BLANK, or SERD_LITERAL) SERD_PURE_API SerdNodeType serd_node_type(const SerdNode* SERD_NONNULL node); /// Return the string value of a node SERD_CONST_API const char* SERD_NONNULL serd_node_string(const SerdNode* SERD_NONNULL node); /// Return the length of the string value of a node in bytes SERD_PURE_API size_t serd_node_length(const SerdNode* SERD_NULLABLE node); /** Return a view of the string in a node. This is a convenience wrapper for serd_node_string() and serd_node_length() that can be used to get both in a single call. */ SERD_PURE_API SerdStringView serd_node_string_view(const SerdNode* SERD_NONNULL node); /** Return a parsed view of the URI in a node. It is best to check the node type before calling this function, though it is safe to call on non-URI nodes. In that case, it will return a null view with all fields zero. Note that this parses the URI string contained in the node, so it is a good idea to keep the value if you will be using it several times in the same scope. */ SERD_API SerdURIView serd_node_uri_view(const SerdNode* SERD_NONNULL node); /// Return the flags (string properties) of a node SERD_PURE_API SerdNodeFlags serd_node_flags(const SerdNode* SERD_NONNULL node); /// Return the datatype of a literal node, or NULL SERD_PURE_API const SerdNode* SERD_NULLABLE serd_node_datatype(const SerdNode* SERD_NONNULL node); /// Return the language tag of a literal node, or NULL SERD_PURE_API const SerdNode* SERD_NULLABLE serd_node_language(const SerdNode* SERD_NONNULL node); /// Return true iff `a` is equal to `b` SERD_PURE_API bool serd_node_equals(const SerdNode* SERD_NULLABLE a, const SerdNode* SERD_NULLABLE b); /** @} @defgroup serd_event Event Handlers @{ */ /** Callback function for errors. @param handle Handle for user data. @param error Error description. */ typedef SerdStatus (*SerdErrorFunc)(void* SERD_NULLABLE handle, const SerdError* SERD_NONNULL error); /// Type of a SerdEvent typedef enum { SERD_BASE = 1, ///< Base URI changed SERD_PREFIX = 2, ///< New URI prefix SERD_STATEMENT = 3, ///< Statement SERD_END = 4 ///< End of anonymous node } SerdEventType; /** Event for base URI changes Emitted whenever the base URI of the serialisation changes. */ typedef struct { SerdEventType type; ///< #SERD_BASE const SerdNode* SERD_NONNULL uri; ///< Base URI } SerdBaseEvent; /** Event for namespace definitions Emitted whenever a prefix is defined in the serialisation. */ typedef struct { SerdEventType type; ///< #SERD_PREFIX const SerdNode* SERD_NONNULL name; ///< Prefix name const SerdNode* SERD_NONNULL uri; ///< Namespace URI } SerdPrefixEvent; /** Event for statements Emitted for every RDF statement in the serialisation. */ typedef struct { SerdEventType type; ///< #SERD_STATEMENT SerdStatementFlags flags; ///< Flags for pretty-printing const SerdStatement* SERD_NONNULL statement; ///< Statement } SerdStatementEvent; /** Event for the end of anonymous node descriptions This is emitted to indicate that the anonymous node with the given `value` will no longer be referred to by any future statements (i.e. the anonymous serialisation of the node is finished). */ typedef struct { SerdEventType type; ///< #SERD_END const SerdNode* SERD_NONNULL node; ///< Anonymous node that is finished } SerdEndEvent; /** An event in a data stream Streams of data are represented as a series of events. Events represent everything that can occur in an RDF document, and are used to plumb together different components. For example, when parsing a document, a reader emits a stream of events which can be sent to a writer to serialise a document, or to an inserter to build a model in memory. */ typedef union { SerdEventType type; ///< Event type (always set) SerdBaseEvent base; ///< Base URI changed SerdPrefixEvent prefix; ///< New namespace prefix SerdStatementEvent statement; ///< Statement SerdEndEvent end; ///< End of anonymous node } SerdEvent; /// Function for handling events typedef SerdStatus (*SerdEventFunc)(void* SERD_NULLABLE handle, const SerdEvent* SERD_NONNULL event); /** @} @defgroup serd_world World @{ */ /** Create a new Serd World. It is safe to use multiple worlds in one process, though no objects can be shared between worlds. */ SERD_MALLOC_API SerdWorld* SERD_ALLOCATED serd_world_new(void); /// Free `world` SERD_API void serd_world_free(SerdWorld* SERD_NULLABLE world); /** Return a unique blank node. The returned node is valid only until the next time serd_world_get_blank() is called or the world is destroyed. */ SERD_API const SerdNode* SERD_NONNULL serd_world_get_blank(SerdWorld* SERD_NONNULL world); /** Set a function to be called when errors occur. The `error_func` will be called with `handle` as its first argument. If no error function is set, errors are printed to stderr. */ SERD_API void serd_world_set_error_func(SerdWorld* SERD_NONNULL world, SerdErrorFunc SERD_NULLABLE error_func, void* SERD_NULLABLE handle); /** @} @defgroup serd_env Environment @{ */ /// Create a new environment SERD_API SerdEnv* SERD_ALLOCATED serd_env_new(SerdStringView base_uri); /// Free `env` SERD_API void serd_env_free(SerdEnv* SERD_NULLABLE env); /// Get the current base URI SERD_PURE_API const SerdNode* SERD_NULLABLE serd_env_base_uri(const SerdEnv* SERD_NONNULL env); /// Set the current base URI SERD_API SerdStatus serd_env_set_base_uri(SerdEnv* SERD_NONNULL env, SerdStringView uri); /** Set a namespace prefix A namespace prefix is used to expand CURIE nodes, for example, with the prefix "xsd" set to "http://www.w3.org/2001/XMLSchema#", "xsd:decimal" will expand to "http://www.w3.org/2001/XMLSchema#decimal". */ SERD_API SerdStatus serd_env_set_prefix(SerdEnv* SERD_NONNULL env, SerdStringView name, SerdStringView uri); /** Qualify `uri` into a CURIE if possible. Returns null if `uri` can not be qualified (usually because no corresponding prefix is defined). */ SERD_API SerdNode* SERD_ALLOCATED serd_env_qualify(const SerdEnv* SERD_NONNULL env, const SerdNode* SERD_NONNULL uri); /** Expand `node`, transforming CURIEs into URIs. If `node` is a relative URI reference, it is expanded to a full URI if possible. If `node` is a literal, its datatype is expanded if necessary. If `node` is a CURIE, it is expanded to a full URI if possible. Returns null if `node` can not be expanded. */ SERD_API SerdNode* SERD_ALLOCATED serd_env_expand(const SerdEnv* SERD_NONNULL env, const SerdNode* SERD_NONNULL node); /// Write all prefixes in `env` to `sink` SERD_API void serd_env_write_prefixes(const SerdEnv* SERD_NONNULL env, const SerdSink* SERD_NONNULL sink); /** @} @defgroup serd_sink Sink @{ */ /// Function to free an opaque handle typedef void (*SerdFreeFunc)(void* SERD_NULLABLE ptr); /** Create a new sink. Initially, the sink has no set functions and will do nothing. Use the serd_sink_set_*_func functions to set handlers for various events. @param handle Opaque handle that will be passed to sink functions. @param event_func Function that will be called for every event @param free_handle Free function to call on handle in serd_sink_free(). */ SERD_API SerdSink* SERD_ALLOCATED serd_sink_new(void* SERD_NULLABLE handle, SerdEventFunc SERD_NULLABLE event_func, SerdFreeFunc SERD_NULLABLE free_handle); /// Free `sink` SERD_API void serd_sink_free(SerdSink* SERD_NULLABLE sink); /// Send an event to the sink SERD_API SerdStatus serd_sink_write_event(const SerdSink* SERD_NONNULL sink, const SerdEvent* SERD_NONNULL event); /// Set the base URI SERD_API SerdStatus serd_sink_write_base(const SerdSink* SERD_NONNULL sink, const SerdNode* SERD_NONNULL uri); /// Set a namespace prefix SERD_API SerdStatus serd_sink_write_prefix(const SerdSink* SERD_NONNULL sink, const SerdNode* SERD_NONNULL name, const SerdNode* SERD_NONNULL uri); /// Write a statement SERD_API SerdStatus serd_sink_write_statement(const SerdSink* SERD_NONNULL sink, SerdStatementFlags flags, const SerdStatement* SERD_NONNULL statement); /// Write a statement from individual nodes SERD_API SerdStatus serd_sink_write(const SerdSink* SERD_NONNULL sink, SerdStatementFlags flags, const SerdNode* SERD_NONNULL subject, const SerdNode* SERD_NONNULL predicate, const SerdNode* SERD_NONNULL object, const SerdNode* SERD_NULLABLE graph); /// Mark the end of an anonymous node SERD_API SerdStatus serd_sink_write_end(const SerdSink* SERD_NONNULL sink, const SerdNode* SERD_NONNULL node); /** @} @defgroup serd_reader Reader @{ */ /// Create a new RDF reader SERD_API SerdReader* SERD_ALLOCATED serd_reader_new(SerdWorld* SERD_NONNULL world, SerdSyntax syntax, const SerdSink* SERD_NONNULL sink, size_t stack_size); /** Enable or disable strict parsing The reader is non-strict (lax) by default, which will tolerate URIs with invalid characters. Setting strict will fail when parsing such files. An error is printed for invalid input in either case. */ SERD_API void serd_reader_set_strict(SerdReader* SERD_NONNULL reader, bool strict); /** Set a prefix to be added to all blank node identifiers. This is useful when multiple files are to be parsed into the same output (a model or a file). Since Serd preserves blank node IDs, this could cause conflicts where two non-equivalent blank nodes are merged, resulting in corrupt data. By setting a unique blank node prefix for each parsed file, this can be avoided, while preserving blank node names. */ SERD_API void serd_reader_add_blank_prefix(SerdReader* SERD_NONNULL reader, const char* SERD_NULLABLE prefix); /// Prepare to read from the file at a local file `uri` SERD_API SerdStatus serd_reader_start_file(SerdReader* SERD_NONNULL reader, const char* SERD_NONNULL uri, bool bulk); /** Prepare to read from a stream. The `read_func` is guaranteed to only be called for `page_size` elements with size 1 (i.e. `page_size` bytes). */ SERD_API SerdStatus serd_reader_start_stream(SerdReader* SERD_NONNULL reader, SerdReadFunc SERD_NONNULL read_func, SerdStreamErrorFunc SERD_NONNULL error_func, void* SERD_NONNULL stream, const SerdNode* SERD_NULLABLE name, size_t page_size); /// Prepare to read from a string SERD_API SerdStatus serd_reader_start_string(SerdReader* SERD_NONNULL reader, const char* SERD_NONNULL utf8, const SerdNode* SERD_NULLABLE name); /** Read a single "chunk" of data during an incremental read This function will read a single top level description, and return. This may be a directive, statement, or several statements; essentially it reads until a '.' is encountered. This is particularly useful for reading directly from a pipe or socket. */ SERD_API SerdStatus serd_reader_read_chunk(SerdReader* SERD_NONNULL reader); /** Read a complete document from the source. This function will continue pulling from the source until a complete document has been read. Note that this may block when used with streams, for incremental reading use serd_reader_read_chunk(). */ SERD_API SerdStatus serd_reader_read_document(SerdReader* SERD_NONNULL reader); /** Finish reading from the source. This should be called before starting to read from another source. */ SERD_API SerdStatus serd_reader_finish(SerdReader* SERD_NONNULL reader); /** Free `reader`. The reader will be finished via `serd_reader_finish()` if necessary. */ SERD_API void serd_reader_free(SerdReader* SERD_NULLABLE reader); /** @} @defgroup serd_writer Writer @{ */ /// Create a new RDF writer SERD_API SerdWriter* SERD_ALLOCATED serd_writer_new(SerdWorld* SERD_NONNULL world, SerdSyntax syntax, SerdWriterFlags flags, SerdEnv* SERD_NONNULL env, SerdWriteFunc SERD_NONNULL ssink, void* SERD_NULLABLE stream); /// Free `writer` SERD_API void serd_writer_free(SerdWriter* SERD_NULLABLE writer); /// Return a sink interface that emits statements via `writer` SERD_CONST_API const SerdSink* SERD_NONNULL serd_writer_sink(SerdWriter* SERD_NONNULL writer); /// Return the env used by `writer` SERD_PURE_API SerdEnv* SERD_NONNULL serd_writer_env(SerdWriter* SERD_NONNULL writer); /** A convenience sink function for writing to a string. This function can be used as a SerdSink to write to a SerdBuffer which is resized as necessary with realloc(). The `stream` parameter must point to an initialized SerdBuffer. When the write is finished, the string should be retrieved with serd_buffer_sink_finish(). */ SERD_API size_t serd_buffer_sink(const void* SERD_NONNULL buf, size_t size, size_t nmemb, void* SERD_NONNULL stream); /** Finish a serialisation to a buffer with serd_buffer_sink(). The returned string is the result of the serialisation, which is null terminated (by this function) and owned by the caller. */ SERD_API char* SERD_NULLABLE serd_buffer_sink_finish(SerdBuffer* SERD_NONNULL stream); /** Set a prefix to be removed from matching blank node identifiers This is the counterpart to serd_reader_add_blank_prefix() which can be used to "undo" added prefixes. */ SERD_API void serd_writer_chop_blank_prefix(SerdWriter* SERD_NONNULL writer, const char* SERD_NULLABLE prefix); /** Set the current output base URI, and emit a directive if applicable. Note this function can be safely casted to SerdBaseSink. */ SERD_API SerdStatus serd_writer_set_base_uri(SerdWriter* SERD_NONNULL writer, const SerdNode* SERD_NULLABLE uri); /** Set the current root URI. The root URI should be a prefix of the base URI. The path of the root URI is the highest path any relative up-reference can refer to. For example, with root and base , will be written as <../>, but will be written non-relatively as . If the root is not explicitly set, it defaults to the base URI, so no up-references will be created at all. */ SERD_API SerdStatus serd_writer_set_root_uri(SerdWriter* SERD_NONNULL writer, const SerdNode* SERD_NULLABLE uri); /** Finish a write This flushes any pending output, for example terminating punctuation, so that the output is a complete document. */ SERD_API SerdStatus serd_writer_finish(SerdWriter* SERD_NONNULL writer); /** @} @defgroup serd_statement Statement @{ */ /// Return the given node in `statement` SERD_PURE_API const SerdNode* SERD_NULLABLE serd_statement_node(const SerdStatement* SERD_NONNULL statement, SerdField field); /// Return the subject in `statement` SERD_PURE_API const SerdNode* SERD_NONNULL serd_statement_subject(const SerdStatement* SERD_NONNULL statement); /// Return the predicate in `statement` SERD_PURE_API const SerdNode* SERD_NONNULL serd_statement_predicate(const SerdStatement* SERD_NONNULL statement); /// Return the object in `statement` SERD_PURE_API const SerdNode* SERD_NONNULL serd_statement_object(const SerdStatement* SERD_NONNULL statement); /// Return the graph in `statement` SERD_PURE_API const SerdNode* SERD_NULLABLE serd_statement_graph(const SerdStatement* SERD_NONNULL statement); /// Return the source location where `statement` originated, or NULL SERD_PURE_API const SerdCursor* SERD_NULLABLE serd_statement_cursor(const SerdStatement* SERD_NONNULL statement); /** @} @defgroup serd_cursor Cursor @{ */ /** Create a new cursor Note that, to minimise model overhead, the cursor does not own the name node, so `name` must have a longer lifetime than the cursor for it to be valid. That is, serd_cursor_name() will return exactly the pointer `name`, not a copy. For cursors from models, this is the lifetime of the model. For user-created cursors, the simplest way to handle this is to use `SerdNodes`. @param name The name of the document or stream (usually a file URI) @param line The line number in the document (1-based) @param col The column number in the document (1-based) @return A new cursor that must be freed with serd_cursor_free() */ SERD_API SerdCursor* SERD_ALLOCATED serd_cursor_new(const SerdNode* SERD_NONNULL name, unsigned line, unsigned col); /// Return a copy of `cursor` SERD_API SerdCursor* SERD_ALLOCATED serd_cursor_copy(const SerdCursor* SERD_NULLABLE cursor); /// Free `cursor` SERD_API void serd_cursor_free(SerdCursor* SERD_NULLABLE cursor); /// Return true iff `lhs` is equal to `rhs` SERD_PURE_API bool serd_cursor_equals(const SerdCursor* SERD_NULLABLE lhs, const SerdCursor* SERD_NULLABLE rhs); /** Return the document name. This is typically a file URI, but may be a descriptive string node for statements that originate from streams. */ SERD_PURE_API const SerdNode* SERD_NONNULL serd_cursor_name(const SerdCursor* SERD_NONNULL cursor); /// Return the one-relative line number in the document SERD_PURE_API unsigned serd_cursor_line(const SerdCursor* SERD_NONNULL cursor); /// Return the zero-relative column number in the line SERD_PURE_API unsigned serd_cursor_column(const SerdCursor* SERD_NONNULL cursor); /** @} @} */ #ifdef __cplusplus # if defined(__GNUC__) # pragma GCC diagnostic pop # endif } /* extern "C" */ #endif #endif /* SERD_SERD_H */