Edit File: reader.h
/* * Copyright (c) 2014 by Farsight Security, Inc. * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. * */ #ifndef FSTRM_READER_H #define FSTRM_READER_H /** * \defgroup fstrm_reader fstrm_reader * * `fstrm_reader` is an interface for reading Frame Streams data from a byte * stream. The underlying byte stream I/O operations are abstracted by the * \ref fstrm_rdwr interface. Thus, the `fstrm_reader` interface can be used to * read Frame Streams data from any source whose read/write operations are * wrapped by an `fstrm_rdwr` object. * * Some basic `fstrm_reader` implementations are already provided in the `fstrm` * library. See fstrm_file_reader_init() to create an `fstrm_reader` object that * reads Frame Streams data from a regular file. * * @{ */ /** * The default `max_frame_size` value. */ #define FSTRM_READER_MAX_FRAME_SIZE_DEFAULT 1048576 /** * Initialize an `fstrm_reader_options` object. * * \return * `fstrm_reader_options` object. */ struct fstrm_reader_options * fstrm_reader_options_init(void); /** * Destroy an `fstrm_reader_options` object. * * \param ropt * Pointer to `fstrm_reader_options` object. */ void fstrm_reader_options_destroy( struct fstrm_reader_options **ropt); /** * Add a "Content Type" value to the set of content types accepted by the * `fstrm_reader`. This function makes a copy of the provided string. This * function may be called multiple times, in which case multiple "Content Type" * values will be accepted by the reader. * * If the reader has no content types set, it will accept any content type. * * \param ropt * `fstrm_reader_options` object. * \param content_type * The "Content Type" string to copy. Note that this string is not * NUL-terminated and may contain embedded NULs. * \param len_content_type * The number of bytes in `content_type`. * * \retval #fstrm_res_success * The "Content Type" field was successfully added. * \retval #fstrm_res_failure * The "Content Type" string is too long. */ fstrm_res fstrm_reader_options_add_content_type( struct fstrm_reader_options *ropt, const void *content_type, size_t len_content_type); /** * Set the maximum frame size that the reader is willing to accept. This * enforces an upper limit on the amount of memory used to buffer incoming data * from the reader's byte stream. * * If this option is not set, it defaults to * #FSTRM_READER_MAX_FRAME_SIZE_DEFAULT. * * \param ropt * `fstrm_reader_options` object. * \param max_frame_size * The maximum frame size value. * * \retval #fstrm_res_success * The `max_frame_size` value was successfully set. * \retval #fstrm_res_failure * The `max_frame_size` value was too large or too small. */ fstrm_res fstrm_reader_options_set_max_frame_size( struct fstrm_reader_options *ropt, size_t max_frame_size); /** * Initialize a new `fstrm_reader` object based on an underlying `fstrm_rdwr` * object and an `fstrm_reader_options` object. * * The underlying `fstrm_rdwr` object MUST have a `read` method. It MAY * optionally have a `write` method, in which case the stream will be treated as * a bi-directional, handshaked stream. Otherwise, if there is no `write` method * the stream will be treated as a uni-directional stream. * * This function is useful for implementing functions that return new types of * `fstrm_reader` objects, such as fstrm_file_reader_init(). * * After a successful call to this function, the ownership of the `fstrm_rdwr` * object passes from the caller to the `fstrm_reader` object. The caller * should perform no further calls on the `fstrm_rdwr` object. The `fstrm_rdwr` * object will be cleaned up on a call to fstrm_reader_destroy(). * * \param ropt * `fstrm_reader_options` object. May be NULL, in which case default values * will be used. * * \param rdwr * Pointer to `fstrm_rdwr` object. Must be non-NULL. The `fstrm_rdwr` * object must have a `read` method, and may optionally have a `write` * method. * * \return * `fstrm_reader` object. * \retval * NULL on failure. */ struct fstrm_reader * fstrm_reader_init( const struct fstrm_reader_options *ropt, struct fstrm_rdwr **rdwr); /** * Destroy an `fstrm_reader` object. This implicitly calls fstrm_reader_close() * if necessary. * * \param r * Pointer to `fstrm_reader` object. * * \retval #fstrm_res_success * \retval #fstrm_res_failure */ fstrm_res fstrm_reader_destroy(struct fstrm_reader **r); /** * Open an `fstrm_reader` object and prepare it to read data. * * This checks that the content type in the byte stream, if specified, matches * one of the content types specified in the `fstrm_reader_options` object used * to initialize the `fstrm_reader` object. * * This function may fail if there was an underlying problem opening the input * stream. * * \param r * `fstrm_reader` object. * * \retval #fstrm_res_success * \retval #fstrm_res_failure */ fstrm_res fstrm_reader_open(struct fstrm_reader *r); /** * Close an `fstrm_reader` object. Once it has been closed, no data frames may * subsequently be read. * * Calling this function is optional; it may be implicitly invoked by a call to * fstrm_reader_destroy(). * * \param r * `fstrm_reader` object. * * \retval #fstrm_res_success * \retval #fstrm_res_failure */ fstrm_res fstrm_reader_close(struct fstrm_reader *r); /** * Read a data frame from an `fstrm_reader` object. This frame is held in an * internal buffer owned by the `fstrm_reader` object and should not be modified * by the caller. The contents of this buffer will be overwritten by a * subsequent call to fstrm_reader_read(). * * This function implicitly calls fstrm_reader_open() if necessary. * * \param r * `fstrm_reader` object. * \param[out] data * Pointer to buffer containing the data frame payload. * \param[out] len_data * The number of bytes available in `data`. * * \retval #fstrm_res_success * A data frame was successfully read. * \retval #fstrm_res_stop * The end of the stream has been reached. * \retval #fstrm_res_failure */ fstrm_res fstrm_reader_read( struct fstrm_reader *r, const uint8_t **data, size_t *len_data); /** * Obtain a pointer to an `fstrm_control` object used during processing. Objects * returned by this function are owned by the `fstrm_reader` object and must not * be modified by the caller. After a call to fstrm_reader_destroy() these * pointers will no longer be valid. * * For example, this function can be used to obtain a pointer to the START * control frame, which can be queried to see which "Content Type" was * negotiated during the opening of the reader. * * This function implicitly calls fstrm_reader_open() if necessary. * * \param r * `fstrm_reader` object. * \param type * Which control frame to return. * \param[out] control * The `fstrm_control` object. * * \retval #fstrm_res_success * If an `fstrm_control` object was returned. * \retval #fstrm_res_failure */ fstrm_res fstrm_reader_get_control( struct fstrm_reader *r, fstrm_control_type type, const struct fstrm_control **control); /**@}*/ #endif /* FSTRM_READER_H */