cannam@87: /* libFLAC - Free Lossless Audio Codec library cannam@87: * Copyright (C) 2004,2005,2006,2007 Josh Coalson cannam@87: * cannam@87: * Redistribution and use in source and binary forms, with or without cannam@87: * modification, are permitted provided that the following conditions cannam@87: * are met: cannam@87: * cannam@87: * - Redistributions of source code must retain the above copyright cannam@87: * notice, this list of conditions and the following disclaimer. cannam@87: * cannam@87: * - Redistributions in binary form must reproduce the above copyright cannam@87: * notice, this list of conditions and the following disclaimer in the cannam@87: * documentation and/or other materials provided with the distribution. cannam@87: * cannam@87: * - Neither the name of the Xiph.org Foundation nor the names of its cannam@87: * contributors may be used to endorse or promote products derived from cannam@87: * this software without specific prior written permission. cannam@87: * cannam@87: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS cannam@87: * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT cannam@87: * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR cannam@87: * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR cannam@87: * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, cannam@87: * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, cannam@87: * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR cannam@87: * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF cannam@87: * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING cannam@87: * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS cannam@87: * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. cannam@87: */ cannam@87: cannam@87: #ifndef FLAC__CALLBACK_H cannam@87: #define FLAC__CALLBACK_H cannam@87: cannam@87: #include "ordinals.h" cannam@87: #include /* for size_t */ cannam@87: cannam@87: /** \file include/FLAC/callback.h cannam@87: * cannam@87: * \brief cannam@87: * This module defines the structures for describing I/O callbacks cannam@87: * to the other FLAC interfaces. cannam@87: * cannam@87: * See the detailed documentation for callbacks in the cannam@87: * \link flac_callbacks callbacks \endlink module. cannam@87: */ cannam@87: cannam@87: /** \defgroup flac_callbacks FLAC/callback.h: I/O callback structures cannam@87: * \ingroup flac cannam@87: * cannam@87: * \brief cannam@87: * This module defines the structures for describing I/O callbacks cannam@87: * to the other FLAC interfaces. cannam@87: * cannam@87: * The purpose of the I/O callback functions is to create a common way cannam@87: * for the metadata interfaces to handle I/O. cannam@87: * cannam@87: * Originally the metadata interfaces required filenames as the way of cannam@87: * specifying FLAC files to operate on. This is problematic in some cannam@87: * environments so there is an additional option to specify a set of cannam@87: * callbacks for doing I/O on the FLAC file, instead of the filename. cannam@87: * cannam@87: * In addition to the callbacks, a FLAC__IOHandle type is defined as an cannam@87: * opaque structure for a data source. cannam@87: * cannam@87: * The callback function prototypes are similar (but not identical) to the cannam@87: * stdio functions fread, fwrite, fseek, ftell, feof, and fclose. If you use cannam@87: * stdio streams to implement the callbacks, you can pass fread, fwrite, and cannam@87: * fclose anywhere a FLAC__IOCallback_Read, FLAC__IOCallback_Write, or cannam@87: * FLAC__IOCallback_Close is required, and a FILE* anywhere a FLAC__IOHandle cannam@87: * is required. \warning You generally CANNOT directly use fseek or ftell cannam@87: * for FLAC__IOCallback_Seek or FLAC__IOCallback_Tell since on most systems cannam@87: * these use 32-bit offsets and FLAC requires 64-bit offsets to deal with cannam@87: * large files. You will have to find an equivalent function (e.g. ftello), cannam@87: * or write a wrapper. The same is true for feof() since this is usually cannam@87: * implemented as a macro, not as a function whose address can be taken. cannam@87: * cannam@87: * \{ cannam@87: */ cannam@87: cannam@87: #ifdef __cplusplus cannam@87: extern "C" { cannam@87: #endif cannam@87: cannam@87: /** This is the opaque handle type used by the callbacks. Typically cannam@87: * this is a \c FILE* or address of a file descriptor. cannam@87: */ cannam@87: typedef void* FLAC__IOHandle; cannam@87: cannam@87: /** Signature for the read callback. cannam@87: * The signature and semantics match POSIX fread() implementations cannam@87: * and can generally be used interchangeably. cannam@87: * cannam@87: * \param ptr The address of the read buffer. cannam@87: * \param size The size of the records to be read. cannam@87: * \param nmemb The number of records to be read. cannam@87: * \param handle The handle to the data source. cannam@87: * \retval size_t cannam@87: * The number of records read. cannam@87: */ cannam@87: typedef size_t (*FLAC__IOCallback_Read) (void *ptr, size_t size, size_t nmemb, FLAC__IOHandle handle); cannam@87: cannam@87: /** Signature for the write callback. cannam@87: * The signature and semantics match POSIX fwrite() implementations cannam@87: * and can generally be used interchangeably. cannam@87: * cannam@87: * \param ptr The address of the write buffer. cannam@87: * \param size The size of the records to be written. cannam@87: * \param nmemb The number of records to be written. cannam@87: * \param handle The handle to the data source. cannam@87: * \retval size_t cannam@87: * The number of records written. cannam@87: */ cannam@87: typedef size_t (*FLAC__IOCallback_Write) (const void *ptr, size_t size, size_t nmemb, FLAC__IOHandle handle); cannam@87: cannam@87: /** Signature for the seek callback. cannam@87: * The signature and semantics mostly match POSIX fseek() WITH ONE IMPORTANT cannam@87: * EXCEPTION: the offset is a 64-bit type whereas fseek() is generally 'long' cannam@87: * and 32-bits wide. cannam@87: * cannam@87: * \param handle The handle to the data source. cannam@87: * \param offset The new position, relative to \a whence cannam@87: * \param whence \c SEEK_SET, \c SEEK_CUR, or \c SEEK_END cannam@87: * \retval int cannam@87: * \c 0 on success, \c -1 on error. cannam@87: */ cannam@87: typedef int (*FLAC__IOCallback_Seek) (FLAC__IOHandle handle, FLAC__int64 offset, int whence); cannam@87: cannam@87: /** Signature for the tell callback. cannam@87: * The signature and semantics mostly match POSIX ftell() WITH ONE IMPORTANT cannam@87: * EXCEPTION: the offset is a 64-bit type whereas ftell() is generally 'long' cannam@87: * and 32-bits wide. cannam@87: * cannam@87: * \param handle The handle to the data source. cannam@87: * \retval FLAC__int64 cannam@87: * The current position on success, \c -1 on error. cannam@87: */ cannam@87: typedef FLAC__int64 (*FLAC__IOCallback_Tell) (FLAC__IOHandle handle); cannam@87: cannam@87: /** Signature for the EOF callback. cannam@87: * The signature and semantics mostly match POSIX feof() but WATCHOUT: cannam@87: * on many systems, feof() is a macro, so in this case a wrapper function cannam@87: * must be provided instead. cannam@87: * cannam@87: * \param handle The handle to the data source. cannam@87: * \retval int cannam@87: * \c 0 if not at end of file, nonzero if at end of file. cannam@87: */ cannam@87: typedef int (*FLAC__IOCallback_Eof) (FLAC__IOHandle handle); cannam@87: cannam@87: /** Signature for the close callback. cannam@87: * The signature and semantics match POSIX fclose() implementations cannam@87: * and can generally be used interchangeably. cannam@87: * cannam@87: * \param handle The handle to the data source. cannam@87: * \retval int cannam@87: * \c 0 on success, \c EOF on error. cannam@87: */ cannam@87: typedef int (*FLAC__IOCallback_Close) (FLAC__IOHandle handle); cannam@87: cannam@87: /** A structure for holding a set of callbacks. cannam@87: * Each FLAC interface that requires a FLAC__IOCallbacks structure will cannam@87: * describe which of the callbacks are required. The ones that are not cannam@87: * required may be set to NULL. cannam@87: * cannam@87: * If the seek requirement for an interface is optional, you can signify that cannam@87: * a data sorce is not seekable by setting the \a seek field to \c NULL. cannam@87: */ cannam@87: typedef struct { cannam@87: FLAC__IOCallback_Read read; cannam@87: FLAC__IOCallback_Write write; cannam@87: FLAC__IOCallback_Seek seek; cannam@87: FLAC__IOCallback_Tell tell; cannam@87: FLAC__IOCallback_Eof eof; cannam@87: FLAC__IOCallback_Close close; cannam@87: } FLAC__IOCallbacks; cannam@87: cannam@87: /* \} */ cannam@87: cannam@87: #ifdef __cplusplus cannam@87: } cannam@87: #endif cannam@87: cannam@87: #endif