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| 1 | pmbaty | 1 | /* libFLAC - Free Lossless Audio Codec library |
| 2 | * Copyright (C) 2004-2009 Josh Coalson |
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| 3 | * Copyright (C) 2011-2016 Xiph.Org Foundation |
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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 | * |
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| 12 | * - Redistributions in binary form must reproduce the above copyright |
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| 13 | * notice, this list of conditions and the following disclaimer in the |
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| 14 | * documentation and/or other materials provided with the distribution. |
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| 15 | * |
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| 16 | * - Neither the name of the Xiph.org Foundation nor the names of its |
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| 17 | * contributors may be used to endorse or promote products derived from |
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| 18 | * this software without specific prior written permission. |
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| 19 | * |
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| 20 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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| 21 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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| 22 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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| 23 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR |
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| 24 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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| 25 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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| 26 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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| 27 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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| 28 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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| 29 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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| 30 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 31 | */ |
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| 32 | |||
| 33 | #ifndef FLAC__CALLBACK_H |
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| 34 | #define FLAC__CALLBACK_H |
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| 35 | |||
| 36 | #include "ordinals.h" |
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| 37 | #include <stdlib.h> /* for size_t */ |
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| 38 | |||
| 39 | /** \file include/FLAC/callback.h |
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| 40 | * |
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| 41 | * \brief |
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| 42 | * This module defines the structures for describing I/O callbacks |
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| 43 | * to the other FLAC interfaces. |
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| 44 | * |
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| 45 | * See the detailed documentation for callbacks in the |
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| 46 | * \link flac_callbacks callbacks \endlink module. |
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| 47 | */ |
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| 48 | |||
| 49 | /** \defgroup flac_callbacks FLAC/callback.h: I/O callback structures |
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| 50 | * \ingroup flac |
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| 51 | * |
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| 52 | * \brief |
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| 53 | * This module defines the structures for describing I/O callbacks |
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| 54 | * to the other FLAC interfaces. |
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| 55 | * |
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| 56 | * The purpose of the I/O callback functions is to create a common way |
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| 57 | * for the metadata interfaces to handle I/O. |
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| 58 | * |
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| 59 | * Originally the metadata interfaces required filenames as the way of |
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| 60 | * specifying FLAC files to operate on. This is problematic in some |
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| 61 | * environments so there is an additional option to specify a set of |
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| 62 | * callbacks for doing I/O on the FLAC file, instead of the filename. |
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| 63 | * |
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| 64 | * In addition to the callbacks, a FLAC__IOHandle type is defined as an |
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| 65 | * opaque structure for a data source. |
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| 66 | * |
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| 67 | * The callback function prototypes are similar (but not identical) to the |
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| 68 | * stdio functions fread, fwrite, fseek, ftell, feof, and fclose. If you use |
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| 69 | * stdio streams to implement the callbacks, you can pass fread, fwrite, and |
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| 70 | * fclose anywhere a FLAC__IOCallback_Read, FLAC__IOCallback_Write, or |
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| 71 | * FLAC__IOCallback_Close is required, and a FILE* anywhere a FLAC__IOHandle |
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| 72 | * is required. \warning You generally CANNOT directly use fseek or ftell |
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| 73 | * for FLAC__IOCallback_Seek or FLAC__IOCallback_Tell since on most systems |
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| 74 | * these use 32-bit offsets and FLAC requires 64-bit offsets to deal with |
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| 75 | * large files. You will have to find an equivalent function (e.g. ftello), |
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| 76 | * or write a wrapper. The same is true for feof() since this is usually |
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| 77 | * implemented as a macro, not as a function whose address can be taken. |
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| 78 | * |
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| 79 | * \{ |
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| 80 | */ |
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| 81 | |||
| 82 | #ifdef __cplusplus |
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| 83 | extern "C" { |
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| 84 | #endif |
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| 85 | |||
| 86 | /** This is the opaque handle type used by the callbacks. Typically |
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| 87 | * this is a \c FILE* or address of a file descriptor. |
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| 88 | */ |
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| 89 | typedef void* FLAC__IOHandle; |
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| 90 | |||
| 91 | /** Signature for the read callback. |
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| 92 | * The signature and semantics match POSIX fread() implementations |
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| 93 | * and can generally be used interchangeably. |
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| 94 | * |
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| 95 | * \param ptr The address of the read buffer. |
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| 96 | * \param size The size of the records to be read. |
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| 97 | * \param nmemb The number of records to be read. |
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| 98 | * \param handle The handle to the data source. |
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| 99 | * \retval size_t |
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| 100 | * The number of records read. |
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| 101 | */ |
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| 102 | typedef size_t (*FLAC__IOCallback_Read) (void *ptr, size_t size, size_t nmemb, FLAC__IOHandle handle); |
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| 103 | |||
| 104 | /** Signature for the write callback. |
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| 105 | * The signature and semantics match POSIX fwrite() implementations |
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| 106 | * and can generally be used interchangeably. |
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| 107 | * |
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| 108 | * \param ptr The address of the write buffer. |
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| 109 | * \param size The size of the records to be written. |
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| 110 | * \param nmemb The number of records to be written. |
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| 111 | * \param handle The handle to the data source. |
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| 112 | * \retval size_t |
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| 113 | * The number of records written. |
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| 114 | */ |
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| 115 | typedef size_t (*FLAC__IOCallback_Write) (const void *ptr, size_t size, size_t nmemb, FLAC__IOHandle handle); |
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| 116 | |||
| 117 | /** Signature for the seek callback. |
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| 118 | * The signature and semantics mostly match POSIX fseek() WITH ONE IMPORTANT |
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| 119 | * EXCEPTION: the offset is a 64-bit type whereas fseek() is generally 'long' |
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| 120 | * and 32-bits wide. |
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| 121 | * |
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| 122 | * \param handle The handle to the data source. |
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| 123 | * \param offset The new position, relative to \a whence |
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| 124 | * \param whence \c SEEK_SET, \c SEEK_CUR, or \c SEEK_END |
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| 125 | * \retval int |
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| 126 | * \c 0 on success, \c -1 on error. |
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| 127 | */ |
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| 128 | typedef int (*FLAC__IOCallback_Seek) (FLAC__IOHandle handle, FLAC__int64 offset, int whence); |
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| 129 | |||
| 130 | /** Signature for the tell callback. |
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| 131 | * The signature and semantics mostly match POSIX ftell() WITH ONE IMPORTANT |
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| 132 | * EXCEPTION: the offset is a 64-bit type whereas ftell() is generally 'long' |
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| 133 | * and 32-bits wide. |
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| 134 | * |
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| 135 | * \param handle The handle to the data source. |
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| 136 | * \retval FLAC__int64 |
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| 137 | * The current position on success, \c -1 on error. |
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| 138 | */ |
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| 139 | typedef FLAC__int64 (*FLAC__IOCallback_Tell) (FLAC__IOHandle handle); |
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| 140 | |||
| 141 | /** Signature for the EOF callback. |
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| 142 | * The signature and semantics mostly match POSIX feof() but WATCHOUT: |
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| 143 | * on many systems, feof() is a macro, so in this case a wrapper function |
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| 144 | * must be provided instead. |
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| 145 | * |
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| 146 | * \param handle The handle to the data source. |
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| 147 | * \retval int |
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| 148 | * \c 0 if not at end of file, nonzero if at end of file. |
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| 149 | */ |
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| 150 | typedef int (*FLAC__IOCallback_Eof) (FLAC__IOHandle handle); |
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| 151 | |||
| 152 | /** Signature for the close callback. |
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| 153 | * The signature and semantics match POSIX fclose() implementations |
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| 154 | * and can generally be used interchangeably. |
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| 155 | * |
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| 156 | * \param handle The handle to the data source. |
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| 157 | * \retval int |
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| 158 | * \c 0 on success, \c EOF on error. |
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| 159 | */ |
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| 160 | typedef int (*FLAC__IOCallback_Close) (FLAC__IOHandle handle); |
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| 161 | |||
| 162 | /** A structure for holding a set of callbacks. |
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| 163 | * Each FLAC interface that requires a FLAC__IOCallbacks structure will |
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| 164 | * describe which of the callbacks are required. The ones that are not |
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| 165 | * required may be set to NULL. |
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| 166 | * |
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| 167 | * If the seek requirement for an interface is optional, you can signify that |
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| 168 | * a data sorce is not seekable by setting the \a seek field to \c NULL. |
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| 169 | */ |
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| 170 | typedef struct { |
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| 171 | FLAC__IOCallback_Read read; |
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| 172 | FLAC__IOCallback_Write write; |
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| 173 | FLAC__IOCallback_Seek seek; |
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| 174 | FLAC__IOCallback_Tell tell; |
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| 175 | FLAC__IOCallback_Eof eof; |
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| 176 | FLAC__IOCallback_Close close; |
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| 177 | } FLAC__IOCallbacks; |
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| 178 | |||
| 179 | /* \} */ |
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| 180 | |||
| 181 | #ifdef __cplusplus |
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| 182 | } |
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| 183 | #endif |
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| 184 | |||
| 185 | #endif |