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| /* | |
| * $Id$ | |
| * Portable Audio I/O Library sample conversion mechanism | |
| * | |
| * Based on the Open Source API proposed by Ross Bencina | |
| * Copyright (c) 1999-2002 Phil Burk, Ross Bencina | |
| * | |
| * 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. | |
| */ | |
| /* | |
| * The text above constitutes the entire PortAudio license; however, | |
| * the PortAudio community also makes the following non-binding requests: | |
| * | |
| * Any person wishing to distribute modifications to the Software is | |
| * requested to send the modifications to the original developer so that | |
| * they can be incorporated into the canonical version. It is also | |
| * requested that these non-binding requests be included along with the | |
| * license above. | |
| */ | |
| /** @file | |
| @ingroup common_src | |
| @brief Conversion functions used to convert buffers of samples from one | |
| format to another. | |
| */ | |
| extern "C" | |
| { | |
| struct PaUtilTriangularDitherGenerator; | |
| /** Choose an available sample format which is most appropriate for | |
| representing the requested format. If the requested format is not available | |
| higher quality formats are considered before lower quality formats. | |
| @param availableFormats A variable containing the logical OR of all available | |
| formats. | |
| @param format The desired format. | |
| @return The most appropriate available format for representing the requested | |
| format. | |
| */ | |
| PaSampleFormat PaUtil_SelectClosestAvailableFormat( | |
| PaSampleFormat availableFormats, PaSampleFormat format ); | |
| /* high level conversions functions for use by implementations */ | |
| /** The generic sample converter prototype. Sample converters convert count | |
| samples from sourceBuffer to destinationBuffer. The actual type of the data | |
| pointed to by these parameters varys for different converter functions. | |
| @param destinationBuffer A pointer to the first sample of the destination. | |
| @param destinationStride An offset between successive destination samples | |
| expressed in samples (not bytes.) It may be negative. | |
| @param sourceBuffer A pointer to the first sample of the source. | |
| @param sourceStride An offset between successive source samples | |
| expressed in samples (not bytes.) It may be negative. | |
| @param count The number of samples to convert. | |
| @param ditherState State information used to calculate dither. Converters | |
| that do not perform dithering will ignore this parameter, in which case | |
| NULL or invalid dither state may be passed. | |
| */ | |
| typedef void PaUtilConverter( | |
| void *destinationBuffer, signed int destinationStride, | |
| void *sourceBuffer, signed int sourceStride, | |
| unsigned int count, struct PaUtilTriangularDitherGenerator *ditherGenerator ); | |
| /** Find a sample converter function for the given source and destinations | |
| formats and flags (clip and dither.) | |
| @return | |
| A pointer to a PaUtilConverter which will perform the requested | |
| conversion, or NULL if the given format conversion is not supported. | |
| For conversions where clipping or dithering is not necessary, the | |
| clip and dither flags are ignored and a non-clipping or dithering | |
| version is returned. | |
| If the source and destination formats are the same, a function which | |
| copies data of the appropriate size will be returned. | |
| */ | |
| PaUtilConverter* PaUtil_SelectConverter( PaSampleFormat sourceFormat, | |
| PaSampleFormat destinationFormat, PaStreamFlags flags ); | |
| /** The generic buffer zeroer prototype. Buffer zeroers copy count zeros to | |
| destinationBuffer. The actual type of the data pointed to varys for | |
| different zeroer functions. | |
| @param destinationBuffer A pointer to the first sample of the destination. | |
| @param destinationStride An offset between successive destination samples | |
| expressed in samples (not bytes.) It may be negative. | |
| @param count The number of samples to zero. | |
| */ | |
| typedef void PaUtilZeroer( | |
| void *destinationBuffer, signed int destinationStride, unsigned int count ); | |
| /** Find a buffer zeroer function for the given destination format. | |
| @return | |
| A pointer to a PaUtilZeroer which will perform the requested | |
| zeroing. | |
| */ | |
| PaUtilZeroer* PaUtil_SelectZeroer( PaSampleFormat destinationFormat ); | |
| /*----------------------------------------------------------------------------*/ | |
| /* low level functions and data structures which may be used for | |
| substituting conversion functions */ | |
| /** The type used to store all sample conversion functions. | |
| @see paConverters; | |
| */ | |
| typedef struct{ | |
| PaUtilConverter *Float32_To_Int32; | |
| PaUtilConverter *Float32_To_Int32_Dither; | |
| PaUtilConverter *Float32_To_Int32_Clip; | |
| PaUtilConverter *Float32_To_Int32_DitherClip; | |
| PaUtilConverter *Float32_To_Int24; | |
| PaUtilConverter *Float32_To_Int24_Dither; | |
| PaUtilConverter *Float32_To_Int24_Clip; | |
| PaUtilConverter *Float32_To_Int24_DitherClip; | |
| PaUtilConverter *Float32_To_Int16; | |
| PaUtilConverter *Float32_To_Int16_Dither; | |
| PaUtilConverter *Float32_To_Int16_Clip; | |
| PaUtilConverter *Float32_To_Int16_DitherClip; | |
| PaUtilConverter *Float32_To_Int8; | |
| PaUtilConverter *Float32_To_Int8_Dither; | |
| PaUtilConverter *Float32_To_Int8_Clip; | |
| PaUtilConverter *Float32_To_Int8_DitherClip; | |
| PaUtilConverter *Float32_To_UInt8; | |
| PaUtilConverter *Float32_To_UInt8_Dither; | |
| PaUtilConverter *Float32_To_UInt8_Clip; | |
| PaUtilConverter *Float32_To_UInt8_DitherClip; | |
| PaUtilConverter *Int32_To_Float32; | |
| PaUtilConverter *Int32_To_Int24; | |
| PaUtilConverter *Int32_To_Int24_Dither; | |
| PaUtilConverter *Int32_To_Int16; | |
| PaUtilConverter *Int32_To_Int16_Dither; | |
| PaUtilConverter *Int32_To_Int8; | |
| PaUtilConverter *Int32_To_Int8_Dither; | |
| PaUtilConverter *Int32_To_UInt8; | |
| PaUtilConverter *Int32_To_UInt8_Dither; | |
| PaUtilConverter *Int24_To_Float32; | |
| PaUtilConverter *Int24_To_Int32; | |
| PaUtilConverter *Int24_To_Int16; | |
| PaUtilConverter *Int24_To_Int16_Dither; | |
| PaUtilConverter *Int24_To_Int8; | |
| PaUtilConverter *Int24_To_Int8_Dither; | |
| PaUtilConverter *Int24_To_UInt8; | |
| PaUtilConverter *Int24_To_UInt8_Dither; | |
| PaUtilConverter *Int16_To_Float32; | |
| PaUtilConverter *Int16_To_Int32; | |
| PaUtilConverter *Int16_To_Int24; | |
| PaUtilConverter *Int16_To_Int8; | |
| PaUtilConverter *Int16_To_Int8_Dither; | |
| PaUtilConverter *Int16_To_UInt8; | |
| PaUtilConverter *Int16_To_UInt8_Dither; | |
| PaUtilConverter *Int8_To_Float32; | |
| PaUtilConverter *Int8_To_Int32; | |
| PaUtilConverter *Int8_To_Int24; | |
| PaUtilConverter *Int8_To_Int16; | |
| PaUtilConverter *Int8_To_UInt8; | |
| PaUtilConverter *UInt8_To_Float32; | |
| PaUtilConverter *UInt8_To_Int32; | |
| PaUtilConverter *UInt8_To_Int24; | |
| PaUtilConverter *UInt8_To_Int16; | |
| PaUtilConverter *UInt8_To_Int8; | |
| PaUtilConverter *Copy_8_To_8; /* copy without any conversion */ | |
| PaUtilConverter *Copy_16_To_16; /* copy without any conversion */ | |
| PaUtilConverter *Copy_24_To_24; /* copy without any conversion */ | |
| PaUtilConverter *Copy_32_To_32; /* copy without any conversion */ | |
| } PaUtilConverterTable; | |
| /** A table of pointers to all required converter functions. | |
| PaUtil_SelectConverter() uses this table to lookup the appropriate | |
| conversion functions. The fields of this structure are initialized | |
| with default conversion functions. Fields may be NULL, indicating that | |
| no conversion function is available. User code may substitute optimised | |
| conversion functions by assigning different function pointers to | |
| these fields. | |
| @note | |
| If the PA_NO_STANDARD_CONVERTERS preprocessor variable is defined, | |
| PortAudio's standard converters will not be compiled, and all fields | |
| of this structure will be initialized to NULL. In such cases, users | |
| should supply their own conversion functions if the require PortAudio | |
| to open a stream that requires sample conversion. | |
| @see PaUtilConverterTable, PaUtilConverter, PaUtil_SelectConverter | |
| */ | |
| extern PaUtilConverterTable paConverters; | |
| /** The type used to store all buffer zeroing functions. | |
| @see paZeroers; | |
| */ | |
| typedef struct{ | |
| PaUtilZeroer *ZeroU8; /* unsigned 8 bit, zero == 128 */ | |
| PaUtilZeroer *Zero8; | |
| PaUtilZeroer *Zero16; | |
| PaUtilZeroer *Zero24; | |
| PaUtilZeroer *Zero32; | |
| } PaUtilZeroerTable; | |
| /** A table of pointers to all required zeroer functions. | |
| PaUtil_SelectZeroer() uses this table to lookup the appropriate | |
| conversion functions. The fields of this structure are initialized | |
| with default conversion functions. User code may substitute optimised | |
| conversion functions by assigning different function pointers to | |
| these fields. | |
| @note | |
| If the PA_NO_STANDARD_ZEROERS preprocessor variable is defined, | |
| PortAudio's standard zeroers will not be compiled, and all fields | |
| of this structure will be initialized to NULL. In such cases, users | |
| should supply their own zeroing functions for the sample sizes which | |
| they intend to use. | |
| @see PaUtilZeroerTable, PaUtilZeroer, PaUtil_SelectZeroer | |
| */ | |
| extern PaUtilZeroerTable paZeroers; | |
| } | |