mirror of
https://github.com/RetroDECK/Duckstation.git
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184 lines
4.6 KiB
C
184 lines
4.6 KiB
C
/*
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** Copyright (c) 2002-2016, Erik de Castro Lopo <erikd@mega-nerd.com>
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** All rights reserved.
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**
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** This code is released under 2-clause BSD license. Please see the
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** file at : https://github.com/erikd/libsamplerate/blob/master/COPYING
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*/
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/*
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** API documentation is available here:
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** http://www.mega-nerd.com/SRC/api.html
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*/
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#ifndef SAMPLERATE_H
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#define SAMPLERATE_H
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#ifdef __cplusplus
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extern "C" {
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#endif /* __cplusplus */
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/* Opaque data type SRC_STATE. */
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typedef struct SRC_STATE_tag SRC_STATE ;
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/* SRC_DATA is used to pass data to src_simple() and src_process(). */
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typedef struct
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{ const float *data_in ;
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float *data_out ;
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long input_frames, output_frames ;
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long input_frames_used, output_frames_gen ;
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int end_of_input ;
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double src_ratio ;
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} SRC_DATA ;
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/*
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** User supplied callback function type for use with src_callback_new()
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** and src_callback_read(). First parameter is the same pointer that was
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** passed into src_callback_new(). Second parameter is pointer to a
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** pointer. The user supplied callback function must modify *data to
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** point to the start of the user supplied float array. The user supplied
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** function must return the number of frames that **data points to.
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*/
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typedef long (*src_callback_t) (void *cb_data, float **data) ;
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/*
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** Standard initialisation function : return an anonymous pointer to the
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** internal state of the converter. Choose a converter from the enums below.
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** Error returned in *error.
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*/
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SRC_STATE* src_new (int converter_type, int channels, int *error) ;
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/*
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** Initilisation for callback based API : return an anonymous pointer to the
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** internal state of the converter. Choose a converter from the enums below.
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** The cb_data pointer can point to any data or be set to NULL. Whatever the
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** value, when processing, user supplied function "func" gets called with
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** cb_data as first parameter.
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*/
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SRC_STATE* src_callback_new (src_callback_t func, int converter_type, int channels,
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int *error, void* cb_data) ;
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/*
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** Cleanup all internal allocations.
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** Always returns NULL.
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*/
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SRC_STATE* src_delete (SRC_STATE *state) ;
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/*
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** Standard processing function.
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** Returns non zero on error.
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*/
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int src_process (SRC_STATE *state, SRC_DATA *data) ;
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/*
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** Callback based processing function. Read up to frames worth of data from
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** the converter int *data and return frames read or -1 on error.
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*/
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long src_callback_read (SRC_STATE *state, double src_ratio, long frames, float *data) ;
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/*
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** Simple interface for performing a single conversion from input buffer to
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** output buffer at a fixed conversion ratio.
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** Simple interface does not require initialisation as it can only operate on
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** a single buffer worth of audio.
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*/
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int src_simple (SRC_DATA *data, int converter_type, int channels) ;
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/*
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** This library contains a number of different sample rate converters,
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** numbered 0 through N.
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**
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** Return a string giving either a name or a more full description of each
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** sample rate converter or NULL if no sample rate converter exists for
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** the given value. The converters are sequentially numbered from 0 to N.
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*/
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const char *src_get_name (int converter_type) ;
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const char *src_get_description (int converter_type) ;
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const char *src_get_version (void) ;
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/*
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** Set a new SRC ratio. This allows step responses
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** in the conversion ratio.
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** Returns non zero on error.
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*/
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int src_set_ratio (SRC_STATE *state, double new_ratio) ;
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/*
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** Get the current channel count.
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** Returns negative on error, positive channel count otherwise
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*/
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int src_get_channels (SRC_STATE *state) ;
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/*
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** Reset the internal SRC state.
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** Does not modify the quality settings.
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** Does not free any memory allocations.
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** Returns non zero on error.
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*/
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int src_reset (SRC_STATE *state) ;
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/*
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** Return TRUE if ratio is a valid conversion ratio, FALSE
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** otherwise.
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*/
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int src_is_valid_ratio (double ratio) ;
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/*
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** Return an error number.
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*/
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int src_error (SRC_STATE *state) ;
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/*
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** Convert the error number into a string.
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*/
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const char* src_strerror (int error) ;
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/*
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** The following enums can be used to set the interpolator type
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** using the function src_set_converter().
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*/
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enum
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{
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SRC_SINC_BEST_QUALITY = 0,
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SRC_SINC_MEDIUM_QUALITY = 1,
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SRC_SINC_FASTEST = 2,
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SRC_ZERO_ORDER_HOLD = 3,
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SRC_LINEAR = 4,
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} ;
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/*
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** Extra helper functions for converting from short to float and
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** back again.
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*/
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void src_short_to_float_array (const short *in, float *out, int len) ;
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void src_float_to_short_array (const float *in, short *out, int len) ;
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void src_int_to_float_array (const int *in, float *out, int len) ;
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void src_float_to_int_array (const float *in, int *out, int len) ;
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#ifdef __cplusplus
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} /* extern "C" */
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#endif /* __cplusplus */
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#endif /* SAMPLERATE_H */
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