File i16_to_f32_core.h¶

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int16-to-float converter with configurable inverse scale. More...

• #include "clib_common.h"
• #include "jm_perf.h"

Classes¶

Public Functions¶

Detailed Description¶

Multiplies the signed int16 sample by 1/scale. The default scale of 32768.0 maps the full Q15 range [-32768, 32767] to [-1.0, ~+1.0), making it the exact inverse of F32ToI16 at its default scale. The inverse scale is pre-computed at construction time so each step is a single multiply with no division on the hot path.

Lifecycle: create -> (step / steps / reset)* -> destroy

>>> from doppler.cvt import I16ToF32
>>> import numpy as np
>>> obj = I16ToF32(scale=32768.0)
>>> float(obj.step(-32768))
-1.0
>>> float(obj.step(0))
0.0
>>> x = np.array([-32768, 0, 32767], dtype=np.int16)
>>> [round(v, 6) for v in obj.steps(x).tolist()]
[-1.0, 0.0, 0.999969]

Public Functions Documentation¶

function i16_to_f32_create¶

Create a i16_to_f32 instance.

i16_to_f32_state_t * i16_to_f32_create (
    float scale
) 

Pre-computes iscale = 1.0f / scale so the hot step path is a single multiply. Any non-zero finite float is a valid scale value.

Parameters:

• scale Denominator scale; 1/scale is applied to each sample (default: 32768.0f). Use 32768.0 to recover normalised [-1, +1] floats from a Q15 int16 stream.

Returns:

Heap-allocated state, or NULL on allocation failure.

Note:

Caller must call i16_to_f32_destroy() when done.

function i16_to_f32_destroy¶

Destroy a i16_to_f32 instance and release all memory.

void i16_to_f32_destroy (
    i16_to_f32_state_t * state
) 

Parameters:

• state May be NULL.

function i16_to_f32_reset¶

No-op reset, provided only for lifecycle symmetry.

void i16_to_f32_reset (
    i16_to_f32_state_t * state
) 

This converter carries no running state beyond the immutable iscale, so there is nothing to clear; the method exists so every converter in the module presents the same create / step / reset / destroy lifecycle.

Parameters:

• state Must be non-NULL.

>>> from doppler.cvt import I16ToF32
>>> c = I16ToF32()
>>> c.reset()           # stateless converter -> reset is a no-op
>>> round(c.step(-32768), 4)
-1.0

function i16_to_f32_step¶

Convert one signed int16 sample to a normalised float via 1/scale .

JM_FORCEINLINE  JM_HOT float i16_to_f32_step (
    const i16_to_f32_state_t * state,
    int16_t x
) 

Returns `(float)x \* iscale, a single multiply on the hot path. No saturation or clipping is possible — every int16 code maps cleanly to float32. At the default scale of 32768 the full Q15 range recovers[-1.0, ~+1.0)`, the exact inverse of F32ToI16.

Parameters:

• state Must be non-NULL.
• x Signed int16 code, normally a Q15 sample in [-32768, 32767].

Returns:

Normalised float, x / scale.

>>> from doppler.cvt import I16ToF32
>>> c = I16ToF32(scale=32768.0)   # Q15 int16 -> normalised float
>>> round(c.step(16384), 4)        # 16384 / 32768
0.5
>>> round(c.step(-32768), 4)       # full-negative code -> -1.0
-1.0

function i16_to_f32_steps¶

Process a block of int16 samples to float32.

void i16_to_f32_steps (
    i16_to_f32_state_t * state,
    const int16_t * input,
    float * output,
    size_t n
) 

Applies step() to every element. Accepts an optional pre-allocated output array; allocates a fresh one when output is NULL.

Parameters:

• state Must be non-NULL.
• input Input int16 array; must contain at least n elements.
• output Output float32 array; must contain at least n elements.
• n Number of samples to process.

>>> from doppler.cvt import I16ToF32
>>> import numpy as np
>>> I16ToF32().steps(
...     np.array([0, 16384, -32768], dtype=np.int16)).tolist()
[0.0, 0.5, -1.0]

The documentation for this class was generated from the following file native/inc/i16_to_f32/i16_to_f32_core.h