transposition.h File Reference

Detailed Description

Unified bit transposition functions for FastLED.

This file consolidates all bit transposition and bit-interleaving functions used throughout FastLED for various parallel LED output methods:

Core 8x1 Bit Transpose (from bitswap.h)

• Basic 8-byte by 8-bit rotation functions
• Based on Hacker's Delight algorithms
• Used by parallel output drivers on ARM, ESP8266, ESP32

SPI Multi-Lane Transposer

• Bit-interleaving for 2/4/8/16-way SPI parallel transmission
• Unified stateless functional design
• Used by APA102, SK9822, LPD8806, WS2801, P9813 controllers

Parallel Strip Transposer (RP2040/RP2350)

• Transpose N LED strips into bit-parallel format for PIO
• Optimized for 2/4/8 strip configurations
• Used by RP2040/RP2350 PIO-based parallel output

Definition in file transposition.h.

#include "fl/stl/compiler_control.h"
#include "fl/stl/int.h"
#include "fl/stl/span.h"
#include "fl/stl/optional.h"
#include "fl/stl/cstring.h"
#include "fl/stl/noexcept.h"

Include dependency graph for transposition.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Classes
union	fl::bitswap_type
	Union containing a full 8 bytes to swap the bit orientation on. More...
struct	fl::bitswap_type.__unnamed0__
union	fl::just8bits
	Structure representing 8 bits of access. More...
struct	fl::just8bits.__unnamed0__
class	fl::SPITransposer
	Unified stateless bit-interleaving transposer for multi-lane SPI parallel LED transmission. More...
struct	fl::SPITransposer::LaneData
	Lane data structure: payload + padding frame. More...
struct	fl::sub4
	Structure representing 32 bits of access. More...

Namespaces
namespace	fl
	Base definition for an LED controller.

Functions
FASTLED_FORCE_INLINE u32	fl::calculate_transpose_buffer_size (u16 num_leds, u8 bytes_per_led) FL_NOEXCEPT
	Calculate output buffer size needed for transposed data.
template<int m, int n>
FASTLED_FORCE_INLINE void	fl::transpose8 (unsigned char *A, unsigned char *B) FL_NOEXCEPT
	Templated 8x8 bit transpose with custom stride.
FASTLED_FORCE_INLINE void	fl::transpose8x1 (unsigned char *A, unsigned char *B) FL_NOEXCEPT
	Simplified 8x1 bit transpose (inline version)
FASTLED_FORCE_INLINE void	fl::transpose8x1_MSB (unsigned char *A, unsigned char *B) FL_NOEXCEPT
	Simplified 8x1 bit transpose with MSB-first output.
void	fl::transpose8x1_noinline (unsigned char *A, unsigned char *B) FL_NOEXCEPT
	Simplified 8x1 bit transpose (non-inline version)
void	fl::transpose_16lane_inline (const u8 *const lanes[16], u8 *output, size_t num_bytes) FL_NOEXCEPT
	Low-level bit-interleaving primitive for 16 lanes (ISR-safe)
void	fl::transpose_2lane_inline (const u8 *lane0_byte, const u8 *lane1_byte, u8 *output, size_t num_bytes) FL_NOEXCEPT
	Low-level bit-interleaving primitive for 2 lanes (ISR-safe)
FASTLED_FORCE_INLINE void	fl::transpose_2strips (const u8 *const input[2], u8 *output, u16 num_leds, u8 bytes_per_led) FL_NOEXCEPT
	Transpose 2 LED strips into parallel bit format.
void	fl::transpose_4lane_inline (const u8 *const lanes[4], u8 *output, size_t num_bytes) FL_NOEXCEPT
	Low-level bit-interleaving primitive for 4 lanes (ISR-safe)
FASTLED_FORCE_INLINE void	fl::transpose_4strips (const u8 *const input[4], u8 *output, u16 num_leds, u8 bytes_per_led) FL_NOEXCEPT
	Transpose 4 LED strips into parallel bit format.
void	fl::transpose_8lane_inline (const u8 *const lanes[8], u8 *output, size_t num_bytes) FL_NOEXCEPT
	Low-level bit-interleaving primitive for 8 lanes (ISR-safe)
FASTLED_FORCE_INLINE void	fl::transpose_8strips (const u8 *const input[8], u8 *output, u16 num_leds, u8 bytes_per_led) FL_NOEXCEPT
	Transpose 8 LED strips into parallel bit format.
template<typename TSource>
void	fl::transpose_generic_inline (const TSource *const lanes[], size_t num_lanes, u8 *output, size_t num_items) FL_NOEXCEPT
	Generic bit-interleaving primitive for N lanes with M-bit source data (ISR-safe)
bool	fl::transpose_strips (u8 num_strips, const u8 *const *input, u8 *output, u16 num_leds, u8 bytes_per_led) FL_NOEXCEPT
	Helper to transpose N strips with automatic dispatch.
FASTLED_FORCE_INLINE FL_IRAM size_t	fl::transpose_wave8byte_parlio (const u8 *FL_RESTRICT_PARAM laneWaveforms, size_t data_width, u8 *FL_RESTRICT_PARAM outputBuffer) FL_NOEXCEPT
template<size_t DATA_WIDTH>
FASTLED_FORCE_INLINE FL_IRAM FL_OPTIMIZE_FUNCTION size_t	fl::transpose_wave8byte_parlio_template (const u8 *FL_RESTRICT_PARAM laneWaveforms, u8 *FL_RESTRICT_PARAM outputBuffer) FL_NOEXCEPT
	Template specialization of transpose for compile-time data_width (optimization)

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Class Documentation

fl::bitswap_type

union fl::bitswap_type

Class Members
struct bitswap_type.__unnamed0__	__unnamed__
u8	bytes[8]	eight 8-bit values to load for swapping
u32	word[2]	two 32-bit values to load for swapping

fl::bitswap_type.__unnamed0__

struct fl::bitswap_type.__unnamed0__

Class Members
sub4	a	32-bit access struct for bit swapping, upper four bytes
sub4	b	32-bit access struct for bit swapping, lower four bytes

fl::just8bits

union fl::just8bits

Class Members
struct just8bits.__unnamed0__	__unnamed__
u8	raw	the entire byte

fl::just8bits.__unnamed0__

struct fl::just8bits.__unnamed0__

Class Members
u32	a0:1	bit 0 (0x01)
u32	a1:1	bit 1 (0x02)
u32	a2:1	bit 2 (0x04)
u32	a3:1	bit 3 (0x08)
u32	a4:1	bit 4 (0x10)
u32	a5:1	bit 5 (0x20)
u32	a6:1	bit 6 (0x40)
u32	a7:1	bit 7 (0x80)

fl::SPITransposer::LaneData

struct fl::SPITransposer::LaneData

Collaboration diagram for fl::SPITransposer::LaneData:

Class Members
span< const u8 >	padding_frame	Black LED frame for padding (repeating pattern)
span< const u8 >	payload	Actual LED data for this lane.

fl::sub4

struct fl::sub4

Class Members
u32	a0:1	byte 'a', bit 0
u32	a1:1	byte 'a', bit 1
u32	a2:1	byte 'a', bit 2
u32	a3:1	byte 'a', bit 3
u32	a4:1	byte 'a', bit 4
u32	a5:1	byte 'a', bit 5
u32	a6:1	byte 'a', bit 6
u32	a7:1	byte 'a', bit 7
u32	b0:1	byte 'b', bit 0
u32	b1:1	byte 'b', bit 1
u32	b2:1	byte 'b', bit 2
u32	b3:1	byte 'b', bit 3
u32	b4:1	byte 'b', bit 4
u32	b5:1	byte 'b', bit 5
u32	b6:1	byte 'b', bit 6
u32	b7:1	byte 'b', bit 7
u32	c0:1	byte 'c', bit 0
u32	c1:1	byte 'c', bit 1
u32	c2:1	byte 'c', bit 2
u32	c3:1	byte 'c', bit 3
u32	c4:1	byte 'c', bit 4
u32	c5:1	byte 'c', bit 5
u32	c6:1	byte 'c', bit 6
u32	c7:1	byte 'c', bit 7
u32	d0:1	byte 'd', bit 0
u32	d1:1	byte 'd', bit 1
u32	d2:1	byte 'd', bit 2
u32	d3:1	byte 'd', bit 3
u32	d4:1	byte 'd', bit 4
u32	d5:1	byte 'd', bit 5
u32	d6:1	byte 'd', bit 6
u32	d7:1	byte 'd', bit 7