rs_ws281x 0.2.3

Wrapper for ws281x library using bindgen to track upstream
Documentation 
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// Copyright (c) 2015, Jacques Supcik, HEIA-FR
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//     * Neither the name of the <organization> nor the
//       names of its contributors may be used to endorse or promote products
//       derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

/*
Interface to ws2811 chip (neopixel driver). Make sure that you have
ws2811.h, rpihw.h, and pwm.h in a GCC include path (e.g. /usr/local/include) and
libws2811.a in a GCC library path (e.g. /usr/local/lib).
See https://github.com/jgarff/rpi_ws281x for instructions
*/

package ws2811

/*
#cgo CFLAGS: -std=c99
#cgo LDFLAGS: -lws2811
#include "ws2811.go.h"
*/
import "C"
import (
	"errors"
	"fmt"
	"unsafe"
)

func Init(gpioPin int, ledCount int, brightness int) error {
	C.ledstring.channel[0].gpionum = C.int(gpioPin)
	C.ledstring.channel[0].count = C.int(ledCount)
	C.ledstring.channel[0].brightness = C.uint8_t(brightness)
	res := int(C.ws2811_init(&C.ledstring))
	if res == 0 {
		return nil
	} else {
		return errors.New(fmt.Sprintf("Error ws2811.init.%d", res))
	}
}

func Fini() {
	C.ws2811_fini(&C.ledstring)
}

func Render() error {
	res := int(C.ws2811_render(&C.ledstring))
	if res == 0 {
		return nil
	} else {
		return errors.New(fmt.Sprintf("Error ws2811.render.%d", res))
	}
}

func Wait() error {
	res := int(C.ws2811_wait(&C.ledstring))
	if res == 0 {
		return nil
	} else {
		return errors.New(fmt.Sprintf("Error ws2811.wait.%d", res))
	}
}

func SetLed(index int, value uint32) {
	C.ws2811_set_led(&C.ledstring, C.int(index), C.uint32_t(value))
}

func Clear() {
	C.ws2811_clear(&C.ledstring)
}

func SetBitmap(a []uint32) {
	C.ws2811_set_bitmap(&C.ledstring, unsafe.Pointer(&a[0]), C.int(len(a)*4))
}