X-Git-Url: http://git.linex4red.de/pub/USBasp.git/blobdiff_plain/d4ca7fb44c7d326b96cf391f0275dc323dbe24de..77a9df36a77d2523dd2bc24fa17f9f04c6c175c5:/Projects/Magstripe/Lib/CircularBitBuffer.c diff --git a/Projects/Magstripe/Lib/CircularBitBuffer.c b/Projects/Magstripe/Lib/CircularBitBuffer.c index 2142ead0e..b31696331 100644 --- a/Projects/Magstripe/Lib/CircularBitBuffer.c +++ b/Projects/Magstripe/Lib/CircularBitBuffer.c @@ -1,113 +1,115 @@ -/* - LUFA Library - Copyright (C) Dean Camera, 2009. - - dean [at] fourwalledcubicle [dot] com - www.fourwalledcubicle.com -*/ - -/* - Copyright 2009 Denver Gingerich (denver [at] ossguy [dot] com) - Copyright 2009 Dean Camera (dean [at] fourwalledcubicle [dot] com) - - Permission to use, copy, modify, distribute, and sell this - software and its documentation for any purpose is hereby granted - without fee, provided that the above copyright notice appear in - all copies and that both that the copyright notice and this - permission notice and warranty disclaimer appear in supporting - documentation, and that the name of the author not be used in - advertising or publicity pertaining to distribution of the - software without specific, written prior permission. - - The author disclaim all warranties with regard to this - software, including all implied warranties of merchantability - and fitness. In no event shall the author be liable for any - special, indirect or consequential damages or any damages - whatsoever resulting from loss of use, data or profits, whether - in an action of contract, negligence or other tortious action, - arising out of or in connection with the use or performance of - this software. -*/ - -/** Circular bit buffer library. This will allow for individual bits - * to be stored in packed form inside circular buffers, to reduce - * overall RAM usage. - */ - -#include "CircularBitBuffer.h" - -/** Function to initialize or reset a bit buffer, ready for data to be stored into it. */ -void BitBuffer_Init(BitBuffer_t* const Buffer) -{ - /* Reset the number of stored bits in the buffer */ - Buffer->Elements = 0; - - /* Reset the data in and out pointer structures in the buffer to the first buffer bit */ - Buffer->In.CurrentByte = Buffer->Data; - Buffer->In.ByteMask = (1 << 0); - Buffer->Out.CurrentByte = Buffer->Data; - Buffer->Out.ByteMask = (1 << 0); -} - -/** Function to store the given bit into the given bit buffer. */ -void BitBuffer_StoreNextBit(BitBuffer_t* const Buffer, const bool Bit) -{ - /* If the bit to store is true, set the next bit in the buffer */ - if (Bit) - *Buffer->In.CurrentByte |= Buffer->In.ByteMask; - - /* Increment the number of stored bits in the buffer counter */ - Buffer->Elements++; - - /* Check if the current buffer byte is full of stored bits */ - if (Buffer->In.ByteMask == (1 << 7)) - { - /* Check if the end of the buffer has been reached, if so reset to start of buffer, otherwise advance to next bit */ - if (Buffer->In.CurrentByte != &Buffer->Data[sizeof(Buffer->Data) - 1]) - Buffer->In.CurrentByte++; - else - Buffer->In.CurrentByte = Buffer->Data; - - /* Reset the storage bit mask in the current buffer byte to the first bit */ - Buffer->In.ByteMask = (1 << 0); - } - else - { - /* Shift the current storage bit mask to the next bit in the current byte */ - Buffer->In.ByteMask <<= 1; - } -} - -/** Function to retrieve the next bit stored in the given bit buffer. */ -bool BitBuffer_GetNextBit(BitBuffer_t* const Buffer) -{ - /* Retrieve the value of the next bit stored in the buffer */ - bool Bit = ((*Buffer->Out.CurrentByte & Buffer->Out.ByteMask) != 0); - - /* Clear the buffer bit */ - *Buffer->Out.CurrentByte &= ~Buffer->Out.ByteMask; - - /* Decrement the number of stored bits in the buffer counter */ - Buffer->Elements--; - - /* Check if the current buffer byte is empty of stored bits */ - if (Buffer->Out.ByteMask == (1 << 7)) - { - /* Check if the end of the buffer has been reached, if so reset to start of buffer, otherwise advance to next bit */ - if (Buffer->Out.CurrentByte != &Buffer->Data[sizeof(Buffer->Data) - 1]) - Buffer->Out.CurrentByte++; - else - Buffer->Out.CurrentByte = Buffer->Data; - - /* Reset the retrieval bit mask in the current buffer byte to the first bit */ - Buffer->Out.ByteMask = (1 << 0); - } - else - { - /* Shift the current retrieval bit mask to the next bit in the current byte */ - Buffer->Out.ByteMask <<= 1; - } - - /* Return the retrieved bit from the buffer */ - return Bit; -} +/* + LUFA Library + Copyright (C) Dean Camera, 2011. + + dean [at] fourwalledcubicle [dot] com + www.lufa-lib.org +*/ + +/* + Copyright 2010 Denver Gingerich (denver [at] ossguy [dot] com) + Copyright 2011 Dean Camera (dean [at] fourwalledcubicle [dot] com) + + Permission to use, copy, modify, distribute, and sell this + software and its documentation for any purpose is hereby granted + without fee, provided that the above copyright notice appear in + all copies and that both that the copyright notice and this + permission notice and warranty disclaimer appear in supporting + documentation, and that the name of the author not be used in + advertising or publicity pertaining to distribution of the + software without specific, written prior permission. + + The author disclaim all warranties with regard to this + software, including all implied warranties of merchantability + and fitness. In no event shall the author be liable for any + special, indirect or consequential damages or any damages + whatsoever resulting from loss of use, data or profits, whether + in an action of contract, negligence or other tortious action, + arising out of or in connection with the use or performance of + this software. +*/ + +/** Circular bit buffer library. This will allow for individual bits + * to be stored in packed form inside circular buffers, to reduce + * overall RAM usage. + */ + +#include "CircularBitBuffer.h" + +/** Function to initialize or reset a bit buffer, ready for data to be stored into it. */ +void BitBuffer_Init(BitBuffer_t* const Buffer) +{ + /* Reset the number of stored bits in the buffer */ + Buffer->Elements = 0; + + /* Reset the data in and out pointer structures in the buffer to the first buffer bit */ + Buffer->In.CurrentByte = Buffer->Data; + Buffer->In.ByteMask = (1 << 0); + Buffer->Out.CurrentByte = Buffer->Data; + Buffer->Out.ByteMask = (1 << 0); +} + +/** Function to store the given bit into the given bit buffer. */ +void BitBuffer_StoreNextBit(BitBuffer_t* const Buffer, + const bool Bit) +{ + /* If the bit to store is true, set the next bit in the buffer */ + if (Bit) + *Buffer->In.CurrentByte |= Buffer->In.ByteMask; + + /* Increment the number of stored bits in the buffer counter */ + Buffer->Elements++; + + /* Check if the current buffer byte is full of stored bits */ + if (Buffer->In.ByteMask == (1 << 7)) + { + /* Check if the end of the buffer has been reached, if so reset to start of buffer, otherwise advance to next bit */ + if (Buffer->In.CurrentByte != &Buffer->Data[sizeof(Buffer->Data) - 1]) + Buffer->In.CurrentByte++; + else + Buffer->In.CurrentByte = Buffer->Data; + + /* Reset the storage bit mask in the current buffer byte to the first bit */ + Buffer->In.ByteMask = (1 << 0); + } + else + { + /* Shift the current storage bit mask to the next bit in the current byte */ + Buffer->In.ByteMask <<= 1; + } +} + +/** Function to retrieve the next bit stored in the given bit buffer. */ +bool BitBuffer_GetNextBit(BitBuffer_t* const Buffer) +{ + /* Retrieve the value of the next bit stored in the buffer */ + bool Bit = ((*Buffer->Out.CurrentByte & Buffer->Out.ByteMask) != 0); + + /* Clear the buffer bit */ + *Buffer->Out.CurrentByte &= ~Buffer->Out.ByteMask; + + /* Decrement the number of stored bits in the buffer counter */ + Buffer->Elements--; + + /* Check if the current buffer byte is empty of stored bits */ + if (Buffer->Out.ByteMask == (1 << 7)) + { + /* Check if the end of the buffer has been reached, if so reset to start of buffer, otherwise advance to next bit */ + if (Buffer->Out.CurrentByte != &Buffer->Data[sizeof(Buffer->Data) - 1]) + Buffer->Out.CurrentByte++; + else + Buffer->Out.CurrentByte = Buffer->Data; + + /* Reset the retrieval bit mask in the current buffer byte to the first bit */ + Buffer->Out.ByteMask = (1 << 0); + } + else + { + /* Shift the current retrieval bit mask to the next bit in the current byte */ + Buffer->Out.ByteMask <<= 1; + } + + /* Return the retrieved bit from the buffer */ + return Bit; +} +