From 990090a4cc9070837d31e66b58d40f0c3d038741 Mon Sep 17 00:00:00 2001 From: Yuval Adam Date: Sun, 16 Mar 2014 14:41:11 +0200 Subject: Add usblib and utils --- utils/ringbuf.c | 712 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 712 insertions(+) create mode 100644 utils/ringbuf.c (limited to 'utils/ringbuf.c') diff --git a/utils/ringbuf.c b/utils/ringbuf.c new file mode 100644 index 0000000..f489239 --- /dev/null +++ b/utils/ringbuf.c @@ -0,0 +1,712 @@ +//***************************************************************************** +// +// ringbuf.c - Ring buffer management utilities. +// +// Copyright (c) 2008-2014 Texas Instruments Incorporated. All rights reserved. +// Software License Agreement +// +// Texas Instruments (TI) is supplying this software for use solely and +// exclusively on TI's microcontroller products. The software is owned by +// TI and/or its suppliers, and is protected under applicable copyright +// laws. You may not combine this software with "viral" open-source +// software in order to form a larger program. +// +// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS. +// NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT +// NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY +// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL +// DAMAGES, FOR ANY REASON WHATSOEVER. +// +// This is part of revision 2.1.0.12573 of the Tiva Utility Library. +// +//***************************************************************************** + +#include +#include +#include "inc/hw_types.h" +#include "driverlib/debug.h" +#include "driverlib/interrupt.h" +#include "utils/ringbuf.h" + +//***************************************************************************** +// +//! \addtogroup ringbuf_api +//! @{ +// +//***************************************************************************** + +//***************************************************************************** +// +// Define NULL, if not already defined. +// +//***************************************************************************** +#ifndef NULL +#define NULL ((void *)0) +#endif + +//***************************************************************************** +// +// Change the value of a variable atomically. +// +// \param pui32Val points to the index whose value is to be modified. +// \param ui32Delta is the number of bytes to increment the index by. +// \param ui32Size is the size of the buffer the index refers to. +// +// This function is used to increment a read or write buffer index that may be +// written in various different contexts. It ensures that the +// read/modify/write sequence is not interrupted and, hence, guards against +// corruption of the variable. The new value is adjusted for buffer wrap. +// +// \return None. +// +//***************************************************************************** +static void +UpdateIndexAtomic(volatile uint32_t *pui32Val, uint32_t ui32Delta, + uint32_t ui32Size) +{ + bool bIntsOff; + + // + // Turn interrupts off temporarily. + // + bIntsOff = IntMasterDisable(); + + // + // Update the variable value. + // + *pui32Val += ui32Delta; + + // + // Correct for wrap. We use a loop here since we don't want to use a + // modulus operation with interrupts off but we don't want to fail in + // case ui32Delta is greater than ui32Size (which is extremely unlikely + // but...) + // + while(*pui32Val >= ui32Size) + { + *pui32Val -= ui32Size; + } + + // + // Restore the interrupt state + // + if(!bIntsOff) + { + IntMasterEnable(); + } +} + +//***************************************************************************** +// +//! Determines whether the ring buffer whose pointers and size are provided +//! is full or not. +//! +//! \param psRingBuf is the ring buffer object to empty. +//! +//! This function is used to determine whether or not a given ring buffer is +//! full. The structure is specifically to ensure that we do not see +//! warnings from the compiler related to the order of volatile accesses +//! being undefined. +//! +//! \return Returns \b true if the buffer is full or \b false otherwise. +// +//***************************************************************************** +bool +RingBufFull(tRingBufObject *psRingBuf) +{ + uint32_t ui32Write; + uint32_t ui32Read; + + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + + // + // Copy the Read/Write indices for calculation. + // + ui32Write = psRingBuf->ui32WriteIndex; + ui32Read = psRingBuf->ui32ReadIndex; + + // + // Return the full status of the buffer. + // + return((((ui32Write + 1) % psRingBuf->ui32Size) == ui32Read) ? true : + false); +} + +//***************************************************************************** +// +//! Determines whether the ring buffer whose pointers and size are provided +//! is empty or not. +//! +//! \param psRingBuf is the ring buffer object to empty. +//! +//! This function is used to determine whether or not a given ring buffer is +//! empty. The structure is specifically to ensure that we do not see +//! warnings from the compiler related to the order of volatile accesses +//! being undefined. +//! +//! \return Returns \b true if the buffer is empty or \b false otherwise. +// +//***************************************************************************** +bool +RingBufEmpty(tRingBufObject *psRingBuf) +{ + uint32_t ui32Write; + uint32_t ui32Read; + + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + + // + // Copy the Read/Write indices for calculation. + // + ui32Write = psRingBuf->ui32WriteIndex; + ui32Read = psRingBuf->ui32ReadIndex; + + // + // Return the empty status of the buffer. + // + return((ui32Write == ui32Read) ? true : false); +} + +//***************************************************************************** +// +//! Empties the ring buffer. +//! +//! \param psRingBuf is the ring buffer object to empty. +//! +//! Discards all data from the ring buffer. +//! +//! \return None. +// +//***************************************************************************** +void +RingBufFlush(tRingBufObject *psRingBuf) +{ + bool bIntsOff; + + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + + // + // Set the Read/Write pointers to be the same. Do this with interrupts + // disabled to prevent the possibility of corruption of the read index. + // + bIntsOff = IntMasterDisable(); + psRingBuf->ui32ReadIndex = psRingBuf->ui32WriteIndex; + if(!bIntsOff) + { + IntMasterEnable(); + } +} + +//***************************************************************************** +// +//! Returns number of bytes stored in ring buffer. +//! +//! \param psRingBuf is the ring buffer object to check. +//! +//! This function returns the number of bytes stored in the ring buffer. +//! +//! \return Returns the number of bytes stored in the ring buffer. +// +//***************************************************************************** +uint32_t +RingBufUsed(tRingBufObject *psRingBuf) +{ + uint32_t ui32Write; + uint32_t ui32Read; + + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + + // + // Copy the Read/Write indices for calculation. + // + ui32Write = psRingBuf->ui32WriteIndex; + ui32Read = psRingBuf->ui32ReadIndex; + + // + // Return the number of bytes contained in the ring buffer. + // + return((ui32Write >= ui32Read) ? (ui32Write - ui32Read) : + (psRingBuf->ui32Size - (ui32Read - ui32Write))); +} + +//***************************************************************************** +// +//! Returns number of bytes available in a ring buffer. +//! +//! \param psRingBuf is the ring buffer object to check. +//! +//! This function returns the number of bytes available in the ring buffer. +//! +//! \return Returns the number of bytes available in the ring buffer. +// +//***************************************************************************** +uint32_t +RingBufFree(tRingBufObject *psRingBuf) +{ + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + + // + // Return the number of bytes available in the ring buffer. + // + return((psRingBuf->ui32Size - 1) - RingBufUsed(psRingBuf)); +} + +//***************************************************************************** +// +//! Returns number of contiguous bytes of data stored in ring buffer ahead of +//! the current read pointer. +//! +//! \param psRingBuf is the ring buffer object to check. +//! +//! This function returns the number of contiguous bytes of data available in +//! the ring buffer ahead of the current read pointer. This represents the +//! largest block of data which does not straddle the buffer wrap. +//! +//! \return Returns the number of contiguous bytes available. +// +//***************************************************************************** +uint32_t +RingBufContigUsed(tRingBufObject *psRingBuf) +{ + uint32_t ui32Write; + uint32_t ui32Read; + + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + + // + // Copy the Read/Write indices for calculation. + // + ui32Write = psRingBuf->ui32WriteIndex; + ui32Read = psRingBuf->ui32ReadIndex; + + // + // Return the number of contiguous bytes available. + // + return((ui32Write >= ui32Read) ? (ui32Write - ui32Read) : + (psRingBuf->ui32Size - ui32Read)); +} + +//***************************************************************************** +// +//! Returns number of contiguous free bytes available in a ring buffer. +//! +//! \param psRingBuf is the ring buffer object to check. +//! +//! This function returns the number of contiguous free bytes ahead of the +//! current write pointer in the ring buffer. +//! +//! \return Returns the number of contiguous bytes available in the ring +//! buffer. +// +//***************************************************************************** +uint32_t +RingBufContigFree(tRingBufObject *psRingBuf) +{ + uint32_t ui32Write; + uint32_t ui32Read; + + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + + // + // Copy the Read/Write indices for calculation. + // + ui32Write = psRingBuf->ui32WriteIndex; + ui32Read = psRingBuf->ui32ReadIndex; + + // + // Return the number of contiguous bytes available. + // + if(ui32Read > ui32Write) + { + // + // The read pointer is above the write pointer so the amount of free + // space is the difference between the two indices minus 1 to account + // for the buffer full condition (write index one behind read index). + // + return((ui32Read - ui32Write) - 1); + } + else + { + // + // If the write pointer is above the read pointer, the amount of free + // space is the size of the buffer minus the write index. We need to + // add a special-case adjustment if the read index is 0 since we need + // to leave 1 byte empty to ensure we can tell the difference between + // the buffer being full and empty. + // + return(psRingBuf->ui32Size - ui32Write - ((ui32Read == 0) ? 1 : 0)); + } +} + +//***************************************************************************** +// +//! Return size in bytes of a ring buffer. +//! +//! \param psRingBuf is the ring buffer object to check. +//! +//! This function returns the size of the ring buffer. +//! +//! \return Returns the size in bytes of the ring buffer. +// +//***************************************************************************** +uint32_t +RingBufSize(tRingBufObject *psRingBuf) +{ + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + + // + // Return the number of bytes available in the ring buffer. + // + return(psRingBuf->ui32Size); +} + +//***************************************************************************** +// +//! Reads a single byte of data from a ring buffer. +//! +//! \param psRingBuf points to the ring buffer to be written to. +//! +//! This function reads a single byte of data from a ring buffer. +//! +//! \return The byte read from the ring buffer. +// +//***************************************************************************** +uint8_t +RingBufReadOne(tRingBufObject *psRingBuf) +{ + uint8_t ui8Temp; + + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + + // + // Verify that space is available in the buffer. + // + ASSERT(RingBufUsed(psRingBuf) != 0); + + // + // Write the data byte. + // + ui8Temp = psRingBuf->pui8Buf[psRingBuf->ui32ReadIndex]; + + // + // Increment the read index. + // + UpdateIndexAtomic(&psRingBuf->ui32ReadIndex, 1, psRingBuf->ui32Size); + + // + // Return the character read. + // + return(ui8Temp); +} + +//***************************************************************************** +// +//! Reads data from a ring buffer. +//! +//! \param psRingBuf points to the ring buffer to be read from. +//! \param pui8Data points to where the data should be stored. +//! \param ui32Length is the number of bytes to be read. +//! +//! This function reads a sequence of bytes from a ring buffer. +//! +//! \return None. +// +//***************************************************************************** +void +RingBufRead(tRingBufObject *psRingBuf, uint8_t *pui8Data, uint32_t ui32Length) +{ + uint32_t ui32Temp; + + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + ASSERT(pui8Data != NULL); + ASSERT(ui32Length != 0); + + // + // Verify that data is available in the buffer. + // + ASSERT(ui32Length <= RingBufUsed(psRingBuf)); + + // + // Read the data from the ring buffer. + // + for(ui32Temp = 0; ui32Temp < ui32Length; ui32Temp++) + { + pui8Data[ui32Temp] = RingBufReadOne(psRingBuf); + } +} + +//***************************************************************************** +// +//! Remove bytes from the ring buffer by advancing the read index. +//! +//! \param psRingBuf points to the ring buffer from which bytes are to be +//! removed. +//! \param ui32NumBytes is the number of bytes to be removed from the buffer. +//! +//! This function advances the ring buffer read index by a given number of +//! bytes, removing that number of bytes of data from the buffer. If +//! \e ui32NumBytes is larger than the number of bytes currently in the buffer, +//! the buffer is emptied. +//! +//! \return None. +// +//***************************************************************************** +void +RingBufAdvanceRead(tRingBufObject *psRingBuf, uint32_t ui32NumBytes) +{ + uint32_t ui32Count; + + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + + // + // Make sure that we are not being asked to remove more data than is + // there to be removed. + // + ui32Count = RingBufUsed(psRingBuf); + ui32Count = (ui32Count < ui32NumBytes) ? ui32Count : ui32NumBytes; + + // + // Advance the buffer read index by the required number of bytes. + // + UpdateIndexAtomic(&psRingBuf->ui32ReadIndex, ui32Count, + psRingBuf->ui32Size); +} + +//***************************************************************************** +// +//! Add bytes to the ring buffer by advancing the write index. +//! +//! \param psRingBuf points to the ring buffer to which bytes have been added. +//! \param ui32NumBytes is the number of bytes added to the buffer. +//! +//! This function should be used by clients who wish to add data to the buffer +//! directly rather than via calls to RingBufWrite() or RingBufWriteOne(). It +//! advances the write index by a given number of bytes. If the +//! \e ui32NumBytes parameter is larger than the amount of free space in the +//! buffer, the read pointer will be advanced to cater for the addition. Note +//! that this will result in some of the oldest data in the buffer being +//! discarded. +//! +//! \return None. +// +//***************************************************************************** +void +RingBufAdvanceWrite(tRingBufObject *psRingBuf, + uint32_t ui32NumBytes) +{ + uint32_t ui32Count; + bool bIntsOff; + + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + + // + // Make sure we were not asked to add a silly number of bytes. + // + ASSERT(ui32NumBytes <= psRingBuf->ui32Size); + + // + // Determine how much free space we currently think the buffer has. + // + ui32Count = RingBufFree(psRingBuf); + + // + // Advance the buffer write index by the required number of bytes and + // check that we have not run past the read index. Note that we must do + // this within a critical section (interrupts disabled) to prevent + // race conditions that could corrupt one or other of the indices. + // + bIntsOff = IntMasterDisable(); + + // + // Update the write pointer. + // + psRingBuf->ui32WriteIndex += ui32NumBytes; + + // + // Check and correct for wrap. + // + if(psRingBuf->ui32WriteIndex >= psRingBuf->ui32Size) + { + psRingBuf->ui32WriteIndex -= psRingBuf->ui32Size; + } + + // + // Did the client add more bytes than the buffer had free space for? + // + if(ui32Count < ui32NumBytes) + { + // + // Yes - we need to advance the read pointer to ahead of the write + // pointer to discard some of the oldest data. + // + psRingBuf->ui32ReadIndex = psRingBuf->ui32WriteIndex + 1; + + // + // Correct for buffer wrap if necessary. + // + if(psRingBuf->ui32ReadIndex >= psRingBuf->ui32Size) + { + psRingBuf->ui32ReadIndex -= psRingBuf->ui32Size; + } + } + + // + // Restore interrupts if we turned them off earlier. + // + if(!bIntsOff) + { + IntMasterEnable(); + } +} + +//***************************************************************************** +// +//! Writes a single byte of data to a ring buffer. +//! +//! \param psRingBuf points to the ring buffer to be written to. +//! \param ui8Data is the byte to be written. +//! +//! This function writes a single byte of data into a ring buffer. +//! +//! \return None. +// +//***************************************************************************** +void +RingBufWriteOne(tRingBufObject *psRingBuf, uint8_t ui8Data) +{ + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + + // + // Verify that space is available in the buffer. + // + ASSERT(RingBufFree(psRingBuf) != 0); + + // + // Write the data byte. + // + psRingBuf->pui8Buf[psRingBuf->ui32WriteIndex] = ui8Data; + + // + // Increment the write index. + // + UpdateIndexAtomic(&psRingBuf->ui32WriteIndex, 1, psRingBuf->ui32Size); +} + +//***************************************************************************** +// +//! Writes data to a ring buffer. +//! +//! \param psRingBuf points to the ring buffer to be written to. +//! \param pui8Data points to the data to be written. +//! \param ui32Length is the number of bytes to be written. +//! +//! This function write a sequence of bytes into a ring buffer. +//! +//! \return None. +// +//***************************************************************************** +void +RingBufWrite(tRingBufObject *psRingBuf, uint8_t *pui8Data, + uint32_t ui32Length) +{ + uint32_t ui32Temp; + + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + ASSERT(pui8Data != NULL); + ASSERT(ui32Length != 0); + + // + // Verify that space is available in the buffer. + // + ASSERT(ui32Length <= RingBufFree(psRingBuf)); + + // + // Write the data into the ring buffer. + // + for(ui32Temp = 0; ui32Temp < ui32Length; ui32Temp++) + { + RingBufWriteOne(psRingBuf, pui8Data[ui32Temp]); + } +} + +//***************************************************************************** +// +//! Initialize a ring buffer object. +//! +//! \param psRingBuf points to the ring buffer to be initialized. +//! \param pui8Buf points to the data buffer to be used for the ring buffer. +//! \param ui32Size is the size of the buffer in bytes. +//! +//! This function initializes a ring buffer object, preparing it to store data. +//! +//! \return None. +// +//***************************************************************************** +void +RingBufInit(tRingBufObject *psRingBuf, uint8_t *pui8Buf, + uint32_t ui32Size) +{ + // + // Check the arguments. + // + ASSERT(psRingBuf != NULL); + ASSERT(pui8Buf != NULL); + ASSERT(ui32Size != 0); + + // + // Initialize the ring buffer object. + // + psRingBuf->ui32Size = ui32Size; + psRingBuf->pui8Buf = pui8Buf; + psRingBuf->ui32WriteIndex = psRingBuf->ui32ReadIndex = 0; +} + +//***************************************************************************** +// +// Close the Doxygen group. +//! @} +// +//***************************************************************************** -- cgit v1.3.1