/* Arduino SdFat Library
* Copyright (C) 2009 by William Greiman
*
* This file is part of the Arduino SdFat Library
*
* This Library is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This Library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the Arduino SdFat Library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#include "Marlin.h"
#ifdef SDSUPPORT
#include "SdFile.h"
/** Create a file object and open it in the current working directory.
*
* \param[in] path A path with a valid 8.3 DOS name for a file to be opened.
*
* \param[in] oflag Values for \a oflag are constructed by a bitwise-inclusive
* OR of open flags. see SdBaseFile::open(SdBaseFile*, const char*, uint8_t).
*/
SdFile::SdFile(const char* path, uint8_t oflag) : SdBaseFile(path, oflag) {
}
bool SdFile::openFilteredGcode(SdBaseFile* dirFile, const char* path){
if( open(dirFile, path, O_READ) ){
// compute the block to start with
if( ! gfComputeNextFileBlock() )
return false;
gfReset();
return true;
} else {
return false;
}
}
bool SdFile::seekSetFilteredGcode(uint32_t pos){
if(! seekSet(pos) )return false;
if(! gfComputeNextFileBlock() )return false;
gfReset();
return true;
}
const uint8_t *SdFile::gfBlockBuffBegin() const {
return vol_->cache()->data; // this is constant for the whole time, so it should be fast and sleek
}
void SdFile::gfReset(){
// reset cache read ptr to its begin
gfReadPtr = gfBlockBuffBegin() + gfOffset;
}
// think twice before allowing this to inline - manipulating 4B longs is costly
// moreover - this function has its parameters in registers only, so no heavy stack usage besides the call/ret
void __attribute__((noinline)) SdFile::gfUpdateCurrentPosition(uint16_t inc){
curPosition_ += inc;
}
#define find_endl(resultP, startP) \
__asm__ __volatile__ ( \
"cycle: \n" \
"ld r22, Z+ \n" \
"cpi r22, 0x0A \n" \
"brne cycle \n" \
: "=z" (resultP) /* result of the ASM code - in our case the Z register (R30:R31) */ \
: "z" (startP) /* input of the ASM code - in our case the Z register as well (R30:R31) */ \
: "r22" /* modifying register R22 - so that the compiler knows */ \
)
// avoid calling the default heavy-weight read() for just one byte
int16_t SdFile::readFilteredGcode(){
if( ! gfEnsureBlock() ){
goto eof_or_fail; // this is unfortunate :( ... other calls are using the cache and we can loose the data block of our gcode file
}
// assume, we have the 512B block cache filled and terminated with a '\n'
{
const uint8_t *start = gfReadPtr;
// It may seem unreasonable to copy the variable into a local one and copy it back at the end of this method,
// but there is an important point of view: the compiler is unsure whether it can optimize the reads/writes
// to gfReadPtr within this method, because it is a class member variable.
// The compiler cannot see, if omitting read/write won't have any incorrect side-effects to the rest of the whole FW.
// So this trick explicitly states, that rdPtr is a local variable limited to the scope of this method,
// therefore the compiler can omit read/write to it (keep it in registers!) as it sees fit.
// And it does! Codesize dropped by 68B!
const uint8_t *rdPtr = gfReadPtr;
// the same applies to gfXBegin, codesize dropped another 100B!
const uint8_t *blockBuffBegin = gfBlockBuffBegin();
uint8_t consecutiveCommentLines = 0;
while( *rdPtr == ';' ){
for(;;){
//while( *(++gfReadPtr) != '\n' ); // skip until a newline is found - suboptimal code!
// Wondering, why this "nice while cycle" is done in such a weird way using a separate find_endl() function?
// Have a look at the ASM code GCC produced!
// At first - a separate find_endl() makes the compiler understand,
// that I don't need to store gfReadPtr every time, I'm only interested in the final address where the '\n' was found
// - the cycle can run on CPU registers only without touching memory besides reading the character being compared.
// Not only makes the code run considerably faster, but is also 40B shorter!
// This was the generated code:
//FORCE_INLINE const uint8_t * find_endl(const uint8_t *p){
// while( *(++p) != '\n' ); // skip until a newline is found
// return p; }
// 11c5e: movw r30, r18
// 11c60: subi r18, 0xFF ; 255
// 11c62: sbci r19, 0xFF ; 255
// 11c64: ld r22, Z
// 11c66: cpi r22, 0x0A ; 10
// 11c68: brne .-12 ; 0x11c5e <get_command()+0x524>
// Still, even that was suboptimal as the compiler seems not to understand the usage of ld r22, Z+ (the plus is important)
// aka automatic increment of the Z register (R30:R31 pair)
// There is no other way than pure ASM!
find_endl(rdPtr, rdPtr);
// found a newline, prepare the next block if block cache end reached
if( rdPtr - blockBuffBegin > 512 ){
// at the end of block cache, fill new data in
gfUpdateCurrentPosition( rdPtr - start - 1 );
if( ! gfComputeNextFileBlock() )goto eof_or_fail;
if( ! gfEnsureBlock() )goto eof_or_fail; // fetch it into RAM
rdPtr = start = blockBuffBegin;
} else {
if(consecutiveCommentLines >= 250){
--rdPtr; // unget the already consumed newline
goto emit_char;
}
// peek the next byte - we are inside the block at least at 511th index - still safe
if( *rdPtr == ';' ){
// consecutive comment
++consecutiveCommentLines;
} else {
--rdPtr; // unget the already consumed newline
goto emit_char;
}
break; // found the real end of the line even across many blocks
}
}
}
emit_char:
{
gfUpdateCurrentPosition( rdPtr - start + 1 );
int16_t rv = *rdPtr++;
if( curPosition_ >= fileSize_ ){
// past the end of file
goto eof_or_fail;
} else if( rdPtr - blockBuffBegin >= 512 ){
// past the end of current bufferred block - prepare the next one...
if( ! gfComputeNextFileBlock() )goto eof_or_fail;
// don't need to force fetch the block here, it will get loaded on the next call
rdPtr = blockBuffBegin;
}
// save the current read ptr for the next run
gfReadPtr = rdPtr;
return rv;
}
}
eof_or_fail:
// make the rdptr point to a safe location - end of file
gfReadPtr = gfBlockBuffBegin() + 512;
return -1;
}
bool SdFile::gfEnsureBlock(){
// this comparison is heavy-weight, especially when there is another one inside cacheRawBlock
// but it is necessary to avoid computing of terminateOfs if not needed
if( gfBlock != vol_->cacheBlockNumber_ ){
if ( ! vol_->cacheRawBlock(gfBlock, SdVolume::CACHE_FOR_READ)){
return false;
}
// terminate with a '\n'
const uint32_t terminateOfs = fileSize_ - gfOffset;
vol_->cache()->data[ terminateOfs < 512 ? terminateOfs : 512 ] = '\n';
}
return true;
}
bool SdFile::gfComputeNextFileBlock() {
// error if not open or write only
if (!isOpen() || !(flags_ & O_READ)) return false;
gfOffset = curPosition_ & 0X1FF; // offset in block
if (type_ == FAT_FILE_TYPE_ROOT_FIXED) {
// SHR by 9 means skip the last byte and shift just 3 bytes by 1
// -> should be 8 instructions... and not the horrible loop shifting 4 bytes at once
// still need to get some work on this
gfBlock = vol_->rootDirStart() + (curPosition_ >> 9);
} else {
uint8_t blockOfCluster = vol_->blockOfCluster(curPosition_);
if (gfOffset == 0 && blockOfCluster == 0) {
// start of new cluster
if (curPosition_ == 0) {
// use first cluster in file
curCluster_ = firstCluster_;
} else {
// get next cluster from FAT
if (!vol_->fatGet(curCluster_, &curCluster_)) return false;
}
}
gfBlock = vol_->clusterStartBlock(curCluster_) + blockOfCluster;
}
return true;
}
//------------------------------------------------------------------------------
/** Write data to an open file.
*
* \note Data is moved to the cache but may not be written to the
* storage device until sync() is called.
*
* \param[in] buf Pointer to the location of the data to be written.
*
* \param[in] nbyte Number of bytes to write.
*
* \return For success write() returns the number of bytes written, always
* \a nbyte. If an error occurs, write() returns -1. Possible errors
* include write() is called before a file has been opened, write is called
* for a read-only file, device is full, a corrupt file system or an I/O error.
*
*/
int16_t SdFile::write(const void* buf, uint16_t nbyte) {
return SdBaseFile::write(buf, nbyte);
}
//------------------------------------------------------------------------------
/** Write a byte to a file. Required by the Arduino Print class.
* \param[in] b the byte to be written.
* Use writeError to check for errors.
*/
#if ARDUINO >= 100
size_t SdFile::write(uint8_t b)
{
return SdBaseFile::write(&b, 1);
}
#else
void SdFile::write(uint8_t b)
{
SdBaseFile::write(&b, 1);
}
#endif
//------------------------------------------------------------------------------
/** Write a string to a file. Used by the Arduino Print class.
* \param[in] str Pointer to the string.
* Use writeError to check for errors.
*/
void SdFile::write(const char* str) {
SdBaseFile::write(str, strlen(str));
}
//------------------------------------------------------------------------------
/** Write a PROGMEM string to a file.
* \param[in] str Pointer to the PROGMEM string.
* Use writeError to check for errors.
*/
void SdFile::write_P(PGM_P str) {
for (uint8_t c; (c = pgm_read_byte(str)); str++) write(c);
}
//------------------------------------------------------------------------------
/** Write a PROGMEM string followed by CR/LF to a file.
* \param[in] str Pointer to the PROGMEM string.
* Use writeError to check for errors.
*/
void SdFile::writeln_P(PGM_P str) {
write_P(str);
write_P(PSTR("\r\n"));
}
#endif