Method create

SerialFlashDirectory.cpp:256–331

//  char strings[stringssize]

bool SerialFlashChip::create(const char *filename, uint32_t length, uint32_t align)
{
	uint32_t maxfiles, stringsize;
	uint32_t index, buf[3];
	uint32_t address, straddr, len;
	SerialFlashFile file;

	// check if the file already exists
	if (exists(filename)) return false;

	// first, get the filesystem parameters
	maxfiles = check_signature();
	if (!maxfiles) return false;
	stringsize = (maxfiles & 0xFFFF0000) >> 14;
	maxfiles &= 0xFFFF;

	// find the first unused slot for this file
	index = find_first_unallocated_file_index(maxfiles);
	if (index >= maxfiles) return false;
	 //Serial.printf("index = %u\n", index);
	// compute where to store the filename and actual data
	straddr = 8 + maxfiles * 12;
	if (index == 0) {
		address = straddr + stringsize;
	} else {
		buf[2] = 0;
		SerialFlash.read(8 + maxfiles * 2 + (index-1) * 10, buf, 10);
		address = buf[0] + buf[1];
		straddr += buf[2] * 4;
		straddr += string_length(straddr);
		straddr = (straddr + 3) & 0x0003FFFC;
	}
	 //Serial.printf("straddr = %u\n", straddr);
	 //Serial.printf("address = %u\n", address);
	 //Serial.printf("length = %u\n", length);
	if (align > 0) {
		// for files aligned to sectors, adjust addr & len
		address += align - 1;
		address /= align;
		address *= align;
		 //Serial.printf("align address = %u\n", address);
		length += align - 1;
		length /= align;
		length *= align;
		 //Serial.printf("align length = %u\n", length);
	} else {
		// always align every file to a page boundary
		// for predictable write latency and to guarantee
		// write suspend for reading another file can't
		// conflict on the same page (2 files never share
		// a write page).
		address = (address + 255) & 0xFFFFFF00;
	}
	 //Serial.printf("address = %u\n", address);
	// last check, if enough space exists...
	len = strlen(filename);
	// TODO: check for enough string space for filename
	uint8_t id[5];