i want to read character by character from file and write that character in another file,
when the character is ";", i want to get the next line and continue read char by char
i used FileReader to read char by char and FileWriter for writing that char
the problem is that i can`t get the next line in the file, the program just processes the first line only
any idea, please
thanks
i have a solution to your problem :
File inputFile = new File("in.txt");
File outputFile = new File("out.txt");
FileReader in = new FileReader(inputFile);
FileWriter out = new FileWriter(outputFile);
int c;
while ((c = in.read()) != -1)
{
if (c == ';')
out.write('\n');
else
out.write(c);
}
in.close();
out.close();
If the first file contain :
hello;my;name;is;john
The second file will be :
hello
my
name
is
john
That's what you want?
If you have any questions you are welcome :)
Related
How I can to insert the value from txt file in to the Qlist...
QList<QString> list_StRead;
list_StRead.insert();
I can sorting txt file ... its mean that my file is a line by line. than after the insert to the Qlist I want to write in to Qtabelewidget. How I must to do?? u must to be completely understand. see the img file
tnx for all....
Here is the pseudo code.
Please try it. (Not tested, code written in notepad. excuse me any syntax errors).
//Your list
QList<QString> list_StRead;
//Text stream object read data and insert in list.
QTextStream in(&file);
while (!in.atEnd())
{
QString line = in.readLine(); //read one line at a time
list_StRead.push_back(line);
}
//loop your list
for(int i =0; i<list_StRead.size(); i++)
{
//Add by create your tablewidget item and append it.
YourTableWidget->setItem(rowNumber,colNumber,new QTableWidgetItem(list_StRead.at(i)))
}
I'm trying to modify graphic assets of the software I'm using (for aesthetic puroposess, I guess it's hard to do something harmful with graphic assets) but developer encrypted them. I'm not sure why he decided to do that since I used and modified a bunch of similar softwares and developers of those didn't bother (as I can see no reason why encrypting those assets would be necessary).
So anyway here are examples of those encrypted graphic assets:
http://www.mediafire.com/view/sx2yc0w5wkr9m2h/avatars_50-alpha.jpg
http://www.mediafire.com/download/i4fc52438hkp55l/avatars_80.png
Is there a way of decrypting those? If so how should I go about this?
The header "CF10" seems to be a privately added signature to signify the rest of the file is "encoded". This is a very simple XOR encoding: xor 8Dh was the first value I tried, and I got it right first time too. The reasoning behind trying that as the first value is that the value 8D occurs very frequently in the first 100 bytes-or-so, where they typically could be lots of zeroes.
"Decrypting" is thus very straightforward: if a file starts with the four bytes CF10, remove them and apply xor 8Dh on the rest of the file. Decoding the files show the first "JPG" is in fact a tiny PNG image (and not a very interesting one to boot), the second is indeed a PNG file:
The file extension may or may not be the original file extension; the one sample called ".jpg" is in fact also a PNG file, as can be seen by its header signature.
The following quick-and-dirty C source will decode the images. The same program can be adjusted to encode them as well, because the xor operation is exactly the same. The only thing needed is add a bit of logic flow:
read the first 4 bytes (maximum) of the input file and test if this forms the string CF10
if not, the file is not encoded:
a. write CF10 to the output file
b. encode the image by applying xor 8Dh on each byte
if so,
b. decode the image by applying xor 8Dh on each byte.
As you can see, there is no "3a" and both "b" steps are the same.
#include <stdio.h>
#include <string.h>
#ifndef MAX_PATH
#define MAX_PATH 256
#endif
#define INPUTPATH "c:\\documents"
#define OUTPUTPATH ""
int main (int argc, char **argv)
{
FILE *inp, *outp;
int i, encode_flag = 0;
char filename_buffer[MAX_PATH];
char sig[] = "CF10", *ptr;
if (argc != 3)
{
printf ("usage: decode [input] [output]\n");
return -1;
}
filename_buffer[0] = 0;
if (!strchr(argv[1], '/') && !strchr(argv[1], 92) && !strchr(argv[1], ':'))
strcpy (filename_buffer, INPUTPATH);
strcat (filename_buffer, argv[1]);
inp = fopen (filename_buffer, "rb");
if (inp == NULL)
{
printf ("bad input file '%s'\n", filename_buffer);
return -2;
}
ptr = sig;
while (*ptr)
{
i = fgetc (inp);
if (*ptr != i)
{
encode_flag = 1;
break;
}
ptr++;
}
if (encode_flag)
{
/* rewind file because we already read some bytes */
fseek (inp, 0, SEEK_SET);
printf ("encoding input file: '%s'\n", filename_buffer);
} else
printf ("decoding input file: '%s'\n", filename_buffer);
filename_buffer[0] = 0;
if (!strchr(argv[2], '/') && !strchr(argv[2], 92) && !strchr(argv[2], ':'))
strcpy (filename_buffer, OUTPUTPATH);
strcat (filename_buffer, argv[2]);
outp = fopen (filename_buffer, "wb");
if (outp == NULL)
{
printf ("bad output file '%s'\n", filename_buffer);
return -2;
}
printf ("output file: '%s'\n", filename_buffer);
if (encode_flag)
fwrite (sig, 1, 4, outp);
do
{
i = fgetc(inp);
if (i != EOF)
fputc (i ^ 0x8d, outp);
} while (i != EOF);
fclose (inp);
fclose (outp);
printf ("all done. bye bye\n");
return 0;
}
Ok so when it comes to practical usage of the code provided by #Jongware that was unclear to me - I figured it out with some help:)
I compiled the code using Visual Studio (you can find guides on how to do that, basically create new Visual C++ project and in Project -> Project Propeties choose C/C++ -> All options and Compile as C Code (/TC)).
Then I opened program in command prompt using parameter "program encrypted_file decrypted_file".
Thanks a lot for help Jongware!
I have the following code
global
File logFile
and inside loop()
DateTime now = rtc.now();
String stringFilename = "";
stringFilename = String(now.year())+"_"+String(now.month())+"_"+String(now.day());
stringFilename += ".csv";
Serial.println(stringFilename);
char filename[stringFilename.length() + 1];
stringFilename.toCharArray(filename, sizeof(filename));
String dataString = "";
dataString += String(now.year());
Serial.print("Filename: ");
Serial.println(filename);
if (!SD.exists(filename)){
Serial.println("File does not exist");
logFile = SD.open(filename, FILE_WRITE);
}
if (logFile){
logFile.println(dataString);
}else{
Serial.println("Could not open file");
}
Filename is something like 2014_5_26.csv. SD empty. The above code won't open file for writing. If I substitute filename with a literal like "datalog.txt" it works. What am I doing wrong?
EDIT: I got what my problem was. The name was to long. It can be only up to 8 characters. Can I ask something different? Can I call SD.begin(chipSelect) in loop to determine if SD is present or is this called always on setup?
You can use it in loop but the program speed will be reduce.
Don't forget to close your file (SD.close()) before to be sure that your data are correctly written to the SD card
8.3 filename rules may apply. Your Date derived ("2014_5_26") filename appears to have 9 characters. When you use "datalog", that has 8 characters, it works.
How can i find a specific character in a QFile which has a text in it?
for example i have ' $5000 ' written somewhere in my file. in want to find the "$" sign so i will realize that I've reached the number.
I tried using QString QTextStream::read(qint64 maxlen) by putting 1 as the maxlen :
QFile myfile("myfile.txt");
myfile.open(QIODevice::ReadWrite | QIODevice::Text);
QTextStream myfile_stream(&myfile);
while(! myfile_stream.atEnd())
{
if( myfile_stream.read(1) == '$')
{
qDebug()<<"found";
break;
}
}
and i get "error: invalid conversion from 'char' to 'const char* "
i also tried using the operator[] but apparently it can't be used for files.
Read in a line at a time and search the text that you've read in
QTextStream stream(&myFile);
QString line;
do
{
line = stream.readLine();
if(line.contains("$"))
{
qDebug()<<"found";
break;
}
} while (!line.isNull());
The error message you've posted doesn't match the issue in your code. Possibly the error was caused by something else.
QTextStream::read returns QString. You can't compare QString and const char* directly, but operator[] can help:
QString s = stream.read(1);
if (s.count() == 1) {
if (s[0] == '$') {
//...
}
}
However reading a file by too small pieces will be very slow. If your file is small enough, you can read it all at once:
QString s = stream.readAll();
int index = s.indexOf('$');
If your file is large, it's better to read file by small chunks (1024 bytes for example) and calculate the index of found character using indexOf result and count of already read chunks.
a single char could be read with
QTextStream myfile_stream(&myfile);
QChar c;
while (!myfile_stream.atEnd())
myfile_stream >> c;
if (c == '$') {
...
}
myfile_stream.read(1) - this is not good practice, you should not read from file one byte at a time. Either read the entire file, or buffered/line by line if there is a risk for the file to be too big to fit in memory.
The error you get is because you compare a QString for equality with a character literal - needless to say that is not going to work as expected. A string is a string even if there is only one character in it. As advised - use either the [] operator or better off for reading - QString::at() const which is guaranteed to create no extra copy. You don't use it on the QFile, nor on the QTextStream, but on the QString that is returned from the read() method of the text stream targeted at the file.
Once you have the text in memory, you can either use the regular QString methods like indexOf() to search for the index of a contained character.
in want to find the "$" sign so i will realize that I've reached the
number.
It sounds to me that you're searching for the '$' symbol because you're more interested in the dollar value that follows it. In this case, I suggest reading the files line by line and running them through a QRegExp to extract any values you're looking for.
QRegExp dollarFind("\\$(\\d+)");
while(!myfile_stream.atEnd()){
QString line = myfile_stream.readLine();
if (dollarFind.exactMatch(line)){
QStringList dollars = dollarFind.capturedTexts();
qDebug() << "Dollar values found: " << dollars.join(", ");
}
}
I have a text file. I need to read it to a QStringList. there are no line seperators. I mean each line in the text file is in a new line. So is there anyway i can do this?
I assume that every line should be a separate string in the list. Use QTextStream::readLine() in a cycle and on each step append the returned value to the QStringList. Like this:
QStringList stringList;
QFile textFile;
//... (open the file for reading, etc.)
QTextStream textStream(&textFile);
while (true)
{
QString line = textStream.readLine();
if (line.isNull())
break;
else
stringList.append(line);
}
QFile TextFile;
//Open file for reading
QStringList SL;
while(!TextFile.atEnd())
SL.append(TextFile.readLine());
If the file isn't too big, read the whole content into a QString and then split() it into a QStringList.
I like using the QRegExp version to handle linefeed from different platforms:
QStringList sList = s.split(QRegExp("(\\r\\n)|(\\n\\r)|\\r|\\n"), QString::SkipEmptyParts);
I like my code to be fully indented/paranthesized with obvious variable names (they may take longer to type but are much easier to debug) so would do the following (but changing "myTextFile" and "myStringList" to more sensible names, such as "employeeListTextFile")
QFile myTextFile;
QStringList myStringList;
if (!myTextFile.open(QIODevice::ReadOnly))
{
QMessageBox::information(0, "Error opening file", myTextFile.errorString());
}
else
{
while(!myTextFile.atEnd())
{
myStringList.append(myTextFile.readLine());
}
myTextFile.close();
}
The below code reads the file
QFile File("/file_path");
if(!File.open(QIODevice::ReadOnly));
{
qDebug("Error");
}
QTextStream in(&File);
while(!in.atEnd())
{
qDebug()<<ReadAll;
ReadAll=in.readAll();
}
File.close();
Now the file is closed, now split the new line i.e \n here \r is carriage return
List= ReadAll.split(QRegExp("[\r\n]"),QString::SkipEmptyParts);