I'm looking to analyze what information developers have put inside the source code as strings.
During the compilation process, is there a way to get GCC to output a list of all string constants used in a C++ programming. For example, if I write:
std::string result = enterLog("The secret word is: elephant");
result = enterLog("Checkpoint reached", "Now");
I would like to output
The secret word is: elephant
Checkpoint reached
Now
I would like to check to see if anyone has put the secret word in the code somewhere without having to check manually.
Related
Like the guy in this question (AWS Signature Version 2 - can't reproduce signature from example) I can't run the example of AWS Signature Version 2 (https://docs.aws.amazon.com/general/latest/gr/signature-version-2.html).
We have the string:
GET\nelasticmapreduce.amazonaws.com\n/\nAWSAccessKeyId=AKIAIOSFODNN7EXAMPLE&Action=DescribeJobFlows&SignatureMethod=HmacSHA256&SignatureVersion=2&Timestamp=2011-10-03T15%3A19%3A30&Version=2009-03-31
and the sample secret key
wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
To be independent of any programming language, lets take an online tool for the hash, which is calculated with HmacSHA256: https://www.liavaag.org/English/SHA-Generator/HMAC/
But I get the following hash value:
xgbYI2xegVYMVTvnhoqc8/opbN0v/5Pn+8i9usAQAjk=
which is sadly not the expected value (not URL-encoded here):
i91nKc4PWAt0JJIdXwz9HxZCJDdiy6cf/Mj6vPxyYIs=
What did I do wrong? Why is my calculation of the hash value not correct? Is the initial string correct? If you manage to get the right result with the online tool, please let me know how it was done.
TLDR: It's the newlines
Although some tools and programming languages, particularly those based on C or originating on Unix where C was heavily used, treat \n as a notation or representation for newline, that webpage does not. If I enter the string from your Q in the webpage's 'text' mode, it computes the HMAC of a value containing a backslash and a lowercase letter 'en', not a newline as required by the AWS spec.
If I enter the correct input (containing newlines) in hex as
4745540a656c61737469636d61707265647563652e616d617a6f6e6177732e636f6d0a2f0a4157534163636573734b657949643d414b4941494f53464f444e4e374558414d504c4526416374696f6e3d44657363726962654a6f62466c6f7773265369676e61747572654d6574686f643d486d6163534841323536265369676e617475726556657273696f6e3d322654696d657374616d703d323031312d31302d3033543135253341313925334133302656657273696f6e3d323030392d30332d3331
or in base64 as
R0VUCmVsYXN0aWNtYXByZWR1Y2UuYW1hem9uYXdzLmNvbQovCkFXU0FjY2Vzc0tleUlkPUFLSUFJT1NGT0ROTjdFWEFNUExFJkFjdGlvbj1EZXNjcmliZUpvYkZsb3dzJlNpZ25hdHVyZU1ldGhvZD1IbWFjU0hBMjU2JlNpZ25hdHVyZVZlcnNpb249MiZUaW1lc3RhbXA9MjAxMS0xMC0wM1QxNSUzQTE5JTNBMzAmVmVyc2lvbj0yMDA5LTAzLTMx
then I get the correct result (and you should too).
In my parser generated by flex, I would like to be able to store each line in the file, so that when reporting errors, I can show the user the line that the error occurred on.
I could of course do this using a vector and read in all lines from the file before/after lexing, but this would just add to the time needed to parse a file.
What I thought I could instead do, is to store the line whenever a new-line character is matched, and insert the current line into a vector. So my questions is, is there a variable/macro that flex that stores the current line inside? (Something like yyline perhaps)
Note: I am also using bison
By itself, lex/flex does not do what you ask. As noted, you want this for reporting error messages. (I do something like this in vi like emacs).
With lex/flex, the only way to store the entire line is to record each token from the current line into your own line-buffer. That can be complicated, especially if your lexer has to handle multi-line content (such as comments or strings).
The yytext variable only shows you the most recently parsed token (and yylength, the corresponding length). If your lexer does a simple ECHO, that is a token just like the ones you pay attention to.
Reading the file in advance as noted is one way to simplify the problem. In vi like emacs, the lexers read via a function from the in-memory buffer rather than from an input stream. It bypasses the normal stream-handling logic by redefining the YY_INPUT macro, e.g.,
#define YY_INPUT(buf,result,max_size) result = flt_input(buf,max_size)
Likewise, ECHO is redefined (since the editor reads the results back rather than letting them go to the standard output):
#define ECHO flt_echo(yytext, yyleng)
and it traps errors detected by the lexer with another redefinition:
#define YY_FATAL_ERROR(msg) flt_failed(msg);
However you do this, the yylineno value reported for a given token will be at the end of parsing a given token.
While it is nice to report the entire line in context in an error message, it is also useful to track the line and column number of each token -- various editors can deal with lines like this
filename:line:col:message
If you build up your line-buffer by tracking tokens, it might be relatively simple to track the column on which each token begins as well.
I have to show/enable a bunch of dialog items in an MFC application. They all have names like IDC_EDIT_CHANNEL1_x, where x is an int value from 0 to 15. The IDs from the resource file are not ordered so I want to get the items by that string.
Is it possible to get the resourceId named IDC_EDIT_CHANNEL1_1, from a string "IDC_EDIT_CHANNEL1_1"?
As you all know GetDlgItem() only works with int values.
The problem you don't see is that the preprocessor replaces IDC_EDIT_CHANNEL1_x with an integer at compile time. This is a macro, not a string.
So your application never "sees" a string. The string has been substituted by the preprocessor before the source code reaches the compiler.
My advice is to use consecutive IDs. I don't know why you don't want to do that, but it will probably be the quickest and most straightforward way to solve your problem.
The other way is to not use macros at all. The resource editor can use strings, and if the preprocessor doesn't replace them with ints, that's what will be used. You can filter them by string then.
I'm working on a C++ project which should do following operations:
Open a .txt file which contains list of strings
(for example String1: "Hi,name_1_is,;Ondrej,age24;year,,88;") with optional values determined by empty commas ",,".
After this check each string using regular expressions for valid input
(like "Hi" shouldn't be a number or "1" must be a number and everything with ",," is optional and can be skipped or user can enter this value as well).
Then evaluate the result and save it to variable or new .txt generated file.
This result shows if whole string is correct with an "ok" message attached to it or it will attach "not ok" message right to the parameter with wrong input.
I have already finished the part with opening a .txt file, checking the whole string and saving the right strings to the new file (using Qt and Visual Studio 2010 Express).
I need to do the part where each parameter will be checked but somehow I don't know how exactly, as I should not build Parser but the whole programm must be build like Interpreter.
Actually I'm stucked at this point because I have no idea how to start to build this like an Interpreter.
All my attempts resulted always with structure similar to Parser
(that means: I used split string, then checked each token or char using regex, then built the string together again, ect.)
Could you provide me with some usefull links or tips of how to achieve that or at least where to start at all please?
Is there anyway I can incorporate a pretty large text file (about 700KBs) into the program itself, so I don't have to ship the text files together in the application directory ? This is the first time I'm trying to do something like this, and I have no idea where to start from.
Help is greatly appreciated (:
Depending on the platform that you are on, you will more than likely be able to embed the file in a resource container of some kind.
If you are programming on the Windows platform, then you might want to look into resource files. You can find a basic intro here:
http://msdn.microsoft.com/en-us/library/y3sk7e6b.aspx
With more detailed information here:
http://msdn.microsoft.com/en-us/library/zabda143.aspx
Have a look at the xxd command and its -include option. You will get a buffer and a length variable in a C formatted file.
If you can figure out how to use a resource file, that would be the preferred method.
It wouldn't be hard to turn a text file into a file that can be compiled directly by your compiler. This might only work for small files - your compiler might have a limit on the size of a single string. If so, a tiny syntax change would make it an array of smaller strings that would work just fine.
You need to convert your file by adding a line at the top, enclosing each line within quotes, putting a newline character at the end of each line, escaping any quotes or backslashes in the text, and adding a semicolon at the end. You can write a program to do this, or it can easily be done in most editors.
This is my example document:
"Four score and seven years ago,"
can be found in the file c:\quotes\GettysburgAddress.txt
Convert it to:
static const char Text[] =
"This is my example document:\n"
"\"Four score and seven years ago,\"\n"
"can be found in the file c:\\quotes\\GettysburgAddress.txt\n"
;
This produces a variable Text which contains a single string with the entire contents of your file. It works because consecutive strings with nothing but whitespace between get concatenated into a single string.