I have some wave files (.wav) and I need to convert them in base64 encoded strings. Could you guide me how to do that in Python/C/C++ ?
#ForceBru's answer
import base64
enc=base64.b64encode(open("file.wav").read())
has one problem. I noticed for some WAV files that I encoded the string generated was shorter than expected.
Python docs for "open()" say
If mode is omitted, it defaults to 'r'.
The default is to use text mode, which may convert '\n' characters to a platform-specific representation on writing and back on reading. Thus, when opening a binary file, you should append 'b' to the mode value to open the file in binary mode, which will improve portability.
Hence, the code snippet doesn't read in binary. So, the below code should be used for better output.
import base64
enc = base64.b64encode(open("file.wav", "rb").read())
Python
The easiest way
from base64 import b64encode
f=open("file.wav")
enc=b64encode(f.read())
f.close()
Now enc contains the encoded value.
You can use a bit simplified version:
import base64
enc=base64.b64encode(open("file.wav").read())
C
See this file for an example of base64 encoding of a file.
C++
Here you can see the base64 conversion of strings. I think it wouldn't be too difficult to do the same for files.
Related
I have a file uploader and in order to validate the file is actually of the type expected, I am inspecting the binary and checking the ASCII identifying characters (see the PDF example here).
The majority of files have an ASCII identifier, however some don't (like XLS files)
How would I best identify these ones?
I see all have a hex values but as it stands, I don't currently have the capability of converting the binary data to Hex.
Workaround...
I don't have a HEX converter, but I can convert both Binary and HEX to Base64 so that is what I am doing and comparing the Base64 output.
The project I'm working on takes xml files and input streams and converts them to pdf's and text. In the unit tests I compare this generated text with a .txt file that has the expected output.
I'm now facing the issue of these .txt files not being encoded in UTF-8 and been written without persisting this information (namely umlauts).
I have read few articles on the topic of persisting and encoding .txt files. Including correcting the encoding, saving and opening files in Visual Studio with encoding, and some more.
I was wondering if there is a text file format that supports meta information about encoding like xml or html for example does.
I'm looking for a solution that is:
Easy adaptable to any coworker on the same team
It being persitant and not depending on me choosing an encoding in an editor
Does not require any additional exotic program
Can be read without or only little modification of the File class and it's input reading of C#
Does at least support UTF-8 encoding
A Unicode Byte Order Mark (BOM) is sometimes used for this purpose. Systems that process Unicode are required to strip off this metadata when passing on the text. File.ReadAllText etc do this. A BOM should exist only at the beginning of files and streams.
A BOM is sometimes conflated with encoding because both affect the file format and BOM applies only to Unicode encodings. In Visual Studio, with UTF-8, it's called "Unicode (UTF-8 with signature) - Codepage 65001".
Some C# code that demonstrates these concepts:
var path = Path.GetTempFileName() + ".txt";
File.WriteAllText(path, "Test", new UTF8Encoding(true, true));
Debug.Assert(File.ReadAllBytes(path).Length == 7);
Debug.Assert(File.ReadAllText(path).Length == 4); // slightly mushy encoding detection
However, this doesn't get anyone past the agreement required when using text files. The fundamental rule is that a text file must be read with the same encoding it was written with. A BOM is not a communication that suffices as a complete agreement for text files in general.
Test editors almost universally adopt the principle that they should guess a file's character encoding first, and—for the most part—allow users to correct them later. Some IDEs with project systems allow recording which encoding a file actually uses.
A reasonable text editor would preserve both the encoding and the presence of a Unicode BOM for existing files.
It seems that you're after a universal strategy. Unfortunately, the history of the concept of a text file doesn't allow one.
I have an rtf file which contains special character as it is without decode to hexadecimal or unicode. I am using lib rtf in c language.
Below is the content from the rtf file. It has not mentioned encoded mode.
\b0\fi-380\li1800 · Going to home
While parsing i will get some junk value for the character. How to get proper character from the rtf file if it contains any character in specula mode only.
Regards,
Try this:
\b0\fi-380\li1800 \u183? Going to home
How to do it:
https://stackoverflow.com/a/20117501/1543816
I've a file that was written on windows with encoding WINDOWS-1256, and I need to write a C program that reads bytes from this file and write them back to a new file with UTF-8 encoding.
How to read a file with a specific encoding in C ??
Other than text mode and binary mode, there is no way to directly read specific encodings with C with standard API.
You would open the file as binary and read it in. Then you can use a library like libiconv to do the encoding / decoding of specific formats.
I am interested in writing utf-8 encoded strings to a file.
I did this with low level functions open() and write().
In the first place I set the locale to a utf-8 aware character set with
setlocale("LC_ALL", "de_DE.utf8").
But the resulting file does not contain utf-8 characters, only iso8859 encoded umlauts. What am I doing wrong?
Addendum: I don't know if my strings are really utf-8 encoded in the first place. I just keep them in the source file in this form: char *msg = "Rote Grütze";
See screenshot for content of the textfile:
alt text http://img19.imageshack.us/img19/9791/picture1jh9.png
Changing the locale won't change the actual data written to the file using write(). You have to actually produce UTF-8 characters to write them to a file. For that purpose you can use libraries as ICU.
Edit after your edit of the question: UTF-8 characters are only different from ISO-8859 in the "special" symbols (ümlauts, áccénts, etc.). So, for all the text that doesn't have any of this symbols, both are equivalent. However, if you include in your program strings with those symbols, you have to make sure your text editor treats the data as UTF-8. Sometimes you just have to tell it to.
To sum up, the text you produce will be in UTF-8 if the strings within the source code are in UTF-8.
Another edit: Just to be sure, you can convert your source code to UTF-8 using iconv:
iconv -f latin1 -t utf8 file.c
This will convert all your latin-1 strings to utf8, and when you print them they will be definitely in UTF-8. If iconv encounters a strange character, or you see the output strings with strange characters, then your strings were in UTF-8 already.
Regards,
Yes, you can do it with glibc. They call it multibyte instead of UTF-8, because it can handle more than one encoding type. Check out this part of the manual.
Look for functions that start with the prefix mb, and also function with wc prefix, for converting from multibyte to wide char. You'll have to set the locale first with setlocale() to UTF-8 so it chooses this implementation of multibyte support.
If you are coming from an Unicode file I believe the function you looking for is wcstombs().
Can you open up the file in a hex editor and verify, with a simple input example, that the written bytes are not the values of Unicode characters that you passed to write(). Sometimes, there is no way for a text editor to determine character set and your text editor may have assumed an ISO8859-1 character set.
Once you have done this, could you edit your original post to add the pertinent information?