CODEWITHSUNDEEP
curl-encoding
ajm113
ajm113

Reputation: 1006

Encoding Url In C With Line Breaks?

I've got this url encoder I found on the internet and made few small changes, however when ever I do something such as this:

char encodedWord[100];
const char* word = "Stack\nOverflow";

urlencode(encodedWord, word);

The output would be something like this: "Stack0X8.51EE00001674P-1022Overflow" instead of x0A in between of Stack Overflow.

Why is it outputting that? I assume because of the "EE0000" part something went wrong with the char to number conversion.

How can I get my encoder to be much more friendly to special characters? i.e "\n,\r,\r".

The Function

int urlencode(char *dest, const char *src)
{
    /* urlencode all non-alphanumeric characters in the C-string 'src'
       store result in the C-string 'dest'
       return the length of the url encoded C-string
    */
    char *d;
    int i;
    for(i=0, d=dest; src[i]; i++) {
        if(isalnum(src[i]) || isdigit(src[i])) {
            *(d++) = src[i];
        } else {
            snprintf(d, 4, "%%%02X", src[i]);
            d += 3;
        }
    }   
    *d = 0;
    return d-dest;
}

System

Windows 10 32bit Mingw32 (gcc 5.1.0)

Make File

#OBJS specifies which files to compile as part of the project

OBJS = $(wildcard ./src/*.c)

#CC specifies which compiler we're using
CC = gcc

#INCLUDE_PATHS specifies the additional include paths we'll need
INCLUDE_PATHS = 

#LIBRARY_PATHS specifies the additional library paths we'll need
LIBRARY_PATHS = 

#COMPILER_FLAGS specifies the additional compilation options we're using
# -w suppresses all warnings
# -Wl,-subsystem,windows gets rid of the console window
COMPILER_FLAGS = -Wall -Wl,-subsystem,console -std=c99

#LINKER_FLAGS specifies the libraries we're linking against
LINKER_FLAGS = -lmingw32 -lws2_32 -lwininet -s -lshlwapi

#OBJ_NAME specifies the name of our executable
OBJ_NAME = project

#This is the target that compiles our executable
all : clean build

build:
    cls
    $(CC) $(OBJS) $(INCLUDE_PATHS) $(LIBRARY_PATHS) $(COMPILER_FLAGS) $(LINKER_FLAGS) -o $(OBJ_NAME)

clean:
    del -f $(OBJ_NAME).exe

Upvotes: 1

Views: 344

Answers (1)

hobbs
hobbs

Reputation: 239861

the urlencode function is working just fine, the problem is how you're printing the output. I was in the middle of writing

0X8.51EE00001674P-1022 is a hexadecimal floating point number, what you would expect to see from a %A printf specifier.

when it struck me that the correct output has %0A in that exact position. Which means that you're making the mistake of passing a non-constant string as the first parameter of printf. Don't do printf(encodedWord); you should be using printf("%s", encodedWord) instead.

Upvotes: 3

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