limitless limitless - 3 months ago 20
C Question

strtok() return NULL in the middle of the parsing

I'm try to parse a line in this format :

1: 2,3,4,5,6,7,8,9,10


so Im using the
strtok()
function with 2 delimiters
and
,
(space and comma)
But for some reason when i get to 6 the funcion return NULL.

fileName = strtok(line, spaceToken);
fileName[strlen(fileName) - 1] = 0; //remove the ':'
...
//doing something with fileName
...
fileName = strtok(NULL, commaToken);
while (fileName != NULL) <-----THE PROBLEM
...
//doing something with fileName
fileName = strtok(NULL, commaToken);
}


So when the fileName should be
6
, i get
NULL
.

With this input :

file1: file2,file3,file4


Where i sould get
file2
for the
fileName
I'm getting
'fil'
, and the next iteration will be
NULL
.

This is the full code if it's help

#include <stdio.h>
#include <memory.h>

#define MAX_LINE_NUMBER 11
#define MAX_FILE_NAME_NUMER 255
#define MAX_FILES 10

//function declaration
void parseFile(char path[]);

int contain(char fileName[]);

int addToDependencieArray(char fileName[], int currentFileIndex);

enum COLOR
{
WHITE, GRAY, BLACK
};

typedef struct MyFile
{
char name[MAX_FILE_NAME_NUMER];
int neighbors[MAX_FILES];
int neighborsCounter;
enum COLOR myColor;
int predecessor;
} MyFile;


//global
MyFile gDependencies[MAX_FILES];
int gCurrentFilesWriten = 0;

int main(int argc, char *argv[])
{
parseFile(argv[1]);
puts("hello");
}

void parseFile(char path[])
{

FILE *fPointer = fopen(path, "r");
char line[MAX_LINE_NUMBER];
char spaceToken[2] = " ";
char commaToken[2] = ",";
char *fileName;
int currentFileIndex = 0;
int sourseFile = 0;
while (fgets(line, sizeof(line), fPointer))
{
fileName = strtok(line, spaceToken);
fileName[strlen(fileName) - 1] = 0; //remove the :
int sourse = contain(fileName);
if (sourse == -1) // isn't contains
{// to create function add.
currentFileIndex = addToDependencieArray(fileName, currentFileIndex);
sourseFile = currentFileIndex - 1;
}
else // contain
{
sourseFile = sourse;
}
fileName = strtok(NULL, commaToken);

while (fileName != NULL)
{
if (contain(fileName) == -1)
{
currentFileIndex = addToDependencieArray(fileName, currentFileIndex);
int neighborIndex = gDependencies[sourseFile].neighborsCounter;
gDependencies[sourseFile].neighbors[neighborIndex] = currentFileIndex - 1;
gDependencies[sourseFile].neighborsCounter++;
}
fileName = strtok(NULL, commaToken);
}

}
fclose(fPointer);
}

int contain(char fileName[])
{
int res = -1;
for (int i = 0; i < gCurrentFilesWriten; i++)
{
if (!strcmp(fileName, gDependencies[i].name))
{
return i;
}
else
{
i++;
}
}
return res;
}

int addToDependencieArray(char fileName[], int currentFileIndex)
{
strcpy(gDependencies[currentFileIndex].name, fileName);
gCurrentFilesWriten++;
gDependencies[currentFileIndex].neighborsCounter = 0;
currentFileIndex++;
return currentFileIndex;
}

cxw cxw
Answer
#define MAX_LINE_NUMBER 11
...
char line[MAX_LINE_NUMBER];
...
while (fgets(line, sizeof(line), fPointer))

You are only reading the first 11 characters of the line! Increase MAX_LINE_NUMBER and rename it to something like MAX_LINE_LENGTH and it should work.

Explanation: when reading using fgets,

fgets() reads in at most one less than size characters from stream

Your examples:

123456789a|bcdef <-- character number - fgets only reads through _a_
1: 2,3,4,5|,6,7,8,9,10  <-- 5 is the last thing you read
file1: fil|e2,file3,file4 <-- "fil" is the end of the string