I'm trying to get myself acquainted with memory allocation and deallocation while writing a program that will actually be usefull for me.
The program is a simple datareader, that tries to read a matrix from file.
The "main" program which works is
'int get_lex(char *in,char *delims,char ***returnvals)'
This will essential return a argv style list of the tokens through 3.parameter.
like
char **line=NULL;
int numToks = get_lex("small.txt"," \t",&line)
for(int i=0;i<numtoks;i++)
printf("%i %s",i,line[i]);The innerworkings of this is a single linked list of char*, that rolls back to a normal array as soon as the cstring is tokenized.
This works.
Now as I loop through the lines of the files I've created another singlelinked list which will have the tokenized argv style string from get_lex, and then a pointer to the next row.
The program works as is!, but I can't nail down a memoryleak that shows up when using valgrind.
A sample file: small.txt would be
1 6 11 16 21
2 7 12 17 22
3 8 13 18 23
4 9 14 19 24
5 10 15 20 25and the program can be run as
'./a.out small.txt'
Heres the full program thanks in advance,
btw I know this can be done easily with std::string and vector or some booost::tokenizer.
But I just want to know how I can fix this faulty program
I know the code is huge but the problemeatic functions are get_lex, readmatrix and friends.
valgrind complains at line 151 the strdup. But I don't know where I should deallocate.
Thanks again
#include <fstream>
#include <cstring>
#include <cstdlib>
#include <iostream>
#define MAX_ELEMS_PER_LINE 1000
typedef struct {
int x;
int y;
int** matrix;
void info(const char *name){
printf("iMatrix:%s dims= (%d,%d) \n",name,x,y);
}
void print(const char *st,const char *file){
if(file==NULL){
if(st!=NULL)
printf("\niMatrix dims: %s = (%d,%d)\n",st,x,y);
for (int i=0;i<x;i++){
for (int j=0;j<y;j++)
printf("%d ",matrix[i][j] );
printf("\n");
}
} else{
FILE *pFile;
pFile = fopen(file,"w");
if(st!=NULL)
fprintf(pFile,"\niMatrix dims of: %s = (%d,%d)\n",st,x,y);
for (int i=0;i<x;i++){
for (int j=0;j<y;j++)
fprintf(pFile,"%d ",matrix[i][j]);
fprintf(pFile,"\n");
}
fclose(pFile);
}
}
}iMatrix ;
void killIntMatrix(int **var){
delete [] *var;
delete [] var;
}
void killMatrix(iMatrix *var){
killIntMatrix(var->matrix);
delete var;
}
#define _fillup_ 1
iMatrix *allocIntMatrix(int x, int y){
try{
iMatrix *tmp = new iMatrix();
int **ppi = new int*[x];
int *curPtr = new int [x * y];
for( int i = 0; i < x; ++i) {
*(ppi + i) = curPtr;
curPtr += y;
}
#if _fillup_
for (int i=0;i<x;i++)
for(int n=0;n<y;n++)
ppi[i][n]=0;
#endif
tmp->matrix=ppi;
tmp->x=x;
tmp->y=y;
return tmp;
}catch(std::exception & e){
printf("\t-> Tried to allocate: %.3f gig memory\n",(float)sizeof(int)*x*y/1000000000);
printf("\t-> Allocation failed, likely cause: need more memory, will exit.\n");
exit(0);
}
}
//single linked list definition
typedef struct node_t{
char *data;
struct node_t *next;
}node;
typedef struct row_t{
char **data;
struct row_t *next;
}row;
//single linked list node memory allocation
node *alloc(char *ary){
node *retVal = new (node);
retVal->data = ary;
retVal->next = NULL;
return retVal;
}
row *allocRow(char **ary){
row *retVal = new (row);
retVal->data = (ary);
retVal->next = NULL;
return retVal;
}
void deleteRow(row *tmp){
char **ary = tmp->data;
delete [] ary;
delete tmp;
}
int get_lex(char *str,const char *delim,char ***tokens){
int len =0;
char *token = 0;
node *head,*current;
//1. tokenize the string to a linked list
token = strtok(str,delim);
if(!token)//catch an empty line
return 0;
head = alloc(token);
current=head;
len++;
while ( token != NULL ){
token = strtok(0,delim);
if(!token)//catch spurious NULL\s (multi delims...)
continue;
current->next = alloc(token);
current = current->next;
len++;
}
if(!tokens)
printf("warning, in you string splitter you have supplied a non null cstring pointer");
//2. populate and array and input the nodes from the linked list.
(*tokens) = new char*[len];
int i=0;
current=head;
while(current){
(*tokens)[i++] =strdup( current->data);
head= current->next;
delete current;
current=head;
}
return len;
}
void print(char** tmp,int len){
int i;
for(i=0;i<len;i++)
printf("%d: %s\n",i,tmp[i]);
}
iMatrix *readmatrix(char *filename){
const int SIZE = MAX_ELEMS_PER_LINE;
char buffer[SIZE];
std::ifstream pFile (filename,std::ios::in);
if(!pFile){
std::cout <<"Problems opening file" <<filename<<std::endl;
exit(0);
}
row *head,*current;
int numberOfColumns;
int numRow=0;
char *scpy;
while(!pFile.eof()){
pFile.getline(buffer,SIZE);
scpy =buffer;// strdup(buffer);
char **line=NULL;
if(numRow==0){
numberOfColumns = get_lex(scpy," \t",&line);
head = allocRow(line);
current = head;
numRow++;
}else{
int tmp = get_lex(scpy," \t",&line);
if(tmp==0){
continue;
}
if(tmp!=numberOfColumns){
printf("\t-> Probs at row: %d columnlength mismatch %d vs. %d\n",numRow,numberOfColumns,tmp);
exit(0);
}
current->next = allocRow(line);
current = current->next;
numRow++;
}
}
printf("dims are:%d %d\n",numRow,numberOfColumns);
//now lets input our rows of chars into the matrix
iMatrix *retVal = allocIntMatrix(numRow,numberOfColumns);
int i=0;//the rows
while(head!=NULL){
for(int j=0;j<numberOfColumns ; j ++)
retVal->matrix[i][j] = atoi(head->data[j]);
current = head->next;
deleteRow(head);
head = current;
i++;
}
return retVal;
}
int main(int argc, char **argv){
iMatrix *var = readmatrix(argv[1]);
var->print(NULL,NULL);
killMatrix(var);
return 0;
}