如何解决由valgrind C中的realloc引起的内存泄漏
我制作了一个my_string对象,其中包含一个char指针,一个大小和一个容量。我试图将单词从词典文本文件中读取到my_string对象中,然后将它们打印到屏幕上。默认容量为7,因此当我读取一个长度超过7个字符的单词时,需要在字符串末尾重新分配一些空间。我还无法正确实现此功能。它似乎正常工作,但是当我在valgrind中运行它时,我的代码中显然存在内存泄漏。不知道它来自哪里,因为我在程序运行后释放了整个字符串。如果有人可以帮我这个忙,那您将是一个救命稻草。这是我的驱动程序代码和my_string.c文件: main.c
#include <stdio.h>
#include <stdlib.h>
#include "my_string.h"
int main(int argc,char* argv[]) {
MY_STRING hMy_String = NULL;
FILE* fp;
hMy_String = my_string_init_default();
fp = fopen("dictionary.txt","r");
int len;
while(my_string_extraction(hMy_String,fp)) {
len = my_string_get_size(hMy_String);
if(len == 8){
my_string_insertion(hMy_String,stdout);
printf("\n");
if(fgetc(fp) == ' '){
printf("Found a space after the string\n");
}
}
}
my_string_destroy(&hMy_String);
fclose(fp);
return 0;
}
my_string.c
#include <stdio.h>
#include <stdlib.h>
#include "my_string.h"
struct my_string {
int size;
int capacity;
char* data;
};
typedef struct my_string My_String;
MY_STRING my_string_init_default(void){
//default capacity of string is 7
//initializes pointer to My_String,set to NULL for good practice
My_String* pMy_String = NULL;
//allocates memory for default string
pMy_String = (My_String*)malloc(sizeof(My_String));
if(pMy_String != NULL) {
pMy_String->size = 0;
pMy_String->capacity = 7;
pMy_String->data = (char*)malloc(sizeof(char) * pMy_String->capacity);
if(pMy_String->data == NULL) {
free(pMy_String);
pMy_String = NULL;
}
}
//returns copy of address to default string
return pMy_String;
}
MY_STRING my_string_init_c_string(char* c_string) {
int i = 0;
//initializes a pointer to a My_String
My_String* theString = NULL;
//loops through string,for every character,i increases 1
while((*c_string) != '\0'){
c_string++;
i++;
}
//resets c_strings value from before the loop
c_string = c_string - i;
i++; //i needs to be 1 greater than the length of the string
//allocation
theString = malloc(sizeof(My_String) + i);
//if there was an error,return NULL
if(theString == NULL)
return NULL;
else {
//sets the values of the object to the given values
(*theString).size = (i - 1);
(*theString).capacity = i;
(*theString).data = c_string;
}
//returns address of the initialized string
return theString;
}
int my_string_get_capacity(MY_STRING hMy_string){
return sizeof(hMy_string);
}
int my_string_get_size(MY_STRING hMy_string) {
char* str = (char*) hMy_string;
int size = 0;
while(str[size] != '\0')
size++;
return size;
}
int my_string_compare(MY_STRING hLeft_string,MY_STRING hRight_string) {
// sets the strings to pointers to the My_String data type
My_String* Left = hLeft_string;
My_String* Right = hRight_string;
//variables for lexicographical value of each string
int left_lex = 0;
int right_lex = 0;
//loops through left string,adds up left_lex value
while((*Left->data) != '\0') {
left_lex += (*Left->data);
(*Left).data++;
}
//loops through right string,adds up right_lex value
while((*Right->data) != '\0') {
right_lex += (*Right->data);
(*Right).data++;
}
//does the comparison and returns the corrosponding value
if(left_lex < right_lex){
return -1;
}else if (left_lex == right_lex) {
return 0;
}else {
return 1;
}
}
Status my_string_extraction(MY_STRING hMy_string,FILE* fp) {
My_String* pMy_string = hMy_string;
int start = 0,end = 0;
char ch;
int strLength,capacity,i;
while(!feof(fp)){
ch = fgetc(fp);
if(ch == ' ' || ch == '\t' || ch == '\n' ||ch == '\r') {
continue;
}
else {
start = ftell(fp) - 1;
end = start + 1;
break;
}
}
if(end == 0){
return FAILURE;
}
while(!feof(fp)) {
ch = fgetc(fp);
end++;
if(ch == ' ' || ch == '\t' || ch == '\n' ||ch == '\r'){
break;
}
}
strLength = end - start - 1;
(*pMy_string).size = strLength;
if(strLength == 0){
return FAILURE;
}
capacity = my_string_get_capacity(hMy_string);
if(strLength >= capacity){
hMy_string = realloc(hMy_string,strLength + 1);
}
fseek(fp,start,SEEK_SET);
char* str = (char*)hMy_string;
for(i = 0; i < strLength; i++) {
str[i] = fgetc(fp);
}
str[i] = '\0';
return SUCCESS;
}
Status my_string_insertion(MY_STRING hMy_string,FILE* fp) {
char* str = (char*)hMy_string;
if(fprintf(fp,"%s",str))
return SUCCESS;
else
return FAILURE;
}
void my_string_destroy(MY_STRING* phMy_string){
free(*phMy_string);
*phMy_string = NULL;
}
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