realloc.c


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#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct
{
    int length;
    char *line;
} sNode;

struct String
{
    int index;
    int size;
    sNode *arr;
};

struct String *string_new(char *str);
void string_append(struct String *a, char *b);
void string_resize(struct String *s);

struct String *string_new(char *str)
{
    struct String *ret = (struct String *) calloc(1, sizeof(struct String));
    ret->arr = (sNode *) calloc(1, (sizeof(sNode) * 200));
    ret->size = 200;
    string_append(ret, str);

    return ret;
}

void string_append(struct String *a, char *b)
{
    if ((a->size-1) == a->index)
        string_resize(a);

    a->arr[a->index].line = b;
    a->arr[a->index].length = strlen(b);
    
    a->index++;
}

void string_resize(struct String *s)
{
    /* quadruple the size */
    int newSize = s->size * 4;
    printf("debug: resizing to new size of %d\n", newSize);

    s->size = newSize;
    sNode *newarr = (sNode *) realloc(s->arr, (sizeof(sNode) * newSize));
    if (!newarr)
    {
        perror("realloc");
        exit(-1);
    }

    /* free old array */
    free(s->arr);
    s->arr = newarr;

}

int main(int argc, char **argv)
{
    if (argc < 2)
    {
        fprintf(stderr,"Usage: app n\n");
        exit(1);
    }

    struct String *str = string_new("");

    int i;
    for (i = 0; i < atoi(argv[1]); i++)
        string_append(str, "anything that can go wrong, will");
}