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

#ifndef CHAR_QUEUE_H
#define CHAR_QUEUE_H
#define QUEUE_INIT_SIZE 128

typedef struct CharQueue_t{
    uint16_t size;
    uint16_t capacity;
    unsigned char *data;
    void (*append) (struct CharQueue_t *, unsigned char);
    void (*destroy) (struct CharQueue_t *);
    unsigned char (*get) (struct CharQueue_t *, uint16_t);
    unsigned char (*next) (struct CharQueue_t *);
} CharQueue_t;

CharQueue_t *CharQueueInit();

void CharQueueAppend(struct CharQueue_t *queue, unsigned char value);

void CharQueueDestroy(struct CharQueue_t *queue);

unsigned char CharQueueGet(struct CharQueue_t *queue, uint16_t idx);

unsigned char CharQueueNext(struct CharQueue_t *queue);

#endif  /* CHAR_QUEUE_H */

CharQueue_t *CharQueueInit() {
    CharQueue_t *queue = malloc(sizeof(CharQueue_t));
    // Initialize size and capacity
    queue->size = 0;
    queue->capacity = QUEUE_INIT_SIZE;
    queue->data = malloc(sizeof(unsigned char) * queue->capacity);
    queue->append = CharQueueAppend;
    queue->destroy = CharQueueDestroy;
    queue->get = CharQueueGet;
    queue->next = CharQueueNext;
    return queue;
}

void CharQueueAppend(struct CharQueue_t *queue, unsigned char value) {
    // Resize the queue if it's at capacity
    if (queue->size >= queue->capacity) {
        queue->capacity *= 2;
        queue->data = realloc(queue->data, sizeof(unsigned char) * queue->capacity);
    }
    queue->data[queue->size] = value;
    queue->size++;
}

void CharQueueDestroy(struct CharQueue_t *queue) {
    free(queue->data);
    free(queue);
}

unsigned char CharQueueGet(struct CharQueue_t *queue, uint16_t idx) {
    if (idx >= queue->size || idx < 0) {
        return 0;
    }
    return queue->data[idx];
}

unsigned char CharQueueNext(struct CharQueue_t *queue) {
    char data = queue->data[0];
    queue->size = queue->size - 1;
    // Move the pointer up the stack -- Does this leak memory?
    *queue->data++;
    return data;
}

int main(void) {
    CharQueue_t *queue = CharQueueInit();
    int i;
    for (i = 0; i < 256; i++) {
        queue->append(queue, i);
    }
    printf("Queue Size is %drn", queue->size);
    for (i = 0; i < 256; i++) {
        printf("#%d in queue: 0x%drn", i, queue->next(queue));
    }
    return 0;
}

// Move the pointer up the stack -- Does this leak memory?
*queue->data++;