zarray.hpp

// This file is part of OpenCV project.
// It is subject to the license terms in the LICENSE file found in the top-level directory
// of this distribution and at http://opencv.org/license.html.
//
// Copyright (C) 2013-2016, The Regents of The University of Michigan.
//
// This software was developed in the APRIL Robotics Lab under the
// direction of Edwin Olson, ebolson@umich.edu. This software may be
// available under alternative licensing terms; contact the address above.
//
// The views and conclusions contained in the software and documentation are those
// of the authors and should not be interpreted as representing official policies,
// either expressed or implied, of the Regents of The University of Michigan.
#ifndef _OPENCV_ZARRAY_HPP_
#define _OPENCV_ZARRAY_HPP_

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

namespace cv {
namespace aruco {


struct sQuad{
    float p[4][2]; // corners
};

/**
 * Defines a structure which acts as a resize-able array ala Java's ArrayList.
 */
typedef struct zarray zarray_t;
struct zarray{
    size_t el_sz; // size of each element

    int size; // how many elements?
    int alloc; // we've allocated storage for how many elements?
    char *data;
};

/**
 * Creates and returns a variable array structure capable of holding elements of
 * the specified size. It is the caller's responsibility to call zarray_destroy()
 * on the returned array when it is no longer needed.
 */
inline static zarray_t *_zarray_create(size_t el_sz){
    zarray_t *za = (zarray_t*) calloc(1, sizeof(zarray_t));
    za->el_sz = el_sz;
    return za;
}

/**
 * Frees all resources associated with the variable array structure which was
 * created by zarray_create(). After calling, 'za' will no longer be valid for storage.
 */
inline static void _zarray_destroy(zarray_t *za){
    if (za == NULL)
        return;

    if (za->data != NULL)
        free(za->data);
    memset(za, 0, sizeof(zarray_t));
    free(za);
}

/**
 * Retrieves the number of elements currently being contained by the passed
 * array, which may be different from its capacity. The index of the last element
 * in the array will be one less than the returned value.
 */
inline static int _zarray_size(const zarray_t *za){
    return za->size;
}

/**
 * Allocates enough internal storage in the supplied variable array structure to
 * guarantee that the supplied number of elements (capacity) can be safely stored.
 */
inline static void _zarray_ensure_capacity(zarray_t *za, int capacity){
    if (capacity <= za->alloc)
        return;

    while (za->alloc < capacity) {
        za->alloc *= 2;
        if (za->alloc < 8)
            za->alloc = 8;
    }

    za->data = (char*) realloc(za->data, za->alloc * za->el_sz);
}

/**
 * Adds a new element to the end of the supplied array, and sets its value
 * (by copying) from the data pointed to by the supplied pointer 'p'.
 * Automatically ensures that enough storage space is available for the new element.
 */
inline static void _zarray_add(zarray_t *za, const void *p){
    _zarray_ensure_capacity(za, za->size + 1);

    memcpy(&za->data[za->size*za->el_sz], p, za->el_sz);
    za->size++;
}

/**
 * Retrieves the element from the supplied array located at the zero-based
 * index of 'idx' and copies its value into the variable pointed to by the pointer
 * 'p'.
 */
inline static void _zarray_get(const zarray_t *za, int idx, void *p){
    CV_DbgAssert(idx >= 0);
    CV_DbgAssert(idx < za->size);

    memcpy(p, &za->data[idx*za->el_sz], za->el_sz);
}

/**
 * Similar to zarray_get(), but returns a "live" pointer to the internal
 * storage, avoiding a memcpy. This pointer is not valid across
 * operations which might move memory around (i.e. zarray_remove_value(),
 * zarray_remove_index(), zarray_insert(), zarray_sort(), zarray_clear()).
 * 'p' should be a pointer to the pointer which will be set to the internal address.
 */
inline static void _zarray_get_volatile(const zarray_t *za, int idx, void *p){
    CV_DbgAssert(idx >= 0);
    CV_DbgAssert(idx < za->size);

    *((void**) p) = &za->data[idx*za->el_sz];
}

inline static void _zarray_truncate(zarray_t *za, int sz){
    za->size = sz;
}

/**
 * Sets the value of the current element at index 'idx' by copying its value from
 * the data pointed to by 'p'. The previous value of the changed element will be
 * copied into the data pointed to by 'outp' if it is not null.
 */
static inline void _zarray_set(zarray_t *za, int idx, const void *p, void *outp){
    CV_DbgAssert(idx >= 0);
    CV_DbgAssert(idx < za->size);

    if (outp != NULL)
        memcpy(outp, &za->data[idx*za->el_sz], za->el_sz);

    memcpy(&za->data[idx*za->el_sz], p, za->el_sz);
}

}
}
#endif