/* Reconstruction without compaction */
static PIXA *
ReconstructPixa1(L_PTRA *papix,
L_PTRA *pabox)
{
l_int32 i, imax, nactual;
BOX *box;
PIX *pix;
PIXA *pixat;
ptraGetMaxIndex(papix, &imax);
ptraGetActualCount(papix, &nactual);
fprintf(stderr, "Before removal: imax = %4d, actual = %4d\n",
imax, nactual);
pixat = pixaCreate(imax + 1);
for (i = 0; i <= imax; i++) {
pix = (PIX *)ptraRemove(papix, i, L_NO_COMPACTION);
box = (BOX *)ptraRemove(pabox, i, L_NO_COMPACTION);
if (pix) pixaAddPix(pixat, pix, L_INSERT);
if (box) pixaAddBox(pixat, box, L_INSERT);
}
ptraGetMaxIndex(papix, &imax);
ptraGetActualCount(papix, &nactual);
fprintf(stderr, "After removal: imax = %4d, actual = %4d\n\n",
imax, nactual);
return pixat;
}
/* Reconstruction with compaction */
static PIXA *
ReconstructPixa2(L_PTRA *papix,
L_PTRA *pabox)
{
l_int32 i, imax, nactual;
BOX *box;
PIX *pix;
PIXA *pixat;
ptraGetMaxIndex(papix, &imax);
ptraGetActualCount(papix, &nactual);
fprintf(stderr, "Before removal: imax = %4d, actual = %4d\n",
imax, nactual);
/* Remove half */
pixat = pixaCreate(imax + 1);
for (i = 0; i <= imax; i++) {
if (i % 2 == 0) {
pix = (PIX *)ptraRemove(papix, i, L_NO_COMPACTION);
box = (BOX *)ptraRemove(pabox, i, L_NO_COMPACTION);
if (pix) pixaAddPix(pixat, pix, L_INSERT);
if (box) pixaAddBox(pixat, box, L_INSERT);
}
}
/* Compact */
ptraGetMaxIndex(papix, &imax);
ptraGetActualCount(papix, &nactual);
fprintf(stderr, "Before compaction: imax = %4d, actual = %4d\n",
imax, nactual);
ptraCompactArray(papix);
ptraCompactArray(pabox);
ptraGetMaxIndex(papix, &imax);
ptraGetActualCount(papix, &nactual);
fprintf(stderr, "After compaction: imax = %4d, actual = %4d\n",
imax, nactual);
/* Remove the rest (and test compaction with removal) */
while (1) {
ptraGetActualCount(papix, &nactual);
if (nactual == 0) break;
pix = (PIX *)ptraRemove(papix, 0, L_COMPACTION);
box = (BOX *)ptraRemove(pabox, 0, L_COMPACTION);
pixaAddPix(pixat, pix, L_INSERT);
pixaAddBox(pixat, box, L_INSERT);
}
ptraGetMaxIndex(papix, &imax);
ptraGetActualCount(papix, &nactual);
fprintf(stderr, "After removal: imax = %4d, actual = %4d\n\n",
imax, nactual);
return pixat;
}
/*!
* ptraReplace()
*
* Input: ptra
* index (element to be replaced)
* item (new generic ptr to a struct; can be null)
* freeflag (TRUE to free old item; FALSE to return it)
* Return: item (old item, if it exists and is not freed),
* or null on error
*/
void *
ptraReplace(L_PTRA *pa,
l_int32 index,
void *item,
l_int32 freeflag)
{
l_int32 imax;
void *olditem;
PROCNAME("ptraReplace");
if (!pa)
return (void *)ERROR_PTR("pa not defined", procName, NULL);
ptraGetMaxIndex(pa, &imax);
if (index < 0 || index > imax)
return (void *)ERROR_PTR("index not in [0 ... imax]", procName, NULL);
olditem = pa->array[index];
pa->array[index] = item;
if (!item && olditem)
pa->nactual--;
else if (item && !olditem)
pa->nactual++;
if (freeflag == FALSE)
return olditem;
if (olditem)
FREE(olditem);
return NULL;
}
/*!
* ptraReverse()
*
* Input: ptra
* Return: 0 if OK, 1 on error
*/
l_int32
ptraReverse(L_PTRA *pa) {
l_int32 i, imax;
PROCNAME("ptraReverse");
if (!pa)
return ERROR_INT("pa not defined", procName, 1);
ptraGetMaxIndex(pa, &imax);
for (i = 0; i < (imax + 1) / 2; i++)
ptraSwap(pa, i, imax - i);
return 0;
}
/*!
* ptraRemoveLast()
*
* Input: ptra
* Return: item, or null on error or if the array is empty
*/
void *
ptraRemoveLast(L_PTRA *pa) {
l_int32 imax;
PROCNAME("ptraRemoveLast");
if (!pa)
return (void *) ERROR_PTR("pa not defined", procName, NULL);
/* Remove the last item in the array. No compaction is required. */
ptraGetMaxIndex(pa, &imax);
if (imax >= 0)
return ptraRemove(pa, imax, L_NO_COMPACTION);
else /* empty */
return NULL;
}
/*!
* ptraRemove()
*
* Input: ptra
* index (element to be removed)
* flag (L_NO_COMPACTION, L_COMPACTION)
* Return: item, or null on error
*
* Notes:
* (1) If flag == L_NO_COMPACTION, this removes the item and
* nulls the ptr on the array. If it takes the last item
* in the array, pa->n is reduced to the next item.
* (2) If flag == L_COMPACTION, this compacts the array for
* for all i >= index. It should not be used repeatedly on
* large arrays, because compaction is O(n).
* (3) The ability to remove without automatic compaction allows
* removal with cost O(1).
*/
void *
ptraRemove(L_PTRA *pa,
l_int32 index,
l_int32 flag)
{
l_int32 i, imax, fromend, icurrent;
void *item;
PROCNAME("ptraRemove");
if (!pa)
return (void *)ERROR_PTR("pa not defined", procName, NULL);
ptraGetMaxIndex(pa, &imax);
if (index < 0 || index > imax)
return (void *)ERROR_PTR("index not in [0 ... imax]", procName, NULL);
item = pa->array[index];
if (item)
pa->nactual--;
pa->array[index] = NULL;
/* If we took the last item, need to reduce pa->n */
fromend = (index == imax);
if (fromend) {
for (i = index - 1; i >= 0; i--) {
if (pa->array[i])
break;
}
pa->imax = i;
imax = i + 1;
}
/* Compact from index to the end of the array */
if (!fromend && flag == L_COMPACTION) {
for (icurrent = index, i = index + 1; i <= imax; i++) {
if (pa->array[i])
pa->array[icurrent++] = pa->array[i];
}
pa->imax = icurrent - 1;
}
return item;
}
/*!
* ptraAdd()
*
* Input: ptra
* item (generic ptr to a struct)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) This adds the element to the next location beyond imax,
* which is the largest occupied ptr in the array. This is
* what you expect from a stack, where all ptrs up to and
* including imax are occupied, but here the occuption of
* items in the array is entirely arbitrary.
*/
l_int32
ptraAdd(L_PTRA *pa,
void *item) {
l_int32 imax;
PROCNAME("ptraAdd");
if (!pa)
return ERROR_INT("pa not defined", procName, 1);
if (!item)
return ERROR_INT("item not defined", procName, 1);
ptraGetMaxIndex(pa, &imax);
if (imax >= pa->nalloc - 1 && ptraExtendArray(pa))
return ERROR_INT("extension failure", procName, 1);
pa->array[imax + 1] = (void *) item;
pa->imax++;
pa->nactual++;
return 0;
}
/*!
* ptraJoin()
*
* Input: ptra1 (add to this one)
* ptra2 (appended to ptra1, and emptied of items; can be null)
* Return: 0 if OK, 1 on error
*/
l_int32
ptraJoin(L_PTRA *pa1,
L_PTRA *pa2) {
l_int32 i, imax;
void *item;
PROCNAME("ptraJoin");
if (!pa1)
return ERROR_INT("pa1 not defined", procName, 1);
if (!pa2)
return 0;
ptraGetMaxIndex(pa2, &imax);
for (i = 0; i <= imax; i++) {
item = ptraRemove(pa2, i, L_NO_COMPACTION);
ptraAdd(pa1, item);
}
return 0;
}
static void
CopyPtras(L_PTRA *papixs,
L_PTRA *paboxs,
L_PTRA **ppapixd,
L_PTRA **ppaboxd)
{
l_int32 i, imax;
BOX *box;
PIX *pix;
ptraGetMaxIndex(papixs, &imax);
*ppapixd = ptraCreate(imax + 1);
*ppaboxd = ptraCreate(imax + 1);
for (i = 0; i <= imax; i++) {
pix = pixCopy(NULL, (PIX *)ptraGetPtrToItem(papixs, i));
box = boxCopy((BOX *)ptraGetPtrToItem(paboxs, i));
ptraAdd(*ppapixd, pix);
ptraAdd(*ppaboxd, box);
}
return;
}
/*!
* ptraSwap()
*
* Input: ptra
* index1
* index2
* Return: 0 if OK, 1 on error
*/
l_int32
ptraSwap(L_PTRA *pa,
l_int32 index1,
l_int32 index2) {
l_int32 imax;
void *item;
PROCNAME("ptraSwap");
if (!pa)
return ERROR_INT("pa not defined", procName, 1);
if (index1 == index2)
return 0;
ptraGetMaxIndex(pa, &imax);
if (index1 < 0 || index1 > imax || index2 < 0 || index2 > imax)
return ERROR_INT("invalid index: not in [0 ... imax]", procName, 1);
item = ptraRemove(pa, index1, L_NO_COMPACTION);
item = ptraReplace(pa, index2, item, FALSE);
ptraInsert(pa, index1, item, L_MIN_DOWNSHIFT);
return 0;
}
/*!
* ptraCompactArray()
*
* Input: ptra
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) This compacts the items on the array, filling any empty ptrs.
* (2) This does not change the size of the array of ptrs.
*/
l_int32
ptraCompactArray(L_PTRA *pa) {
l_int32 i, imax, nactual, index;
PROCNAME("ptraCompactArray");
if (!pa)
return ERROR_INT("pa not defined", procName, 1);
ptraGetMaxIndex(pa, &imax);
ptraGetActualCount(pa, &nactual);
if (imax + 1 == nactual) return 0;
/* Compact the array */
for (i = 0, index = 0; i <= imax; i++) {
if (pa->array[i])
pa->array[index++] = pa->array[i];
}
pa->imax = index - 1;
if (nactual != index)
L_ERROR("index = %d; != nactual\n", procName, index);
return 0;
}
/*!
* ptraInsert()
*
* Input: ptra
* index (location in ptra to insert new value)
* item (generic ptr to a struct; can be null)
* shiftflag (L_AUTO_DOWNSHIFT, L_MIN_DOWNSHIFT, L_FULL_DOWNSHIFT)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) This checks first to see if the location is valid, and
* then if there is presently an item there. If there is not,
* it is simply inserted into that location.
* (2) If there is an item at the insert location, items must be
* moved down to make room for the insert. In the downward
* shift there are three options, given by @shiftflag.
* - If @shiftflag == L_AUTO_DOWNSHIFT, a decision is made
* whether, in a cascade of items, to downshift a minimum
* amount or for all items above @index. The decision is
* based on the expectation of finding holes (null ptrs)
* between @index and the bottom of the array.
* Assuming the holes are distributed uniformly, if 2 or more
* holes are expected, we do a minimum shift.
* - If @shiftflag == L_MIN_DOWNSHIFT, the downward shifting
* cascade of items progresses a minimum amount, until
* the first empty slot is reached. This mode requires
* some computation before the actual shifting is done.
* - If @shiftflag == L_FULL_DOWNSHIFT, a shifting cascade is
* performed where pa[i] --> pa[i + 1] for all i >= index.
* Then, the item is inserted at pa[index].
* (3) If you are not using L_AUTO_DOWNSHIFT, the rule of thumb is
* to use L_FULL_DOWNSHIFT if the array is compacted (each
* element points to an item), and to use L_MIN_DOWNSHIFT
* if there are a significant number of null pointers.
* There is no penalty to using L_MIN_DOWNSHIFT for a
* compacted array, however, because the full shift is required
* and we don't do the O(n) computation to look for holes.
* (4) This should not be used repeatedly on large arrays,
* because the function is generally O(n).
* (5) However, it can be used repeatedly if we start with an empty
* ptr array and insert only once at each location. For example,
* you can support an array of Numa, where at each ptr location
* you store either 0 or 1 Numa, and the Numa can be added
* randomly to the ptr array.
*/
l_int32
ptraInsert(L_PTRA *pa,
l_int32 index,
void *item,
l_int32 shiftflag)
{
l_int32 i, ihole, imax;
l_float32 nexpected;
PROCNAME("ptraInsert");
if (!pa)
return ERROR_INT("pa not defined", procName, 1);
if (index < 0 || index > pa->nalloc)
return ERROR_INT("index not in [0 ... nalloc]", procName, 1);
if (shiftflag != L_AUTO_DOWNSHIFT && shiftflag != L_MIN_DOWNSHIFT &&
shiftflag != L_FULL_DOWNSHIFT)
return ERROR_INT("invalid shiftflag", procName, 1);
if (item) pa->nactual++;
if (index == pa->nalloc) { /* can happen when index == n */
if (ptraExtendArray(pa))
return ERROR_INT("extension failure", procName, 1);
}
/* We are inserting into a hole or adding to the end of the array.
* No existing items are moved. */
ptraGetMaxIndex(pa, &imax);
if (pa->array[index] == NULL) {
pa->array[index] = item;
if (item && index > imax) /* new item put beyond max so far */
pa->imax = index;
return 0;
}
/* We are inserting at the location of an existing item,
* forcing the existing item and those below to shift down.
* First, extend the array automatically if the last element
* (nalloc - 1) is occupied (imax). This may not be necessary
* in every situation, but only an anomalous sequence of insertions
* into the array would cause extra ptr allocation. */
if (imax >= pa->nalloc - 1 && ptraExtendArray(pa))
return ERROR_INT("extension failure", procName, 1);
/* If there are no holes, do a full downshift.
* Otherwise, if L_AUTO_DOWNSHIFT, use the expected number
* of holes between index and n to determine the shift mode */
if (imax + 1 == pa->nactual) {
shiftflag = L_FULL_DOWNSHIFT;
} else if (shiftflag == L_AUTO_DOWNSHIFT) {
if (imax < 10) {
shiftflag = L_FULL_DOWNSHIFT; /* no big deal */
} else {
nexpected = (l_float32)(imax - pa->nactual) *
(l_float32)((imax - index) / imax);
shiftflag = (nexpected > 2.0) ? L_MIN_DOWNSHIFT : L_FULL_DOWNSHIFT;
}
}
if (shiftflag == L_MIN_DOWNSHIFT) { /* run down looking for a hole */
for (ihole = index + 1; ihole <= imax; ihole++) {
if (pa->array[ihole] == NULL)
break;
}
} else { /* L_FULL_DOWNSHIFT */
ihole = imax + 1;
}
for (i = ihole; i > index; i--)
pa->array[i] = pa->array[i - 1];
pa->array[index] = (void *)item;
if (ihole == imax + 1) /* the last item was shifted down */
pa->imax++;
return 0;
}
int main(int argc,
char **argv)
{
l_int32 i, n, w, h, nactual, imax;
BOX *box;
BOXA *boxa;
PIX *pixs, *pixd, *pix;
PIXA *pixas, *pixat, *pixac;
L_PTRA *papix, *pabox, *papix2, *pabox2;
static char mainName[] = "ptra1_reg";
if (argc != 1)
return ERROR_INT(" Syntax: ptra1_reg", mainName, 1);
setLeptDebugOK(1);
pixac = pixaCreate(0);
if ((pixs = pixRead("lucasta.1.300.tif")) == NULL)
return ERROR_INT("pixs not made", mainName, 1);
pixGetDimensions(pixs, &w, &h, NULL);
boxa = pixConnComp(pixs, &pixas, 8);
pixDestroy(&pixs);
boxaDestroy(&boxa);
n = pixaGetCount(pixas);
/* Fill ptras with clones and reconstruct */
fprintf(stderr, "Fill with clones and reconstruct\n");
MakePtrasFromPixa(pixas, &papix, &pabox, L_CLONE);
pixat = ReconstructPixa(papix, pabox, CHOOSE_RECON);
ptraDestroy(&papix, 0, 1);
ptraDestroy(&pabox, 0, 1);
DisplayResult(pixac, &pixat, w, h, 1);
/* Remove every other one for the first half;
* with compaction at each removal */
fprintf(stderr, "Remove every other in 1st half, with compaction\n");
MakePtrasFromPixa(pixas, &papix, &pabox, L_COPY);
for (i = 0; i < n / 2; i++) {
if (i % 2 == 0) {
pix = (PIX *)ptraRemove(papix, i, L_COMPACTION);
box = (BOX *)ptraRemove(pabox, i, L_COMPACTION);
pixDestroy(&pix);
boxDestroy(&box);
}
}
pixat = ReconstructPixa(papix, pabox, CHOOSE_RECON);
ptraDestroy(&papix, 0, 1);
ptraDestroy(&pabox, 0, 1);
DisplayResult(pixac, &pixat, w, h, 0);
/* Remove every other one for the entire set,
* but without compaction at each removal */
fprintf(stderr,
"Remove every other in 1st half, without & then with compaction\n");
MakePtrasFromPixa(pixas, &papix, &pabox, L_COPY);
for (i = 0; i < n; i++) {
if (i % 2 == 0) {
pix = (PIX *)ptraRemove(papix, i, L_NO_COMPACTION);
box = (BOX *)ptraRemove(pabox, i, L_NO_COMPACTION);
pixDestroy(&pix);
boxDestroy(&box);
}
}
ptraCompactArray(papix); /* now do the compaction */
ptraCompactArray(pabox);
pixat = ReconstructPixa(papix, pabox, CHOOSE_RECON);
ptraDestroy(&papix, 0, 1);
ptraDestroy(&pabox, 0, 1);
DisplayResult(pixac, &pixat, w, h, 0);
/* Fill ptras using insert at head, and reconstruct */
fprintf(stderr, "Insert at head and reconstruct\n");
papix = ptraCreate(n);
pabox = ptraCreate(n);
for (i = 0; i < n; i++) {
pix = pixaGetPix(pixas, i, L_CLONE);
box = pixaGetBox(pixas, i, L_CLONE);
ptraInsert(papix, 0, pix, L_MIN_DOWNSHIFT);
ptraInsert(pabox, 0, box, L_FULL_DOWNSHIFT);
}
pixat = ReconstructPixa(papix, pabox, CHOOSE_RECON);
ptraDestroy(&papix, 0, 1);
ptraDestroy(&pabox, 0, 1);
DisplayResult(pixac, &pixat, w, h, 1);
/* Reverse the arrays by swapping */
fprintf(stderr, "Reverse by swapping\n");
MakePtrasFromPixa(pixas, &papix, &pabox, L_CLONE);
for (i = 0; i < n / 2; i++) {
ptraSwap(papix, i, n - i - 1);
ptraSwap(pabox, i, n - i - 1);
}
ptraCompactArray(papix); /* already compact; shouldn't do anything */
ptraCompactArray(pabox);
pixat = ReconstructPixa(papix, pabox, CHOOSE_RECON);
ptraDestroy(&papix, 0, 1);
ptraDestroy(&pabox, 0, 1);
DisplayResult(pixac, &pixat, w, h, 0);
/* Remove at the top of the array and push the hole to the end
* by neighbor swapping (!). This is O(n^2), so it's not a
* recommended way to copy a ptra. [joke] */
fprintf(stderr,
"Remove at top, pushing hole to end by swapping -- O(n^2)\n");
MakePtrasFromPixa(pixas, &papix, &pabox, L_CLONE);
papix2 = ptraCreate(0);
pabox2 = ptraCreate(0);
while (1) {
ptraGetActualCount(papix, &nactual);
if (nactual == 0) break;
ptraGetMaxIndex(papix, &imax);
pix = (PIX *)ptraRemove(papix, 0, L_NO_COMPACTION);
box = (BOX *)ptraRemove(pabox, 0, L_NO_COMPACTION);
ptraAdd(papix2, pix);
ptraAdd(pabox2, box);
for (i = 1; i <= imax; i++) {
ptraSwap(papix, i - 1, i);
ptraSwap(pabox, i - 1, i);
}
}
ptraCompactArray(papix); /* should be empty */
ptraCompactArray(pabox); /* ditto */
pixat = ReconstructPixa(papix, pabox, CHOOSE_RECON);
ptraDestroy(&papix, 0, 1);
ptraDestroy(&pabox, 0, 1);
DisplayResult(pixac, &pixat, w, h, 1); /* nothing there */
pixat = ReconstructPixa(papix2, pabox2, CHOOSE_RECON);
ptraDestroy(&papix2, 0, 1);
ptraDestroy(&pabox2, 0, 1);
DisplayResult(pixac, &pixat, w, h, 0);
/* Remove and insert one position above, allowing minimum downshift.
* If you specify L_AUTO_DOWNSHIFT, because there is only 1 hole,
* it will do a full downshift at each insert. This is a
* situation where the heuristic (expected number of holes)
* fails to do the optimal thing. */
fprintf(stderr, "Remove and insert one position above (min downshift)\n");
MakePtrasFromPixa(pixas, &papix, &pabox, L_CLONE);
for (i = 1; i < n; i++) {
pix = (PIX *)ptraRemove(papix, i, L_NO_COMPACTION);
box = (BOX *)ptraRemove(pabox, i, L_NO_COMPACTION);
ptraInsert(papix, i - 1, pix, L_MIN_DOWNSHIFT);
ptraInsert(pabox, i - 1, box, L_MIN_DOWNSHIFT);
}
pixat = ReconstructPixa(papix, pabox, CHOOSE_RECON);
ptraDestroy(&papix, 0, 1);
ptraDestroy(&pabox, 0, 1);
DisplayResult(pixac, &pixat, w, h, 1);
/* Remove and insert one position above, but this time
* forcing a full downshift at each step. */
fprintf(stderr, "Remove and insert one position above (full downshift)\n");
MakePtrasFromPixa(pixas, &papix, &pabox, L_CLONE);
for (i = 1; i < n; i++) {
pix = (PIX *)ptraRemove(papix, i, L_NO_COMPACTION);
box = (BOX *)ptraRemove(pabox, i, L_NO_COMPACTION);
ptraInsert(papix, i - 1, pix, L_AUTO_DOWNSHIFT);
ptraInsert(pabox, i - 1, box, L_AUTO_DOWNSHIFT);
}
/* ptraCompactArray(papix);
ptraCompactArray(pabox); */
pixat = ReconstructPixa(papix, pabox, CHOOSE_RECON);
ptraDestroy(&papix, 0, 1);
ptraDestroy(&pabox, 0, 1);
DisplayResult(pixac, &pixat, w, h, 0);
pixd = pixaDisplay(pixac, 0, 0);
pixDisplay(pixd, 100, 100);
pixWrite("/tmp/junkptra1.png", pixd, IFF_PNG);
pixDestroy(&pixd);
pixaDestroy(&pixac);
pixaDestroy(&pixas);
return 0;
}
