Utility Structures

/**
 * Stack data structure
 */
class L_STACK extends Pointer {
    int n(); // number of elements
    int nalloc(); // allocated capacity
    Pointer auxstack(); // auxiliary stack for object pointers
}

/**
 * Queue data structure
 */
class L_QUEUE extends Pointer {
    int nalloc(); // allocated capacity
    int nhead(); // head index
    int ntail(); // tail index
    int nelem(); // number of elements
    Pointer array(); // element array
}

/**
 * Priority heap
 */
class L_HEAP extends Pointer {
    int n(); // number of elements
    int nalloc(); // allocated capacity
    FloatPointer array(); // value array
    int direction(); // L_SORT_INCREASING or L_SORT_DECREASING
}

/**
 * Hash map
 */
class L_HASHMAP extends Pointer {
    int nitems(); // number of items
    int nbuckets(); // number of hash buckets
    L_HASHITEM array(); // hash item array
}

/**
 * Hash map item
 */
class L_HASHITEM extends Pointer {
    long key(); // hash key
    Pointer value(); // stored value
    L_HASHITEM next(); // next item in bucket
}

// Stack operations
L_STACK lstackCreate(int nalloc);
int lstackAdd(L_STACK lstack, Pointer item);
Pointer lstackRemove(L_STACK lstack);
int lstackGetCount(L_STACK lstack);

// Queue operations
L_QUEUE lqueueCreate(int nalloc);
int lqueueAdd(L_QUEUE lqueue, Pointer item);
Pointer lqueueRemove(L_QUEUE lqueue);
int lqueueGetCount(L_QUEUE lqueue);

// Heap operations
L_HEAP lheapCreate(int nalloc, int direction);
int lheapAdd(L_HEAP lh, Pointer item);
Pointer lheapRemove(L_HEAP lh);
int lheapGetCount(L_HEAP lh);

// Hash map operations
L_HASHMAP hashmapCreate(int nbuckets);
int hashmapLookup(L_HASHMAP hmap, long key, Pointer pval);
int hashmapInsert(L_HASHMAP hmap, long key, Pointer val);
int hashmapDelete(L_HASHMAP hmap, long key);

import org.bytedeco.leptonica.*;
import static org.bytedeco.leptonica.global.leptonica.*;

// Stack for region processing
L_STACK regionStack = lstackCreate(100);
lstackAdd(regionStack, seedRegion);

while (lstackGetCount(regionStack) > 0) {
    BOX region = (BOX)lstackRemove(regionStack);
    // Process region and add neighbors...
}

// Priority queue for pathfinding
L_HEAP priorityQueue = lheapCreate(500, L_SORT_INCREASING);
lheapAdd(priorityQueue, startNode);

while (lheapGetCount(priorityQueue) > 0) {
    PathNode current = (PathNode)lheapRemove(priorityQueue);
    // Process current node...
}

// Hash map for caching results
L_HASHMAP cache = hashmapCreate(1024);
hashmapInsert(cache, imageHash, processedResult);

// Later lookup
Pointer cached = new Pointer();
if (hashmapLookup(cache, imageHash, cached) == 0) {
    // Use cached result
}

/**
 * Dynamic byte array
 */
class L_BYTEA extends Pointer {
    int nalloc(); // allocated size
    int size(); // actual size
    BytePointer data(); // byte data
}

/**
 * Byte buffer for I/O
 */
class L_BBUFFER extends Pointer {
    int nalloc(); // allocated size
    int n(); // actual size
    int nwritten(); // bytes written
    BytePointer array(); // buffer data
}

/**
 * Create byte array
 * @param nbytes - Initial capacity
 * @return L_BYTEA or null on failure
 */
L_BYTEA l_byteaCreate(int nbytes);

/**
 * Append data to byte array
 * @param ba - Target byte array
 * @param newdata - Data to append
 * @param size - Size of data
 * @return 0 on success, 1 on failure
 */
int l_byteaAppendData(L_BYTEA ba, BytePointer newdata, int size);

/**
 * Get data from byte array
 * @param ba - Source byte array
 * @param psize - Returns data size
 * @return BytePointer to data or null on failure
 */
BytePointer l_byteaGetData(L_BYTEA ba, IntPointer psize);

/**
 * Create byte buffer
 * @param nbytes - Initial capacity
 * @return L_BBUFFER or null on failure
 */
L_BBUFFER bbufferCreate(int nbytes);

/**
 * Read data into buffer
 * @param bb - Target buffer
 * @param src - Source data
 * @param nbytes - Number of bytes to read
 * @return 0 on success, 1 on failure
 */
int bbufferRead(L_BBUFFER bb, BytePointer src, int nbytes);

/**
 * Write data from buffer
 * @param bb - Source buffer
 * @param dest - Destination
 * @param nbytes - Number of bytes to write
 * @return 0 on success, 1 on failure
 */
int bbufferWrite(L_BBUFFER bb, BytePointer dest, int nbytes);

// Dynamic byte array for accumulating data
L_BYTEA accumulator = l_byteaCreate(1024);

// Append image data
BytePointer imageData = pixGetData(pix);
int imageSize = pixGetHeight(pix) * pixGetWpl(pix) * 4;
l_byteaAppendData(accumulator, imageData, imageSize);

// Get accumulated data
IntPointer totalSize = new IntPointer(1);
BytePointer allData = l_byteaGetData(accumulator, totalSize);
System.out.println("Accumulated " + totalSize.get() + " bytes");

// Byte buffer for I/O operations
L_BBUFFER buffer = bbufferCreate(4096);
bbufferRead(buffer, inputData, dataSize);
// ... process buffer ...
bbufferWrite(buffer, outputData, processedSize);

/**
 * Timer structure
 */
class L_TIMER extends Pointer {
    // Internal timer state
}

/**
 * Wall clock timer
 */
class L_WALLTIMER extends Pointer {
    long start_sec(); // start seconds
    long start_usec(); // start microseconds
    long stop_sec(); // stop seconds
    long stop_usec(); // stop microseconds
}

/**
 * Start timing
 * @return L_TIMER or null on failure
 */
L_TIMER startTimer();

/**
 * Stop timing and get elapsed time
 * @param timer - Timer to stop
 * @return Elapsed time in seconds
 */
float stopTimer(L_TIMER timer);

/**
 * Start wall clock timer
 * @return L_WALLTIMER or null on failure
 */
L_WALLTIMER startWallTimer();

/**
 * Stop wall clock timer
 * @param timer - Wall timer to stop
 * @return Elapsed time in seconds
 */
float stopWallTimer(L_WALLTIMER timer);

/**
 * Get current timestamp
 * @return Current time in seconds since epoch
 */
float getCurrentTime();

// Time image processing operation
L_TIMER timer = startTimer();

PIX processed = pixGaussianBlur(sourceImage, 3.0f, 3.0f);
processed = pixScale(processed, 2.0f, 2.0f);
processed = pixRotate(processed, 0.1f, L_ROTATE_AREA_MAP, L_BRING_IN_WHITE, 0, 0);

float elapsed = stopTimer(timer);
System.out.println("Processing took " + elapsed + " seconds");

// Wall clock timing for I/O operations
L_WALLTIMER wallTimer = startWallTimer();

for (int i = 0; i < 100; i++) {
    PIX image = pixRead("image_" + i + ".jpg");
    PIX result = pixScale(image, 0.5f, 0.5f);
    pixWrite("thumb_" + i + ".jpg", result, IFF_JPEG);
}

float totalTime = stopWallTimer(wallTimer);
System.out.println("Batch processing: " + totalTime + " seconds");

/**
 * Count pixels in binary image
 * @param pix - Binary image
 * @param pcount - Returns pixel count
 * @param tab8 - Lookup table (can be null)
 * @return 0 on success, 1 on failure
 */
int pixCountPixels(PIX pix, IntPointer pcount, IntPointer tab8);

/**
 * Get average pixel value in region
 * @param pixs - Source image
 * @param pixm - Mask image (can be null)
 * @param x - Region x coordinate
 * @param y - Region y coordinate
 * @param w - Region width
 * @param h - Region height
 * @param factor - Sampling factor
 * @param pval - Returns average value
 * @return 0 on success, 1 on failure
 */
int pixGetAverageMasked(PIX pixs, PIX pixm, int x, int y, int w, int h, int factor, FloatPointer pval);

/**
 * Get pixel variance in region
 * @param pixs - Source image
 * @param pixm - Mask image (can be null)
 * @param x - Region x coordinate  
 * @param y - Region y coordinate
 * @param w - Region width
 * @param h - Region height
 * @param factor - Sampling factor
 * @param pvar - Returns variance
 * @return 0 on success, 1 on failure
 */
int pixGetVarianceMasked(PIX pixs, PIX pixm, int x, int y, int w, int h, int factor, FloatPointer pvar);

/**
 * Find extreme pixel values
 * @param pixs - Source image
 * @param pminval - Returns minimum value (can be null)
 * @param pmaxval - Returns maximum value (can be null)
 * @param pminloc - Returns minimum location (can be null)
 * @param pmaxloc - Returns maximum location (can be null)
 * @return 0 on success, 1 on failure
 */
int pixGetExtremeValue(PIX pixs, IntPointer pminval, IntPointer pmaxval, IntPointer pminloc, IntPointer pmaxloc);

/**
 * Check if images are equal
 * @param pix1 - First image
 * @param pix2 - Second image
 * @param psame - Returns 1 if equal, 0 otherwise
 * @return 0 on success, 1 on failure
 */
int pixEqual(PIX pix1, PIX pix2, IntPointer psame);

/**
 * Calculate correlation between images
 * @param pix1 - First image
 * @param pix2 - Second image
 * @param pcorrel - Returns correlation coefficient
 * @return 0 on success, 1 on failure
 */
int pixCorrelationBinary(PIX pix1, PIX pix2, FloatPointer pcorrel);

// Count foreground pixels
IntPointer pixelCount = new IntPointer(1);
pixCountPixels(binaryImage, pixelCount, null);
System.out.println("Foreground pixels: " + pixelCount.get());

// Get region statistics
FloatPointer average = new FloatPointer(1);
FloatPointer variance = new FloatPointer(1);

pixGetAverageMasked(grayImage, null, 100, 100, 50, 50, 1, average);
pixGetVarianceMasked(grayImage, null, 100, 100, 50, 50, 1, variance);

System.out.println("Region stats: mean=" + average.get() + ", var=" + variance.get());

// Find extreme values
IntPointer minVal = new IntPointer(1);
IntPointer maxVal = new IntPointer(1);
IntPointer minLoc = new IntPointer(1);
IntPointer maxLoc = new IntPointer(1);

pixGetExtremeValue(grayImage, minVal, maxVal, minLoc, maxLoc);
System.out.println("Range: " + minVal.get() + " to " + maxVal.get());

// Compare images
IntPointer same = new IntPointer(1);
pixEqual(image1, image2, same);
if (same.get() == 1) {
    System.out.println("Images are identical");
}

// Calculate similarity
FloatPointer correlation = new FloatPointer(1);
pixCorrelationBinary(binary1, binary2, correlation);
System.out.println("Correlation: " + correlation.get());

/**
 * Allocate memory
 * @param nbytes - Number of bytes to allocate
 * @return Pointer to allocated memory or null on failure
 */
Pointer lept_malloc(long nbytes);

/**
 * Reallocate memory
 * @param ptr - Existing pointer
 * @param nbytes - New size in bytes
 * @return Pointer to reallocated memory or null on failure
 */
Pointer lept_realloc(Pointer ptr, long nbytes);

/**
 * Free memory
 * @param ptr - Pointer to free
 */
void lept_free(Pointer ptr);

/**
 * Get memory usage statistics
 * @param pnalloc - Returns number of allocations
 * @param pnfree - Returns number of frees
 * @param pnbytes - Returns bytes allocated
 * @return 0 on success, 1 on failure
 */
int lept_getAllocStats(IntPointer pnalloc, IntPointer pnfree, IntPointer pnbytes);

// Manual memory management (rarely needed with JavaCPP)
Pointer buffer = lept_malloc(1024);
// ... use buffer ...
lept_free(buffer);

// Check memory statistics
IntPointer allocCount = new IntPointer(1);
IntPointer freeCount = new IntPointer(1); 
IntPointer bytesAlloc = new IntPointer(1);

lept_getAllocStats(allocCount, freeCount, bytesAlloc);
System.out.println("Memory: " + allocCount.get() + " allocs, " + 
                  freeCount.get() + " frees, " + bytesAlloc.get() + " bytes");

// Direction constants
static final int L_SORT_INCREASING = 1;
static final int L_SORT_DECREASING = 2;

// Access flags
static final int L_COPY = 0;
static final int L_CLONE = 1;
static final int L_INSERT = 2;
static final int L_NOCOPY = 3;

// Buffer sizes
static final int L_DEFAULT_BUFFER_SIZE = 4096;

// Region growing with stack
L_STACK growStack = lstackCreate(1000);
lstackAdd(growStack, seedPoint);

while (lstackGetCount(growStack) > 0) {
    Point current = (Point)lstackRemove(growStack);
    
    // Check neighbors and add to stack
    if (isValidGrowthPoint(current.x + 1, current.y)) {
        lstackAdd(growStack, new Point(current.x + 1, current.y));
    }
    // ... check other neighbors ...
}

// Performance monitoring
L_TIMER overallTimer = startTimer();

for (int i = 0; i < imageCount; i++) {
    L_TIMER imageTimer = startTimer();
    
    PIX processed = processImage(images[i]);
    
    float imageTime = stopTimer(imageTimer);
    System.out.println("Image " + i + ": " + imageTime + " seconds");
}

float totalTime = stopTimer(overallTimer);
System.out.println("Total processing: " + totalTime + " seconds");