Telegram-Android/TMessagesProj/jni/image.c

#include <jni.h>
#include <stdio.h>
#include <setjmp.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <android/bitmap.h>
#include <libwebp/webp/decode.h>
#include <libwebp/webp/encode.h>
#include "c_utils.h"
#include "image.h"

jclass jclass_NullPointerException;
jclass jclass_RuntimeException;

jclass jclass_Options;
jfieldID jclass_Options_inJustDecodeBounds;
jfieldID jclass_Options_outHeight;
jfieldID jclass_Options_outWidth;

const uint32_t PGPhotoEnhanceHistogramBins = 256;
const uint32_t PGPhotoEnhanceSegments = 4;

jclass createGlobarRef(JNIEnv *env, jclass class) {
    if (class) {
        return (*env)->NewGlobalRef(env, class);
    }
    return 0;
}

jint imageOnJNILoad(JavaVM *vm, JNIEnv *env) {
    jclass_NullPointerException = createGlobarRef(env, (*env)->FindClass(env, "java/lang/NullPointerException"));
    if (jclass_NullPointerException == 0) {
        return JNI_FALSE;
    }
    jclass_RuntimeException = createGlobarRef(env, (*env)->FindClass(env, "java/lang/RuntimeException"));
    if (jclass_RuntimeException == 0) {
        return JNI_FALSE;
    }
    
    jclass_Options = createGlobarRef(env, (*env)->FindClass(env, "android/graphics/BitmapFactory$Options"));
    if (jclass_Options == 0) {
        return JNI_FALSE;
    }
    jclass_Options_inJustDecodeBounds = (*env)->GetFieldID(env, jclass_Options, "inJustDecodeBounds", "Z");
    if (jclass_Options_inJustDecodeBounds == 0) {
        return JNI_FALSE;
    }
    jclass_Options_outHeight = (*env)->GetFieldID(env, jclass_Options, "outHeight", "I");
    if (jclass_Options_outHeight == 0) {
        return JNI_FALSE;
    }
    jclass_Options_outWidth = (*env)->GetFieldID(env, jclass_Options, "outWidth", "I");
    if (jclass_Options_outWidth == 0) {
        return JNI_FALSE;
    }
    
    return JNI_TRUE;
}

static inline uint64_t getColors(const uint8_t *p) {
    return p[0] + (p[1] << 16) + ((uint64_t) p[2] << 32);
}

static inline uint64_t getColors565(const uint8_t *p) {
    uint16_t *ps = (uint16_t *) p;
    return ((((ps[0] & 0xF800) >> 11) * 255) / 31) + (((((ps[0] & 0x07E0) >> 5) * 255) / 63) << 16) + ((uint64_t) (((ps[0] & 0x001F) * 255) / 31) << 32);
}

static void fastBlurMore(int32_t w, int32_t h, int32_t stride, uint8_t *pix, int32_t radius) {
    const int32_t r1 = radius + 1;
    const int32_t div = radius * 2 + 1;
    
    if (radius > 15 || div >= w || div >= h || w * h > 150 * 150 || stride > w * 4) {
        return;
    }

    uint64_t *rgb = malloc(w * h * sizeof(uint64_t));
    if (rgb == NULL) {
        return;
    }

    int32_t x, y, i;

    int32_t yw = 0;
    const int32_t we = w - r1;
    for (y = 0; y < h; y++) {
        uint64_t cur = getColors(&pix[yw]);
        uint64_t rgballsum = -radius * cur;
        uint64_t rgbsum = cur * ((r1 * (r1 + 1)) >> 1);
        
        for (i = 1; i <= radius; i++) {
            cur = getColors(&pix[yw + i * 4]);
            rgbsum += cur * (r1 - i);
            rgballsum += cur;
        }
        
        x = 0;
        
    #define update(start, middle, end) \
            rgb[y * w + x] = (rgbsum >> 6) & 0x00FF00FF00FF00FF; \
            rgballsum += getColors(&pix[yw + (start) * 4]) - 2 * getColors(&pix[yw + (middle) * 4]) + getColors(&pix[yw + (end) * 4]); \
            rgbsum += rgballsum; \
            x++; \

        while (x < r1) {
            update (0, x, x + r1);
        }
        while (x < we) {
            update (x - r1, x, x + r1);
        }
        while (x < w) {
            update (x - r1, x, w - 1);
        }
    #undef update
        
        yw += stride;
    }
    
    const int32_t he = h - r1;
    for (x = 0; x < w; x++) {
        uint64_t rgballsum = -radius * rgb[x];
        uint64_t rgbsum = rgb[x] * ((r1 * (r1 + 1)) >> 1);
        for (i = 1; i <= radius; i++) {
            rgbsum += rgb[i * w + x] * (r1 - i);
            rgballsum += rgb[i * w + x];
        }
        
        y = 0;
        int32_t yi = x * 4;
        
    #define update(start, middle, end) \
            int64_t res = rgbsum >> 6; \
            pix[yi] = res;              \
            pix[yi + 1] = res >> 16;    \
            pix[yi + 2] = res >> 32;    \
            rgballsum += rgb[x + (start) * w] - 2 * rgb[x + (middle) * w] + rgb[x + (end) * w]; \
            rgbsum += rgballsum; \
            y++; \
            yi += stride;
        
        while (y < r1) {
            update (0, y, y + r1);
        }
        while (y < he) {
            update (y - r1, y, y + r1);
        }
        while (y < h) {
            update (y - r1, y, h - 1);
        }
    #undef update
    }
}

static void fastBlur(int32_t w, int32_t h, int32_t stride, uint8_t *pix, int32_t radius) {
    if (pix == NULL) {
        return;
    }
    const int32_t r1 = radius + 1;
    const int32_t div = radius * 2 + 1;
    int32_t shift;
    if (radius == 1) {
        shift = 2;
    } else if (radius == 3) {
        shift = 4;
    } else if (radius == 7) {
        shift = 6;
    } else if (radius == 15) {
        shift = 8;
    } else {
        return;
    }
    
    if (radius > 15 || div >= w || div >= h || w * h > 150 * 150 || stride > w * 4) {
        return;
    }

    uint64_t *rgb = malloc(w * h * sizeof(uint64_t));
    if (rgb == NULL) {
        return;
    }

    int32_t x, y, i;

    int32_t yw = 0;
    const int32_t we = w - r1;
    for (y = 0; y < h; y++) {
        uint64_t cur = getColors(&pix[yw]);
        uint64_t rgballsum = -radius * cur;
        uint64_t rgbsum = cur * ((r1 * (r1 + 1)) >> 1);
        
        for (i = 1; i <= radius; i++) {
            cur = getColors(&pix[yw + i * 4]);
            rgbsum += cur * (r1 - i);
            rgballsum += cur;
        }
        
        x = 0;
        
        #define update(start, middle, end)  \
                rgb[y * w + x] = (rgbsum >> shift) & 0x00FF00FF00FF00FFLL; \
                rgballsum += getColors(&pix[yw + (start) * 4]) - 2 * getColors(&pix[yw + (middle) * 4]) + getColors(&pix[yw + (end) * 4]); \
                rgbsum += rgballsum;        \
                x++;                        \

        while (x < r1) {
            update (0, x, x + r1);
        }
        while (x < we) {
            update (x - r1, x, x + r1);
        }
        while (x < w) {
            update (x - r1, x, w - 1);
        }
        
        #undef update
        
        yw += stride;
    }
    
    const int32_t he = h - r1;
    for (x = 0; x < w; x++) {
        uint64_t rgballsum = -radius * rgb[x];
        uint64_t rgbsum = rgb[x] * ((r1 * (r1 + 1)) >> 1);
        for (i = 1; i <= radius; i++) {
            rgbsum += rgb[i * w + x] * (r1 - i);
            rgballsum += rgb[i * w + x];
        }
        
        y = 0;
        int32_t yi = x * 4;
        
        #define update(start, middle, end)  \
                int64_t res = rgbsum >> shift;   \
                pix[yi] = res;              \
                pix[yi + 1] = res >> 16;    \
                pix[yi + 2] = res >> 32;    \
                rgballsum += rgb[x + (start) * w] - 2 * rgb[x + (middle) * w] + rgb[x + (end) * w]; \
                rgbsum += rgballsum;        \
                y++;                        \
                yi += stride;
        
        while (y < r1) {
            update (0, y, y + r1);
        }
        while (y < he) {
            update (y - r1, y, y + r1);
        }
        while (y < h) {
            update (y - r1, y, h - 1);
        }
        #undef update
    }
    
    free(rgb);
}

static void fastBlurMore565(int32_t w, int32_t h, int32_t stride, uint8_t *pix, int32_t radius) {
    const int32_t r1 = radius + 1;
    const int32_t div = radius * 2 + 1;

    if (radius > 15 || div >= w || div >= h || w * h > 150 * 150 || stride > w * 2) {
        return;
    }

    uint64_t *rgb = malloc(w * h * sizeof(uint64_t));
    if (rgb == NULL) {
        return;
    }

    int32_t x, y, i;

    int32_t yw = 0;
    const int32_t we = w - r1;
    for (y = 0; y < h; y++) {
        uint64_t cur = getColors565(&pix[yw]);
        uint64_t rgballsum = -radius * cur;
        uint64_t rgbsum = cur * ((r1 * (r1 + 1)) >> 1);

        for (i = 1; i <= radius; i++) {
            cur = getColors565(&pix[yw + i * 2]);
            rgbsum += cur * (r1 - i);
            rgballsum += cur;
        }

        x = 0;

#define update(start, middle, end) \
            rgb[y * w + x] = (rgbsum >> 6) & 0x00FF00FF00FF00FF; \
            rgballsum += getColors565(&pix[yw + (start) * 2]) - 2 * getColors565(&pix[yw + (middle) * 2]) + getColors565(&pix[yw + (end) * 2]); \
            rgbsum += rgballsum; \
            x++; \

        while (x < r1) {
            update (0, x, x + r1);
        }
        while (x < we) {
            update (x - r1, x, x + r1);
        }
        while (x < w) {
            update (x - r1, x, w - 1);
        }
#undef update

        yw += stride;
    }

    const int32_t he = h - r1;
    for (x = 0; x < w; x++) {
        uint64_t rgballsum = -radius * rgb[x];
        uint64_t rgbsum = rgb[x] * ((r1 * (r1 + 1)) >> 1);
        for (i = 1; i <= radius; i++) {
            rgbsum += rgb[i * w + x] * (r1 - i);
            rgballsum += rgb[i * w + x];
        }

        y = 0;
        int32_t yi = x * 2;

#define update(start, middle, end) \
            int64_t res = rgbsum >> 6; \
            pix[yi] = ((res >> 13) & 0xe0) | ((res >> 35) & 0x1f); \
            pix[yi + 1] = (res & 0xf8) | ((res >> 21) & 0x7); \
            rgballsum += rgb[x + (start) * w] - 2 * rgb[x + (middle) * w] + rgb[x + (end) * w]; \
            rgbsum += rgballsum; \
            y++; \
            yi += stride;

        while (y < r1) {
            update (0, y, y + r1);
        }
        while (y < he) {
            update (y - r1, y, y + r1);
        }
        while (y < h) {
            update (y - r1, y, h - 1);
        }
#undef update
    }
}

static void fastBlur565(int32_t w, int32_t h, int32_t stride, uint8_t *pix, int32_t radius) {
    if (pix == NULL) {
        return;
    }
    const int32_t r1 = radius + 1;
    const int32_t div = radius * 2 + 1;
    int32_t shift;
    if (radius == 1) {
        shift = 2;
    } else if (radius == 3) {
        shift = 4;
    } else if (radius == 7) {
        shift = 6;
    } else if (radius == 15) {
        shift = 8;
    } else {
        return;
    }

    if (radius > 15 || div >= w || div >= h || w * h > 150 * 150 || stride > w * 2) {
        return;
    }

    uint64_t *rgb = malloc(w * h * sizeof(uint64_t));
    if (rgb == NULL) {
        return;
    }

    int32_t x, y, i;

    int32_t yw = 0;
    const int32_t we = w - r1;
    for (y = 0; y < h; y++) {
        uint64_t cur = getColors565(&pix[yw]);
        uint64_t rgballsum = -radius * cur;
        uint64_t rgbsum = cur * ((r1 * (r1 + 1)) >> 1);

        for (i = 1; i <= radius; i++) {
            cur = getColors565(&pix[yw + i * 2]);
            rgbsum += cur * (r1 - i);
            rgballsum += cur;
        }

        x = 0;

#define update(start, middle, end)  \
                rgb[y * w + x] = (rgbsum >> shift) & 0x00FF00FF00FF00FFLL; \
                rgballsum += getColors565(&pix[yw + (start) * 2]) - 2 * getColors565(&pix[yw + (middle) * 2]) + getColors565(&pix[yw + (end) * 2]); \
                rgbsum += rgballsum;        \
                x++;

        while (x < r1) {
            update(0, x, x + r1);
        }
        while (x < we) {
            update(x - r1, x, x + r1);
        }
        while (x < w) {
            update(x - r1, x, w - 1);
        }

#undef update

        yw += stride;
    }

    const int32_t he = h - r1;
    for (x = 0; x < w; x++) {
        uint64_t rgballsum = -radius * rgb[x];
        uint64_t rgbsum = rgb[x] * ((r1 * (r1 + 1)) >> 1);
        for (i = 1; i <= radius; i++) {
            rgbsum += rgb[i * w + x] * (r1 - i);
            rgballsum += rgb[i * w + x];
        }

        y = 0;
        int32_t yi = x * 2;

#define update(start, middle, end)  \
                uint64_t res = rgbsum >> shift;   \
                pix[yi] = ((res >> 13) & 0xe0) | ((res >> 35) & 0x1f); \
                pix[yi + 1] = (res & 0xf8) | ((res >> 21) & 0x7); \
                rgballsum += rgb[x + (start) * w] - 2 * rgb[x + (middle) * w] + rgb[x + (end) * w]; \
                rgbsum += rgballsum;        \
                y++;                        \
                yi += stride;

        while (y < r1) {
            update (0, y, y + r1);
        }
        while (y < he) {
            update (y - r1, y, y + r1);
        }
        while (y < h) {
            update (y - r1, y, h - 1);
        }
#undef update
    }

    free(rgb);
}

JNIEXPORT int Java_org_telegram_messenger_Utilities_needInvert(JNIEnv *env, jclass class, jobject bitmap, jint unpin, jint width, jint height, jint stride) {
    if (!bitmap) {
        return 0;
    }

    if (!width || !height || !stride || stride != width * 4 || width * height > 150 * 150) {
        return 0;
    }

    void *pixels = 0;
    if (AndroidBitmap_lockPixels(env, bitmap, &pixels) < 0) {
        return 0;
    }
    if (pixels == NULL) {
        return 0;
    }
    uint8_t *pix = (uint8_t *) pixels;

    int32_t hasAlpha = 0;
    float matching = 0;
    float total = 0;
    for (int32_t y = 0; y < height; y++) {
        for (int32_t x = 0; x < width; x++) {
            int32_t index = y * stride + x * 4;
            uint8_t a = pix[index + 3];
            float alpha = a / 255.0f;

            uint8_t r = (uint8_t) (pix[index] * alpha);
            uint8_t g = (uint8_t) (pix[index + 1] * alpha);
            uint8_t b = (uint8_t) (pix[index + 2] * alpha);

            uint8_t cmax = (r > g) ? r : g;
            if (b > cmax) {
                cmax = b;
            }
            uint8_t cmin = (r < g) ? r : g;
            if (b < cmin) {
                cmin = b;
            }

            float saturation;
            float brightness = ((float) cmax) / 255.0f;
            if (cmax != 0) {
                saturation = ((float) (cmax - cmin)) / ((float) cmax);
            } else {
                saturation = 0;
            }

            if (alpha < 1.0) {
                hasAlpha = 1;
            }

            if (alpha > 0.0) {
                total += 1;
                if (saturation < 0.1f && brightness < 0.25f) {
                    matching += 1;
                }
            }
        }
    }
    if (unpin) {
        AndroidBitmap_unlockPixels(env, bitmap);
    }
    return hasAlpha && matching / total > 0.85;
}

JNIEXPORT void Java_org_telegram_messenger_Utilities_blurBitmap(JNIEnv *env, jclass class, jobject bitmap, jint radius, jint unpin, jint width, jint height, jint stride) {
    if (!bitmap) {
        return;
    }
    
    if (!width || !height || !stride) {
        return;
    }
    
    void *pixels = 0;
    if (AndroidBitmap_lockPixels(env, bitmap, &pixels) < 0) {
        return;
    }
    if (stride == width * 2) {
        if (radius <= 3) {
            fastBlur565(width, height, stride, pixels, radius);
        } else {
            fastBlurMore565(width, height, stride, pixels, radius);
        }
    } else {
        if (radius <= 3) {
            fastBlur(width, height, stride, pixels, radius);
        } else {
            fastBlurMore(width, height, stride, pixels, radius);
        }
    }
    if (unpin) {
        AndroidBitmap_unlockPixels(env, bitmap);
    }
}

JNIEXPORT void Java_org_telegram_messenger_Utilities_calcCDT(JNIEnv *env, jclass class, jobject hsvBuffer, jint width, jint height, jobject buffer) {
    float imageWidth = width;
    float imageHeight = height;
    float _clipLimit = 1.25f;

    uint32_t totalSegments = PGPhotoEnhanceSegments * PGPhotoEnhanceSegments;
    uint32_t tileArea = (uint32_t) (floorf(imageWidth / PGPhotoEnhanceSegments) * floorf(imageHeight / PGPhotoEnhanceSegments));
    uint32_t clipLimit = (uint32_t) MAX(1, _clipLimit * tileArea / (float) PGPhotoEnhanceHistogramBins);
    float scale = 255.0f / (float) tileArea;

    unsigned char *bytes = (*env)->GetDirectBufferAddress(env, hsvBuffer);

    uint32_t **hist = calloc(totalSegments, sizeof(uint32_t *));
    uint32_t **cdfs = calloc(totalSegments, sizeof(uint32_t *));
    uint32_t *cdfsMin = calloc(totalSegments, sizeof(uint32_t));
    uint32_t *cdfsMax = calloc(totalSegments, sizeof(uint32_t));
    
    for (uint32_t a = 0; a < totalSegments; a++) {
        hist[a] = calloc(PGPhotoEnhanceHistogramBins, sizeof(uint32_t));
        cdfs[a] = calloc(PGPhotoEnhanceHistogramBins, sizeof(uint32_t));
    }
    
    float xMul = PGPhotoEnhanceSegments / imageWidth;
    float yMul = PGPhotoEnhanceSegments / imageHeight;
    
    for (uint32_t y = 0; y < imageHeight; y++) {
        uint32_t yOffset = y * width * 4;
        for (uint32_t x = 0; x < imageWidth; x++) {
            uint32_t index = x * 4 + yOffset;
            
            uint32_t tx = (uint32_t)(x * xMul);
            uint32_t ty = (uint32_t)(y * yMul);
            uint32_t t = ty * PGPhotoEnhanceSegments + tx;
            
            hist[t][bytes[index + 2]]++;
        }
    }
    
    for (uint32_t i = 0; i < totalSegments; i++) {
        if (clipLimit > 0) {
            uint32_t clipped = 0;
            for (uint32_t j = 0; j < PGPhotoEnhanceHistogramBins; ++j) {
                if (hist[i][j] > clipLimit) {
                    clipped += hist[i][j] - clipLimit;
                    hist[i][j] = clipLimit;
                }
            }
            
            uint32_t redistBatch = clipped / PGPhotoEnhanceHistogramBins;
            uint32_t residual = clipped - redistBatch * PGPhotoEnhanceHistogramBins;
            
            for (uint32_t j = 0; j < PGPhotoEnhanceHistogramBins; ++j) {
                hist[i][j] += redistBatch;
            }
            
            for (uint32_t j = 0; j < residual; ++j) {
                hist[i][j]++;
            }
        }
        memcpy(cdfs[i], hist[i], PGPhotoEnhanceHistogramBins * sizeof(uint32_t));
        
        uint32_t hMin = PGPhotoEnhanceHistogramBins - 1;
        for (uint32_t j = 0; j < hMin; ++j) {
            if (cdfs[j] != 0) {
                hMin = j;
            }
        }
        
        uint32_t cdf = 0;
        for (uint32_t j = hMin; j < PGPhotoEnhanceHistogramBins; ++j) {
            cdf += cdfs[i][j];
            cdfs[i][j] = (uint8_t) MIN(255, cdf * scale);
        }
        
        cdfsMin[i] = cdfs[i][hMin];
        cdfsMax[i] = cdfs[i][PGPhotoEnhanceHistogramBins - 1];
    }
    
    uint32_t resultSize = 4 * PGPhotoEnhanceHistogramBins * totalSegments;
    uint32_t resultBytesPerRow = 4 * PGPhotoEnhanceHistogramBins;
    
    unsigned char *result = (*env)->GetDirectBufferAddress(env, buffer);
    for (uint32_t tile = 0; tile < totalSegments; tile++) {
        uint32_t yOffset = tile * resultBytesPerRow;
        for (uint32_t i = 0; i < PGPhotoEnhanceHistogramBins; i++) {
            uint32_t index = i * 4 + yOffset;
            result[index] = (uint8_t)cdfs[tile][i];
            result[index + 1] = (uint8_t)cdfsMin[tile];
            result[index + 2] = (uint8_t)cdfsMax[tile];
            result[index + 3] = 255;
        }
    }

    for (uint32_t a = 0; a < totalSegments; a++) {
        free(hist[a]);
        free(cdfs[a]);
    }
    free(hist);
    free(cdfs);
    free(cdfsMax);
    free(cdfsMin);
}

JNIEXPORT jint Java_org_telegram_messenger_Utilities_pinBitmap(JNIEnv *env, jclass class, jobject bitmap) {
    if (bitmap == NULL) {
        return 0;
    }
    unsigned char *pixels;
    return AndroidBitmap_lockPixels(env, bitmap, &pixels) >= 0 ? 1 : 0;
}

JNIEXPORT void Java_org_telegram_messenger_Utilities_unpinBitmap(JNIEnv *env, jclass class, jobject bitmap) {
    if (bitmap == NULL) {
        return;
    }
    AndroidBitmap_unlockPixels(env, bitmap);
}

JNIEXPORT jboolean Java_org_telegram_messenger_Utilities_loadWebpImage(JNIEnv *env, jclass class, jobject outputBitmap, jobject buffer, jint len, jobject options, jboolean unpin) {
    if (!buffer) {
        (*env)->ThrowNew(env, jclass_NullPointerException, "Input buffer can not be null");
        return 0;
    }
    
    jbyte *inputBuffer = (*env)->GetDirectBufferAddress(env, buffer);
    
    int32_t bitmapWidth = 0;
    int32_t bitmapHeight = 0;
    if (!WebPGetInfo((uint8_t*)inputBuffer, len, &bitmapWidth, &bitmapHeight)) {
        (*env)->ThrowNew(env, jclass_RuntimeException, "Invalid WebP format");
        return 0;
    }
    
    if (options && (*env)->GetBooleanField(env, options, jclass_Options_inJustDecodeBounds) == JNI_TRUE) {
        (*env)->SetIntField(env, options, jclass_Options_outWidth, bitmapWidth);
        (*env)->SetIntField(env, options, jclass_Options_outHeight, bitmapHeight);
        return 1;
    }
    
    if (!outputBitmap) {
        (*env)->ThrowNew(env, jclass_NullPointerException, "output bitmap can not be null");
        return 0;
    }
    
    AndroidBitmapInfo bitmapInfo;
    if (AndroidBitmap_getInfo(env, outputBitmap, &bitmapInfo) != ANDROID_BITMAP_RESUT_SUCCESS) {
        (*env)->ThrowNew(env, jclass_RuntimeException, "Failed to get Bitmap information");
        return 0;
    }
    
    void *bitmapPixels = 0;
    if (AndroidBitmap_lockPixels(env, outputBitmap, &bitmapPixels) != ANDROID_BITMAP_RESUT_SUCCESS) {
        (*env)->ThrowNew(env, jclass_RuntimeException, "Failed to lock Bitmap pixels");
        return 0;
    }
    
    if (!WebPDecodeRGBAInto((uint8_t*)inputBuffer, len, (uint8_t*)bitmapPixels, bitmapInfo.height * bitmapInfo.stride, bitmapInfo.stride)) {
        AndroidBitmap_unlockPixels(env, outputBitmap);
        (*env)->ThrowNew(env, jclass_RuntimeException, "Failed to decode webp image");
        return 0;
    }
    
    if (unpin && AndroidBitmap_unlockPixels(env, outputBitmap) != ANDROID_BITMAP_RESUT_SUCCESS) {
        (*env)->ThrowNew(env, jclass_RuntimeException, "Failed to unlock Bitmap pixels");
        return 0;
    }
    
    return 1;
}

#define SQUARE(i) ((i)*(i))
inline static void zeroClearInt(int* p, size_t count) { memset(p, 0, sizeof(int) * count); }

JNIEXPORT void Java_org_telegram_messenger_Utilities_stackBlurBitmap(JNIEnv* env, jclass class, jobject bitmap, jint radius){
    if(radius<1) return;

    AndroidBitmapInfo info;
    if(AndroidBitmap_getInfo(env, bitmap, &info)!=ANDROID_BITMAP_RESULT_SUCCESS)
        return;
    if(info.format!=ANDROID_BITMAP_FORMAT_RGBA_8888)
        return;

    int w=info.width;
    int h=info.height;
    int stride=info.stride;

    unsigned char* pixels=0;
    AndroidBitmap_lockPixels(env, bitmap, (void **) &pixels);
    if(!pixels){
        return;
    }
    // Constants
    //const int radius = (int)inradius; // Transform unsigned into signed for further operations
    const int wm = w - 1;
    const int hm = h - 1;
    const int wh = w*h;
    const int div = radius + radius + 1;
    const int r1 = radius + 1;
    const int divsum = SQUARE((div+1)>>1);

    // Small buffers
    int stack[div*3];
    zeroClearInt(stack, div*3);

    int vmin[MAX(w,h)];
    zeroClearInt(vmin, MAX(w,h));

    // Large buffers
    int *r = malloc(wh*sizeof(int));
    int *g = malloc(wh*sizeof(int));
    int *b = malloc(wh*sizeof(int));
    zeroClearInt(r, wh);
    zeroClearInt(g, wh);
    zeroClearInt(b, wh);

    const size_t dvcount = 256 * divsum;
    int *dv = malloc(sizeof(int) * dvcount);
    int i;
    for (i = 0;(size_t)i < dvcount;i++) {
        dv[i] = (i / divsum);
    }

    // Variables
    int x, y;
    int *sir;
    int routsum,goutsum,boutsum;
    int rinsum,ginsum,binsum;
    int rsum, gsum, bsum, p, yp;
    int stackpointer;
    int stackstart;
    int rbs;

    int yw = 0, yi = 0;
    for (y = 0;y < h;y++) {
        rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;

        for(i = -radius;i <= radius;i++){
            sir = &stack[(i + radius)*3];
            int offset = (y*stride + (MIN(wm, MAX(i, 0)))*4);
            sir[0] = pixels[offset];
            sir[1] = pixels[offset + 1];
            sir[2] = pixels[offset + 2];

            rbs = r1 - abs(i);
            rsum += sir[0] * rbs;
            gsum += sir[1] * rbs;
            bsum += sir[2] * rbs;
            if (i > 0){
                rinsum += sir[0];
                ginsum += sir[1];
                binsum += sir[2];
            } else {
                routsum += sir[0];
                goutsum += sir[1];
                boutsum += sir[2];
            }
        }
        stackpointer = radius;

        for (x = 0;x < w;x++) {
            r[yi] = dv[rsum];
            g[yi] = dv[gsum];
            b[yi] = dv[bsum];

            rsum -= routsum;
            gsum -= goutsum;
            bsum -= boutsum;

            stackstart = stackpointer - radius + div;
            sir = &stack[(stackstart % div)*3];

            routsum -= sir[0];
            goutsum -= sir[1];
            boutsum -= sir[2];

            if (y == 0){
                vmin[x] = MIN(x + radius + 1, wm);
            }

            int offset = (y*stride + vmin[x]*4);
            sir[0] = pixels[offset];
            sir[1] = pixels[offset + 1];
            sir[2] = pixels[offset + 2];
            rinsum += sir[0];
            ginsum += sir[1];
            binsum += sir[2];

            rsum += rinsum;
            gsum += ginsum;
            bsum += binsum;

            stackpointer = (stackpointer + 1) % div;
            sir = &stack[(stackpointer % div)*3];

            routsum += sir[0];
            goutsum += sir[1];
            boutsum += sir[2];

            rinsum -= sir[0];
            ginsum -= sir[1];
            binsum -= sir[2];

            yi++;
        }
        yw += w;
    }

    for (x = 0;x < w;x++) {
        rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
        yp = -radius*w;
        for(i = -radius;i <= radius;i++) {
            yi = MAX(0, yp) + x;

            sir = &stack[(i + radius)*3];

            sir[0] = r[yi];
            sir[1] = g[yi];
            sir[2] = b[yi];

            rbs = r1 - abs(i);

            rsum += r[yi]*rbs;
            gsum += g[yi]*rbs;
            bsum += b[yi]*rbs;

            if (i > 0) {
                rinsum += sir[0];
                ginsum += sir[1];
                binsum += sir[2];
            } else {
                routsum += sir[0];
                goutsum += sir[1];
                boutsum += sir[2];
            }

            if (i < hm) {
                yp += w;
            }
        }
        stackpointer = radius;
        for (y = 0;y < h;y++) {
            int offset = stride*y+x*4;
            pixels[offset]     = dv[rsum];
            pixels[offset + 1] = dv[gsum];
            pixels[offset + 2] = dv[bsum];
            rsum -= routsum;
            gsum -= goutsum;
            bsum -= boutsum;

            stackstart = stackpointer - radius + div;
            sir = &stack[(stackstart % div)*3];

            routsum -= sir[0];
            goutsum -= sir[1];
            boutsum -= sir[2];

            if (x == 0){
                vmin[y] = (MIN(y + r1, hm))*w;
            }
            p = x + vmin[y];

            sir[0] = r[p];
            sir[1] = g[p];
            sir[2] = b[p];

            rinsum += sir[0];
            ginsum += sir[1];
            binsum += sir[2];

            rsum += rinsum;
            gsum += ginsum;
            bsum += binsum;

            stackpointer = (stackpointer + 1) % div;
            sir = &stack[stackpointer*3];

            routsum += sir[0];
            goutsum += sir[1];
            boutsum += sir[2];

            rinsum -= sir[0];
            ginsum -= sir[1];
            binsum -= sir[2];

            yi += w;
        }
    }

    free(r);
    free(g);
    free(b);
    free(dv);
    AndroidBitmap_unlockPixels(env, bitmap);
}