Add mhash

benchmark.cpp

@@ -63,6 +63,17 @@ static void BM_ahash(benchmark::State &state) {
     free(buf);
 }
 
+static void BM_mhash(benchmark::State &state) {
+    size_t size;
+    void *buf = load_test_file(&size);
+
+    for (auto _ : state) {
+        mhash_mem(buf, tmp, size, state.range());
+    }
+
+    free(buf);
+}
+
 static void BM_multi(benchmark::State &state) {
     size_t size;
     void *buf = load_test_file(&size);
@@ -83,6 +94,7 @@ BENCHMARK(BM_phash)->ArgName("size")->Arg(8);
 BENCHMARK(BM_whash)->ArgName("size")->Arg(8);
 BENCHMARK(BM_dhash)->ArgName("size")->Arg(8);
 BENCHMARK(BM_ahash)->ArgName("size")->Arg(8);
+BENCHMARK(BM_mhash)->ArgName("size")->Arg(8);
 BENCHMARK(BM_multi)->ArgName("size")->Arg(8);
 
 

fastimagehash.cpp

@@ -31,6 +31,17 @@ double median(double *arr, size_t len) {
     }
 }
 
+__always_inline
+double median(uchar *arr, size_t len) {
+    std::sort(arr, arr + len);
+
+    if (len % 2 == 0) {
+        return (double)(arr[(len / 2) - 1] + arr[len / 2]) / 2;
+    } else {
+        return arr[(len + 1 / 2)];
+    }
+}
+
 void hash_to_hex_string(const uchar *h, char *out, int hash_size) {
     int hash_len = hash_size * hash_size / 4;
 
@@ -121,6 +132,42 @@ int ahash_mem(void *buf, uchar *out, size_t buf_len, int hash_size) {
     return FASTIMAGEHASH_OK;
 }
 
+int mhash_file(const char *filepath, uchar *out, int hash_size) {
+    size_t size;
+    void *buf = load_file_in_mem(filepath, &size);
+
+    if (buf == nullptr) {
+        return FASTIMAGEHASH_READ_ERR;
+    }
+
+    int ret = mhash_mem(buf, out, size, hash_size);
+    free(buf);
+    return ret;
+}
+
+int mhash_mem(void *buf, uchar *out, size_t buf_len, int hash_size) {
+    Mat im;
+    try {
+        im = imdecode(Mat(1, buf_len, CV_8UC1, buf), IMREAD_GRAYSCALE);
+        resize(im, im, Size(hash_size, hash_size), 0, 0, INTER_AREA);
+    } catch (Exception &e) {
+        return FASTIMAGEHASH_DECODE_ERR;
+    }
+
+    uchar *pixel = im.ptr(0);
+    const int endPixel = im.cols * im.rows;
+
+    uchar sorted[im.cols * im.rows];
+    memcpy(sorted, pixel, endPixel);
+    double med = median(sorted, endPixel);
+
+    for (int i = 0; i < endPixel; i++) {
+        set_bit_at(out, i, pixel[i] > med);
+    }
+
+    return FASTIMAGEHASH_OK;
+}
+
 int dhash_file(const char *filepath, uchar *out, int hash_size) {
     size_t size;
     void *buf = load_file_in_mem(filepath, &size);
@@ -298,12 +345,13 @@ int phash_mem(void *buf, uchar *out, size_t buf_len, const int hash_size, int hi
 
 multi_hash_t *multi_hash_create(int hash_size) {
     auto multi_hash = (multi_hash_t *) malloc(sizeof(multi_hash_t));
-    auto data = (uchar *) malloc((hash_size + 1) * 4);
+    auto data = (uchar *) malloc((hash_size + 1) * 5);
 
     multi_hash->ahash = data;
     multi_hash->phash = data + (hash_size + 1);
     multi_hash->dhash = data + (hash_size + 1) * 2;
     multi_hash->whash = data + (hash_size + 1) * 3;
+    multi_hash->mhash = data + (hash_size + 1) * 4;
 
     return multi_hash;
 }
@@ -336,7 +384,7 @@ int multi_hash_mem(void *buf, multi_hash_t *out, size_t buf_len,
         return FASTIMAGEHASH_DECODE_ERR;
     }
 
-    Mat ahash_im;
+    Mat ahash_im; // Also used for mhash!
     Mat dhash_im;
     Mat phash_im;
     Mat whash_im;
@@ -383,8 +431,15 @@ int multi_hash_mem(void *buf, multi_hash_t *out, size_t buf_len,
 
     uchar *pixel = ahash_im.ptr(0);
     int endPixel = ahash_im.cols * ahash_im.rows;
+
+    // mhash
+    uchar mhash_sorted [ahash_im.cols * ahash_im.rows];
+    mempcpy(mhash_sorted, pixel, endPixel);
+    double m_median = median(mhash_sorted, endPixel);
+
     for (int i = 0; i < endPixel; i++) {
         set_bit_at(out->ahash, i, pixel[i] > avg);
+        set_bit_at(out->mhash, i, pixel[i] > m_median);
     }
 
     //dhash

fastimagehash.h

@@ -13,6 +13,7 @@ typedef struct multi_hash {
     uchar *phash;
     uchar *dhash;
     uchar *whash;
+    uchar *mhash;
 } multi_hash_t;
 
 #ifdef __cplusplus
@@ -31,12 +32,10 @@ void hash_to_hex_string_reversed(const uchar *h, char *out, int hash_size);
 
 void hash_to_hex_string(const uchar *h, char *out, int hash_size);
 
-/**
+int mhash_mem(void *buf, uchar *out, size_t buf_len, int hash_size);
- *
+
- * @param buf
+int mhash_file(const char *filepath, uchar *out, int hash_size);
- * @param buf_len
+
- * @param hash_size
- */
 int ahash_mem(void *buf, uchar *out, size_t buf_len, int hash_size);
 
 int ahash_file(const char *filepath, uchar *out, int hash_size);

imhash.c

@@ -14,7 +14,7 @@ int main(int argc, char *argv[]) {
         return 0;
     }
 
-    int do_phash = 0, do_ahash = 0, do_whash = 0, do_dhash = 0;
+    int do_phash = 0, do_ahash = 0, do_whash = 0, do_dhash = 0, do_mhash = 0;
 
     for (int i = 1; i < argc; i++) {
         if (strcmp(argv[i], "--phash") == 0) {
@@ -25,6 +25,8 @@ int main(int argc, char *argv[]) {
             do_whash = 1;
         } else if (strcmp(argv[i], "--dhash") == 0) {
             do_dhash = 1;
+        } else if (strcmp(argv[i], "--mhash") == 0) {
+            do_mhash = 1;
         } else {
 
             uchar hash[9];
@@ -54,6 +56,12 @@ int main(int argc, char *argv[]) {
                     printf("%s\tw:%s\n", argv[i], hashstr);
                 }
             }
+            if (do_mhash) {
+                if (mhash_file(argv[i], hash, 8) == 0) {
+                    hash_to_hex_string_reversed(hash, hashstr, 8);
+                    printf("%s\tm:%s\n", argv[i], hashstr);
+                }
+            }
 
             multi_hash_t *m = multi_hash_create(8);
             multi_hash_file(argv[i], m, 8, 4, 0);
@@ -66,6 +74,8 @@ int main(int argc, char *argv[]) {
             printf("%s\tmd:%s\n", argv[i], hashstr);
             hash_to_hex_string_reversed(m->whash, hashstr, 8);
             printf("%s\tmw:%s\n", argv[i], hashstr);
+            hash_to_hex_string_reversed(m->mhash, hashstr, 8);
+            printf("%s\tmm:%s\n", argv[i], hashstr);
 
             multi_hash_destroy(m);
         }