From ed47c1557915bb2472f6959e723cd76155312a98 Mon Sep 17 00:00:00 2001
From: Chris Xiong <chirs241097@gmail.com>
Date: Mon, 6 Apr 2020 00:50:58 +0800
Subject: Add deduper (unfinished tool for finding image duplicates).

---
 deduper/libpuzzle/src/vector_ops.c | 95 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 deduper/libpuzzle/src/vector_ops.c

(limited to 'deduper/libpuzzle/src/vector_ops.c')

diff --git a/deduper/libpuzzle/src/vector_ops.c b/deduper/libpuzzle/src/vector_ops.c
new file mode 100644
index 0000000..4fad5bf
--- /dev/null
+++ b/deduper/libpuzzle/src/vector_ops.c
@@ -0,0 +1,95 @@
+#include "puzzle_common.h"
+#include "puzzle_p.h"
+#include "puzzle.h"
+#include "globals.h"
+
+int puzzle_vector_sub(PuzzleContext * const context,
+                      PuzzleCvec * const cvecr,
+                      const PuzzleCvec * const cvec1,
+                      const PuzzleCvec * const cvec2,
+                      const int fix_for_texts)
+{
+    size_t remaining;
+    signed char c1, c2, cr;
+
+    (void) context;
+    if (cvec1->sizeof_vec != cvec2->sizeof_vec ||
+        cvec1->sizeof_vec <= (size_t) 0U) {
+        puzzle_err_bug(__FILE__, __LINE__);
+    }
+    if (cvecr->vec != NULL) {
+        puzzle_err_bug(__FILE__, __LINE__);
+    }
+    cvecr->sizeof_vec = cvec1->sizeof_vec;    
+    if ((cvecr->vec = calloc(cvecr->sizeof_vec, sizeof *cvecr->vec)) == NULL) {
+        return -1;
+    }
+    remaining = cvec1->sizeof_vec;
+    if (fix_for_texts != 0) {
+        do {
+            remaining--;
+            c1 = cvec1->vec[remaining];
+            c2 = cvec2->vec[remaining];
+            if ((c1 == 0 && c2 == -2) || (c1 == -2 && c2 == 0)) {
+                cr = -3;
+            } else if ((c1 == 0 && c2 == +2) || (c1 == +2 && c2 == 0)) {
+                cr = +3;
+            } else {
+                cr = c1 - c2;
+            }
+            cvecr->vec[remaining] = cr;
+        } while (remaining > (size_t) 0U);        
+    } else {
+        do {
+            remaining--;
+            cvecr->vec[remaining] =
+                cvec1->vec[remaining] - cvec2->vec[remaining];
+        } while (remaining > (size_t) 0U);
+    }
+    return 0;
+}
+
+double puzzle_vector_euclidean_length(PuzzleContext * const context,
+                                      const PuzzleCvec * const cvec)
+{
+    unsigned long t = 0U;
+    unsigned long c;
+    int c2;
+    size_t remaining;
+
+    (void) context;
+    if ((remaining = cvec->sizeof_vec) <= (size_t) 0U) {
+        return 0.0;
+    }
+    do {
+        remaining--;
+        c2 = (int) cvec->vec[remaining];
+        c = (unsigned long) (c2 * c2);
+        if (ULONG_MAX - t < c) {
+            puzzle_err_bug(__FILE__, __LINE__);
+        }
+        t += c;
+    } while (remaining > (size_t) 0U);
+    
+    return sqrt((double) t);
+}
+
+double puzzle_vector_normalized_distance(PuzzleContext * const context,
+                                         const PuzzleCvec * const cvec1,
+                                         const PuzzleCvec * const cvec2,
+                                         const int fix_for_texts)
+{
+    PuzzleCvec cvecr;
+    double dt, dr;
+
+    puzzle_init_cvec(context, &cvecr);
+    puzzle_vector_sub(context, &cvecr, cvec1, cvec2, fix_for_texts);
+    dt = puzzle_vector_euclidean_length(context, &cvecr);
+    puzzle_free_cvec(context, &cvecr);
+    dr = puzzle_vector_euclidean_length(context, cvec1)
+        + puzzle_vector_euclidean_length(context, cvec2);
+    if (dr == 0.0) {
+        return 0.0;
+    }
+    return dt / dr;
+}
-- 
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