Undo

[redakcja.git] / src / redakcja / static / js / lib / diff.js

diff --git a/src/redakcja/static/js/lib/diff.js b/src/redakcja/static/js/lib/diff.js
new file mode 100644 (file)
index 0000000..4dda274
--- /dev/null
+++ b/src/redakcja/static/js/lib/diff.js
@@ -0,0 +1,86 @@
+$.wiki.diff = function(a, b) {
+    MAXD = 500;
+
+    let VV = new Array(),
+        N = a.length,
+        M = b.length,
+        V, Vp, D, x, y, k;
+    V = VV[-1] = Array();
+    V[1] = 0;
+    let endD = null;
+    for (D = 0; D < MAXD && endD === null; D++) {
+        Vp = V;
+        V = VV[D] = Array();
+        for (k = -D; k <= D; k += 2) {
+            if (k == -D || (k != D && Vp[k-1] < Vp[k + 1])) {
+                x = Vp[k + 1];
+            } else {
+                x = Vp[k - 1] + 1;
+            }
+            y = x - k;
+            while (x < N && y < M && a[x] == b[y]) {
+                x ++;
+                y ++;
+            }
+            V[k] = x;
+            if (x == N && y == M) {
+                endD = D;
+                break;
+            }
+        }
+    }
+    if (endD === null) {
+        // Max D limit reached, diff too big. Bail and just return the whole target text.
+        return b;
+    }
+
+    // Now go back.
+    result = []
+    let snake, px, py;
+    for (D = endD; D; --D) {
+        k = x - y;
+        V = VV[D - 1];
+        if (V[k - 1] === undefined || V[k + 1] > V[k - 1]) {
+            // move up
+            k ++;
+            px = V[k];
+            py = px - k;
+            if (result.length && result[0][0] && result[0][1] == px) {
+                result[0][2] = b[py] + result[0][2];
+            } else {
+                result.unshift(
+                    [true, px, b[py]]
+                )
+            }
+        } else {
+            // move down
+            k --;
+            px = V[k];
+            py = px - k;
+            if (result.length && !result[0][0] && result[0][1] == px + 1) {
+                result[0][1]--;
+                result[0][2]++;
+            } else {
+                result.unshift(
+                    [false, px, 1]
+                )
+            }
+        }
+        x = px;
+        y = py;
+    }
+    return result
+}
+
+
+$.wiki.patch = function(a, p) {
+    for (i = p.length - 1; i >= 0; -- i) {
+        let c = p[i];
+        if (c[0]) {
+            a = a.substr(0, c[1]) + c[2] + a.substr(c[1]);
+        } else {
+            a = a.substr(0, c[1]) + a.substr(c[1] + c[2]);
+        }
+    }
+    return a;
+}