1 files changed, 180 insertions, 0 deletions
diff --git a/FreeFileSync/Source/base/multi_rename.cpp b/FreeFileSync/Source/base/multi_rename.cpp
new file mode 100644
index 00000000..bc1e48ad
--- /dev/null
+++ b/FreeFileSync/Source/base/multi_rename.cpp
@@ -0,0 +1,180 @@
+// *****************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under    *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
+// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
+// *****************************************************************************
+
+#include "multi_rename.h"
+#include <zen/string_tools.h>
+
+using namespace zen;
+using namespace fff;
+
+
+namespace
+{
+std::wstring_view findLongestSubstring(const std::vector<std::wstring_view>& strings)
+{
+    if (strings.empty())
+        return {};
+
+    const std::wstring_view strMin = *std::min_element(strings.begin(), strings.end(),
+    /**/[](const std::wstring_view lhs, const std::wstring_view rhs) { return lhs.size() < rhs.size(); });
+
+    for (size_t sz = strMin.size(); sz > 0; --sz) //iterate over size, descending
+        for (size_t i = 0; i + sz <= strMin.size(); ++i)
+        {
+            const std::wstring_view substr(strMin.data() + i, sz);
+            //perf: duplicate substrings, especially für size = 1?
+
+            const bool isCommon = [&]
+            {
+                for (const std::wstring_view str : strings)
+                    if (str.data() != strMin.data()) //sufficient check: an extension of strMin wouldn't prune anyway
+                        if (!contains(str, substr))
+                            return false;
+                return true;
+            }();
+
+            if (isCommon)
+                return substr; //*first* occuring substring of maximum size
+        }
+
+    return {};
+}
+
+
+struct StringPart
+{
+    std::vector<std::wstring_view> diff; //may be empty, but only at beginning
+    std::wstring_view common;            //may be empty, but only at end
+};
+
+std::vector<StringPart> getStringParts(std::vector<std::wstring_view>&& strings)
+{
+    std::wstring_view substr = findLongestSubstring(strings);
+    if (!substr.empty())
+    {
+        std::vector<std::wstring_view> head;
+        std::vector<std::wstring_view> tail;
+
+        for (const std::wstring_view str : strings)
+        {
+            head.push_back(beforeFirst(str, substr, IfNotFoundReturn::none));
+            tail.push_back(afterFirst (str, substr, IfNotFoundReturn::none));
+        }
+
+        std::vector<StringPart> np = getStringParts(std::move(head));
+        assert(np.empty() || np.back().common.empty()); //otherwise we could construct an even longer substring!
+
+        if (np.empty())
+            np.push_back({{}, substr});
+        else
+            np.back().common = substr;
+
+        const std::vector<StringPart> npTail = getStringParts(std::move(tail));
+        assert(npTail.empty() || !npTail.front().diff.empty()); //otherwise we could construct an even longer substring!
+
+        append(np, npTail);
+        return np;
+    }
+    else
+    {
+        if (std::all_of(strings.begin(), strings.end(), [](const std::wstring_view str) { return str.empty(); }))
+        /**/return {};
+
+        return {{std::move(strings), {}}};
+    }
+}
+
+
+constexpr wchar_t placeholders[] = //http://xahlee.info/comp/unicode_circled_numbers.html
+{
+    //L'\u24FF', //⓿ <- rendered bigger than the rest (same for ⓫) on Centos Linux
+    L'\u2776', //❶
+    L'\u2777', //❷
+    L'\u2778', //❸
+    L'\u2779', //❹
+    L'\u277A', //❺
+    L'\u277B', //❻
+    L'\u277C', //❼
+    L'\u277D', //❽
+    L'\u277E', //❾
+    L'\u277F', //❿ -> last one is special: represents "all the rest"
+};
+
+
+inline
+size_t getPlaceholderIndex(wchar_t c)
+{
+    static_assert(std::size(placeholders) == 10);
+    if (placeholders[0] <= c && c <= placeholders[9])
+        return static_cast<size_t>(c - placeholders[0]);
+
+    return static_cast<size_t>(-1);
+}
+}
+
+struct fff::RenameBuf
+{
+    explicit RenameBuf(const std::vector<std::wstring>& s) : strings(s) {}
+
+    std::vector<std::wstring> strings;
+    std::vector<StringPart> parts = getStringParts({strings.begin(), strings.end()});
+};
+
+
+//e.g. "Season ❶, Episode ❷ - ❸.avi"
+std::pair<std::wstring /*phrase*/, SharedRef<const RenameBuf>> fff::getPlaceholderPhrase(const std::vector<std::wstring>& strings)
+{
+   auto renameBuf = makeSharedRef<const RenameBuf>(strings);
+
+    std::wstring phrase;
+    size_t placeIdx = 0;
+
+    for (const StringPart& p : renameBuf.ref().parts)
+    {
+        if (!p.diff.empty())
+        {
+            phrase += placeholders[placeIdx++];
+
+            if (placeIdx >= std::size(placeholders))
+                break; //represent "all the rest" with last placeholder
+        }
+        phrase += p.common; //TODO: what if common part already contains placeholder character!?
+    }
+    return {phrase, renameBuf};
+}
+
+
+const std::vector<std::wstring> fff::resolvePlaceholderPhrase(const std::wstring_view phrase, const RenameBuf& buf)
+{
+    std::vector<std::vector<std::wstring_view>> diffByIdx;
+
+    for (const StringPart& p : buf.parts)
+        if (!p.diff.empty())
+            diffByIdx.push_back(std::move(p.diff)), assert(diffByIdx.back().size() == buf.strings.size());
+
+    std::vector<std::wstring> output;
+
+    for (size_t i = 0; i < buf.strings.size(); ++i)
+    {
+        std::wstring resolved;
+
+        for (const wchar_t c : phrase)
+            if (const size_t placeIdx = getPlaceholderIndex(c);
+                placeIdx < diffByIdx.size())
+            {
+                if (placeIdx == std::size(placeholders) - 1) //last placeholder represents "all the rest"
+                    resolved.append(diffByIdx[placeIdx][i].data(), buf.strings[i].data() + buf.strings[i].size());
+                else
+                    resolved += diffByIdx[placeIdx][i];
+            }
+            else
+                resolved += c;
+
+        output.push_back(std::move(resolved));
+    }
+
+    return output;
+}