Updated FindPattern implementation to use boyre-moore pattern for faster scanning.

plugins/ADK/AS_Memory.h

@@ -31,7 +31,6 @@
 #endif
 
 #include <Windows.h>
-#include <algorithm>
 #include <sstream>
 #include <vector>
 
@@ -41,16 +40,80 @@ namespace Ashita
     {
     public:
         /**
-         * Locates a pattern of data within a large block of memory.
+         * Determines the length of data from the given offset valid to scan with.
          *
-         * @param {std::vector} data - The data to scan for the pattern within.
-         * @param {uintptr_t} baseAddress - The base address to add to the offset when the pattern is found.
-         * @param {const char*} pattern - The pattern to scan for.
-         * @param {uintptr_t} offset - The offset to add after the pattern has been found.
-         * @param {uintptr_t} count - The result count to use if the pattern is found multiple times.
+         * @param {std::vector} pattern - The pattern to find the length within.
+         * @param {uintptr_t} offset - The offset to begin iterating at.
+         * @returns {uintptr_t} The length of data from the given offset.
+         */
+        static uintptr_t FindLength(const std::vector<std::pair<uint8_t, bool>>& pattern, uintptr_t offset)
+        {
+            // Ensure the offset is within the pattern range..
+            if (offset >= pattern.size())
+                return 0;
+
+            auto len = 0;
+            for (size_t x = 0; x < pattern.size(); x++)
+            {
+                // Compare the data for wildcards or null characters..
+                if (pattern[x].second == false ||
+                    pattern[x].first == 0x00)
+                    break;
+
+                len++;
+            }
+
+            return len;
+        }
+
+        /**
+         * Finds the largest chunk of valid data within the pattern to scan for.
+         *
+         * @param {std::vector} pattern - The pattern to find the chunk within.
+         * @param {int32_t [2]} output - The output data to store the offset and length of data to use.
+         */
+        static void FindLargestChunk(const std::vector<std::pair<uint8_t, bool>>& pattern, uintptr_t output[2])
+        {
+            auto offset = (uintptr_t)0;
+            auto length = (uintptr_t)FindLength(pattern, 0);
+            auto maxlen = (uintptr_t)pattern.size();
+
+            // Loop the pattern and find its largest chunk..
+            for (auto x = length; x < maxlen; x++)
+            {
+                // Ensure the data is required..
+                if (pattern[x].second != true)
+                    continue;
+
+                // Find the length at the given offset..
+                auto count = FindLength(pattern, x);
+                if (count > length)
+                {
+                    offset = x;
+                    length = count;
+                }
+
+                // Step past the current data..
+                if (count > 0)
+                    x += count - 1;
+            }
+
+            // Return the largest offset and length..
+            output[0] = offset;
+            output[1] = length;
+        }
+
+        /**
+         * Finds a pattern within the given range of data.
+         *
+         * @param {uintptr_t} baseAddress - The address of the data to begin searching within.
+         * @param {uintptr_t} baseSize - The size of the data to search within.
+         * @param {const char*} pattern - The pattern to search for.
+         * @param {uintptr_t} offset - The offset from the found location to add to the pointer.
+         * @param {uintptr_t} count - The result count to use if the pattern is found more than once.
          * @returns {uintptr_t} The address where the pattern was located, 0 otherwise.
          */
-        static uintptr_t FindPattern(const std::vector<uint8_t>& data, uintptr_t baseAddress, const char* pattern, uintptr_t offset, uintptr_t count)
+        static uintptr_t FindPattern(uintptr_t baseAddress, uintptr_t baseSize, const char* pattern, uintptr_t offset, uintptr_t count)
         {
             // Ensure the incoming pattern is properly aligned..
             if (strlen(pattern) % 2 > 0)
@@ -73,33 +136,69 @@ namespace Ashita
                 }
             }
 
-            auto scanStart = data.begin();
-            auto result = (uintptr_t)0;
+            // Find the largest chunk of valid data to scan with..
+            uintptr_t p[2] = { 0 };
+            FindLargestChunk(vpattern, p);
+
+            // Prepare the required variables..
+            const auto psize = vpattern.size();
+            const auto pstart = p[0];
+            const auto plen = (intptr_t)p[1];
+            const auto pfirst = vpattern[0].first;
+
+            // Build the wildcard table..
+            uint8_t wildcard[UCHAR_MAX + 1] = { 0 };
+            for (auto x = pstart; x < pstart + plen; x++)
+                wildcard[(uint8_t)vpattern[x].first] = 1;
+
+            const auto data = (uint8_t*)baseAddress;
+            const auto size = (uint32_t)baseSize;
 
-            while (true)
+            std::vector<uintptr_t> matches;
+
+            // Loop the data and look for the pattern..
+            for (intptr_t x = size - psize; x >= 0; x--)
             {
-                // Search for the pattern..
-                auto ret = std::search(scanStart, data.end(), vpattern.begin(), vpattern.end(),
-                    [&](uint8_t curr, std::pair<uint8_t, bool> currPattern)
+                auto c = data[x];
+                auto w = wildcard[c];
+                auto k = 0;
+
+                // Step over wildcard characters..
+                while (w == 0 && x > (intptr_t)plen)
                 {
-                    return (!currPattern.second) || curr == currPattern.first;
-                });
+                    x -= plen;
+                    w = wildcard[data[x]];
+                    k = 1;
+                }
 
-                // Did we find a match..
-                if (ret != data.end())
+                if (k == 1)
                 {
-                    // If we hit the usage count, return the result..
-                    if (result == count || count == 0)
-                        return (std::distance(data.begin(), ret) + baseAddress) + offset;
+                    x++;
+                    continue;
+                }
+
+                // Ensure the first byte matches..
+                if (c != pfirst) continue;
 
-                    // Increment the found count and scan again..
-                    ++result;
-                    scanStart = ++ret;
+                // Validate the size..
+                if (x - pstart < 0 || x - pstart + psize > size)
+                    return 0;
+
+                // Walk the pattern and match its data..
+                for (size_t y = 0; y < psize - 1; y++)
+                {
+                    if (y == pstart || vpattern[y].second != true)
+                        continue;
+                    if (data[x - pstart + y] != vpattern[y].first)
+                        break;
+                    if (y + 1 == psize - 1)
+                        matches.insert(matches.begin(), (uintptr_t)(data + (x - pstart)) + offset);
                 }
-                else
-                    break;
             }
 
+            // Handle the count match..
+            if (count < matches.size())
+                return matches[count];
             return 0;
         }