From dc3be8f0d0eaa62700eeeb04a08b18bf2a3e6d1c Mon Sep 17 00:00:00 2001
From: lifegpc <root@lifegpc.com>
Date: Sun, 20 Apr 2025 22:15:25 +0800
Subject: [PATCH] Add support to patch bp

---
 patch_bp.py | 163 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 163 insertions(+)
 create mode 100644 patch_bp.py

diff --git a/patch_bp.py b/patch_bp.py
new file mode 100644
index 0000000..9ad38e2
--- /dev/null
+++ b/patch_bp.py
@@ -0,0 +1,163 @@
+import struct
+import sys
+import json
+
+
+class BPScript:
+    def __init__(self, path: str):
+        self.path = path
+        with open(path, 'rb') as f:
+            self.data = bytearray(f.read())
+        self.len = len(self.data)
+        self.read_header()
+        self.iPos = self.header_size
+
+    def read_header(self):
+        self.header_size = struct.unpack('<L', self.data[0:4])[0]
+        self.instr_size = struct.unpack('<L', self.data[4:8])[0]
+        if self.len != self.header_size + self.instr_size:
+            raise ValueError("Invalid BPScript file size")
+        self.iPos = self.header_size
+        self.last_pos = 0
+        while self.iPos < self.len - 4:
+            d = struct.unpack('<L', self.data[self.iPos:self.iPos + 4])[0]
+            if d == 0x17:
+                self.last_pos = self.iPos
+            self.iPos += 4
+
+    def extract_string(self):
+        offset = struct.unpack('<h', self.data[self.iPos:self.iPos + 2])[0]
+        start_pos = self.iPos + offset - 1
+        self.iPos += 2
+        if start_pos < self.last_pos or start_pos >= self.len or ((start_pos > self.last_pos + 1) and self.data[start_pos-1] != 0):
+            self.iPos -= 2
+            return None
+        pos = start_pos
+        while True:
+            if self.data[pos] == 0x00:
+                break
+            pos += 1
+        data = self.data[start_pos:pos]
+        try:
+            data = data.decode('cp932')
+        except UnicodeDecodeError:
+            data = data.decode('utf-8')
+            data = "utf8:" + data
+        if not data:
+            return None
+        return start_pos, self.iPos - 2
+
+    def extract_values(self):
+        str_pos = {}
+        self.iPos = self.header_size
+        while self.iPos < self.last_pos:
+            ins = self.data[self.iPos]
+            self.iPos += 1
+            if ins == 0x5:
+                try:
+                    t = self.extract_string()
+                    if t is not None:
+                        if t[0] not in str_pos:
+                            str_pos[t[0]] = [t[1]]
+                        else:
+                            str_pos[t[0]].append(t[1])
+                except UnicodeDecodeError:
+                    self.iPos -= 2
+        return str_pos
+    
+    def extract_strings(self):
+        self.iPos = self.last_pos + 1
+        while self.data[self.iPos] == 0:
+            self.iPos += 1
+        strings = []
+        start_pos = self.iPos
+        while self.iPos < self.len:
+            if self.data[self.iPos] == 0:
+                data = self.data[start_pos:self.iPos]
+                data_len = len(data)
+                try:
+                    data = data.decode('cp932')
+                except UnicodeDecodeError:
+                    data = data.decode('utf-8')
+                    data = "utf8:" + data
+                if data:
+                    strings.append((start_pos, data_len))
+                start_pos = self.iPos + 1
+            self.iPos += 1
+        return dict(strings)
+
+    def setup_values(self, values: dict):
+        data = bytearray(self.data)
+        goffsets = self.extract_values()
+        offsets = self.extract_strings()
+        print(offsets)
+        self.iPos = self.header_size
+        all_keys = list(int(i) for i in values.keys())
+        all_keys.sort()
+        new_offsets = {}
+        for key in all_keys:
+            new_offsets[key] = key
+        last_len = 0
+        last_key = all_keys[-1]
+        for i in range(len(all_keys)):
+            key = all_keys[i]
+            ori_len = offsets[key] + 1
+            v = values[f"{key}"]
+            if v.startswith("utf8:"):
+                v = v[5:]
+                v = v.encode("utf-8")
+            else:
+                v = v.encode("cp932")
+            v += b'\0'
+            new_len = len(v)
+            last_len = new_len
+            if new_len == ori_len:
+                continue
+            for j in range(i + 1, len(all_keys)):
+                off = all_keys[j]
+                new_offsets[off] += new_len - ori_len
+        print(new_offsets)
+        old_len = last_key + last_len
+        new_len = new_offsets[last_key] + last_len
+        # 对齐到16字节
+        new_len = new_len + (16 - new_len % 16)
+        data = bytearray(data[:all_keys[0]] + b'\0' * (new_len - old_len) + data[all_keys[0] + last_len:])
+        self.len = new_len
+        data[4:8] = struct.pack('<L', self.len - self.header_size)
+        for i in all_keys:
+            start = new_offsets[i]
+            v = values[f"{i}"]
+            if v.startswith("utf8:"):
+                v = v[5:]
+                v = v.encode("utf-8")
+            else:
+                v = v.encode("cp932")
+            v += b'\0'
+            end = start + len(v)
+            data[start:end] = v
+            print(data[start:end])
+        for k, v in goffsets.items():
+            for i in v:
+                data[i:i+2] = struct.pack('<H', new_offsets[k] - i + 1)
+        self.data = data
+    
+    def save_as(self, path: str):
+        with open(path, 'wb') as f:
+            f.write(self.data)
+
+
+base = sys.argv[1]
+json_f = f"{base}.json"
+if len(sys.argv) >= 3:
+    json_f = sys.argv[2]
+output = f"../patched/{base}"
+if len(sys.argv) >= 4:
+    output = sys.argv[3]
+scr = BPScript(base)
+print(scr.header_size)
+print(scr.iPos)
+print(scr.last_pos)
+with open(json_f, "r", encoding="utf-8") as f:
+    data = json.load(f)
+scr.setup_values(data)
+scr.save_as(output)