Prefix image data with its length and increment TS_VERSION to 22 (aar…

…dappel#433) - This increments the TreeSheets file format version to 22. - This adds a wxInt64/int64_t before the actual image data indicating its length. - This updates the corresponding loading and saving procedures. - This updates the file format specification.
AntonBogun · Jun 4, 2023 · 9784aa2 · 9784aa2
1 parent 6059e7e
commit 9784aa2
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Showing 4 changed files with 40 additions and 32 deletions.
diff --git a/TS/docs/file_format_spec.txt b/TS/docs/file_format_spec.txt
@@ -22,9 +22,9 @@ struct Image
 {
     char ident;   // marks start of image
     // Character value depends on image type, i.e. 'I' for PNG and 'J' for JPEG
+    double display_scale; // display scale of image
+    int64_t imagelen; // length of image (8 bytes)
     char image_data[len]; // whatever format wxImage::LoadFile uses
-    // to know len, you need to parse the png chunks
-    // sadly this means there's no way to read the Cells without doing so
 }
 
 struct Cell

diff --git a/src/document.h b/src/document.h
@@ -205,7 +205,9 @@ struct Document {
                 if (image.trefc) {
                     fos.PutC(image.image_type);
                     sos.WriteDouble(image.display_scale);
-                    fos.Write(image.image_data.data(), image.image_data.size());
+                    wxInt64 imagelen(image.image_data.size());
+                    sos.Write64(imagelen);
+                    fos.Write(image.image_data.data(), imagelen);
                     image.savedindex = realindex++;
                 }
             }

diff --git a/src/main.cpp b/src/main.cpp
@@ -34,7 +34,7 @@ static const std::array<uint, 42> celltextcolors = {
 };
 enum { CUSTOMCOLORIDX = 0 };
 
-enum { TS_VERSION = 21, TS_TEXT = 0, TS_GRID, TS_BOTH, TS_NEITHER };
+enum { TS_VERSION = 22, TS_TEXT = 0, TS_GRID, TS_BOTH, TS_NEITHER };
 
 static const uint TS_SELECTION_MASK = 0x80;
 

diff --git a/src/system.h b/src/system.h
@@ -302,37 +302,43 @@ struct System {
                         if (versionlastloaded < 9) dis.ReadString();
                         double sc = versionlastloaded >= 19 ? dis.ReadDouble() : 1.0;
                         vector<uint8_t> image_data;
-                        off_t beforeimage = fis.TellI();
-
-                        if(iti == 'I') {
-                            uchar header[8];
-                            fis.Read(header, 8);
-                            uchar expected[] = {0x89, 'P', 'N', 'G', '\r', '\n', 0x1A, '\n'};
-                            if (memcmp(header, expected, 8)) return _(L"Corrupt PNG header.");
-                            dis.BigEndianOrdered(true);
-                            for (;;) {  // Skip all chunks.
-                                wxInt32 len = dis.Read32();
-                                char fourcc[4];
-                                fis.Read(fourcc, 4);
-                                fis.SeekI(len, wxFromCurrent);  // skip data
-                                dis.Read32();                   // skip CRC
-                                if (memcmp(fourcc, "IEND", 4) == 0) break;
-                            }
-                        } else if(iti == 'J') {
-                            wxImage im;
-                            im.LoadFile(fis); // fixme: write own parser logic to avoid LoadFile
-                            if(!im.IsOk()) {
-                                return _(L"JPEG file is corrupted!");
+                        if(versionlastloaded >= 22) {
+                            size_t imagelen = (size_t) dis.Read64();
+                            image_data.resize(imagelen);
+                            fis.Read(image_data.data(), imagelen);
+                        } else {
+                            off_t beforeimage = fis.TellI();
+
+                            if(iti == 'I') {
+                                uchar header[8];
+                                fis.Read(header, 8);
+                                uchar expected[] = {0x89, 'P', 'N', 'G', '\r', '\n', 0x1A, '\n'};
+                                if (memcmp(header, expected, 8)) return _(L"Corrupt PNG header.");
+                                dis.BigEndianOrdered(true);
+                                for (;;) {  // Skip all chunks.
+                                    wxInt32 len = dis.Read32();
+                                    char fourcc[4];
+                                    fis.Read(fourcc, 4);
+                                    fis.SeekI(len, wxFromCurrent);  // skip data
+                                    dis.Read32();                   // skip CRC
+                                    if (memcmp(fourcc, "IEND", 4) == 0) break;
+                                }
+                            } else if(iti == 'J') {
+                                wxImage im;
+                                im.LoadFile(fis);
+                                if(!im.IsOk()) {
+                                    return _(L"JPEG file is corrupted!");
+                                }
                             }
+
+                            off_t afterimage = fis.TellI();
+                            fis.SeekI(beforeimage);
+                            auto sz = afterimage - beforeimage;
+                            image_data.resize(sz);
+                            fis.Read(image_data.data(), sz);
+                            fis.SeekI(afterimage);
                         }
-
-                        off_t afterimage = fis.TellI();
-                        fis.SeekI(beforeimage);
-                        auto sz = afterimage - beforeimage;
-                        image_data.resize(sz);
-                        fis.Read(image_data.data(), sz);
                         if (!fis.IsOk()) image_data.clear();
-                        fis.SeekI(afterimage);
 
                         loadimageids.push() = AddImageToList(sc, std::move(image_data), iti);
                         break;