1 files changed, 49 insertions, 20 deletions

diff --git a/src/streams.cpp b/src/streams.cpp
index cdd36a86fe..5f7baf92b9 100644
--- a/src/streams.cpp
+++ b/src/streams.cpp
@@ -4,21 +4,29 @@
 
 #include <span.h>
 #include <streams.h>
+#include <util/fs_helpers.h>
 
 #include <array>
 
+AutoFile::AutoFile(std::FILE* file, std::vector<std::byte> data_xor)
+    : m_file{file}, m_xor{std::move(data_xor)}
+{
+    if (!IsNull()) {
+        auto pos{std::ftell(m_file)};
+        if (pos >= 0) m_position = pos;
+    }
+}
+
 std::size_t AutoFile::detail_fread(Span<std::byte> dst)
 {
     if (!m_file) throw std::ios_base::failure("AutoFile::read: file handle is nullptr");
-    if (m_xor.empty()) {
-        return std::fread(dst.data(), 1, dst.size(), m_file);
-    } else {
-        const auto init_pos{std::ftell(m_file)};
-        if (init_pos < 0) throw std::ios_base::failure("AutoFile::read: ftell failed");
-        std::size_t ret{std::fread(dst.data(), 1, dst.size(), m_file)};
-        util::Xor(dst.subspan(0, ret), m_xor, init_pos);
-        return ret;
+    size_t ret = std::fread(dst.data(), 1, dst.size(), m_file);
+    if (!m_xor.empty()) {
+        if (!m_position.has_value()) throw std::ios_base::failure("AutoFile::read: position unknown");
+        util::Xor(dst.subspan(0, ret), m_xor, *m_position);
     }
+    if (m_position.has_value()) *m_position += ret;
+    return ret;
 }
 
 void AutoFile::seek(int64_t offset, int origin)
@@ -29,18 +37,23 @@ void AutoFile::seek(int64_t offset, int origin)
     if (std::fseek(m_file, offset, origin) != 0) {
         throw std::ios_base::failure(feof() ? "AutoFile::seek: end of file" : "AutoFile::seek: fseek failed");
     }
+    if (origin == SEEK_SET) {
+        m_position = offset;
+    } else if (origin == SEEK_CUR && m_position.has_value()) {
+        *m_position += offset;
+    } else {
+        int64_t r{std::ftell(m_file)};
+        if (r < 0) {
+            throw std::ios_base::failure("AutoFile::seek: ftell failed");
+        }
+        m_position = r;
+    }
 }
 
 int64_t AutoFile::tell()
 {
-    if (IsNull()) {
-        throw std::ios_base::failure("AutoFile::tell: file handle is nullptr");
-    }
-    int64_t r{std::ftell(m_file)};
-    if (r < 0) {
-        throw std::ios_base::failure("AutoFile::tell: ftell failed");
-    }
-    return r;
+    if (!m_position.has_value()) throw std::ios_base::failure("AutoFile::tell: position unknown");
+    return *m_position;
 }
 
 void AutoFile::read(Span<std::byte> dst)
@@ -60,6 +73,7 @@ void AutoFile::ignore(size_t nSize)
             throw std::ios_base::failure(feof() ? "AutoFile::ignore: end of file" : "AutoFile::ignore: fread failed");
         }
         nSize -= nNow;
+        if (m_position.has_value()) *m_position += nNow;
     }
 }
 
@@ -70,19 +84,34 @@ void AutoFile::write(Span<const std::byte> src)
         if (std::fwrite(src.data(), 1, src.size(), m_file) != src.size()) {
             throw std::ios_base::failure("AutoFile::write: write failed");
         }
+        if (m_position.has_value()) *m_position += src.size();
     } else {
-        auto current_pos{std::ftell(m_file)};
-        if (current_pos < 0) throw std::ios_base::failure("AutoFile::write: ftell failed");
+        if (!m_position.has_value()) throw std::ios_base::failure("AutoFile::write: position unknown");
         std::array<std::byte, 4096> buf;
         while (src.size() > 0) {
             auto buf_now{Span{buf}.first(std::min<size_t>(src.size(), buf.size()))};
             std::copy(src.begin(), src.begin() + buf_now.size(), buf_now.begin());
-            util::Xor(buf_now, m_xor, current_pos);
+            util::Xor(buf_now, m_xor, *m_position);
             if (std::fwrite(buf_now.data(), 1, buf_now.size(), m_file) != buf_now.size()) {
                 throw std::ios_base::failure{"XorFile::write: failed"};
             }
             src = src.subspan(buf_now.size());
-            current_pos += buf_now.size();
+            *m_position += buf_now.size();
         }
     }
 }
+
+bool AutoFile::Commit()
+{
+    return ::FileCommit(m_file);
+}
+
+bool AutoFile::IsError()
+{
+    return ferror(m_file);
+}
+
+bool AutoFile::Truncate(unsigned size)
+{
+    return ::TruncateFile(m_file, size);
+}