feat: completed BufferStream.

NEED TEST: BufferStream.

2 files changed, 12 insertions, 11 deletions

diff --git a/include/cru/common/Buffer.h b/include/cru/common/Buffer.h
index 69c47aff..5c1f7ba3 100644
--- a/include/cru/common/Buffer.h
+++ b/include/cru/common/Buffer.h
@@ -23,6 +23,9 @@ class Buffer final {
   bool IsNull() const { return ptr_ == nullptr; }
   bool IsUsedReachEnd() const { return used_end_ == size_; }
 
+  Index GetFrontFree() const { return used_begin_; }
+  Index GetBackFree() const { return size_ - used_end_; }
+
   Index GetUsedBegin() const { return used_begin_; }
   Index GetUsedEnd() const { return used_end_; }
 
diff --git a/include/cru/common/io/BufferStream.h b/include/cru/common/io/BufferStream.h
index a95b3487..b3a5e9d1 100644
--- a/include/cru/common/io/BufferStream.h
+++ b/include/cru/common/io/BufferStream.h
@@ -31,13 +31,18 @@ struct BufferStreamOptions {
    * @brief Total size limit of saved data in buffer. Use default value if < 0.
    * No limit if == 0.
    *
-   * The size will be ceil(total_size_limit / block_size). When the buffer is
+   * The size will be floor(total_size_limit / block_size). When the buffer is
    * filled, it will block and wait for user to read to get free space of buffer
    * to continue read.
    */
   Index total_size_limit = 0;
 };
 
+/**
+ * @brief SPSC (Single Producer Single Consumer) buffer stream.
+ *
+ * If used by multiple producer or multiple consumer, the behavior is undefined.
+ */
 class BufferStream : public Stream {
  public:
   /**
@@ -50,7 +55,7 @@ class BufferStream : public Stream {
    * Actually I have no ideas about the best value for this. May change it later
    * when I get some ideas.
    */
-  constexpr static Index kDefaultTotalSizeLimit = 1024;
+  constexpr static Index kDefaultTotalSizeLimit = 1024 * 1024;
 
  public:
   BufferStream(const BufferStreamOptions& options);
@@ -63,19 +68,12 @@ class BufferStream : public Stream {
   bool CanRead() override;
   Index Read(std::byte* buffer, Index offset, Index size) override;
 
-  bool CanWrite() = 0;
-  Index Write(const std::byte* buffer, Index offset, Index size) = 0;
-
-  virtual void Flush();
-
-  virtual void Close();
+  bool CanWrite() override;
+  Index Write(const std::byte* buffer, Index offset, Index size) override;
 
   void SetEof();
 
  private:
-  bool CheckClosed();
-
- private:
   Index block_size_;
   Index total_size_limit_;
   Index block_count_limit_;