From 467f9418ef2c70994ea40cb0bf619bddbf2def64 Mon Sep 17 00:00:00 2001
From: foo86 <foo86@users.noreply.github.com>
Date: Fri, 17 Apr 2015 18:13:05 +0300
Subject: [PATCH] Add API to calculate padded frame buffer size.

---
 libdcadec/dca_frame.c  |  8 ++++++++
 libdcadec/dca_frame.h  | 17 +++++++++++++++++
 libdcadec/dca_stream.c |  6 ++----
 3 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/libdcadec/dca_frame.c b/libdcadec/dca_frame.c
index 223b1f5..12f4c37 100644
--- a/libdcadec/dca_frame.c
+++ b/libdcadec/dca_frame.c
@@ -142,3 +142,11 @@ DCADEC_API int dcadec_frame_parse_header(const uint8_t *data, size_t *size)
         return -DCADEC_ENOSYNC;
     }
 }
+
+DCADEC_API size_t dcadec_frame_buffer_size(size_t size)
+{
+    size_t padding = -size & (DCADEC_FRAME_BUFFER_ALIGN - 1);
+    if (padding < DCADEC_BUFFER_PADDING)
+        padding = DCADEC_BUFFER_PADDING;
+    return size + padding;
+}
diff --git a/libdcadec/dca_frame.h b/libdcadec/dca_frame.h
index 882580b..4203a5d 100644
--- a/libdcadec/dca_frame.h
+++ b/libdcadec/dca_frame.h
@@ -85,4 +85,21 @@ DCADEC_API int dcadec_frame_convert_bitstream(uint8_t *dst, size_t *dst_size,
  */
 DCADEC_API int dcadec_frame_parse_header(const uint8_t *data, size_t *size);
 
+/**
+ * Given the raw frame size returned by dcadec_frame_parse_header(), calculate
+ * minimum required buffer size for performing bitstream format conversion and
+ * (possibly) parsing the frame.
+ *
+ * It is recommended to use this function instead of calculating buffer size
+ * manually based on DCADEC_FRAME_BUFFER_ALIGN and DCADEC_BUFFER_PADDING
+ * constants since alignment requirements may change in the future.
+ *
+ * @param size      Raw frame size, in bytes.
+ *
+ * @return          Buffer size, in bytes, padded to the minimum value that
+ *                  satisfies both dcadec_frame_convert_bitstream() alignment
+ *                  requirement and dcadec_context_parse() padding requirement.
+ */
+DCADEC_API size_t dcadec_frame_buffer_size(size_t size);
+
 #endif
diff --git a/libdcadec/dca_stream.c b/libdcadec/dca_stream.c
index b5830c0..629c250 100644
--- a/libdcadec/dca_stream.c
+++ b/libdcadec/dca_stream.c
@@ -202,9 +202,7 @@ DCADEC_API void dcadec_stream_close(struct dcadec_stream *stream)
 
 static uint8_t *prepare_packet_buffer(struct dcadec_stream *stream, size_t size)
 {
-    size = DCA_ALIGN(size, DCADEC_FRAME_BUFFER_ALIGN);
-    size += stream->packet_size + DCADEC_BUFFER_PADDING;
-    size = DCA_ALIGN(size, BUFFER_ALIGN);
+    size = DCA_ALIGN(stream->packet_size + size, BUFFER_ALIGN);
 
     uint8_t *buf = ta_realloc_size(stream, stream->buffer, size);
     if (buf) {
@@ -265,7 +263,7 @@ static int read_frame(struct dcadec_stream *stream, uint32_t *sync_p)
         return ret;
 
     // Reallocate packet buffer
-    if (!(buf = prepare_packet_buffer(stream, frame_size)))
+    if (!(buf = prepare_packet_buffer(stream, dcadec_frame_buffer_size(frame_size))))
         return -DCADEC_ENOMEM;
 
     // Restore frame header