From 71be31bb61a4af808bd674b2cd4b70f7fa060676 Mon Sep 17 00:00:00 2001
From: RichardBarry <3073890+RichardBarry@users.noreply.github.com>
Date: Sat, 10 Oct 2020 21:47:54 -0700
Subject: [PATCH] xStreamBufferSend() caps the maximum amount of data a stream
 buffer can send to the maximum capacity of the buffer - however the value to
 which the length is capped was wrong, and is correct by this check in. 
 Likewise when sending to a message buffer if the send length is too long the
 block time is set to 0 to ensure the sending task does not wait indefinitely
 for the impossible send to complete - but the length check was wrong, and is
 corrected by this check in. (#195)

---
 stream_buffer.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/stream_buffer.c b/stream_buffer.c
index c2d600ed5..9dd4ad04e 100644
--- a/stream_buffer.c
+++ b/stream_buffer.c
@@ -518,6 +518,10 @@ size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer,
     size_t xRequiredSpace = xDataLengthBytes;
     TimeOut_t xTimeOut;
 
+    /* The maximum amount of space a stream buffer will ever report is its length
+     * minus 1. */
+    const size_t xMaxReportedSpace = pxStreamBuffer->xLength - ( size_t ) 1;
+
     configASSERT( pvTxData );
     configASSERT( pxStreamBuffer );
 
@@ -534,7 +538,7 @@ size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer,
 
         /* If this is a message buffer then it must be possible to write the
          * whole message. */
-        if( xRequiredSpace > pxStreamBuffer->xLength )
+        if( xRequiredSpace > xMaxReportedSpace )
         {
             /* The message would not fit even if the entire buffer was empty,
              * so don't wait for space. */
@@ -550,9 +554,9 @@ size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer,
         /* If this is a stream buffer then it is acceptable to write only part
          * of the message to the buffer.  Cap the length to the total length of
          * the buffer. */
-        if( xRequiredSpace > pxStreamBuffer->xLength )
+        if( xRequiredSpace > xMaxReportedSpace )
         {
-            xRequiredSpace = pxStreamBuffer->xLength;
+            xRequiredSpace = xMaxReportedSpace;
         }
         else
         {