Add support for writing cstrings

faststreams/outputs.nim

@@ -524,23 +524,22 @@ proc tryMovingToNextPage(c: var WriteCursor) =
   fsAssert false, "Attempt to write past the end of a cursor"
 
 template writeToNewSpanImpl(s: OutputStream, b: byte, awaiter, writeOp, drainOp: untyped) =
-  # Unsafe memory outputs don't use pages at all, so if our cursor
-  # reached here, this is a range violation defect:
-  fsAssert canExtendOutput(s)
-
-  if s.vtable == nil or s.extCursorsCount > 0:
+  if s.buffers == nil:
+    fsAssert s.vtable != nil # This is an unsafe memory output and we've reached
+                             # the end of the buffer which is range violation defect
+    fsAssert s.vtable.writeOp != nil
+    awaiter s.vtable.writeOp(s, unsafeAddr b, 1)
+  elif s.vtable == nil or s.extCursorsCount > 0:
     # This is the main cursor of a stream, but we are either not
     # ready to flush due to outstanding delayed writes or this is
     # just a memory output stream. In both cases, we just need to
     # allocate more memory and continue writing:
     addPage(s)
-  elif s.buffers == nil:
-    awaiter s.vtable.writeOp(nil, unsafeAddr b, 1)
+    writeByte(s.span, b)
   else:
     trackWrittenToEnd(s.buffers)
     awaiter drainOp(s, nil, 0)
-
-  writeByte(s.span, b)
+    writeByte(s.span, b)
 
 proc write*(c: var WriteCursor, b: byte) =
   if atEnd(c.span):
@@ -638,6 +637,10 @@ proc write*(s: OutputStream, chars: openArray[char]) =
 proc write*(s: MaybeAsyncOutputStream, value: string) {.inline.} =
   write s, value.toOpenArrayByte(0, value.len - 1)
 
+proc write*(s: OutputStream, value: cstring) =
+  for c in value:
+    write s, c
+
 template memCopyToBytes(value: auto): untyped =
   type T = type(value)
   static: assert supportsCopyMem(T)

tests/test_outputs.nim

@@ -9,6 +9,9 @@ proc bytes(s: string): seq[byte] =
   result = newSeqOfCap[byte](s.len)
   for c in s: result.add byte(c)
 
+proc bytes(s: cstring): seq[byte] =
+  for c in s: result.add byte(c)
+
 template bytes(c: char): byte = byte(c)
 template bytes(b: seq[byte]): seq[byte] = b
 template bytes[N, T](b: array[N, T]): seq[byte] = @b
@@ -58,14 +61,11 @@ suite "output stream":
 
   template output(val: auto) {.dirty.} =
     nimSeq.add bytes(val)
-
     memStream.write val
     smallPageSizeStream.write val
     largePageSizeStream.write val
-
     fileStream.write val
     unbufferedFileStream.write val
-
     streamWritingToExistingBuffer.write val
 
   template outputText(val: auto) =
@@ -154,6 +154,15 @@ suite "output stream":
 
     checkOutputsMatch()
 
+  test "cstrings":
+    for i in 1 .. 100:
+      output cstring("cstring sent by output ")
+      output cstring("")
+      outputText cstring("cstring sent by outputText ")
+      outputText cstring("")
+
+    checkOutputsMatch()
+
   test "memcpy":
     var x = 0x42'u8