pem: convenience API (#29)

bearssl/pem.nim

@@ -1,4 +1,45 @@
 import
+  typetraits,
   ./abi/bearssl_pem
 
 export bearssl_pem
+
+func init*(v: var PemDecoderContext) =
+  # Careful, PemDecoderContext items are not copyable!
+  # TODO prevent copying
+  pemDecoderInit(v)
+
+func push*(ctx: var PemDecoderContext, data: openArray[byte|char]): int =
+  if data.len > 0:
+    let consumed = pemDecoderPush(
+      ctx, unsafeAddr data[0], uint data.len)
+    int(consumed)
+  else:
+    0
+
+func setdest*(
+    ctx: var PemDecoderContext;
+    dest: proc (destCtx: pointer;
+      src: pointer; len: uint) {.cdecl, gcsafe, noSideEffect, raises: [].};
+    destCtx: pointer) =
+  pemDecoderSetdest(ctx, dest, destCtx)
+
+func lastEvent*(ctx: var PemDecoderContext): cint =
+  pemDecoderEvent(ctx)
+
+func banner*(ctx: PemDecoderContext): string =
+  ## Return the `name` field as a string
+  if ctx.name[ctx.name.high] == char(0):
+    $(unsafeAddr ctx.name)
+  else:
+    var res = newString(ctx.name.len)
+    for i, c in ctx.name: res[i] = ctx.name[i]
+    res
+
+func pemEncode*(
+    data: openArray[byte|char], banner: cstring, flags: cuint = 0): string =
+  let bytes = pemEncode(nil, nil, uint data.len, banner, flags)
+  result.setLen(int bytes + 1)
+  discard pemEncode(
+    addr result[0], unsafeAddr data[0], uint data.len, banner, flags)
+  result.setLen(int bytes)

tests/test_pem.nim

@@ -0,0 +1,32 @@
+import
+  unittest2,
+  ../bearssl/pem
+
+suite "PEM":
+  test "roundtrip":
+    let
+      data = [byte 0, 1, 2, 3]
+      pem = pemEncode(data, "")
+
+    var
+      ctx: PemDecoderContext
+      called = false
+
+    ctx.init()
+
+    proc test(dctx: pointer, data: pointer, len: uint) {.cdecl.} =
+      cast[ptr bool](dctx)[] = true
+
+    ctx.setdest(test, addr called)
+
+    var read = 0
+    while read < pem.len:
+      let
+        consumed = ctx.push(pem.toOpenArray(read, pem.high))
+      read += consumed
+      if read < pem.len:
+        check: ctx.lastEvent > 0
+
+    check:
+      pem.len > data.len
+      called