Use a compiler to marshall/unmarshall the sessions

This way changes are easier, all is needed is to change the session.asn1
file to add or remove elements, and different session types can also be
supported at the same time.

1 files changed, 93 insertions, 0 deletions

diff --git a/src/asn1c/per_decoder.c b/src/asn1c/per_decoder.c
new file mode 100644
index 0000000..220d7f9
--- /dev/null
+++ b/src/asn1c/per_decoder.c
@@ -0,0 +1,93 @@
+#include <asn_application.h>
+#include <asn_internal.h>
+#include <per_decoder.h>
+
+/*
+ * Decode a "Production of a complete encoding", X.691#10.1.
+ * The complete encoding contains at least one byte, and is an integral
+ * multiple of 8 bytes.
+ */
+asn_dec_rval_t
+uper_decode_complete(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td, void **sptr, const void *buffer, size_t size) {
+	asn_dec_rval_t rval;
+
+	rval = uper_decode(opt_codec_ctx, td, sptr, buffer, size, 0, 0);
+	if(rval.consumed) {
+		/*
+		 * We've always given 8-aligned data,
+		 * so convert bits to integral bytes.
+		 */
+		rval.consumed += 7;
+		rval.consumed >>= 3;
+	} else if(rval.code == RC_OK) {
+		if(size) {
+			if(((const uint8_t *)buffer)[0] == 0) {
+				rval.consumed = 1;	/* 1 byte */
+			} else {
+				ASN_DEBUG("Expecting single zeroed byte");
+				rval.code = RC_FAIL;
+			}
+		} else {
+			/* Must contain at least 8 bits. */
+			rval.code = RC_WMORE;
+		}
+	}
+
+	return rval;
+}
+
+asn_dec_rval_t
+uper_decode(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td, void **sptr, const void *buffer, size_t size, int skip_bits, int unused_bits) {
+	asn_codec_ctx_t s_codec_ctx;
+	asn_dec_rval_t rval;
+	asn_per_data_t pd;
+
+	if(skip_bits < 0 || skip_bits > 7
+	|| unused_bits < 0 || unused_bits > 7
+	|| (unused_bits > 0 && !size))
+		_ASN_DECODE_FAILED;
+
+	/*
+	 * Stack checker requires that the codec context
+	 * must be allocated on the stack.
+	 */
+	if(opt_codec_ctx) {
+		if(opt_codec_ctx->max_stack_size) {
+			s_codec_ctx = *opt_codec_ctx;
+			opt_codec_ctx = &s_codec_ctx;
+		}
+	} else {
+		/* If context is not given, be security-conscious anyway */
+		memset(&s_codec_ctx, 0, sizeof(s_codec_ctx));
+		s_codec_ctx.max_stack_size = _ASN_DEFAULT_STACK_MAX;
+		opt_codec_ctx = &s_codec_ctx;
+	}
+
+	/* Fill in the position indicator */
+	memset(&pd, 0, sizeof(pd));
+	pd.buffer = (const uint8_t *)buffer;
+	pd.nboff = skip_bits;
+	pd.nbits = 8 * size - unused_bits; /* 8 is CHAR_BIT from <limits.h> */
+	if(pd.nboff > pd.nbits)
+		_ASN_DECODE_FAILED;
+
+	/*
+	 * Invoke type-specific decoder.
+	 */
+	if(!td->uper_decoder)
+		_ASN_DECODE_FAILED;	/* PER is not compiled in */
+	rval = td->uper_decoder(opt_codec_ctx, td, 0, sptr, &pd);
+	if(rval.code == RC_OK) {
+		/* Return the number of consumed bits */
+		rval.consumed = ((pd.buffer - (const uint8_t *)buffer) << 3)
+					+ pd.nboff - skip_bits;
+		ASN_DEBUG("PER decoding consumed %ld, counted %ld",
+			(long)rval.consumed, (long)pd.moved);
+		assert(rval.consumed == pd.moved);
+	} else {
+		/* PER codec is not a restartable */
+		rval.consumed = 0;
+	}
+	return rval;
+}
+