From 7512dfb8454b8f80cefec7c8bb85380f4e9c5087 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers3@gmail.com>
Date: Mon, 14 Jan 2019 21:37:48 -0800
Subject: [PATCH] test_incomplete_codes: add another test case

---
 programs/test_incomplete_codes.c | 86 ++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/programs/test_incomplete_codes.c b/programs/test_incomplete_codes.c
index cbeb338..436cd9b 100644
--- a/programs/test_incomplete_codes.c
+++ b/programs/test_incomplete_codes.c
@@ -286,6 +286,91 @@ test_singleton_offset_code(void)
 			     expected_out, sizeof(expected_out));
 }
 
+/* Test that an offset code containing only one symbol is accepted, even if that
+ * symbol is not symbol 0.  The codeword should be '0' in either case. */
+static void
+test_singleton_offset_code_notsymzero(void)
+{
+	static const u8 expected_out[] = { 254, 255, 254, 255, 254 };
+	u8 in[128];
+	u8 out[128];
+	struct output_bitstream os = { .next = in, .end = in + sizeof(in) };
+	int i;
+
+	ASSERT(put_bits(&os, 1, 1));	/* BFINAL: 1 */
+	ASSERT(put_bits(&os, 2, 2));	/* BTYPE: DYNAMIC_HUFFMAN */
+
+	/*
+	 * Litlen code:
+	 *	litlensym_254			len=2 codeword=00
+	 *	litlensym_255			len=2 codeword=10
+	 *	litlensym_256 (end-of-block)	len=2 codeword=01
+	 *	litlensym_257 (len 3)		len=2 codeword=11
+	 * Offset code:
+	 *	offsetsym_1 (offset 2)		len=1 codeword=0
+	 *
+	 * Litlen and offset codeword lengths:
+	 *	[0..253] = 0	presym_{18,18}
+	 *	[254]	 = 2	presym_2
+	 *	[255]	 = 2	presym_2
+	 *	[256]	 = 2	presym_2
+	 *	[257]	 = 2	presym_2
+	 *	[258]	 = 0	presym_0
+	 *	[259]	 = 1	presym_1
+	 *
+	 * Precode:
+	 *	presym_0	len=2 codeword=00
+	 *	presym_1	len=2 codeword=10
+	 *	presym_2	len=2 codeword=01
+	 *	presym_18	len=2 codeword=11
+	 */
+
+	ASSERT(put_bits(&os, 1, 5));	/* num_litlen_syms: 1 + 257 */
+	ASSERT(put_bits(&os, 1, 5));	/* num_offset_syms: 1 + 1 */
+	ASSERT(put_bits(&os, 14, 4));	/* num_explicit_precode_lens: 14 + 4 */
+	/*
+	 * Precode codeword lengths: order is
+	 * [16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15]
+	 */
+	for (i = 0; i < 2; i++)		/* presym_{16,17}: len=0 */
+		ASSERT(put_bits(&os, 0, 3));
+	ASSERT(put_bits(&os, 2, 3));	/* presym_18: len=2 */
+	ASSERT(put_bits(&os, 2, 3));	/* presym_0: len=2 */
+	for (i = 0; i < 11; i++)	/* presym_{8,...,13}: len=0 */
+		ASSERT(put_bits(&os, 0, 3));
+	ASSERT(put_bits(&os, 2, 3));	/* presym_2: len=2 */
+	ASSERT(put_bits(&os, 0, 3));	/* presym_14: len=0 */
+	ASSERT(put_bits(&os, 2, 3));	/* presym_1: len=2 */
+
+	/* Litlen and offset codeword lengths */
+	ASSERT(put_bits(&os, 0x3, 2) &&	/* presym_18, 128 zeroes */
+	       put_bits(&os, 117, 7));
+	ASSERT(put_bits(&os, 0x3, 2) &&	/* presym_18, 126 zeroes */
+	       put_bits(&os, 115, 7));
+	ASSERT(put_bits(&os, 0x1, 2));	/* presym_2 */
+	ASSERT(put_bits(&os, 0x1, 2));	/* presym_2 */
+	ASSERT(put_bits(&os, 0x1, 2));	/* presym_2 */
+	ASSERT(put_bits(&os, 0x1, 2));	/* presym_2 */
+	ASSERT(put_bits(&os, 0x0, 2));	/* presym_0 */
+	ASSERT(put_bits(&os, 0x2, 2));	/* presym_1 */
+
+	/* Literals */
+	ASSERT(put_bits(&os, 0x0, 2));	/* litlensym_254 */
+	ASSERT(put_bits(&os, 0x2, 2));	/* litlensym_255 */
+
+	/* Match */
+	ASSERT(put_bits(&os, 0x3, 2));	/* litlensym_257 */
+	ASSERT(put_bits(&os, 0x0, 1));	/* offsetsym_1 */
+
+	/* End of block */
+	ASSERT(put_bits(&os, 0x1, 2));	/* litlensym_256 */
+
+	ASSERT(flush_bits(&os));
+
+	verify_decompression(in, os.next - in, out, sizeof(out),
+			     expected_out, sizeof(expected_out));
+}
+
 int
 tmain(int argc, tchar *argv[])
 {
@@ -294,6 +379,7 @@ tmain(int argc, tchar *argv[])
 	test_empty_offset_code();
 	test_singleton_litrunlen_code();
 	test_singleton_offset_code();
+	test_singleton_offset_code_notsymzero();
 
 	return 0;
 }