Add tests for aom_wb_write_uvlc()
Change-Id: If28f9aa3450a35f77acf82967e5e944703b2d22b
diff --git a/test/bitwriter_buffer_test.cc b/test/bitwriter_buffer_test.cc
new file mode 100644
index 0000000..b1ba78a
--- /dev/null
+++ b/test/bitwriter_buffer_test.cc
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2025, Alliance for Open Media. All rights reserved.
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+#include "gtest/gtest.h"
+
+#include "aom_dsp/bitwriter_buffer.h"
+
+namespace {
+
+// Test the examples in Table 25 in ITU-T H.274 (V3) (09/2023) and a few more.
+//
+// Bit string codeNum
+// 1 0
+// 010 1
+// 011 2
+// 00100 3
+// 00101 4
+// 00110 5
+// 00111 6
+// 0001000 7
+// 0001001 8
+// 0001010 9
+// 0001011 10
+// 0001100 11
+// 0001101 12
+// 0001110 13
+// 0001111 14
+TEST(BitwriterBufferTest, UvlcOneByte) {
+ static constexpr struct {
+ uint32_t bit_offset;
+ uint8_t byte;
+ } kExpected[] = {
+ { 1, 0x80 }, // 0
+ { 3, 0x40 }, // 1
+ { 3, 0x60 }, // 2
+ { 5, 0x20 }, // 3
+ { 5, 0x28 }, // 4
+ { 5, 0x30 }, // 5
+ { 5, 0x38 }, // 6
+ { 7, 0x10 }, // 7
+ { 7, 0x12 }, // 8
+ { 7, 0x14 }, // 9
+ { 7, 0x16 }, // 10
+ { 7, 0x18 }, // 11
+ { 7, 0x1a }, // 12
+ { 7, 0x1c }, // 13
+ { 7, 0x1e }, // 14
+ };
+ uint8_t dst[1];
+
+ for (int i = 0; i < 15; i++) {
+ struct aom_write_bit_buffer wb = { dst, 0 };
+ aom_wb_write_uvlc(&wb, i);
+ ASSERT_EQ(wb.bit_offset, kExpected[i].bit_offset);
+ EXPECT_EQ(wb.bit_buffer[0], kExpected[i].byte);
+ }
+}
+
+// Tests two values with the maximum number (31) of leading zero bits.
+TEST(BitwriterBufferTest, Uvlc31LeadingZeros) {
+ uint8_t dst[8];
+
+ // 2^31 - 1
+ {
+ struct aom_write_bit_buffer wb = { dst, 0 };
+ aom_wb_write_uvlc(&wb, 0x7fffffff);
+ ASSERT_EQ(wb.bit_offset, 63u);
+ EXPECT_EQ(wb.bit_buffer[0], 0x00);
+ EXPECT_EQ(wb.bit_buffer[1], 0x00);
+ EXPECT_EQ(wb.bit_buffer[2], 0x00);
+ EXPECT_EQ(wb.bit_buffer[3], 0x01);
+ EXPECT_EQ(wb.bit_buffer[4], 0x00);
+ EXPECT_EQ(wb.bit_buffer[5], 0x00);
+ EXPECT_EQ(wb.bit_buffer[6], 0x00);
+ EXPECT_EQ(wb.bit_buffer[7], 0x00);
+ }
+
+ // 2^32 - 2
+ {
+ struct aom_write_bit_buffer wb = { dst, 0 };
+ aom_wb_write_uvlc(&wb, 0xfffffffe);
+ ASSERT_EQ(wb.bit_offset, 63u);
+ EXPECT_EQ(wb.bit_buffer[0], 0x00);
+ EXPECT_EQ(wb.bit_buffer[1], 0x00);
+ EXPECT_EQ(wb.bit_buffer[2], 0x00);
+ EXPECT_EQ(wb.bit_buffer[3], 0x01);
+ EXPECT_EQ(wb.bit_buffer[4], 0xff);
+ EXPECT_EQ(wb.bit_buffer[5], 0xff);
+ EXPECT_EQ(wb.bit_buffer[6], 0xff);
+ EXPECT_EQ(wb.bit_buffer[7], 0xfe);
+ }
+}
+
+} // namespace
diff --git a/test/test.cmake b/test/test.cmake
index 9dfc20f..9a9cac1 100644
--- a/test/test.cmake
+++ b/test/test.cmake
@@ -141,6 +141,7 @@
"${AOM_ROOT}/test/aom_mem_test.cc"
"${AOM_ROOT}/test/av1_common_int_test.cc"
"${AOM_ROOT}/test/av1_scale_test.cc"
+ "${AOM_ROOT}/test/bitwriter_buffer_test.cc"
"${AOM_ROOT}/test/cdef_test.cc"
"${AOM_ROOT}/test/cfl_test.cc"
"${AOM_ROOT}/test/convolve_test.cc"
