lib: Add unit test for buffer truncate

src/lib/test-buffer.c

@@ -148,8 +148,121 @@ static void test_buffer_set_used_size(void)
 	test_end();
 }
 
+
+#if 0
+
+/* this code is left here to produce the output found in
+ * buffer.h should it be needed for debugging purposes */
+#include "str.h"
+#include "hex-binary.h"
+static const char *binary_to_10(const unsigned char *data, size_t size)
+{
+	string_t *str = t_str_new(size*8);
+
+	for (size_t i = 0; i < size; i++) {
+		for (int j = 0; j < 8; j++) {
+			if ((data[i] & (1 << (7-j))) != 0)
+				str_append_c(str, '1');
+			else
+				str_append_c(str, '0');
+		}
+	}
+	return str_c(str);
+}
+
+static void test_foo(void)
+{
+	buffer_t *buf = buffer_create_dynamic(default_pool, 100);
+
+	for (int i = 1; i <= 24; i++) {
+		buffer_set_used_size(buf, 0);
+		buffer_append_c(buf, 0xff);
+		buffer_append_c(buf, 0xff);
+		buffer_append_c(buf, 0xff);
+		buffer_truncate_rshift_bits(buf, i);
+		printf("%2d bits: %24s %s\n", i,
+		       binary_to_hex(buf->data, buf->used),
+		       binary_to_10(buf->data, buf->used));
+	}
+}
+
+#endif
+
+static void test_buffer_truncate_bits(void)
+{
+	buffer_t *buf;
+	test_begin("buffer_test_truncate_bits");
+
+	struct {
+		buffer_t input;
+		size_t bits;
+		buffer_t output;
+	} test_cases[] = {
+                { { "\xff\xff\xff", 3, {0} },  0, { "",  0, {0} } },
+                { { "\xff\xff\xff", 3, {0} },  1, { "\x01", 1, {0} } },
+                { { "\xff\xff\xff", 3, {0} },  2, { "\x03", 1, {0} } },
+                { { "\xff\xff\xff", 3, {0} },  3, { "\x07", 1, {0} } },
+                { { "\xff\xff\xff", 3, {0} },  4, { "\x0f", 1, {0} } },
+                { { "\xff\xff\xff", 3, {0} },  5, { "\x1f", 1, {0} } },
+                { { "\xff\xff\xff", 3, {0} },  6, { "\x3f", 1, {0} } },
+                { { "\xff\xff\xff", 3, {0} },  7, { "\x7f", 1, {0} } },
+                { { "\xff\xff\xff", 3, {0} },  8, { "\xff", 1, {0} } },
+                { { "\xff\xff\xff", 3, {0} },  9, { "\x01\xff", 2, {0} } },
+                { { "\xff\xff\xff", 3, {0} }, 10, { "\x03\xff", 2, {0} } },
+                { { "\xff\xff\xff", 3, {0} }, 11, { "\x07\xff", 2, {0} } },
+                { { "\xff\xff\xff", 3, {0} }, 12, { "\x0f\xff", 2, {0} } },
+                { { "\xff\xff\xff", 3, {0} }, 13, { "\x1f\xff", 2, {0} } },
+                { { "\xff\xff\xff", 3, {0} }, 14, { "\x3f\xff", 2, {0} } },
+                { { "\xff\xff\xff", 3, {0} }, 15, { "\x7f\xff", 2, {0} } },
+                { { "0123456789", 10, {0} }, 16, { "01",  2, {0} } },
+                { { "0123456789", 10, {0} }, 24, { "012",  3, {0} } },
+                { { "0123456789", 10, {0} }, 32, { "0123",  4, {0} } },
+                { { "0123456789", 10, {0} }, 40, { "01234",  5, {0} } },
+                { { "0123456789", 10, {0} }, 48, { "012345",  6, {0} } },
+                { { "0123456789", 10, {0} }, 56, { "0123456",  7, {0} } },
+                { { "0123456789", 10, {0} }, 64, { "01234567",  8, {0} } },
+                { { "0123456789", 10, {0} }, 72, { "012345678",  9, {0} } },
+		{ { "0123456789", 10, {0} }, 80, { "0123456789", 10, {0} } },
+
+		{ { "\x58\x11\xed\x02\x4d\x87\x4a\xe2\x5c\xb2\xfa\x69\xf0\xa9\x46\x2e\x04\xca\x5d\x82", 20, {0} },
+		  13,
+		  { "\x0b\x02", 2, {0} }
+		},
+
+		/* special test cases for auth policy */
+
+		{ { "\x34\x40\xc8\xc9\x3a\xb6\xe7\xc4\x3f\xc1\xc3\x4d\xd5\x56\xa3\xea\xfb\x5a\x33\x57\xac\x11\x39\x2c\x71\xcb\xee\xbb\xc8\x66\x2f\x64", 32, {0} },
+		  12,
+		  { "\x03\x44", 2, {0} }
+		},
+
+		{ { "\x49\xe5\x8a\x88\x76\xd3\x25\x68\xc9\x89\x4a\xe0\x64\xe4\x04\xf4\xf9\x13\xec\x88\x97\x47\x30\x7f\x3f\xcd\x8f\x74\x4f\x40\xd1\x25", 32, {0} },
+                  12,
+                  { "\x04\x9e", 2, {0} }
+                },
+
+		{ { "\x08\x3c\xdc\x14\x61\x80\x1c\xe8\x43\x81\x98\xfa\xc0\x64\x04\x7a\xa2\x73\x25\x6e\xe6\x4b\x85\x42\xd0\xe2\x78\xd7\x91\xb4\x89\x3f", 32, {0} },
+                  12,
+                  { "\x00\x83", 2, {0} }
+                },
+
+	};
+
+	buf = buffer_create_dynamic(pool_datastack_create(), 10);
+
+	for(size_t i = 0; i < N_ELEMENTS(test_cases); i++) {
+		buffer_set_used_size(buf, 0);
+		buffer_copy(buf, 0, &test_cases[i].input, 0, (size_t)-1);
+		buffer_truncate_rshift_bits(buf, test_cases[i].bits);
+		test_assert_idx(buffer_cmp(buf, &test_cases[i].output) == TRUE, i);
+	}
+
+	test_end();
+}
+
 void test_buffer(void)
 {
 	test_buffer_random();
 	test_buffer_set_used_size();
+	test_buffer_truncate_bits();
 }