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[lib/cbuf] [app/tests] fix off by one in lib/cbuf. add a test.

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Previously, if tail was == 0, and we wrote exactly enough bytes to
the end of the buffer, then head would end up at 0 as well. This
would make the buffer instaneously empty, as head == tail.
This commit is contained in:
Girts
2016-10-29 17:24:11 -07:00
committed by Travis Geiselbrecht
parent a77295ae63
commit 61d06e19fc
6 changed files with 142 additions and 8 deletions
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116
app/tests/cbuf_tests.c Normal file
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@@ -0,0 +1,116 @@
#include <assert.h>
#include <debug.h>
#include <err.h>
#include <lib/cbuf.h>
#include <lib/console.h>
#include <lib/heap.h>
#include <rand.h>
#include <stdlib.h>
#define ASSERT_EQ(a, b) \
do { \
int _a = (a); \
int _b = (b); \
if (_a != _b) { \
panic("%d != %d (%s:%d)\n", a, b, __FILE__, __LINE__); \
} \
} while (0);
#define ASSERT_LEQ(a, b) \
do { \
int _a = (a); \
int _b = (b); \
if (_a > _b) { \
panic("%d not <= %d (%s:%d)\n", a, b, __FILE__, __LINE__); \
} \
} while (0);
int cbuf_tests(int argc, const cmd_args *argv)
{
cbuf_t cbuf;
printf("running basic tests...\n");
cbuf_initialize(&cbuf, 16);
ASSERT_EQ(15, cbuf_space_avail(&cbuf));
ASSERT_EQ(8, cbuf_write(&cbuf, "abcdefgh", 8, false));
ASSERT_EQ(7, cbuf_space_avail(&cbuf));
// Only 7 bytes should fit since if we write all 16 bytes,
// head == tail and we can't distinguish it from the start case.
ASSERT_EQ(7, cbuf_write(&cbuf, "ijklmnop", 8, false));
ASSERT_EQ(0, cbuf_space_avail(&cbuf));
// Nothing should fit.
ASSERT_EQ(0, cbuf_write(&cbuf, "XXXXXXXX", 8, false));
ASSERT_EQ(0, cbuf_space_avail(&cbuf));
// Read a few bytes.
{
char buf[32];
ASSERT_EQ(3, cbuf_read(&cbuf, buf, 3, false));
for (int i = 0; i < 3; ++i) {
ASSERT_EQ(buf[i], 'a' + i);
}
// Try reading 32 bytes.
ASSERT_EQ(12, cbuf_read(&cbuf, buf, 32, false));
for (int i = 0; i < 12; ++i) {
ASSERT_EQ(buf[i], 'd' + i);
}
}
cbuf_reset(&cbuf);
ASSERT_EQ(15, cbuf_space_avail(&cbuf));
// Random tests. Keep writing in random chunks up to 8 bytes, then
// reading in chunks up to 8 bytes. Verify values.
int pos_out = 0;
int pos_in = 0;
printf("running random tests...\n");
while (pos_in < 256) {
if (pos_out < 256) {
// Write up to 8 bytes.
char buf_out[8];
int to_write_random = rand() & 7;
int to_write = MIN(to_write_random, 256 - pos_out);
for (int i = 0; i < to_write; ++i) {
buf_out[i] = pos_out + i;
}
// Advance the out pointer based on how many bytes fit.
int wrote = cbuf_write(&cbuf, buf_out, to_write, false);
ASSERT_LEQ(wrote, to_write);
pos_out += wrote;
}
// Read up to 8 bytes, make sure they are right.
if (pos_in < pos_out) {
char buf_in[8];
int to_read_random = rand() & 7;
int to_read = MIN(to_read_random, pos_out - pos_in);
int read = cbuf_read(&cbuf, buf_in, to_read, false);
ASSERT_LEQ(read, to_read);
for (int i = 0; i < read; ++i) {
ASSERT_EQ(pos_in + i, buf_in[i]);
}
pos_in += read;
}
ASSERT_LEQ(pos_in, pos_out);
}
free(cbuf.buf);
printf("cbuf tests passed\n");
return NO_ERROR;
}

11
app/tests/include/app/tests.h
View File

@@ -25,14 +25,15 @@
#include <lib/console.h>
int thread_tests(void);
int cbuf_tests(int argc, const cmd_args *argv);
int fibo(int argc, const cmd_args *argv);
int port_tests(void);
int spinner(int argc, const cmd_args *argv);
int thread_tests(void);
void benchmarks(void);
void clock_tests(void);
void printf_tests(void);
void printf_tests_float(void);
void clock_tests(void);
void benchmarks(void);
int fibo(int argc, const cmd_args *argv);
int spinner(int argc, const cmd_args *argv);
#endif

4
app/tests/rules.mk
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@@ -5,6 +5,7 @@ MODULE := $(LOCAL_DIR)
MODULE_SRCS += \
$(LOCAL_DIR)/benchmarks.c \
$(LOCAL_DIR)/cache_tests.c \
$(LOCAL_DIR)/cbuf_tests.c \
$(LOCAL_DIR)/clock_tests.c \
$(LOCAL_DIR)/fibo.c \
$(LOCAL_DIR)/float.c \
@@ -18,6 +19,9 @@ MODULE_SRCS += \
MODULE_ARM_OVERRIDE_SRCS := \
MODULE_DEPS += \
lib/cbuf
MODULE_COMPILEFLAGS += -Wno-format -fno-builtin
include make/module.mk

1
app/tests/tests.c
View File

@@ -37,6 +37,7 @@ STATIC_COMMAND("clock_tests", "test clocks", (console_cmd)&clock_tests)
STATIC_COMMAND("bench", "miscellaneous benchmarks", (console_cmd)&benchmarks)
STATIC_COMMAND("fibo", "threaded fibonacci", (console_cmd)&fibo)
STATIC_COMMAND("spinner", "create a spinning thread", (console_cmd)&spinner)
STATIC_COMMAND("cbuf_tests", "test lib/cbuf", &cbuf_tests)
STATIC_COMMAND_END(tests);
#endif

14
lib/cbuf/cbuf.c
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@@ -84,8 +84,19 @@ size_t cbuf_write(cbuf_t *cbuf, const void *_buf, size_t len, bool canreschedule
while (pos < len && cbuf_space_avail(cbuf) > 0) {
if (cbuf->head >= cbuf->tail) {
write_len = MIN(valpow2(cbuf->len_pow2) - cbuf->head, len - pos);
if (cbuf->tail == 0) {
// Special case - if tail is at position 0, we can't write all
// the way to the end of the buffer. Otherwise, head ends up at
// 0, head == tail, and buffer is considered "empty" again.
write_len =
MIN(valpow2(cbuf->len_pow2) - cbuf->head - 1, len - pos);
} else {
// Write to the end of the buffer.
write_len =
MIN(valpow2(cbuf->len_pow2) - cbuf->head, len - pos);
}
} else {
// Write from head to tail-1.
write_len = MIN(cbuf->tail - cbuf->head - 1, len - pos);
}
@@ -260,4 +271,3 @@ retry:
return ret;
}

4
lib/cbuf/include/lib/cbuf.h
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@@ -47,6 +47,7 @@ typedef struct cbuf {
*
* @param[in] cbuf A pointer to the cbuf structure to allocate.
* @param[in] len The minimum number of bytes for the underlying data buffer.
* Must be a power of two.
*/
void cbuf_initialize(cbuf_t *cbuf, size_t len);
@@ -56,7 +57,8 @@ void cbuf_initialize(cbuf_t *cbuf, size_t len);
* Initialize a cbuf structure using the supplied buffer for internal storage.
*
* @param[in] cbuf A pointer to the cbuf structure to allocate.
* @param[in] len The size of the supplied buffer, in bytes.
* @param[in] len The size of the supplied buffer, in bytes. Must be a power
* of two.
* @param[in] buf A pointer to the memory to be used for internal storage.
*/
void cbuf_initialize_etc(cbuf_t *cbuf, size_t len, void *buf);