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Merge pull request #3178 from kaspar030/bf_get_unset

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sys: bitfield: add bf_get_unset
This commit is contained in:
Kaspar Schleiser 2015-07-08 01:13:35 +02:00
commit c0f2759e60
6 changed files with 201 additions and 0 deletions
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1
sys/bitfield/Makefile Normal file
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@ -0,0 +1 @@
include $(RIOTBASE)/Makefile.base

48
sys/bitfield/bitfield.c Normal file
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@ -0,0 +1,48 @@
/*
* Copyright (C) 2015 Kaspar Schleiser <kaspar@schleiser.de>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup sys_util
* @{
*
* @file
* @brief Bitfield auxillary functions
*
* @author Kaspar Schleiser <kaspar@schleiser.de>
*
* @}
*/
#include <stdint.h>
#include "bitfield.h"
#include "irq.h"
int bf_get_unset(uint8_t field[], int size)
{
int result = -1;
int nbytes = (size + 7) / 8;
int i = 0;
unsigned state = disableIRQ();
/* skip full bytes */
for (int j = 0; (j < nbytes) && (field[j] == 255); j++) {
i += 8;
}
for (; i < size; i++) {
if (!bf_isset(field, i)) {
bf_set(field, i);
result = i;
break;
}
}
restoreIRQ(state);
return(result);
}

13
sys/include/bitfield.h
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@ -85,6 +85,19 @@ static inline bool bf_isset(uint8_t field[], size_t idx)
return (field[idx / 8] & (1u << (idx % 8)));
}
/**
* @brief Atomically get the number of an unset bit and set it
*
* This function can be used to record e.g., empty entries in an array.
*
* @param[in,out] field The bitfield
* @param[in] size The size of the bitfield
*
* @return number of bit that was set
* @return -1 if no bit was unset
*/
int bf_get_unset(uint8_t field[], int size);
#ifdef __cplusplus
}
#endif

1
tests/unittests/tests-bitfield/Makefile Normal file
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include $(RIOTBASE)/Makefile.base

1
tests/unittests/tests-bitfield/Makefile.include Normal file
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@ -0,0 +1 @@
USEMODULE += bitfield

137
tests/unittests/tests-bitfield/tests-bitfield.c Normal file
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/*
* Copyright (C) 2015 Kaspar Schleiser <kaspar@schleiser.de>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
#include <stdint.h>
#include <string.h>
#include "embUnit.h"
#include "bitfield.h"
static void test_bf_get_unset_empty(void)
{
int res = 0;
uint8_t field[5];
memset(field, 0, sizeof(field));
res = bf_get_unset(field, 0);
TEST_ASSERT_EQUAL_INT(-1, res);
memset(field, 0, sizeof(field));
res = bf_get_unset(field, 1);
TEST_ASSERT_EQUAL_INT(0, res);
memset(field, 0, sizeof(field));
res = bf_get_unset(field, 3);
TEST_ASSERT_EQUAL_INT(0, res);
memset(field, 0, sizeof(field));
res = bf_get_unset(field, 8);
TEST_ASSERT_EQUAL_INT(0, res);
memset(field, 0, sizeof(field));
res = bf_get_unset(field, 9);
TEST_ASSERT_EQUAL_INT(0, res);
memset(field, 0, sizeof(field));
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(0, res);
}
static void test_bf_get_unset_firstbyte(void)
{
int res = 0;
uint8_t field[5];
memset(field, 0xff, sizeof(field));
field[0] = 0x00;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(0, res);
field[0] = 0x01;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(1, res);
field[0] = 0x0f;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(4, res);
field[0] = 0x7f;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(7, res);
field[0] = 0xff;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(-1, res);
}
static void test_bf_get_unset_middle(void)
{
int res = 0;
uint8_t field[5];
memset(field, 0xff, sizeof(field));
field[2] = 0x00;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(16, res);
field[2] = 0x01;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(17, res);
field[2] = 0x0f;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(20, res);
field[2] = 0x7f;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(23, res);
}
static void test_bf_get_unset_lastbyte(void)
{
int res = 0;
uint8_t field[5];
memset(field, 0xff, sizeof(field));
field[4] = 0x00;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(32, res);
field[4] = 0x01;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(33, res);
field[4] = 0x0f;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(36, res);
field[4] = 0x7f;
res = bf_get_unset(field, 40);
TEST_ASSERT_EQUAL_INT(39, res);
}
Test *tests_bitfield_tests(void)
{
EMB_UNIT_TESTFIXTURES(fixtures) {
new_TestFixture(test_bf_get_unset_empty),
new_TestFixture(test_bf_get_unset_firstbyte),
new_TestFixture(test_bf_get_unset_middle),
new_TestFixture(test_bf_get_unset_lastbyte),
};
EMB_UNIT_TESTCALLER(bitfield_tests, NULL, NULL, fixtures);
return (Test *)&bitfield_tests;
}
void tests_bitfield(void)
{
TESTS_RUN(tests_bitfield_tests());
}