diff options
| -rw-r--r-- | include/util.h | 2 | ||||
| -rw-r--r-- | lib/Makemodule.am | 2 | ||||
| -rw-r--r-- | lib/util/crc32.c | 31 | ||||
| -rw-r--r-- | tests/Makemodule.am | 7 | ||||
| -rw-r--r-- | tests/crc32.c | 35 |
5 files changed, 74 insertions, 3 deletions
diff --git a/include/util.h b/include/util.h index 0c36160..2d5d521 100644 --- a/include/util.h +++ b/include/util.h @@ -76,4 +76,6 @@ int popd(void); */ int padd_file(int outfd, uint64_t size, size_t blocksize); +uint32_t update_crc32(uint32_t crc, const void *data, size_t size); + #endif /* UTIL_H */ diff --git a/lib/Makemodule.am b/lib/Makemodule.am index 218adcd..5f0cdae 100644 --- a/lib/Makemodule.am +++ b/lib/Makemodule.am @@ -44,7 +44,7 @@ libutil_a_SOURCES += lib/util/read_data.c include/util.h libutil_a_SOURCES += lib/util/print_version.c lib/util/mkdir_p.c libutil_a_SOURCES += lib/util/str_table.c include/str_table.h libutil_a_SOURCES += lib/util/dirstack.c lib/util/padd_file.c -libutil_a_SOURCES += lib/util/read_data_at.c +libutil_a_SOURCES += lib/util/read_data_at.c lib/util/crc32.c if WITH_GZIP libcompress_a_SOURCES += lib/comp/gzip.c diff --git a/lib/util/crc32.c b/lib/util/crc32.c new file mode 100644 index 0000000..ffe0044 --- /dev/null +++ b/lib/util/crc32.c @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-3.0-or-later */ +#include "config.h" +#include "util.h" + +/* + Karl Malbrain's compact CRC-32. See "A compact CCITT crc16 and crc32 C + implementation that balances processor cache usage against speed" + */ +static const uint32_t s_crc32[16] = { + 0x00000000, 0x1DB71064, 0x3B6E20C8, 0x26D930AC, + 0x76DC4190, 0x6B6B51F4, 0x4DB26158, 0x5005713C, + 0xEDB88320, 0xF00F9344, 0xD6D6A3E8, 0xCB61B38C, + 0x9B64C2B0, 0x86D3D2D4, 0xA00AE278, 0xBDBDF21C +}; + +uint32_t update_crc32(uint32_t crc, const void *data, size_t size) +{ + const uint8_t *ptr = data; + uint8_t b; + + crc = ~crc; + + while (size--) { + b = *ptr++; + + crc = (crc >> 4) ^ s_crc32[(crc & 0x0F) ^ (b & 0x0F)]; + crc = (crc >> 4) ^ s_crc32[(crc & 0x0F) ^ (b >> 4)]; + } + + return ~crc; +} diff --git a/tests/Makemodule.am b/tests/Makemodule.am index 60312dc..e681a33 100644 --- a/tests/Makemodule.am +++ b/tests/Makemodule.am @@ -73,12 +73,15 @@ test_str_table_SOURCES = tests/str_table.c test_str_table_LDADD = libutil.a test_str_table_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(top_srcdir)/tests +test_crc32_SOURCES = tests/crc32.c +test_crc32_LDADD = libutil.a + check_PROGRAMS += test_canonicalize_name test_mknode_simple test_mknode_slink check_PROGRAMS += test_mknode_reg test_mknode_dir test_gen_inode_table check_PROGRAMS += test_add_by_path test_get_path test_fstree_sort check_PROGRAMS += test_fstree_from_file test_fstree_init test_fstree_xattr check_PROGRAMS += test_tar_ustar test_tar_pax test_tar_gnu test_tar_sparse_gnu -check_PROGRAMS += test_tar_sparse_gnu1 test_tar_sparse_gnu2 +check_PROGRAMS += test_tar_sparse_gnu1 test_tar_sparse_gnu2 test_crc32 check_PROGRAMS += test_tar_xattr_bsd test_tar_xattr_schily test_str_table TESTS += test_canonicalize_name test_mknode_simple test_mknode_slink @@ -87,6 +90,6 @@ TESTS += test_add_by_path test_get_path test_fstree_sort test_fstree_from_file TESTS += test_fstree_init test_fstree_xattr test_tar_ustar test_tar_pax TESTS += test_tar_gnu test_tar_sparse_gnu test_tar_sparse_gnu1 TESTS += test_tar_sparse_gnu2 test_tar_xattr_bsd test_tar_xattr_schily -TESTS += test_str_table +TESTS += test_str_table test_crc32 EXTRA_DIST += $(top_srcdir)/tests/tar $(top_srcdir)/tests/words.txt diff --git a/tests/crc32.c b/tests/crc32.c new file mode 100644 index 0000000..290f5cf --- /dev/null +++ b/tests/crc32.c @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-3.0-or-later */ +#include "config.h" +#include "util.h" + +#include <stdlib.h> +#include <string.h> +#include <stdio.h> + +static const struct { + const char *str; + uint32_t result; +} test_vectors[] = { + { "", 0 }, + { "Hello, World!", 0xEC4AC3D0 }, + { "The quick brown fox jumps over the lazy dog", 0x414FA339 }, +}; + +int main(void) +{ + uint32_t crc; + size_t i; + + for (i = 0; i < sizeof(test_vectors) / sizeof(test_vectors[0]); ++i) { + crc = update_crc32(0, test_vectors[i].str, + strlen(test_vectors[i].str)); + + if (crc != test_vectors[i].result) { + fprintf(stderr, "Case %zu failed: %08X != %08X\n", i, + crc, test_vectors[i].result); + return EXIT_FAILURE; + } + } + + return EXIT_SUCCESS; +} |