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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:19:15 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:19:15 +0000 |
commit | 6eb9c5a5657d1fe77b55cc261450f3538d35a94d (patch) | |
tree | 657d8194422a5daccecfd42d654b8a245ef7b4c8 /src/include/lib/qunique.h | |
parent | Initial commit. (diff) | |
download | postgresql-13-6eb9c5a5657d1fe77b55cc261450f3538d35a94d.tar.xz postgresql-13-6eb9c5a5657d1fe77b55cc261450f3538d35a94d.zip |
Adding upstream version 13.4.upstream/13.4upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/include/lib/qunique.h')
-rw-r--r-- | src/include/lib/qunique.h | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/src/include/lib/qunique.h b/src/include/lib/qunique.h new file mode 100644 index 0000000..95d9fef --- /dev/null +++ b/src/include/lib/qunique.h @@ -0,0 +1,67 @@ +/*------------------------------------------------------------------------- + * + * qunique.h + * inline array unique functions + * Portions Copyright (c) 2019-2020, PostgreSQL Global Development Group + * + * IDENTIFICATION + * src/include/lib/qunique.h + *------------------------------------------------------------------------- + */ + +#ifndef QUNIQUE_H +#define QUNIQUE_H + +/* + * Remove duplicates from a pre-sorted array, according to a user-supplied + * comparator. Usually the array should have been sorted with qsort() using + * the same arguments. Return the new size. + */ +static inline size_t +qunique(void *array, size_t elements, size_t width, + int (*compare) (const void *, const void *)) +{ + char *bytes = (char *) array; + size_t i, + j; + + if (elements <= 1) + return elements; + + for (i = 1, j = 0; i < elements; ++i) + { + if (compare(bytes + i * width, bytes + j * width) != 0 && + ++j != i) + memcpy(bytes + j * width, bytes + i * width, width); + } + + return j + 1; +} + +/* + * Like qunique(), but takes a comparator with an extra user data argument + * which is passed through, for compatibility with qsort_arg(). + */ +static inline size_t +qunique_arg(void *array, size_t elements, size_t width, + int (*compare) (const void *, const void *, void *), + void *arg) +{ + char *bytes = (char *) array; + size_t i, + j; + + if (elements <= 1) + return elements; + + for (i = 1, j = 0; i < elements; ++i) + { + if (compare(bytes + i * width, bytes + j * width, arg) != 0 && + ++j != i) + memcpy(bytes + j * width, bytes + i * width, width); + } + + return j + 1; +} + +#endif /* QUNIQUE_H */ |