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mdbx: refine mdbx_page_copy().

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Change-Id: I73ad272b468430e7bf79462750887e75ef71bd60
This commit is contained in:
Leonid Yuriev 2019-10-03 19:40:05 +03:00
parent bf818ddf1e
commit daddd53793
1 changed files with 12 additions and 11 deletions
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23
src/elements/core.c
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@ -3262,19 +3262,20 @@ __hot static void mdbx_page_copy(MDBX_page *dst, MDBX_page *src,
unsigned psize) {
STATIC_ASSERT(UINT16_MAX > MAX_PAGESIZE - PAGEHDRSZ);
STATIC_ASSERT(MIN_PAGESIZE > PAGEHDRSZ + NODESIZE * 42);
enum { Align = sizeof(pgno_t) };
indx_t upper = src->mp_upper, lower = src->mp_lower, unused = upper - lower;
if (!IS_LEAF2(src)) {
size_t upper = src->mp_upper, lower = src->mp_lower, unused = upper - lower;
/* If page isn't full, just copy the used portion. Adjust
* alignment so memcpy may copy words instead of bytes. */
if ((unused &= -Align) && !IS_LEAF2(src)) {
upper = (upper + PAGEHDRSZ) & -Align;
memcpy(dst, src, (lower + PAGEHDRSZ + (Align - 1)) & -Align);
memcpy((pgno_t *)((char *)dst + upper), (pgno_t *)((char *)src + upper),
psize - upper);
} else {
memcpy(dst, src, psize - unused);
/* If page isn't full, just copy the used portion. Adjust
* alignment so memcpy may copy words instead of bytes. */
if (unused > sizeof(void *) * 42) {
lower = mdbx_roundup2(lower + PAGEHDRSZ, sizeof(void *));
upper = (upper + PAGEHDRSZ) & ~(sizeof(void *) - 1);
memcpy(dst, src, lower);
memcpy((char *)dst + upper, (char *)src + upper, psize - upper);
return;
}
}
memcpy(dst, src, psize);
}
/* Pull a page off the txn's spill list, if present.