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FFI: Change priority of table initializer variants for structs.

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This commit is contained in:
Mike Pall 2012-11-15 00:21:01 +01:00
parent 2689f32453
commit 16f23458bc
2 changed files with 10 additions and 9 deletions
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14
doc/ext_ffi_semantics.html
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@ -517,17 +517,17 @@ A VLA is only initialized with the element(s) given in the table.
Depending on the use case, you may need to explicitly add a
<tt>NULL</tt> or <tt>0</tt> terminator to a VLA.</li>
<li>If the table has a non-empty hash part, a
<tt>struct</tt>/<tt>union</tt> is initialized by looking up each field
name (as a string key) in the table. Each non-<tt>nil</tt> value is
used to initialize the corresponding field.</li>
<li>Otherwise a <tt>struct</tt>/<tt>union</tt> is initialized in the
<li>A <tt>struct</tt>/<tt>union</tt> can be initialized in the
order of the declaration of its fields. Each field is initialized with
the consecutive table elements, starting at either index <tt>[0]</tt>
consecutive table elements, starting at either index <tt>[0]</tt>
or <tt>[1]</tt>. This process stops at the first <tt>nil</tt> table
element.</li>
<li>Otherwise, if neither index <tt>[0]</tt> nor <tt>[1]</tt> is present,
a <tt>struct</tt>/<tt>union</tt> is initialized by looking up each field
name (as a string key) in the table. Each non-<tt>nil</tt> value is
used to initialize the corresponding field.</li>
<li>Uninitialized fields of a <tt>struct</tt> are filled with zero
bytes, except for the trailing VLA of a VLS.</li>

5
src/lj_cconv.c
View File

@ -493,17 +493,19 @@ static void cconv_substruct_tab(CTState *cts, CType *d, uint8_t *dp,
id = df->sib;
if (ctype_isfield(df->info) || ctype_isbitfield(df->info)) {
TValue *tv;
int32_t i = *ip;
int32_t i = *ip, iz = i;
if (!gcref(df->name)) continue; /* Ignore unnamed fields. */
if (i >= 0) {
retry:
tv = (TValue *)lj_tab_getint(t, i);
if (!tv || tvisnil(tv)) {
if (i == 0) { i = 1; goto retry; } /* 1-based tables. */
if (iz == 0) { *ip = i = -1; goto tryname; } /* Init named fields. */
break; /* Stop at first nil. */
}
*ip = i + 1;
} else {
tryname:
tv = (TValue *)lj_tab_getstr(t, gco2str(gcref(df->name)));
if (!tv || tvisnil(tv)) continue;
}
@ -524,7 +526,6 @@ static void cconv_struct_tab(CTState *cts, CType *d,
{
int32_t i = 0;
memset(dp, 0, d->size); /* Much simpler to clear the struct first. */
if (t->hmask) i = -1; else if (t->asize == 0) return; /* Fast exit. */
cconv_substruct_tab(cts, d, dp, t, &i, flags);
}