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Avoid O(n**2) growth rate of token buffer arena-based reallocation (103042, r=jband, sr=shaver).

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brendan%mozilla.org 2001-10-10 20:19:12 +00:00
parent 03583963c2
commit 064c4cae19
1 changed files with 10 additions and 8 deletions
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18
js/src/jsscan.c
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@ -627,33 +627,35 @@ js_PeekTokenSameLine(JSContext *cx, JSTokenStream *ts)
return tt;
}
#define TBINCR 64
#define TBMIN 64
static JSBool
GrowTokenBuf(JSContext *cx, JSTokenBuf *tb)
{
jschar *base;
ptrdiff_t offset, length;
size_t tbincr, tbsize;
size_t tbsize;
JSArenaPool *pool;
base = tb->base;
offset = PTRDIFF(tb->ptr, base, jschar);
length = PTRDIFF(tb->limit, base, jschar);
tbincr = (length + TBINCR) * sizeof(jschar);
pool = &cx->tempPool;
if (!base) {
JS_ARENA_ALLOCATE_CAST(base, jschar *, pool, tbincr);
tbsize = TBMIN * sizeof(jschar);
length = TBMIN;
JS_ARENA_ALLOCATE_CAST(base, jschar *, pool, tbsize);
} else {
tbsize = (size_t)(length * sizeof(jschar));
JS_ARENA_GROW_CAST(base, jschar *, pool, tbsize, tbincr);
length = PTRDIFF(tb->limit, base, jschar);
tbsize = length * sizeof(jschar);
length <<= 1;
JS_ARENA_GROW_CAST(base, jschar *, pool, tbsize, tbsize);
}
if (!base) {
JS_ReportOutOfMemory(cx);
return JS_FALSE;
}
tb->base = base;
tb->limit = base + length + length + TBINCR;
tb->limit = base + length;
tb->ptr = base + offset;
return JS_TRUE;
}