Optimize String.fromCharCode and String.fromCodePoint (#391)

- test for common case: single integer argument and create string directly
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Charlie Gordon 2024-04-21 08:28:02 +02:00 committed by GitHub
parent 83726bb00c
commit a77873d657
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@ -39335,6 +39335,17 @@ static JSValue js_string_fromCharCode(JSContext *ctx, JSValue this_val,
int i;
StringBuffer b_s, *b = &b_s;
// shortcut for single argument common case
if (argc == 1 && JS_VALUE_GET_TAG(argv[0]) == JS_TAG_INT) {
uint16_t c16 = JS_VALUE_GET_INT(argv[0]);
if (c16 < 128) {
uint8_t c8 = c16;
return js_new_string8(ctx, &c8, 1);
} else {
return js_new_string16(ctx, &c16, 1);
}
}
string_buffer_init(ctx, b, argc);
for(i = 0; i < argc; i++) {
@ -39352,10 +39363,30 @@ static JSValue js_string_fromCodePoint(JSContext *ctx, JSValue this_val,
{
double d;
int i, c;
StringBuffer b_s, *b = &b_s;
StringBuffer b_s, *b = NULL;
// shortcut for single argument common case
if (argc == 1 && JS_VALUE_GET_TAG(argv[0]) == JS_TAG_INT) {
c = JS_VALUE_GET_INT(argv[0]);
if (c < 0 || c > 0x10ffff)
goto range_error;
if (c < 128) {
uint8_t c8 = c;
return js_new_string8(ctx, &c8, 1);
}
if (c < 0x10000) {
uint16_t c16 = c;
return js_new_string16(ctx, &c16, 1);
} else {
uint16_t c16[2];
c16[0] = get_hi_surrogate(c);
c16[1] = get_lo_surrogate(c);
return js_new_string16(ctx, c16, 2);
}
}
/* XXX: could pre-compute string length if all arguments are JS_TAG_INT */
b = &b_s;
if (string_buffer_init(ctx, b, argc))
goto fail;
for(i = 0; i < argc; i++) {
@ -39377,7 +39408,7 @@ static JSValue js_string_fromCodePoint(JSContext *ctx, JSValue this_val,
range_error:
JS_ThrowRangeError(ctx, "invalid code point");
fail:
string_buffer_free(b);
if (b) string_buffer_free(b);
return JS_EXCEPTION;
}