Add optimization for creating zerofill string
``` require 'benchmark' n = 1 * 1024 * 1024 * 1024 Benchmark.bmbm do |x| x.report("*") { 0.chr * n } x.report("ljust") { String.new(capacity: n).ljust(n, "\0") } end ``` Before ```% ./ruby test.rb Rehearsal ----------------------------------------- * 0.358396 0.392753 0.751149 ( 1.134231) ljust 0.203277 0.389223 0.592500 ( 0.594816) -------------------------------- total: 1.343649sec user system total real * 0.282647 0.304600 0.587247 ( 0.589205) ljust 0.201834 0.283801 0.485635 ( 0.487617) ``` After ```% ./ruby test.rb Rehearsal ----------------------------------------- * 0.000522 0.000021 0.000543 ( 0.000534) ljust 0.208551 0.321030 0.529581 ( 0.542083) -------------------------------- total: 0.530124sec user system total real * 0.000069 0.000006 0.000075 ( 0.000069) ljust 0.206698 0.301032 0.507730 ( 0.517674) ``` git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59614 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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12
string.c
12
string.c
@ -1905,6 +1905,18 @@ rb_str_times(VALUE str, VALUE times)
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if (len < 0) {
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rb_raise(rb_eArgError, "negative argument");
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}
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if (RSTRING_LEN(str) == 1 && RSTRING_PTR(str)[0] == 0) {
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str2 = str_alloc(rb_obj_class(str));
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if (!STR_EMBEDDABLE_P(len, 1)) {
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RSTRING(str2)->as.heap.aux.capa = len;
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RSTRING(str2)->as.heap.ptr = ZALLOC_N(char, (size_t)len + 1);
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STR_SET_NOEMBED(str2);
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}
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STR_SET_LEN(str2, len);
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rb_enc_copy(str2, str);
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OBJ_INFECT(str2, str);
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return str2;
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}
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if (len && LONG_MAX/len < RSTRING_LEN(str)) {
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rb_raise(rb_eArgError, "argument too big");
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}
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