5aaeb550b
Denys Vlasenko
2021-10-09
Subject
ash: speed up ${x//\*/|} too, make it independent of ASH_OPTIMIZE_FOR_SIZE
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shell/ash.c+12 -6
| @@ -7251,7 +7251,7 @@ subevalvar(char *start, char *str, int strloc, | |
| #if BASH_PATTERN_SUBST | |
| workloc = expdest - (char *)stackblock(); | |
| if (subtype == VSREPLACE || subtype == VSREPLACEALL) { | |
| - | size_t no_meta_len; |
| + | size_t no_meta_len, first_escaped; |
| int len; | |
| char *idx, *end; | |
| @@ -7269,28 +7269,34 @@ subevalvar(char *start, char *str, int strloc, | |
| if (str[0] == '\0') | |
| goto out1; | |
| - | no_meta_len = (ENABLE_ASH_OPTIMIZE_FOR_SIZE || strpbrk(str, "*?[\\")) ? 0 : strlen(str); |
| + | first_escaped = (str[0] == '\\' && str[1]); |
| + | /* "first_escaped" trick allows to treat e.g. "\*no_glob_chars" |
| + | * as literal too (as it is semi-common, and easy to accomodate |
| + | * by just using str + 1). |
| + | */ |
| + | no_meta_len = strpbrk(str + first_escaped * 2, "*?[\\") ? 0 : strlen(str); |
| len = 0; | |
| idx = startp; | |
| end = str - 1; | |
| while (idx <= end) { | |
| try_to_match: | |
| if (no_meta_len == 0) { | |
| - | /* pattern has meta chars, have to glob; or ENABLE_ASH_OPTIMIZE_FOR_SIZE */ |
| + | /* pattern has meta chars, have to glob */ |
| loc = scanright(idx, rmesc, rmescend, str, quotes, /*match_at_start:*/ 1); | |
| } else { | |
| /* Testcase for very slow replace (performs about 22k replaces): | |
| * x=:::::::::::::::::::::: | |
| * x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;echo ${#x} | |
| * echo "${x//:/|}" | |
| + | * To test "first_escaped" logic, replace : with *. |
| */ | |
| - | if (strncmp(rmesc, str, no_meta_len) != 0) |
| + | if (strncmp(rmesc, str + first_escaped, no_meta_len - first_escaped) != 0) |
| goto no_match; | |
| loc = idx; | |
| if (!quotes) { | |
| - | loc += no_meta_len; |
| + | loc += no_meta_len - first_escaped; |
| } else { | |
| - | size_t n = no_meta_len; |
| + | size_t n = no_meta_len - first_escaped; |
| do { | |
| if ((unsigned char)*loc == CTLESC) | |
| loc++; | |