d1d6d9c5d
Denys Vlasenko
2018-04-06
Subject
sort: smaller and more agressive FEATURE_SORT_OPTIMIZE_MEMORY
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Commit Diff GitHub →
coreutils/sort.c+12 -12
| @@ -18,11 +18,11 @@ | |
| //config: sort is used to sort lines of text in specified files. | |
| //config: | |
| //config:config FEATURE_SORT_BIG | |
| - | //config: bool "Full SuSv3 compliant sort (support -ktcbdfiozgM)" |
| + | //config: bool "Full SuSv3 compliant sort (support -ktcbdfiogM)" |
| //config: default y | |
| //config: depends on SORT | |
| //config: help | |
| - | //config: Without this, sort only supports -r, -u, -s, and an integer version |
| + | //config: Without this, sort only supports -rusz, and an integer version |
| //config: of -n. Selecting this adds sort keys, floating point support, and | |
| //config: more. This adds a little over 3k to a nonstatic build on x86. | |
| //config: | |
| @@ -66,12 +66,10 @@ | |
| //usage: "\n -r Reverse sort order" | |
| //usage: "\n -s Stable (don't sort ties alphabetically)" | |
| //usage: "\n -u Suppress duplicate lines" | |
| - | //usage: IF_FEATURE_SORT_BIG( |
| //usage: "\n -z Lines are terminated by NUL, not newline" | |
| ///////: "\n -m Ignored for GNU compatibility" | |
| ///////: "\n -S BUFSZ Ignored for GNU compatibility" | |
| ///////: "\n -T TMPDIR Ignored for GNU compatibility" | |
| - | //usage: ) |
| //usage: | |
| //usage:#define sort_example_usage | |
| //usage: "$ echo -e \"e\\nf\\nb\\nd\\nc\\na\" | sort\n" | |
| @@ -413,6 +411,7 @@ int sort_main(int argc UNUSED_PARAM, char **argv) | |
| #if ENABLE_FEATURE_SORT_OPTIMIZE_MEMORY | |
| bool can_drop_dups; | |
| size_t prev_len = 0; | |
| + | char *prev_line = (char*) ""; |
| /* Postpone optimizing if the input is small, < 16k lines: | |
| * even just free()ing duplicate lines takes time. | |
| */ | |
| @@ -533,32 +532,33 @@ int sort_main(int argc UNUSED_PARAM, char **argv) | |
| if (count_to_optimize_dups == 0) { | |
| size_t len; | |
| char *new_line; | |
| - | char first = *line; |
| /* On kernel/linux/arch/ *.[ch] files, | |
| * this reduces memory usage by 6%. | |
| * yes | head -99999999 | sort | |
| * goes down from 1900Mb to 380 Mb. | |
| */ | |
| - | if (first == '\0' || first == '\n') { |
| - | len = !(first == '\0'); |
| - | new_line = (char*)"\n" + 1 - len; |
| - | goto replace; |
| - | } |
| len = strlen(line); | |
| if (len <= prev_len) { | |
| - | new_line = lines[linecount-1] + (prev_len - len); |
| + | new_line = prev_line + (prev_len - len); |
| if (strcmp(line, new_line) == 0) { | |
| + | /* it's a tail of the prev line */ |
| if (can_drop_dups && prev_len == len) { | |
| + | /* it's identical to prev line */ |
| free(line); | |
| continue; | |
| } | |
| - | replace: |
| free(line); | |
| line = new_line; | |
| + | /* continue using longer prev_line |
| + | * for future tail tests. |
| + | */ |
| + | goto skip; |
| } | |
| } | |
| prev_len = len; | |
| + | prev_line = line; |
| + | skip: ; |
| } | |
| #else | |
| //TODO: lighter version which only drops total dups if can_drop_dups == true | |