diff options
| -rw-r--r-- | coreutils/sort.c | 86 |
1 files changed, 80 insertions, 6 deletions
diff --git a/coreutils/sort.c b/coreutils/sort.c index b39297a..b8bb687 100644 --- a/coreutils/sort.c +++ b/coreutils/sort.c @@ -18,16 +18,24 @@ //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 -ktcsbdfiozgM)" +//config: bool "Full SuSv3 compliant sort (support -ktcbdfiozgM)" //config: default y //config: depends on SORT //config: help -//config: Without this, sort only supports -r, -u, and an integer version +//config: Without this, sort only supports -r, -u, -s, 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: //config: The SuSv3 sort standard is available at: //config: http://www.opengroup.org/onlinepubs/007904975/utilities/sort.html +//config: +//config:config FEATURE_SORT_OPTIMIZE_MEMORY +//config: bool "Use less memory (but might be slower)" +//config: default n # defaults to N since we are size-paranoid tribe +//config: depends on SORT +//config: help +//config: Attempt to use less memory (by storing only one copy +//config: of duplicated lines, and such). Useful if you work on huge files. //applet:IF_SORT(APPLET_NOEXEC(sort, sort, BB_DIR_USR_BIN, BB_SUID_DROP, sort)) @@ -46,19 +54,17 @@ //usage: "\n -f Ignore case" //usage: "\n -i Ignore unprintable characters" //usage: "\n -d Dictionary order (blank or alphanumeric only)" -//usage: "\n -g General numerical sort" -//usage: "\n -M Sort month" //usage: ) //-h, --human-numeric-sort: compare human readable numbers (e.g., 2K 1G) //usage: "\n -n Sort numbers" //usage: IF_FEATURE_SORT_BIG( +//usage: "\n -g General numerical sort" +//usage: "\n -M Sort month" //usage: "\n -t CHAR Field separator" //usage: "\n -k N[,M] Sort by Nth field" //usage: ) //usage: "\n -r Reverse sort order" -//usage: IF_FEATURE_SORT_BIG( //usage: "\n -s Stable (don't sort ties alphabetically)" -//usage: ) //usage: "\n -u Suppress duplicate lines" //usage: IF_FEATURE_SORT_BIG( //usage: "\n -z Lines are terminated by NUL, not newline" @@ -404,6 +410,14 @@ int sort_main(int argc UNUSED_PARAM, char **argv) int i; int linecount; unsigned opts; +#if ENABLE_FEATURE_SORT_OPTIMIZE_MEMORY + bool can_drop_dups; + size_t prev_len = 0; + /* Postpone optimizing if the input is small, < 16k lines: + * even just free()ing duplicate lines takes time. + */ + size_t count_to_optimize_dups = 0x3fff; +#endif xfunc_error_retval = 2; @@ -412,6 +426,29 @@ int sort_main(int argc UNUSED_PARAM, char **argv) sort_opt_str, &str_ignored, &str_ignored, &str_o, &lst_k, &str_t ); +#if ENABLE_FEATURE_SORT_OPTIMIZE_MEMORY + /* Can drop dups only if -u but no "complicating" options, + * IOW: if we do a full line compares. Safe options: + * -o FILE Output to FILE + * -z Lines are terminated by NUL, not newline + * -r Reverse sort order + * -s Stable (don't sort ties alphabetically) + * Not sure about these: + * -b Ignore leading blanks + * -f Ignore case + * -i Ignore unprintable characters + * -d Dictionary order (blank or alphanumeric only) + * -n Sort numbers + * -g General numerical sort + * -M Sort month + */ + can_drop_dups = ((opts & ~(FLAG_o|FLAG_z|FLAG_r|FLAG_s)) == FLAG_u); + /* Stable sort needs every line to be uniquely allocated, + * disable optimization to reuse strings: + */ + if (opts & FLAG_s) + count_to_optimize_dups = (size_t)-1L; +#endif /* global b strips leading and trailing spaces */ if (opts & FLAG_b) option_mask32 |= FLAG_bb; @@ -489,6 +526,41 @@ int sort_main(int argc UNUSED_PARAM, char **argv) char *line = GET_LINE(fp); if (!line) break; + +#if ENABLE_FEATURE_SORT_OPTIMIZE_MEMORY + if (count_to_optimize_dups != 0) + count_to_optimize_dups--; + 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); + if (strcmp(line, new_line) == 0) { + if (can_drop_dups && prev_len == len) { + free(line); + continue; + } + replace: + free(line); + line = new_line; + } + } + prev_len = len; + } +#endif lines = xrealloc_vector(lines, 6, linecount); lines[linecount++] = line; } @@ -510,6 +582,8 @@ int sort_main(int argc UNUSED_PARAM, char **argv) } return EXIT_SUCCESS; } +#else +//TODO: lighter version which only drops total dups if can_drop_dups == true #endif /* For stable sort, store original line position beyond terminating NUL */ |