sort: make sort -o FILE FILE (same FILE) work. Closes bug 785. -3 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 36 insertions, 20 deletions

diff --git a/coreutils/sort.c b/coreutils/sort.c
index e2e7983a1..5c3fa1a71 100644
--- a/coreutils/sort.c
+++ b/coreutils/sort.c
@@ -278,27 +278,32 @@ static unsigned str2u(char **str)
 int sort_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int sort_main(int argc UNUSED_PARAM, char **argv)
 {
-        FILE *fp, *outfile = stdout;
-        char *line, **lines = NULL;
+        char *line, **lines;
         char *str_ignored, *str_o, *str_t;
         llist_t *lst_k = NULL;
         int i, flag;
-        int linecount = 0;
+        int linecount;
+        unsigned opts;
 
         xfunc_error_retval = 2;
 
         /* Parse command line options */
         /* -o and -t can be given at most once */
-        opt_complementary = "o--o:t--t:" /* -t, -o: maximum one of each */
+        opt_complementary = "o--o:t--t:" /* -t, -o: at most one of each */
                         "k::"; /* -k takes list */
-        getopt32(argv, OPT_STR, &str_ignored, &str_ignored, &str_o, &lst_k, &str_t);
+        opts = getopt32(argv, OPT_STR, &str_ignored, &str_ignored, &str_o, &lst_k, &str_t);
+        /* global b strips leading and trailing spaces */
+        if (opts & FLAG_b)
+                option_mask32 |= FLAG_bb;
 #if ENABLE_FEATURE_SORT_BIG
-        if (option_mask32 & FLAG_o) outfile = xfopen_for_write(str_o);
-        if (option_mask32 & FLAG_t) {
+        if (opts & FLAG_t) {
                 if (!str_t[0] || str_t[1])
                         bb_error_msg_and_die("bad -t parameter");
                 key_separator = str_t[0];
         }
+        /* note: below this point we use option_mask32, not opts,
+         * since that reduces register pressure and makes code smaller */
+
         /* parse sort key */
         while (lst_k) {
                 enum {
@@ -315,7 +320,6 @@ int sort_main(int argc UNUSED_PARAM, char **argv)
                 };
                 struct sort_key *key = add_key();
                 char *str_k = llist_pop(&lst_k);
-                const char *temp2;
 
                 i = 0; /* i==0 before comma, 1 after (-k3,6) */
                 while (*str_k) {
@@ -327,11 +331,13 @@ int sort_main(int argc UNUSED_PARAM, char **argv)
                                 key->range[2*i+1] = str2u(&str_k);
                         }
                         while (*str_k) {
+                                const char *temp2;
+
                                 if (*str_k == ',' && !i++) {
                                         str_k++;
                                         break;
                                 } /* no else needed: fall through to syntax error
-                                         because comma isn't in OPT_STR */
+                                        because comma isn't in OPT_STR */
                                 temp2 = strchr(OPT_STR, *str_k);
                                 if (!temp2)
                                         bb_error_msg_and_die("unknown key option");
@@ -339,27 +345,29 @@ int sort_main(int argc UNUSED_PARAM, char **argv)
                                 if (flag & ~FLAG_allowed_for_k)
                                         bb_error_msg_and_die("unknown sort type");
                                 /* b after ',' means strip _trailing_ space */
-                                if (i && flag == FLAG_b) flag = FLAG_bb;
+                                if (i && flag == FLAG_b)
+                                        flag = FLAG_bb;
                                 key->flags |= flag;
                                 str_k++;
                         }
                 }
         }
 #endif
-        /* global b strips leading and trailing spaces */
-        if (option_mask32 & FLAG_b) option_mask32 |= FLAG_bb;
 
         /* Open input files and read data */
         argv += optind;
         if (!*argv)
                 *--argv = (char*)"-";
+        linecount = 0;
+        lines = NULL;
         do {
                 /* coreutils 6.9 compat: abort on first open error,
                  * do not continue to next file: */
-                fp = xfopen_stdin(*argv);
+                FILE *fp = xfopen_stdin(*argv);
                 for (;;) {
                         line = GET_LINE(fp);
-                        if (!line) break;
+                        if (!line)
+                                break;
                         lines = xrealloc_vector(lines, 6, linecount);
                         lines[linecount++] = line;
                 }
@@ -373,16 +381,17 @@ int sort_main(int argc UNUSED_PARAM, char **argv)
         /* handle -c */
         if (option_mask32 & FLAG_c) {
                 int j = (option_mask32 & FLAG_u) ? -1 : 0;
-                for (i = 1; i < linecount; i++)
+                for (i = 1; i < linecount; i++) {
                         if (compare_keys(&lines[i-1], &lines[i]) > j) {
-                                fprintf(stderr, "Check line %d\n", i);
+                                fprintf(stderr, "Check line %u\n", i);
                                 return EXIT_FAILURE;
                         }
+                }
                 return EXIT_SUCCESS;
         }
 #endif
         /* Perform the actual sort */
-        qsort(lines, linecount, sizeof(char *), compare_keys);
+        qsort(lines, linecount, sizeof(lines[0]), compare_keys);
         /* handle -u */
         if (option_mask32 & FLAG_u) {
                 flag = 0;
@@ -390,17 +399,24 @@ int sort_main(int argc UNUSED_PARAM, char **argv)
                 /* -- disabling last-resort compare... */
                 option_mask32 |= FLAG_s;
                 for (i = 1; i < linecount; i++) {
-                        if (!compare_keys(&lines[flag], &lines[i]))
+                        if (compare_keys(&lines[flag], &lines[i]) == 0)
                                 free(lines[i]);
                         else
                                 lines[++flag] = lines[i];
                 }
-                if (linecount) linecount = flag+1;
+                if (linecount)
+                        linecount = flag+1;
         }
+
         /* Print it */
+#if ENABLE_FEATURE_SORT_BIG
+        /* Open output file _after_ we read all input ones */
+        if (option_mask32 & FLAG_o)
+                xmove_fd(xopen3(str_o, O_WRONLY, 0666), STDOUT_FILENO);
+#endif
         flag = (option_mask32 & FLAG_z) ? '\0' : '\n';
         for (i = 0; i < linecount; i++)
-                fprintf(outfile, "%s%c", lines[i], flag);
+                printf("%s%c", lines[i], flag);
 
         fflush_stdout_and_exit(EXIT_SUCCESS);
 }