[hackers] [sbase] sort: add support for delimiter strings || Jakob Kramer

[git]

commit 2d9d224a1b69231edabfa014f738ed2c73dd6eb3
Author: Jakob Kramer <jakob.kra...@gmx.de>
Date:   Sun Feb 1 21:00:37 2015 +0100

    sort: add support for delimiter strings
    
    Instead of just single characters.  This also fixes
    some bugs in columns().  Example bug:
    
        $ printf "a b\nc b x\n" | sort -k 2,2 -k 1,1

diff --git a/sort.c b/sort.c
index 3e4f3a3..e5c3d21 100644
--- a/sort.c
+++ b/sort.c
@@ -33,10 +33,11 @@ static struct kdlist *tail = NULL;
 static void addkeydef(char *, int);
 static void check(FILE *);
 static int linecmp(const char **, const char **);
-static char *skipblank(char *);
 static int parse_flags(char **, int *, int);
 static int parse_keydef(struct keydef *, char *, int);
-static char *nextcol(char *);
+static char *skipblank(char *);
+static char *skipnonblank(char *);
+static char *skipcolumn(char *, char *, int);
 static char *columns(char *, const struct keydef *);
 
 static int Cflag = 0, cflag = 0, uflag = 0;
@@ -173,24 +174,30 @@ parse_keydef(struct keydef *kd, char *s, int flags)
 static char *
 skipblank(char *s)
 {
-       while (*s && isblank(*s))
+       while (isblank(*s))
                s++;
+       return s;
+}
 
+static char *
+skipnonblank(char *s)
+{
+       while (*s && *s != '\n' && !isblank(*s))
+               s++;
        return s;
 }
 
 static char *
-nextcol(char *s)
+skipcolumn(char *s, char *eol, int next_col)
 {
-       if (!fieldsep) {
-               s = skipblank(s);
-               while (*s && !isblank(*s))
-                       s++;
-       } else {
-               if (!strchr(s, *fieldsep))
-                       s = strchr(s, '\0');
+       if (fieldsep) {
+               if ((s = strstr(s, fieldsep)))
+                       s += next_col ? strlen(fieldsep) : 0;
                else
-                       s = strchr(s, *fieldsep) + 1;
+                       s = eol;
+       } else {
+               s = skipblank(s);
+               s = skipnonblank(s);
        }
        return s;
 }
@@ -198,30 +205,28 @@ nextcol(char *s)
 static char *
 columns(char *line, const struct keydef *kd)
 {
-       char *start, *end;
+       char *start, *end, *eol = strchr(line, '\n');
        int i;
 
        for (i = 1, start = line; i < kd->start_column; i++)
-               start = nextcol(start);
+               start = skipcolumn(start, eol, 1);
        if (kd->flags & MOD_STARTB)
                start = skipblank(start);
-       start += MIN(kd->start_char, nextcol(start) - start) - 1;
+       start = MIN(eol, start + kd->start_char - 1);
 
        if (kd->end_column) {
                for (i = 1, end = line; i < kd->end_column; i++)
-                       end = nextcol(end);
+                       end = skipcolumn(end, eol, 1);
                if (kd->flags & MOD_ENDB)
                        end = skipblank(end);
                if (kd->end_char)
-                       end += MIN(kd->end_char, nextcol(end) - end);
+                       end = MIN(eol, end + kd->end_char);
                else
-                       end = nextcol(end);
+                       end = skipcolumn(end, eol, 0);
        } else {
-               if (!(end = strchr(line, '\n')))
-                       end = strchr(line, '\0');
+               end = eol;
        }
-
-       return enstrndup(2, start, end - start);
+       return enstrndup(2, start, start > end ? 0 : end - start);
 }
 
 static void
@@ -270,8 +275,6 @@ main(int argc, char *argv[])
                break;
        case 't':
                fieldsep = EARGF(usage());
-               if (strlen(fieldsep) != 1)
-                       usage();
                break;
        case 'u':
                uflag = 1;