commit 6f7e9a5078614306bfd01c08fc4cf81fa25d2114
Author: Jakob Kramer <[email protected]>
Date:   Tue May 6 16:07:05 2014 +0200

    sort: add support for "per-keydef" flags

diff --git a/sort.1 b/sort.1
index 7a2057f..955cebd 100644
--- a/sort.1
+++ b/sort.1
@@ -1,4 +1,4 @@
-.TH NL 1 sbase\-VERSION
+.TH SORT 1 sbase\-VERSION
 .SH NAME
 sort \- sort lines
 .SH SYNOPSIS
@@ -27,15 +27,26 @@ reverses the sort.
 prints equal lines only once.
 .TP
 .B \-k key
-specifies a key definition of the form BSR[.BsR][,BER[.BeR]],
+specifies a key definition of the form
+.BR S [. s ][ f ][, E [. e ][ f ]]
 where
-.B S,
-.B s,
-.B E,
+.BR S ,
+.BR s ,
+.BR E ,
 and
 .B e
 are the starting column, starting character in that column, ending column and
 the ending character of that column respectively.  If they are not specified,
-s refers to the first character of the specified starting column, E refers to
-the last column of every line, and e refers to the last character of that last
-column.
+.B s
+refers to the first character of the specified starting column,
+.B E
+refers to the last column of every line, and
+.B e
+refers to the last character of that last column.
+.B f
+can be used to specify options
+.RB ( n ,
+.BR b )
+that only apply to this key definition.
+.B b
+is special in that it only applies to the column that it was specified after.
diff --git a/sort.c b/sort.c
index 26d287d..203490b 100644
--- a/sort.c
+++ b/sort.c
@@ -13,6 +13,14 @@ struct keydef {
        int end_column;
        int start_char;
        int end_char;
+       int flags;
+};
+
+enum {
+       MOD_N      = 1 << 1,
+       MOD_STARTB = 1 << 2,
+       MOD_ENDB   = 1 << 3,
+       MOD_R      = 1 << 4
 };
 
 struct kdlist {
@@ -23,20 +31,18 @@ struct kdlist {
 static struct kdlist *head = NULL;
 static struct kdlist *curr = NULL;
 
-static void addkeydef(char *);
+static void addkeydef(char *, int);
 static void freelist(void);
 static int linecmp(const char **, const char **);
 static char *next_nonblank(char *);
 static char *next_blank(char *);
-static int parse_keydef(struct keydef *, char *);
-static char *skip_columns(char *, size_t);
+static int parse_flags(char **, int *, int);
+static int parse_keydef(struct keydef *, char *, int);
+static char *skip_columns(char *, size_t, bool);
 static char *end_column(char *);
 static char *columns(char *, const struct keydef *);
 
-static bool rflag = false;
 static bool uflag = false;
-static bool nflag = false;
-static bool bflag = false;
 
 static void
 usage(void)
@@ -50,28 +56,31 @@ main(int argc, char *argv[])
        long i;
        FILE *fp;
        struct linebuf linebuf = EMPTY_LINEBUF;
+       int global_flags = 0;
 
        ARGBEGIN {
        case 'n':
-               nflag = true;
+               global_flags |= MOD_N;
                break;
        case 'r':
-               rflag = true;
+               global_flags |= MOD_R;
                break;
        case 'u':
                uflag = true;
                break;
        case 'b':
-               bflag = true;
+               global_flags |= MOD_STARTB | MOD_ENDB;
                break;
        case 'k':
-               addkeydef(EARGF(usage()));
+               addkeydef(EARGF(usage()), global_flags);
                break;
        default:
                usage();
        } ARGEND;
 
-       addkeydef("1");
+       if(!head && global_flags)
+               addkeydef("1", global_flags);
+       addkeydef("1", global_flags & MOD_R);
 
        if(argc == 0) {
                getlines(stdin, &linebuf);
@@ -98,7 +107,7 @@ main(int argc, char *argv[])
 }
 
 static void
-addkeydef(char *def)
+addkeydef(char *def, int flags)
 {
        struct kdlist *node;
 
@@ -107,7 +116,7 @@ addkeydef(char *def)
                enprintf(2, "malloc:");
        if(!head)
                head = node;
-       if(parse_keydef(&node->keydef, def))
+       if(parse_keydef(&node->keydef, def, flags))
                enprintf(2, "faulty key definition
");
        if(curr)
                curr->next = node;
@@ -145,19 +154,42 @@ linecmp(const char **a, const char **b)
                        res = 0;
                else if(!(node == head) && !node->next)
                        res = strcmp(s1, s2);
-               else if(nflag)
+               else if(node->keydef.flags & MOD_N)
                        res = strtol(s1, 0, 10) - strtol(s2, 0, 10);
                else
                        res = strcmp(s1, s2);
 
+               if(node->keydef.flags & MOD_R)
+                       res = -res;
+
                free(s1);
                free(s2);
        }
-       return rflag ? -res : res;
+       return res;
 }
 
 static int
-parse_keydef(struct keydef *kd, char *s)
+parse_flags(char **s, int *flags, int bflag)
+{
+       while(isalpha(**s))
+               switch(*((*s)++)) {
+               case 'b':
+                       *flags |= bflag;
+                       break;
+               case 'n':
+                       *flags |= MOD_N;
+                       break;
+               case 'r':
+                       *flags |= MOD_R;
+                       break;
+               default:
+                       return -1;
+               }
+       return 0;
+}
+
+static int
+parse_keydef(struct keydef *kd, char *s, int flags)
 {
        char *rest = s;
 
@@ -166,6 +198,7 @@ parse_keydef(struct keydef *kd, char *s)
        /* 0 means end of line */
        kd->end_column = 0;
        kd->end_char = 0;
+       kd->flags = flags;
 
        kd->start_column = strtol(rest, &rest, 10);
        if(kd->start_column < 1)
@@ -174,6 +207,8 @@ parse_keydef(struct keydef *kd, char *s)
                kd->start_char = strtol(rest+1, &rest, 10);
        if(kd->start_char < 1)
                return -1;
+       if(parse_flags(&rest, &kd->flags, MOD_STARTB) == -1)
+               return -1;
        if(*rest == ',') {
                kd->end_column = strtol(rest+1, &rest, 10);
                if(kd->end_column && kd->end_column < kd->start_column)
@@ -183,6 +218,8 @@ parse_keydef(struct keydef *kd, char *s)
                        if(kd->end_char < 1)
                                return -1;
                }
+               if(parse_flags(&rest, &kd->flags, MOD_ENDB) == -1)
+                       return -1;
        }
        if(*rest != '

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