tawk: split record into runes for empty FS (#292) - plan9port - [fork] Plan 9 from user space
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       ---
   DIR commit 1309450668aa571dee97f4373f9555b4fddcf1aa
   DIR parent 715807d706cd13bc583588477a84090fbf02e057
  HTML Author: Fazlul Shahriar <fshahriar@gmail.com>
       Date:   Tue, 29 Oct 2019 10:04:06 -0400
       
       awk: split record into runes for empty FS (#292)
       
       awk was splitting records into bytes instead of runes for empty FS.
       For example, this was printing only the first byte of the utf-8 encoding
       of é:
       
               echo é | awk 'BEGIN{FS=""}{print $1}'
       
       The change just copies how the `split` function handles runes.
       
       Originally reported by kris on twitter:
       https://twitter.com/p9luv/status/1180436083433201665
       Diffstat:
         M src/cmd/awk/lib.c                   |      13 +++++++++----
       
       1 file changed, 9 insertions(+), 4 deletions(-)
       ---
   DIR diff --git a/src/cmd/awk/lib.c b/src/cmd/awk/lib.c
       t@@ -29,6 +29,7 @@ THIS SOFTWARE.
        #include <errno.h>
        #include <stdlib.h>
        #include <stdarg.h>
       +#include <utf.h>
        #include "awk.h"
        #include "y.tab.h"
        
       t@@ -293,15 +294,19 @@ void fldbld(void)        /* create fields from current record */
                        }
                        *fr = 0;
                } else if ((sep = *inputFS) == 0) {                /* new: FS="" => 1 char/field */
       -                for (i = 0; *r != 0; r++) {
       -                        char buf[2];
       +                int nb;
       +                for (i = 0; *r != 0; r += nb) {
       +                        Rune rr;
       +                        char buf[UTFmax+1];
       +
                                i++;
                                if (i > nfields)
                                        growfldtab(i);
                                if (freeable(fldtab[i]))
                                        xfree(fldtab[i]->sval);
       -                        buf[0] = *r;
       -                        buf[1] = 0;
       +                        nb = chartorune(&rr, r);
       +                        memmove(buf, r, nb);
       +                        buf[nb] = '\0';
                                fldtab[i]->sval = tostring(buf);
                                fldtab[i]->tval = FLD | STR;
                        }