wall: convert homebrew buffering to open_memstream()

The struct buffer system duplicates a plethora of standard I/O
functions (including a fork of fputc_careful())
and adds a lot of complexity ‒ open_memstream() is standard,
and fits perfectly into this niche

diff --git a/term-utils/wall.c b/term-utils/wall.c
index c601d3e5b73582dfaa20edf04b2a61e8384a7f1f..a51a9282935ee61d740e14448a1fc4c2f8d3e1e4 100644 (file)
--- a/term-utils/wall.c
+++ b/term-utils/wall.c
@@ -274,74 +274,22 @@ int main(int argc, char **argv)
        exit(EXIT_SUCCESS);
 }
 
-struct buffer {
-       size_t  sz;
-       size_t  used;
-       char    *data;
-};
-
-static void buf_enlarge(struct buffer *bs, size_t len)
+static void buf_putc_careful(FILE *fs, int c)
 {
-       if (bs->sz == 0 || len > bs->sz - bs->used) {
-               bs->sz += len < 128 ? 128 : len;
-               bs->data = xrealloc(bs->data, bs->sz);
-       }
-}
-
-static void buf_puts(struct buffer *bs, const char *s)
-{
-       size_t len = strlen(s);
-
-       buf_enlarge(bs, len + 1);
-       memcpy(bs->data + bs->used, s, len + 1);
-       bs->used += len;
-}
-
-static void __attribute__((__format__ (__printf__, 2, 3)))
-       buf_printf(struct buffer *bs, const char *fmt, ...)
-{
-       int rc;
-       va_list ap;
-       size_t limit;
-
-       buf_enlarge(bs, 0);     /* default size */
-       limit = bs->sz - bs->used;
-
-       va_start(ap, fmt);
-       rc = vsnprintf(bs->data + bs->used, limit, fmt, ap);
-       va_end(ap);
-
-       if (rc >= 0 && (size_t) rc >= limit) {  /* not enough, enlarge */
-               buf_enlarge(bs, (size_t)rc + 1);
-               limit = bs->sz - bs->used;
-               va_start(ap, fmt);
-               rc = vsnprintf(bs->data  + bs->used, limit, fmt, ap);
-               va_end(ap);
-       }
-
-       if (rc > 0)
-               bs->used += rc;
-}
-
-static void buf_putc_careful(struct buffer *bs, int c)
-{
-       if (isprint(c) || c == '\a' || c == '\t' || c == '\r' || c == '\n') {
-               buf_enlarge(bs, 1);
-               bs->data[bs->used++] = c;
-       } else if (!c_isascii(c))
-               buf_printf(bs, "\\%3o", (unsigned char)c);
-       else {
-               char tmp[] = { '^', c ^ 0x40, '\0' };
-               buf_puts(bs, tmp);
-       }
+       if (isprint(c) || c == '\a' || c == '\t' || c == '\r' || c == '\n')
+               fputc(c, fs);
+       else if (!c_isascii(c))
+               fprintf(fs, "\\%3o", (unsigned char)c);
+       else
+               fputs((char[]){ '^', c ^ 0x40, '\0' }, fs);
 }
 
 static char *makemsg(char *fname, char **mvec, int mvecsz,
                     size_t *mbufsize, int print_banner)
 {
-       struct buffer _bs = {.used = 0}, *bs = &_bs;
        register int ch, cnt;
-       char *p, *lbuf;
+       char *p, *lbuf, *retbuf;
+       FILE * fs = open_memstream(&retbuf, mbufsize);
        long line_max;
 
        line_max = sysconf(_SC_LINE_MAX);
@@ -379,15 +327,15 @@ static char *makemsg(char *fname, char **mvec, int mvecsz,
                 */
                /* snprintf is not always available, but the sprintf's here
                   will not overflow as long as %d takes at most 100 chars */
-               buf_printf(bs, "\r%*s\r\n", TERM_WIDTH, " ");
+               fprintf(fs, "\r%*s\r\n", TERM_WIDTH, " ");
 
                snprintf(lbuf, line_max,
                                _("Broadcast message from %s@%s (%s) (%s):"),
                                whom, hostname, where, date);
-               buf_printf(bs, "%-*.*s\007\007\r\n", TERM_WIDTH, TERM_WIDTH, lbuf);
+               fprintf(fs, "%-*.*s\007\007\r\n", TERM_WIDTH, TERM_WIDTH, lbuf);
                free(hostname);
        }
-       buf_printf(bs, "%*s\r\n", TERM_WIDTH, " ");
+       fprintf(fs, "%*s\r\n", TERM_WIDTH, " ");
 
         if (mvec) {
                /*
@@ -396,11 +344,11 @@ static char *makemsg(char *fname, char **mvec, int mvecsz,
                int i;
 
                for (i = 0; i < mvecsz; i++) {
-                       buf_puts(bs, mvec[i]);
+                       fputs(mvec[i], fs);
                        if (i < mvecsz - 1)
-                               buf_puts(bs, " ");
+                               fputc(' ', fs);
                }
-               buf_puts(bs, "\r\n");
+               fputs("\r\n", fs);
        } else {
                /*
                 * read message from <file>
@@ -428,23 +376,20 @@ static char *makemsg(char *fname, char **mvec, int mvecsz,
                while (fgets(lbuf, line_max, stdin)) {
                        for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) {
                                if (cnt == TERM_WIDTH || ch == '\n') {
-                                       for (; cnt < TERM_WIDTH; ++cnt)
-                                               buf_puts(bs, " ");
-                                       buf_puts(bs, "\r\n");
+                                       fprintf(fs, "%*s\r\n", TERM_WIDTH - cnt, "");
                                        cnt = 0;
                                }
                                if (ch == '\t')
                                        cnt += (7 - (cnt % 8));
                                if (ch != '\n')
-                                       buf_putc_careful(bs, ch);
+                                       buf_putc_careful(fs, ch);
                        }
                }
        }
-       buf_printf(bs, "%*s\r\n", TERM_WIDTH, " ");
+       fprintf(fs, "%*s\r\n", TERM_WIDTH, " ");
 
        free(lbuf);
 
-       bs->data[bs->used] = '\0';      /* be paranoid */
-       *mbufsize = bs->used;
-       return bs->data;
+       fclose(fs);
+       return retbuf;
 }