1 files changed, 63 insertions, 0 deletions
diff --git a/src/helpers/s6-frontend-helper-echore.c b/src/helpers/s6-frontend-helper-echore.c
new file mode 100644
index 0000000..28fcd73
--- /dev/null
+++ b/src/helpers/s6-frontend-helper-echore.c
@@ -0,0 +1,63 @@
+/* ISC license. */
+
+#include <stdint.h>
+#include <unistd.h>
+
+#include <skalibs/buffer.h>
+#include <skalibs/prog.h>
+#include <skalibs/strerr.h>
+
+#define USAGE "s6-frontend-helper-echore list"
+
+/*
+	0	1	2
+st\ev	\0	\n	other
+
+0			^p
+START	END	START	WORD
+
+1	n	n	p
+WORD	END	START	WORD
+
+^	0x10	print ^
+n	0x20	print /\n
+p	0x40	print cur
+*/
+
+static inline uint8_t cclass (char c)
+{
+  switch (c)
+  {
+    case '\0' : return 0 ;
+    case '\n' : return 1 ;
+    default : return 2 ;
+  }
+}
+
+static void do_print (char const *s)
+{
+  static uint8_t const table[2][3] =
+  {
+    { 0x02, 0x00, 0x51 },
+    { 0x22, 0x20, 0x41 },
+  } ;
+  uint8_t state = 0 ;
+  while (state < 2)
+  {
+    char cur = *s++ ;
+    uint8_t c = table[state][cclass(cur)] ;
+    state = c & 0x03 ;
+    if (c & 0x10) if (buffer_put(buffer_1, "^", 1) < 1) strerr_diefusys(111, "write to stdout") ;
+    if (c & 0x20) if (buffer_put(buffer_1, "/\n", 2) < 2) strerr_diefusys(111, "write to stdout") ;
+    if (c & 0x40) if (buffer_put(buffer_1, &cur, 1) < 1) strerr_diefusys(111, "write to stdout") ;
+  }
+}
+
+int main (int argc, char const *const *argv)
+{
+  PROG = "s6-frontend-helper-echore" ;
+  if (argc < 2) strerr_dieusage(100, USAGE) ;
+  do_print(argv[1]) ;
+  if (!buffer_flush(buffer_1)) strerr_diefusys(111, "write to stdout") ;
+  _exit(0) ;
+}