2 files changed, 122 insertions, 0 deletions
diff --git a/src/util/ragel/ragel.h b/src/util/ragel/ragel.h
new file mode 100644
index 0000000..b2c7572
--- /dev/null
+++ b/src/util/ragel/ragel.h
@@ -0,0 +1,30 @@
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+struct ragel_mem {
+   const char *data, *end;
+   bool binary; // binary input bit
+};
+
+struct ragel {
+   struct ragel_mem input; // block of input data
+   uint64_t lineno; // current line
+   const char *p, *pe, *eof; // see ragel doc
+   const char *cl; // current line start
+   const char *name; // may be current file name for example
+   bool error; // error thrown bit
+};
+
+__attribute__((format(printf, 2, 3))) void
+ragel_throw_error(struct ragel *ragel, const char *fmt, ...);
+
+void
+ragel_set_name(struct ragel *ragel, const char *name);
+
+void
+ragel_advance_line(struct ragel *ragel);
+
+void
+ragel_feed_input(struct ragel *ragel, const bool eof, const struct ragel_mem *input);
diff --git a/src/util/ragel/ragel.rl b/src/util/ragel/ragel.rl
new file mode 100644
index 0000000..c52f27b
--- /dev/null
+++ b/src/util/ragel/ragel.rl
@@ -0,0 +1,92 @@
+#include "ragel.h"
+
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <assert.h>
+
+%%{
+   machine ragel;
+   write data noerror nofinal;
+
+   action red { fputs("\x1b[31m", stderr); }
+   action reset { fputs("\x1b[0m", stderr); }
+   action end { fputs("\x1b[0m\n", stderr); }
+   action mark { fputc((fpc == *error ? '^' : '~'), stderr); }
+   action lead { fputc(' ', stderr); }
+   action char { fputc(fc, stderr); }
+
+   valid = ^cntrl - space - punct;
+   mark_token = (space valid | punct) ${ *error = fpc; };
+   search_err := ((any | mark_token) when { fpc != ragel->pe && fpc <= ragel->p })*;
+
+   word = print | valid*;
+   until_err = (any when { fpc != *error })*;
+   print_err := (until_err <: (word - '\n') >red %reset <: (print - '\n')*) $char >*lead %!end %/end;
+   print_mark := (until_err $lead <: (any | word) >red $mark) >*lead %!end %/end;
+}%%
+
+static void
+ragel_exec_error(const struct ragel *ragel, const int start_cs, const char **error)
+{
+   (void)ragel_start;
+   assert(ragel && ragel->cl && error);
+   int cs = start_cs;
+   const char *p = ragel->cl, *pe = ragel->pe, *eof = ragel->eof;
+   assert(p <= pe);
+   %% write exec;
+}
+
+void
+ragel_throw_error(struct ragel *ragel, const char *fmt, ...)
+{
+   assert(ragel && fmt);
+   ragel->error = true;
+
+   const char *error = ragel->p;
+
+   if (!ragel->input.binary)
+      ragel_exec_error(ragel, ragel_en_search_err, &error);
+
+   const char *name = (ragel->name ? ragel->name : "");
+   assert(error >= ragel->cl);
+   uint64_t column = (error - ragel->cl);
+   fprintf(stderr, "\x1b[37m%s:%" PRIu64 ":%" PRIu64 " \x1b[31merror: \x1b[0m", name, ragel->lineno, column);
+
+   va_list args;
+   va_start(args, fmt);
+   vfprintf(stderr, fmt, args);
+   va_end(args);
+   fputc('\n', stderr);
+
+   if (!ragel->input.binary) {
+      ragel_exec_error(ragel, ragel_en_print_err, &error);
+      ragel_exec_error(ragel, ragel_en_print_mark, &error);
+   }
+}
+
+void
+ragel_set_name(struct ragel *ragel, const char *name)
+{
+   assert(ragel);
+   ragel->name = name;
+}
+
+void
+ragel_advance_line(struct ragel *ragel)
+{
+   assert(ragel);
+   ++ragel->lineno;
+   ragel->cl = ragel->p;
+}
+
+void
+ragel_feed_input(struct ragel *ragel, const bool eof, const struct ragel_mem *input)
+{
+   assert(ragel);
+   ragel->input = *input;
+   ragel->cl = ragel->p = ragel->input.data;
+   ragel->pe = ragel->input.end;
+   ragel->eof = (eof ? ragel->pe : NULL);
+   assert(ragel->p <= ragel->pe);
+}