Add an implementation of tabfile

The original one is a horrible thing.  Now we're self-reliant.

CMakeLists.txt

@@ -163,7 +163,7 @@ if (gtk_FOUND)
 endif ()
 
 # Tools
-set (tools add-pronunciation query-tool transform)
+set (tools tabfile add-pronunciation query-tool transform)
 foreach (tool ${tools})
 	add_executable (${tool} EXCLUDE_FROM_ALL
 		src/${tool}.c ${project_common_sources})

src/tabfile.c

@@ -0,0 +1,163 @@
+/*
+ * A clean reimplementation of StarDict's tabfile
+ *
+ * Copyright (c) 2020 - 2021, Přemysl Eric Janouch <p@janouch.name>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <locale.h>
+
+#include <glib.h>
+#include <gio/gio.h>
+
+#include "stardict.h"
+#include "stardict-private.h"
+#include "generator.h"
+#include "utils.h"
+
+static gboolean
+set_data_error (GError **error, const char *message)
+{
+	g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_INVALID_DATA, message);
+	return FALSE;
+}
+
+static const gchar escapes[256] = { ['n'] = '\n', ['t'] = '\t', ['\\'] = '\\' };
+
+static gboolean
+inplace_unescape (char *line, GError **error)
+{
+	gboolean escape = FALSE;
+	char *dest = line;
+	for (char *src = line; *src; src++)
+	{
+		if (escape)
+		{
+			escape = FALSE;
+			if (!(*dest++ = escapes[(guchar) *src]))
+				return set_data_error (error, "unsupported escape");
+		}
+		else if (*src == '\\')
+			escape = TRUE;
+		else
+			*dest++ = *src;
+	}
+	if (escape)
+		return set_data_error (error, "trailing escape character");
+
+	*dest = 0;
+	return TRUE;
+}
+
+static gboolean
+import_line (Generator *generator, char *line, size_t len, GError **error)
+{
+	if (!len)
+		return TRUE;
+
+	char *separator = strchr (line, '\t');
+	if (!separator)
+		return set_data_error (error, "keyword separator not found");
+
+	*separator++ = 0;
+	if (strchr (line, '\\'))
+		// The index wouldn't be sorted correctly with our method
+		return set_data_error (error, "escapes not allowed in keywords");
+
+	char *newline = strpbrk (separator, "\r\n");
+	if (newline)
+		*newline = 0;
+
+	if (!inplace_unescape (line, error)
+	 || !inplace_unescape (separator, error))
+		return FALSE;
+
+	generator_begin_entry (generator);
+	return generator_write_string (generator, separator, TRUE, error)
+		&& generator_finish_entry (generator, line, error);
+}
+
+static gboolean
+transform (FILE *fsorted, Generator *generator, GError **error)
+{
+	char *line = NULL;
+	size_t size = 0, ln = 1;
+	for (ssize_t read; (read = getline (&line, &size, fsorted)) >= 0; ln++)
+		if (!import_line (generator, line, read, error))
+			break;
+
+	free (line);
+	if (ferror (fsorted))
+	{
+		g_set_error_literal (error, G_IO_ERROR,
+			g_io_error_from_errno (errno), g_strerror (errno));
+		return FALSE;
+	}
+	if (!feof (fsorted))
+	{
+		// You'll only get good line number output with presorted input!
+		g_prefix_error (error, "line %zu: ", ln);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+int
+main (int argc, char *argv[])
+{
+	// The GLib help includes an ellipsis character, for some reason
+	(void) setlocale (LC_ALL, "");
+
+	GError *error = NULL;
+	GOptionContext *ctx = g_option_context_new ("output-basename < input");
+	g_option_context_set_summary (ctx,
+		"Create a StarDict dictionary from plaintext.");
+	if (!g_option_context_parse (ctx, &argc, &argv, &error))
+		fatal ("Error: option parsing failed: %s\n", error->message);
+
+	if (argc != 2)
+		fatal ("%s", g_option_context_get_help (ctx, TRUE, FALSE));
+	g_option_context_free (ctx);
+
+	// This actually implements stardict_strcmp(), POSIX-compatibly.
+	// Your sort(1) is not expected to be stable by default, like bsdsort is.
+	FILE *fsorted = popen ("LC_ALL=C sort -t'\t' -k1f,1", "r");
+	if (!fsorted)
+		fatal ("%s: %s\n", "popen", g_strerror (errno));
+
+	Generator *generator = generator_new (argv[1], &error);
+	if (!generator)
+		fatal ("Error: failed to create the output dictionary: %s\n",
+			error->message);
+
+	StardictInfo *info = generator->info;
+	info->version = SD_VERSION_3_0_0;
+	info->book_name = g_strdup (argv[1]);
+	info->same_type_sequence = g_strdup ("m");
+
+	// This gets incremented each time an entry is finished
+	info->word_count = 0;
+
+	if (!transform (fsorted, generator, &error)
+	 || !generator_finish (generator, &error))
+		fatal ("Error: failed to write the dictionary: %s\n", error->message);
+
+	generator_free (generator);
+	fclose (fsorted);
+	return 0;
+}

src/transform.c

@@ -3,7 +3,7 @@
  *
  * The external filter needs to process NUL-separated textual entries.
  *
- * Example: transform input.info output -- perl -p0e s/bullshit/soykaf/g
+ * Example: transform input.ifo output -- perl -p0e s/bullshit/soykaf/g
  *
  * Copyright (c) 2020, Přemysl Eric Janouch <p@janouch.name>
  *