Simplify code for working with halfwidth/fullwidth kana conversion filter

There's no need to dynamically allocate a struct to hold the 'mode' parameter;
just store it directly in `filt->opaque`. Some other things were also being done
in an unnecessarily roundabout way.

Also, the 'copy' function for CP50220 conversion filters was *both* broken
and unnecessary. Broken, because it malloc'd memory which was never freed by
anything. Unnecessary, because the point of the copy is so that various
algorithms can try running bytes through a conversion filter and see how many
output bytes or characters result, and then back out by restoring the filters
to their previous state. But here's the thing; CP50220 conversion filters don't
hold cached bytes, which is the main thing which would need to be restored to a
previous state.

Author: alexdowad

ext/mbstring/libmbfl/filters/mbfilter_cp5022x.c

@@ -31,14 +31,8 @@
 #include "unicode_table_jis.h"
 #include "cp932_table.h"
 
-typedef struct _mbfl_filt_conv_wchar_cp50220_ctx {
-	mbfl_filt_tl_jisx0201_jisx0208_param tl_param;
-	mbfl_convert_filter last;
-} mbfl_filt_conv_wchar_cp50220_ctx;
-
 static void mbfl_filt_conv_wchar_cp50220_ctor(mbfl_convert_filter *filt);
 static void mbfl_filt_conv_wchar_cp50220_dtor(mbfl_convert_filter *filt);
-static void mbfl_filt_conv_wchar_cp50220_copy(mbfl_convert_filter *src, mbfl_convert_filter *dest);
 static int mbfl_filt_conv_cp5022x_wchar_flush(mbfl_convert_filter *filter);
 
 /* Previously, a dubious 'encoding' called 'cp50220raw' was supported
@@ -102,7 +96,7 @@ const struct mbfl_convert_vtbl vtbl_wchar_cp50220 = {
 	mbfl_filt_conv_wchar_cp50220_dtor,
 	mbfl_filt_conv_wchar_cp50221,
 	mbfl_filt_conv_any_jis_flush,
-	mbfl_filt_conv_wchar_cp50220_copy
+	NULL,
 };
 
 const struct mbfl_convert_vtbl vtbl_cp50221_wchar = {
@@ -327,44 +321,27 @@ static int mbfl_filt_conv_cp5022x_wchar_flush(mbfl_convert_filter *filter)
 /*
  * wchar => CP50220
  */
-static void
-mbfl_filt_conv_wchar_cp50220_ctor(mbfl_convert_filter *filt)
+static void mbfl_filt_conv_wchar_cp50220_ctor(mbfl_convert_filter *filt)
 {
-	mbfl_filt_conv_wchar_cp50220_ctx *ctx;
+	/* Insert a new convert filter into the chain, after this one, which will
+	 * actually perform the CP50220 conversion. Alter this filter so that it
+	 * converts halfwidth katakana instead */
+	mbfl_convert_filter *cp50220_filt = emalloc(sizeof(mbfl_convert_filter));
+	*cp50220_filt = *filt;
 
+	/* Reinitialize */
 	mbfl_filt_conv_common_ctor(filt);
-
-	ctx = emalloc(sizeof(mbfl_filt_conv_wchar_cp50220_ctx));
-	ctx->tl_param.mode = MBFL_FILT_TL_HAN2ZEN_KATAKANA | MBFL_FILT_TL_HAN2ZEN_GLUE;
-
-	ctx->last = *filt;
-	ctx->last.opaque = ctx;
-	ctx->last.data = filt->data;
 	filt->filter_function = vtbl_tl_jisx0201_jisx0208.filter_function;
 	filt->filter_flush = (filter_flush_t)vtbl_tl_jisx0201_jisx0208.filter_flush;
-	filt->output_function = (output_function_t)ctx->last.filter_function;
-	filt->flush_function = (flush_function_t)ctx->last.filter_flush;
-	filt->data = &ctx->last;
-	filt->opaque = ctx;
+	filt->output_function = (output_function_t)cp50220_filt->filter_function;
+	filt->flush_function = (flush_function_t)cp50220_filt->filter_flush;
+	filt->data = cp50220_filt;
+	filt->opaque = (void*)(MBFL_FILT_TL_HAN2ZEN_KATAKANA | MBFL_FILT_TL_HAN2ZEN_GLUE);
 }
 
-static void
-mbfl_filt_conv_wchar_cp50220_copy(mbfl_convert_filter *src, mbfl_convert_filter *dest)
+static void mbfl_filt_conv_wchar_cp50220_dtor(mbfl_convert_filter *filt)
 {
-	mbfl_filt_conv_wchar_cp50220_ctx *ctx;
-
-	*dest = *src;
-	ctx = emalloc(sizeof(mbfl_filt_conv_wchar_cp50220_ctx));
-	dest->opaque = ctx;
-	dest->data = &ctx->last;
-}
-
-static void
-mbfl_filt_conv_wchar_cp50220_dtor(mbfl_convert_filter *filt)
-{
-	if (filt->opaque != NULL) {
-		efree(filt->opaque);
-	}
+	efree(filt->data);
 }
 
 /*

ext/mbstring/libmbfl/filters/mbfilter_tl_jisx0201_jisx0208.c

@@ -22,14 +22,15 @@
  *
  */
 
+#include <stdint.h>
 #include "mbfilter_tl_jisx0201_jisx0208.h"
 #include "translit_kana_jisx0201_jisx0208.h"
 
 int
 mbfl_filt_tl_jisx0201_jisx0208(int c, mbfl_convert_filter *filt)
 {
 	int s, n;
-	int mode = ((mbfl_filt_tl_jisx0201_jisx0208_param *)filt->opaque)->mode;
+	int mode = (intptr_t)filt->opaque;
 
 	s = c;
 
@@ -262,7 +263,7 @@ int
 mbfl_filt_tl_jisx0201_jisx0208_flush(mbfl_convert_filter *filt)
 {
 	int ret, n;
-	int mode = ((mbfl_filt_tl_jisx0201_jisx0208_param *)filt->opaque)->mode;
+	int mode = (intptr_t)filt->opaque;
 
 	ret = 0;
 	if (filt->status) {

ext/mbstring/libmbfl/filters/mbfilter_tl_jisx0201_jisx0208.h

@@ -70,11 +70,6 @@
 	MBFL_FILT_TL_ZEN2HAN_COMPAT1 | \
 	MBFL_FILT_TL_ZEN2HAN_COMPAT2)
 
-
-typedef struct _mbfl_filt_tl_jisx0201_jisx0208_param {
-	int mode;
-} mbfl_filt_tl_jisx0201_jisx0208_param;
-
 extern const struct mbfl_convert_vtbl vtbl_tl_jisx0201_jisx0208;
 
 #endif /* MBFILTER_TL_KANA_JISX0201_JISX0208_H */

ext/mbstring/libmbfl/mbfl/mbfilter.c

@@ -1484,7 +1484,6 @@ mbfl_ja_jp_hantozen(
 	mbfl_convert_filter *encoder = NULL;
 	mbfl_convert_filter *tl_filter = NULL;
 	mbfl_convert_filter *next_filter = NULL;
-	mbfl_filt_tl_jisx0201_jisx0208_param *param = NULL;
 
 	mbfl_memory_device_init(&device, string->len, 0);
 	mbfl_string_init(result);
@@ -1500,20 +1499,16 @@ mbfl_ja_jp_hantozen(
 	}
 	next_filter = decoder;
 
-	param = emalloc(sizeof(mbfl_filt_tl_jisx0201_jisx0208_param));
-	param->mode = mode;
-
 	tl_filter = mbfl_convert_filter_new2(
 		&vtbl_tl_jisx0201_jisx0208,
 		(int(*)(int, void*))next_filter->filter_function,
 		(flush_function_t)next_filter->filter_flush,
 		next_filter);
 	if (tl_filter == NULL) {
-		efree(param);
 		goto out;
 	}
 
-	tl_filter->opaque = param;
+	tl_filter->opaque = (void*)((intptr_t)mode);
 	next_filter = tl_filter;
 
 	encoder = mbfl_convert_filter_new(
@@ -1542,9 +1537,6 @@ mbfl_ja_jp_hantozen(
 	result = mbfl_memory_device_result(&device, result);
 out:
 	if (tl_filter != NULL) {
-		if (tl_filter->opaque != NULL) {
-			efree(tl_filter->opaque);
-		}
 		mbfl_convert_filter_delete(tl_filter);
 	}