[vlc-commits] JSON representation and Javascript unescaping
Rémi Denis-Courmont
git at videolan.org
Sun Sep 27 15:16:36 CEST 2020
vlc | branch: master | Rémi Denis-Courmont <remi at remlab.net> | Sun Sep 27 15:19:42 2020 +0300| [c4c1bc81e819cee65f673a10f58e40f56eab9704] | committer: Rémi Denis-Courmont
JSON representation and Javascript unescaping
> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=c4c1bc81e819cee65f673a10f58e40f56eab9704
---
modules/demux/Makefile.am | 7 +++
modules/demux/json/json.c | 145 ++++++++++++++++++++++++++++++++++++++++++++++
modules/demux/json/json.h | 73 +++++++++++++++++++++++
3 files changed, 225 insertions(+)
diff --git a/modules/demux/Makefile.am b/modules/demux/Makefile.am
index 675b2d10af..f46fcdb92e 100644
--- a/modules/demux/Makefile.am
+++ b/modules/demux/Makefile.am
@@ -512,3 +512,10 @@ libdemux_mock_plugin_la_SOURCES = demux/mock.c
libdemux_mock_plugin_la_LDFLAGS = $(AM_LDFLAGS) -rpath '$(demuxdir)'
libdemux_mock_plugin_la_LIBADD = $(LIBM)
noinst_LTLIBRARIES += libdemux_mock_plugin.la
+
+libvlc_json_la_SOURCES = \
+ demux/json/json.c demux/json/json.h
+libvlc_json_la_CPPFLAGS = $(AM_CPPFLAGS) -I$(srcdir)/demux/json
+libvlc_json_la_LIBADD = $(LTLIBVLCCORE) ../compat/libcompat.la
+libvlc_json_la_LDFLAGS = -static
+noinst_LTLIBRARIES += libvlc_json.la
diff --git a/modules/demux/json/json.c b/modules/demux/json/json.c
new file mode 100644
index 0000000000..d0ab86120a
--- /dev/null
+++ b/modules/demux/json/json.c
@@ -0,0 +1,145 @@
+/*****************************************************************************
+ * json/json.c: JSON parsing library
+ *****************************************************************************
+ * Copyright © 2020 Rémi Denis-Courmont
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <assert.h>
+#include <math.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <vlc_common.h>
+#include <vlc_charset.h>
+#include "json.h"
+
+#ifdef WORDS_BIGENDIAN
+# define ENDIAN(x) x "BE"
+#else
+# define ENDIAN(x) x "LE"
+#endif
+
+char *json_unescape(const char *in, size_t inlen)
+{
+ /* 1) Convert UTF-8 to UTF-16.
+ * This will catch any invalid UTF-8 byte sequence.
+ */
+ size_t buflen = 2 * (inlen + 1);
+ void *buf = malloc(buflen);
+
+ if (unlikely(buf == NULL))
+ return NULL;
+
+ vlc_iconv_t hd = vlc_iconv_open(ENDIAN("UTF-16") , "UTF-8");
+
+ if (unlikely(hd == (vlc_iconv_t)-1)) {
+ free(buf);
+ return NULL;
+ }
+
+ char *out = buf;
+ size_t outlen = buflen;
+ size_t val = vlc_iconv(hd, &in, &inlen, &out, &outlen);
+
+ vlc_iconv_close(hd);
+
+ if (val == (size_t)-1) {
+ free(buf);
+ return NULL;
+ }
+
+ /* 2) Unescape in UTF-16 (in place).
+ */
+ const uint16_t *in2 = buf, *end2 = in2 + ((buflen - outlen) / 2);
+ uint16_t *out2 = buf;
+
+ while (in2 < end2) {
+ uint16_t c = *(in2++);
+
+ if (c == '\\') {
+ switch (*(in2++)) {
+ case 'b':
+ c = '\b';
+ break;
+ case 'f':
+ c = '\f';
+ break;
+ case 'n':
+ c = '\n';
+ break;
+ case 'r':
+ c = '\r';
+ break;
+ case 't':
+ c = '\t';
+ break;
+ case 'u': {
+ char hex[5] = { in2[0], in2[1], in2[2], in2[3], 0 };
+
+ /* Tokeniser requires 4 hex-digits, so this cannot fail. */
+ if (sscanf(hex, "%4"SCNx16, &c) != 1)
+ vlc_assert_unreachable();
+
+ in2 += 4;
+ break;
+ }
+ default:
+ /* Invalid escape is not allowed by tokeniser. */
+ vlc_assert_unreachable();
+ }
+ }
+
+ assert(out2 < in2); /* Safely in place */
+ *(out2++) = c;
+ }
+
+ /* 3) Convert back to UTF-8.
+ * This will catch any invalid sequence of escaped UTF-16 surrogates.
+ */
+ char *ret = FromCharset(ENDIAN("UTF-16"), buf, (char *)out2 - (char *)buf);
+
+ free(buf);
+ return ret;
+}
+
+const struct json_value *json_get(const struct json_object *obj,
+ const char *name)
+{
+ for (size_t i = 0; i < obj->count; i++)
+ if (!strcmp(obj->members[i].name, name))
+ return &obj->members[i].value;
+
+ return NULL;
+}
+
+const char *json_get_str(const struct json_object *obj, const char *name)
+{
+ const struct json_value *v = json_get(obj, name);
+
+ return (v != NULL && v->type == JSON_STRING) ? v->string : NULL;
+}
+
+double json_get_num(const struct json_object *obj, const char *name)
+{
+ const struct json_value *v = json_get(obj, name);
+
+ return (v != NULL && v->type == JSON_NUMBER) ? v->number : NAN;
+}
diff --git a/modules/demux/json/json.h b/modules/demux/json/json.h
new file mode 100644
index 0000000000..e468ec871f
--- /dev/null
+++ b/modules/demux/json/json.h
@@ -0,0 +1,73 @@
+/*****************************************************************************
+ * json/json.h:
+ *****************************************************************************
+ * Copyright © 2020 Rémi Denis-Courmont
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifndef JSON_H
+#define JSON_H
+
+#include <stdbool.h>
+#include <stdio.h>
+
+enum json_type {
+ JSON_NULL,
+ JSON_BOOLEAN,
+ JSON_NUMBER,
+ JSON_STRING,
+ JSON_ARRAY,
+ JSON_OBJECT,
+};
+
+struct json_array {
+ size_t size;
+ struct json_value *entries;
+};
+
+struct json_object {
+ size_t count;
+ struct json_member *members;
+};
+
+struct json_value {
+ enum json_type type;
+ union {
+ bool boolean;
+ double number;
+ char *string;
+ struct json_array array;
+ struct json_object object;
+ };
+};
+
+struct json_member {
+ char *name;
+ struct json_value value;
+};
+
+void json_parse_error(void *log, const char *msg);
+char *json_unescape(const char *, size_t);
+
+int json_parse(void *log, FILE *in, struct json_object *result);
+void json_free(struct json_object *);
+
+const struct json_value *json_get(const struct json_object *obj,
+ const char *name);
+const char *json_get_str(const struct json_object *obj, const char *name);
+double json_get_num(const struct json_object *obj, const char *name);
+
+#endif
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