Univalue: Do not build JSON escape list at runtime

No need to waste startup time building something that can be done
at compile time.

This also resolves a clang++ warning originally reported in #4714,
univalue/univalue_write.cpp:33:12: warning: array subscript is of type 'char
escapes['"'] = "\\"";
^~~~

etc.

1 files changed, 78 insertions, 0 deletions

diff --git a/src/univalue/gen.cpp b/src/univalue/gen.cpp
new file mode 100644
index 0000000000..881948f46e
--- /dev/null
+++ b/src/univalue/gen.cpp
@@ -0,0 +1,78 @@
+// Copyright 2014 BitPay Inc.
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+//
+// To re-create univalue_escapes.h:
+// $ g++ -o gen gen.cpp
+// $ ./gen > univalue_escapes.h
+//
+
+#include <ctype.h>
+#include <stdio.h>
+#include <string.h>
+#include "univalue.h"
+
+using namespace std;
+
+static bool initEscapes;
+static const char *escapes[256];
+
+static void initJsonEscape()
+{
+    escapes[(int)'"'] = "\\\"";
+    escapes[(int)'\\'] = "\\\\";
+    escapes[(int)'/'] = "\\/";
+    escapes[(int)'\b'] = "\\b";
+    escapes[(int)'\f'] = "\\f";
+    escapes[(int)'\n'] = "\\n";
+    escapes[(int)'\r'] = "\\r";
+    escapes[(int)'\t'] = "\\t";
+
+    initEscapes = true;
+}
+
+static void outputEscape()
+{
+	printf(	"// Automatically generated file. Do not modify.\n"
+		"#ifndef __UNIVALUE_ESCAPES_H__\n"
+		"#define __UNIVALUE_ESCAPES_H__\n"
+		"static const char *escapes[256] = {\n");
+
+	for (unsigned int i = 0; i < 256; i++) {
+		if (!escapes[i]) {
+			printf("\tNULL,\n");
+		} else {
+			printf("\t\"");
+
+			unsigned int si;
+			for (si = 0; si < strlen(escapes[i]); si++) {
+				char ch = escapes[i][si];
+				switch (ch) {
+				case '"':
+					printf("\\\"");
+					break;
+				case '\\':
+					printf("\\\\");
+					break;
+				default:
+					printf("%c", escapes[i][si]);
+					break;
+				}
+			}
+
+			printf("\",\n");
+		}
+	}
+
+	printf(	"};\n"
+		"#endif // __UNIVALUE_ESCAPES_H__\n");
+}
+
+int main (int argc, char *argv[])
+{
+	initJsonEscape();
+	outputEscape();
+	return 0;
+}
+