1/*
2 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 */
24
25using System;
26using System.IO;
27using System.Text;
28
29/*
30 * A simple class for writing out bytes as hexadecimal constants or
31 * explicit expressions for the initializer of a C array of 'unsigned
32 * char'. It starts every line with a given number of tabs, and aims at
33 * keeping lines below a given threshold (each indentation tab counts as
34 * 8 characters). An explicit newline is inserted before the first
35 * element, and commas are used as separators.
36 */
37
38class BlobWriter {
39
40	TextWriter w;
41	int maxLineLen;
42	int indent;
43	int lineLen;
44
45	/*
46	 * Create a new instance. 'maxLineLen' is in characters, and
47	 * 'indent' is the number of tab characters at the start of
48	 * each line.
49	 */
50	internal BlobWriter(TextWriter w, int maxLineLen, int indent)
51	{
52		this.w = w;
53		this.maxLineLen = maxLineLen;
54		this.indent = indent;
55		lineLen = -1;
56	}
57
58	void DoNL()
59	{
60		w.WriteLine();
61		for (int i = 0; i < indent; i ++) {
62			w.Write('\t');
63		}
64		lineLen = (indent << 3);
65	}
66
67	/*
68	 * Append a new byte value; it will be converted to an hexadecimal
69	 * constant in the output.
70	 */
71	internal void Append(byte b)
72	{
73		if (lineLen < 0) {
74			DoNL();
75		} else {
76			w.Write(',');
77			lineLen ++;
78			if ((lineLen + 5) > maxLineLen) {
79				DoNL();
80			} else {
81				w.Write(' ');
82				lineLen ++;
83			}
84		}
85		w.Write("0x{0:X2}", b);
86		lineLen += 4;
87	}
88
89	/*
90	 * Append a C expression, which will be used as is. The expression
91	 * may resolve to several bytes if it uses internal commas. The
92	 * writer will try to honour the expected line length, but it
93	 * won't insert a newline character inside the expression.
94	 */
95	internal void Append(string expr)
96	{
97		if (lineLen < 0) {
98			DoNL();
99		} else {
100			w.Write(',');
101			lineLen ++;
102			if ((lineLen + 1 + expr.Length) > maxLineLen) {
103				DoNL();
104			} else {
105				w.Write(' ');
106				lineLen ++;
107			}
108		}
109		w.Write("{0}", expr);
110		lineLen += expr.Length;
111	}
112}
113