_ Git - BearSSL/blob - T0/BlobWriter.cs

   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
  25 using System;
  26 using System.IO;
  27 using 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
  38 class 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 }