util/blobtool: Add new tool for compiling/decompiling data blobs

Given a specification of bitfields defined e.g. as follows:

	specfile:
		{
			"field1" : 8,
			"field2" : 4,
			"field3" : 4
		}
and a set of values for setting defaults:
	setterfile:
		{
			"field1" = 0xff,
			"field2" = 0xf,
			"field3" = 0xf
		}

You can generate a binary packed blob as follows:
	./blobtool specfile setterfile binaryoutput
	binaryoutput:	ff ff

The reverse is also possible, i.e. you can regenerate the setter:
	./blobtool -d specfile binaryoutput setterorig
	setterorig:
		# AUTOGENERATED SETTER BY BLOBTOOL
		{
			"field1" = 0xff,
			"field2" = 0xf,
			"field3" = 0xf
		}

This tool comes with spec/set files for X200 flash descriptor
and ICH9M GbE region, and can be extended or used to decompile
other data blobs with known specs.

Change-Id: I744d6b421003feb4fc460133603af7e6bd80b1d6
Signed-off-by: Damien Zammit <damien@zamaudio.com>
Reviewed-on: https://review.coreboot.org/17445
Tested-by: build bot (Jenkins)
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Martin Roth <martinroth@google.com>

util/blobtool/blobtool.l

@@ -0,0 +1,145 @@
+/*
+ * blobtool - Compiler/Decompiler for data blobs with specs
+ * Copyright (C) 2017 Damien Zammit <damien@zamaudio.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 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 General Public License for more details.
+ */
+
+%{
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "blobtool.tab.h"
+
+extern struct blob binary;
+
+unsigned int parsehex (char *s)
+{
+	unsigned int i, nib, val = 0;
+	unsigned int nibs = strlen(s) - 2;
+
+	for (i = 2; i < nibs + 2; i++) {
+		if (s[i] >= '0' && s[i] <= '9') {
+			nib = s[i] - '0';
+		} else if (s[i] >= 'a' && s[i] <= 'f') {
+			nib = s[i] - 'a' + 10;
+		} else if (s[i] >= 'A' && s[i] <= 'F') {
+			nib = s[i] - 'A' + 10;
+		} else {
+			return 0;
+		}
+		val |= nib << (((nibs - 1) - (i - 2)) * 4);
+	}
+	return val;
+}
+
+char* stripquotes (char *string)
+{
+	char *stripped;
+	unsigned int len = strlen(string);
+	if (len >= 2 && string[0] == '\"' && string[len-1] == '\"') {
+		stripped = (char *) malloc (len - 2 + 1);
+		snprintf (stripped, len - 2 + 1, "%s", string+1);
+		stripped[len-2] = '\0';
+		return stripped;
+	} else {
+		return 0;
+	}
+}
+
+%}
+
+%option noyywrap
+%option nounput
+
+DIGIT1to9 [1-9]
+DIGIT [0-9]
+DIGITS {DIGIT}+
+INT {DIGIT}|{DIGIT1to9}{DIGITS}|-{DIGIT}|-{DIGIT1to9}{DIGITS}
+FRAC [.]{DIGITS}
+E [eE][+-]?
+EXP {E}{DIGITS}
+HEX_DIGIT [0-9a-fA-F]
+HEX_DIGITS {HEX_DIGIT}+
+NUMBER {INT}|{INT}{FRAC}|{INT}{EXP}|{INT}{FRAC}{EXP}
+UNICODECHAR \\u{HEX_DIGIT}{HEX_DIGIT}{HEX_DIGIT}{HEX_DIGIT}
+ALPHA [a-zA-Z]
+SPECIAL [()\[\]"'@_\-+:;/\\.,<> 	]
+VARCHAR {ALPHA}|{DIGIT}|{SPECIAL}
+CHAR {VARCHAR}|{UNICODECHAR}
+CHARS {CHAR}+
+QUOTE ["]
+HEX_PREFIX [0][x]
+HEX {HEX_PREFIX}{HEX_DIGITS}
+STRING {QUOTE}{QUOTE}|{QUOTE}{CHARS}{QUOTE}
+COMMENT [#]{CHARS}[\n]|[#]\n
+
+%%
+
+{STRING} {
+    yylval.str = stripquotes(yytext);
+    return name;
+};
+
+{NUMBER} {
+    yylval.u32 = atoi(yytext);
+    return val;
+};
+
+{HEX} {
+    yylval.u32 = parsehex(yytext);
+    return val;
+};
+
+\{ {
+    return '{';
+};
+
+\} {
+    return '}';
+};
+
+\[ {
+    return '[';
+};
+
+\] {
+    return ']';
+};
+
+, {
+    return ',';
+};
+
+: {
+    return ':';
+};
+
+= {
+    return '=';
+};
+
+[ \t\n]+ /* ignore whitespace */;
+
+{COMMENT} /* ignore comments */
+
+\% {
+    return '%';
+};
+
+<<EOF>> { return eof; };
+
+%%
+
+void set_input_string(char* in) {
+	yy_scan_string(in);
+}
+