2 files changed, 250 insertions, 0 deletions
diff --git a/bin/bit.y b/bin/bit.y
new file mode 100644
index 00000000..798103f1
--- /dev/null
+++ b/bin/bit.y
@@ -0,0 +1,183 @@
+/* Copyright (C) 2019  June McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+%{
+
+#include <ctype.h>
+#include <err.h>
+#include <histedit.h>
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sysexits.h>
+
+int yylex(void);
+void yyerror(const char *str);
+
+#define YYSTYPE uint64_t
+
+enum { RingLen = 64 };
+static struct {
+	uint64_t vals[RingLen];
+	size_t len;
+} ring;
+
+static void push(uint64_t val) {
+	ring.vals[ring.len++ % RingLen] = val;
+}
+static uint64_t get(size_t i) {
+	return ring.vals[i % RingLen];
+}
+
+%}
+
+%token Int Shl Shr Sar
+
+%left '|'
+%left '^'
+%left '&'
+%left Shl Shr Sar
+%left '+' '-'
+%left '*' '/' '%'
+%right '~'
+%left 'K' 'M' 'G'
+
+%%
+
+input:
+	expr { push($1); }
+	| input ',' expr { push($3); }
+	|
+	;
+
+expr:
+	Int
+	| '_' { $$ = get(ring.len - 1); }
+	| '[' Int ']' { $$ = get($2); }
+	| '(' expr ')' { $$ = $2; }
+	| expr 'K' { $$ = $1 << 10; }
+	| expr 'M' { $$ = $1 << 20; }
+	| expr 'G' { $$ = $1 << 30; }
+	| '~' expr { $$ = ~$2; }
+	| '-' expr { $$ = -$2; }
+	| expr '*' expr { $$ = $1 * $3; }
+	| expr '/' expr { $$ = $1 / $3; }
+	| expr '%' expr { $$ = $1 % $3; }
+	| expr '+' expr { $$ = $1 + $3; }
+	| expr '-' expr { $$ = $1 - $3; }
+	| expr Shl expr { $$ = $1 << $3; }
+	| expr Shr expr { $$ = $1 >> $3; }
+	| expr Sar expr { $$ = (int64_t)$1 >> $3; }
+	| expr '&' expr { $$ = $1 & $3; }
+	| expr '^' expr { $$ = $1 ^ $3; }
+	| expr '|' expr { $$ = $1 | $3; }
+	;
+
+%%
+
+#include "bitlex.c"
+
+int yywrap(void) {
+	return 1;
+}
+
+void yyerror(const char *str) {
+	if (yychar < 128 && isprint(yychar)) {
+		warnx("%s at '%c'", str, yychar);
+	} else {
+		warnx("%s at %d", str, yychar);
+	}
+}
+
+static char *prompt(EditLine *el) {
+	(void)el;
+	static char buf[64];
+	snprintf(buf, sizeof(buf), "[%zu]: ", ring.len);
+	return buf;
+}
+
+static void print(size_t i) {
+	uint64_t val = get(i);
+
+	int bits = val > UINT32_MAX ? 64
+		: val > UINT16_MAX ? 32
+		: val > UINT8_MAX ? 16
+		: 8;
+
+	char bin[65] = {0};
+	for (int i = 0; i < 64; ++i) {
+		bin[i] = '0' + (val >> (63 - i) & 1);
+	}
+
+	printf(
+		"[%zu]: %"PRId64" 0x%0*"PRIX64" 0b%s",
+		i, (int64_t)val, bits >> 2, val, &bin[64 - bits]
+	);
+
+	if (val) {
+		if (!(val & (1 << 30) - 1)) {
+			printf(" %"PRId64"G", val >> 30);
+		} else if (!(val & (1 << 20) - 1)) {
+			printf(" %"PRId64"M", val >> 20);
+		} else if (!(val & (1 << 10) - 1)) {
+			printf(" %"PRId64"K", val >> 10);
+		}
+	}
+
+	if (val < 128 && isprint(val)) {
+		printf(" '%c'", (char)val);
+	}
+
+	printf("\n");
+}
+
+int main(void) {
+	HistEvent ev;
+	History *hist = history_init();
+	if (!hist) err(EX_OSERR, "history_init");
+	history(hist, &ev, H_SETSIZE, 64);
+	history(hist, &ev, H_SETUNIQUE, 1);
+
+	EditLine *el = el_init("bit", stdin, stdout, stderr);
+	if (!el) err(EX_IOERR, "el_init");
+	el_set(el, EL_PROMPT, prompt);
+	el_set(el, EL_HIST, history, hist);
+
+	for (;;) {
+		int len;
+		const char *line = el_gets(el, &len);
+		if (!len) break;
+
+		HistEvent ev;
+		history(hist, &ev, H_ENTER, line);
+
+		size_t i = ring.len;
+
+		YY_BUFFER_STATE state = yy_scan_string(line);
+		int error = yyparse();
+		yy_delete_buffer(state);
+		if (error) continue;
+
+		for (; i < ring.len; ++i) {
+			print(i);
+		}
+		printf("\n");
+	}
+
+	el_end(el);
+	history_end(hist);
+}
diff --git a/bin/bitlex.l b/bin/bitlex.l
new file mode 100644
index 00000000..c6519b39
--- /dev/null
+++ b/bin/bitlex.l
@@ -0,0 +1,67 @@
+/* Copyright (C) 2019  June McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+%option noinput
+%option nounput
+
+%{
+
+#include <stdint.h>
+
+static uint64_t parseInt(uint64_t base, const char *str) {
+	uint64_t num = 0;
+	for (const char *ch = str; *ch; ++ch) {
+		if (*ch == '_') continue;
+		num *= base;
+		if (*ch >= '0' && *ch <= '9') num += *ch - '0';
+		if (*ch >= 'A' && *ch <= 'F') num += 0xA + *ch - 'A';
+		if (*ch >= 'a' && *ch <= 'f') num += 0xA + *ch - 'a';
+	}
+	return num;
+}
+
+%}
+
+%%
+
+[ \t\n]	;
+
+0b[01_]+ {
+	yylval = parseInt(2, &yytext[2]);
+	return Int;
+}
+0[0-7_]+ {
+	yylval = parseInt(8, &yytext[1]);
+	return Int;
+}
+[0-9][0-9_]* {
+	yylval = parseInt(10, yytext);
+	return Int;
+}
+0x[0-9A-Fa-f_]+ {
+	yylval = parseInt(16, &yytext[2]);
+	return Int;
+}
+'.' {
+	yylval = yytext[1];
+	return Int;
+}
+
+"<<"	return Shl;
+">>"	return Shr;
+"->>"	return Sar;
+
+.	return yytext[0];