%{
#include <fxos.h>
#include <errors.h>
#include <util.h>

/* Values for tokens generated by the lexer */
static union {
	char *text;
	long long integer;
} yylval;

/* Token list */
#define NUMBER 0
#define SYMBOL 1

%}

%option prefix="reg"
%option noyywrap
%option nounput

decimal  0|[1-9][0-9]*
octal    0[0-7]+
hexa     0x[0-9a-fA-F]+
number   {decimal}|{octal}|{hexa}

symbol   [^0-9 \t\n][^\n]*

space    [ \t]+

%%

^#[^\n]*  ;
{space}   ;
[\n]      yylineno++;

{number}  { yylval.integer = integer(yytext, NULL); return NUMBER; }
{symbol}  { yylval.text = strdup(yytext); return SYMBOL; }

<<EOF>>    return -1;

%%

#include <stdio.h>

/* lex_reg(): Peripheral register table lexer and parser */
struct reg_address *lex_reg(void *data, size_t len, int *count)
{
	/* Count number of register descriptions (upper bound) */

	YY_BUFFER_STATE buf = yy_scan_bytes(data, len);
	yylineno = 1;

	int total = 0, t;
	while((t = yylex()) != -1)
	{
		total += (t == NUMBER);
		if(t == SYMBOL) free(yylval.text);
	}

	yy_delete_buffer(buf);

	/* Allocate a large enough register array */

	struct reg_address *table = calloc(total, sizeof *table);
	if(!table)
	{
		errf(ERR_ERRNO, "cannot allocate memory for database");
		return 0;
	}

	/* Lex all instructions and fill in the array */

	buf = yy_scan_bytes(data, len);
	yylineno = 1;

	struct reg_address *reg = table - 1;
	int line = -1;

	while(1)
	{
		t = yylex();

		if(t == NUMBER || t == -1)
		{
			/* Finalize current instruction */
			if(reg >= table && !reg->name)
				err("%d: unnamed register", line);
			else reg++;
		}
		if(t == -1) break;

		if(t == NUMBER)
		{
			reg->address = yylval.integer;
			line = yylineno;
		}
		else if(t == SYMBOL && reg < table)
		{
			err("%d: expected register address", yylineno);
			free(yylval.text);
		}
		else if(t == SYMBOL && !reg->name)
		{
			reg->name = yylval.text;
		}
		else if(t == SYMBOL)
		{
			err("%d: excess names for 0x%08x\n", reg->address);
			free(yylval.text);
		}
	}

	yy_delete_buffer(buf);
	if(count) *count = reg - table;
	return table;
}