#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <ctype.h>

#include "tools/gendec.h"

#define CONSUME_CHAR(x) if( **str != x ) { fprintf( stderr, "Unexpected input character '%c', expected '%c' at line %d\n", **str, x, yyline ); return -1; } else { (*str)++; }

static int yyline;

struct rule *new_rule() {

    struct rule *rule = malloc( sizeof( struct rule ) );

    memset( rule, 0, sizeof( struct rule ) );

    return rule;

}

int parse_registers_block( char *buf, int buflen, FILE *f );

int parse_rule( char **str, struct rule *rule );

int parse_bitstring( char **str, struct rule *rule );

int parse_bitoperand( char **str, struct rule *rule );

int parse_integer( char **str );

int parse_rule_format( char **str, struct rule *rule );

int parse_operand_uses( char **str, struct rule *rule );

struct ruleset *parse_ruleset_file( FILE *f ) 

{

    struct ruleset *rules = malloc( sizeof(struct ruleset ) );

    char buf[512];

    rules->rule_count = 0;

    yyline = 0;

    while( fgets( buf, sizeof(buf), f ) != NULL ) {

	yyline++;

	if( strncasecmp(buf, "registers", 9) == 0 ) {

	    parse_registers_block(buf, sizeof(buf), f);

	} else if( buf[0] != '\0' && buf[0] != '#' && buf[0] != '\n' ) {

	    struct rule *rule;

	    char *p = buf;

	    rule = new_rule();

	    if( parse_rule( &p, rule ) != 0 ) {

		free( rule );

	    } else {

		rules->rules[rules->rule_count++] = rule;

	    }

	}

    }

    return rules;

}

int parse_registers_block( char *buf, int buflen, FILE *f ) {

    do {

	if( strchr(buf, '}') != NULL ) {

	    break;

	}

    } while( fgets( buf, buflen, f ) != NULL );

    return 0;

}

/**

 * Parse a single complete rule

 * @return 0 on success, non-zero on failure

 */

int parse_rule( char **str, struct rule *rule ) 

{

    if( parse_bitstring( str, rule ) != 0 ) {

	return -1;

    }

    /* consume whitespace in between */

    while( isspace(**str) ) (*str)++;

    if( **str == '\0' ) {

	fprintf( stderr, "Unexpected end of file in rule on line %d\n", yyline );

	return -1;

    }

    int result = parse_rule_format( str, rule );

    if( result == 0 ) {

	/* Reverse operand bit shifts */

	int j;

	for( j=0; j<rule->operand_count; j++ ) {

	    rule->operands[j].bit_shift = 

		rule->bit_count - rule->operands[j].bit_shift - rule->operands[j].bit_count;

	}

	if( **str == '!' ) {

	    (*str)++;

	    result = parse_operand_uses( str, rule );

	}

    }

    return 0;

}

int parse_bitstring( char **str, struct rule *rule )

{

    while( !isspace(**str) ) {

	int ch = **str;

	(*str)++;

	switch( ch ) {

	case '0':

	    rule->bits = rule->bits << 1;

	    rule->mask = (rule->mask << 1) | 1;

	    rule->bit_count++;

	    break;

	case '1':

	    rule->bits = (rule->bits << 1) | 1;

	    rule->mask = (rule->mask << 1) | 1;

	    rule->bit_count++;

	    break;

	case '(':

	    if( parse_bitoperand( str, rule ) != 0 ) {

		return -1 ;

	    }

	    break;

	default:

	    (*str)--;

	    fprintf( stderr, "Unexpected character '%c' in bitstring at line %d\n", ch, yyline );

	    return -1;

	}

    }

    return 0;

}

int parse_bitoperand( char **str, struct rule *rule )

{

    char *p = rule->operands[rule->operand_count].name;

    if( rule->operand_count == MAX_OPERANDS ) {

	fprintf( stderr, "Maximum operands/rule exceeded (%d) at line %d\n", MAX_OPERANDS, yyline );

	return -1;

    }

    while( isalnum(**str) || **str == '_' ) {

	*p++ = *(*str)++;

    }

    *p = '\0';

    CONSUME_CHAR(':');

    int size = parse_integer( str );

    if( size == -1 ) {

	return -1; 

    }

    rule->operands[rule->operand_count].bit_count = size;

    if( **str == 's' || **str == 'S' ) {

	(*str)++;

	rule->operands[rule->operand_count].is_signed = 1;

    } else if( **str == 'u' || **str == 'U' ) {

	(*str)++;

	rule->operands[rule->operand_count].is_signed = 0;

    }

    if( **str == '<' ) {

	(*str)++;

	CONSUME_CHAR('<');

	int lsl = parse_integer(str);

	if( lsl == -1 ) {

	    return -1;

	}

	rule->operands[rule->operand_count].left_shift = lsl;

    }

    CONSUME_CHAR(')');

    rule->operands[rule->operand_count].bit_shift = rule->bit_count;

    rule->bit_count += size;

    rule->bits = rule->bits << size;

    rule->mask = rule->mask << size;

    rule->operand_count++;

    return 0;

}

int parse_integer( char **str )

{

    uint32_t val = 0;

    if( !isdigit(**str) ) {

	fprintf(stderr, "Expected digit (0-9) but was '%c' at line %d\n", **str, yyline );

	return -1;

    }

    do {

	val = val * 10 + (**str - '0');

	(*str)++;

    } while( isdigit(**str) );

    return val;

}

int parse_rule_format( char **str, struct rule *rule )

{

    char tmp[64];

    char *p = tmp;

    while( **str != '\n' && **str != '\0' && **str != '!' ) {

	*p++ = *(*str)++;

    }

    *p = '\0';

    strcpy( rule->format, tmp );

    return 0;

}

int parse_operand_uses( char **str, struct rule *rule )

{

    return 0;

}

void dump_ruleset( struct ruleset *rules, FILE *f ) 

{

    int i, j;

    fprintf( f, "Rulset: %d rules\n", rules->rule_count );

    for( i=0; i<rules->rule_count; i++ ) {

	struct rule *rule = rules->rules[i];

	fprintf( f, "Match: %08X/%08X %s: ", rule->bits, rule->mask, rule->format );

	for( j=0; j<rule->operand_count; j++ ) {

	    fprintf( f, "%s = (%s)(ir>>%d)&0x%X ", rule->operands[j].name,

		     rule->operands[j].is_signed ? "signed" : "unsigned", 

		     rule->operands[j].bit_shift,

		     (1<<rule->operands[j].bit_count)-1 );

	}

	fprintf( f, "\n" );

    }

}

void dump_rulesubset( struct ruleset *rules, int ruleidx[], int rule_count, FILE *f )

{

    int i,j;

    for( i=0; i<rule_count; i++ ) {

	struct rule *rule = rules->rules[ruleidx[i]];

	fprintf( f, "Match: %08X/%08X %s: ", rule->bits, rule->mask, rule->format );

	for( j=0; j<rule->operand_count; j++ ) {

	    fprintf( f, "%s = (%s)(ir>>%d)&0x%X ", rule->operands[j].name,

		     rule->operands[j].is_signed ? "signed" : "unsigned", 

		     rule->operands[j].bit_shift,

		     (1<<rule->operands[j].bit_count)-1 );

	}

	fprintf( f, "\n" );

    }

}