static int bracket_handle(struct calc_info *info)
{
assert(info != NULL);
char opr = *info->cur;
switch (opr) {
case '(':
OPR_PUSH(opr);
break;
case ')':
{
char top_c;
while (1) {
if (OPR_TOP(top_c) < 0) {
fprintf(stderr, "Error:缺少左括号\n");
goto err_miss_left_bracket;
}
if (top_c == '(') {
OPR_POP(top_c); goto out;
} else {
do_stack(info);
}
}
}
default:
break;
}
out:
return 0;
err_miss_left_bracket:
return -1;
}
/* 运算时 数据栈出栈两次 操作符栈出栈一次
* 运算完之后的结果压栈
* */
static int do_operate(struct calc *calc)
{
num_t a, b;
char c;
if (NUM_POP(b) < 0) {
fprintf(stderr,"Error: num pop failed.\n");
return -1;
}
if (NUM_POP(a) < 0) {
fprintf(stderr,"Error: num pop failed.\n");
return -1;
}
if (OPR_POP(c) < 0) {
fprintf(stderr,"Error: opr pop failed.\n");
return -2;
}
num_t res = 0;
switch(c) {
case '+': res = a + b; break;
case '-': res = a - b; break;
case '*': res = a * b; break;
case '/': res = a / b; break;
case '%': res = a % b; break;
default : break;
}
#ifdef _DEBUG
printf("DEBUG %d %c %d = %d\n",a, c, b, res);
#endif
NUM_PUSH(res);
return 0;
}
static int opr_advance(struct calc *calc)
{
char c = *calc->cur;
int zero = 0;
if (calc->pre_flag == F_NUM) {
calc->pre_flag = F_OPR;
} else if (calc->pre_flag == F_OPR) {
if (c == '-') {
NUM_PUSH(zero);
OPR_PUSH(c);
calc->pre_flag = F_OPR;
return 0;
} else if (c == '+') {
return 0;
} else if (c == '*') {
if (OPR_POP(c)) {
fprintf(stderr, "Error: opr pop error\n");
return -1;
}
c = '^';
OPR_PUSH(c);
return 0;
} else if (c == '/') {
if (OPR_POP(c)) {
fprintf(stderr, "Error: opr pop error\n");
return -1;
}
c = '#';
OPR_PUSH(c);
return 0;
}
} else {
fprintf(stderr, "unknow character\n");
return -2;
}
return 0;
}
static int right_bracket_handler(struct calc *calc)
{
assert(calc != NULL);
char c;
while(1) {
if (OPR_TOP(c) < 0) {
fprintf(stderr, "Error: opr top failed\n");
return -1;
}
if (c == '(') {
if (OPR_POP(c) < 0) {
fprintf(stderr, "Error: opr pop failed\n");
return -1;
}
return 0;
}
if (do_operate(calc) < 0) {
fprintf(stderr, "Error: do operate failed.\n");
return -1;
}
}
return 0;
}
/*出栈
1. 数字栈取两次
2. 运算符中取一次
3. 运算
4. 再把结果写入数字栈
*/
static int do_stack(struct calc_info *info)
{
assert(info != NULL);
num_t a, b, ret;
char opr;
if (NUM_POP(b) < 0) {
fprintf(stderr, "num_pop failed\n");
goto err_num_pop;
}
if (NUM_POP(a) < 0) {
fprintf(stderr, "num_pop failed\n");
goto err_num_pop;
}
if (OPR_POP(opr) < 0) {
fprintf(stderr, "opr_pop failed\n");
goto err_opr_pop;
}
switch (opr) {
case '+':
ret = a + b;
break;
case '-':
ret = a - b;
break;
case '*':
ret = a * b;
break;
case '/':
if (b == 0) {
fprintf(stderr, "不能除0\n");
goto err_divd_zero;
}
ret = a / b;
break;
case '%':
ret = a % b;
break;
default:
fprintf(stderr,"取出不支持的运算符:'%c'\n", opr);
break;
}
#ifdef DEBUG
printf("%d %c %d = %d\n", a, opr, b, ret);
#endif
NUM_PUSH(ret);
return 0;
err_num_pop:
return -1;
err_opr_pop:
return -2;
err_divd_zero:
return -3;
}
