number.c

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#include <string.h>
 
#include "number.h"
#include "logging.h"
 
 
int number_char_to_digit(char c) {
    if ('0' <= c && c <= '9')
        return c - '0';
    if ('a' <= c && c <= 'f')
        c += 'A' - 'a';
    if ('A' <= c && c <= 'F')
        return c - 'A' + 10;
    return NUMBER_ERROR;
}
 
 
int number_parse_number(char* str) {
    int count = strlen(str);
 
    int base = 10;
    int ptr = 0;
    int num = 0;
    if (str[0] == '$') {
        base = 16;
        ptr++;
    }
    while (ptr < count) {
        num *= base;
        int digit = number_char_to_digit(str[ptr]);
        if (digit == NUMBER_ERROR || digit >= base) {
            ERROR("Can not interpret number: '%.*s'\n", count, str);
            return NUMBER_ERROR;
        }
 
        num += digit;
        ptr++;
    }
    return num;
}
 
int number_get_raw(State* s, char* str) {
    if (str[0] == '@' || str[0] == '&') {
        Map* m = str[0] == '@' ? s->defines : s->labels;
        int n = map_get(m, &str[1]);
        if (n < 0) {
            return str[0] == '@' ? NUMBER_ERROR : NUMBER_LABEL_NODEF;
        }
        return n;
    }
    // pass error (NUMBER_ERROR value)
    return number_parse_number(str);
}
 
int number_get_number(State* s, char* str) {
 
    int p = (str[0] == '>' || str[0] == '<') ? 1 : 0;
    int num = number_get_raw(s, &str[p]);
 
    if (num < 0) return num;
 
    num = str[0] == '>' ? num >> 8 : num;
    num &= str[0] == '>' || str[0] == '<' ? 0xff : 0xffff;
 
    return num;
}