umoria roff

roff.c

static vtype roffbuf;         // Line buffer.
static char *roffp = roffbuf; // Pointer into line buffer.
static int roffpline = 0;     // Place to print line now being loaded.

static uint8_t count_previous_non_blank_chars(const char *from);

// Print out strings, filling up lines as we go.
static void roff(const char *p) {
    uint8_t count;
loop:
    switch (*p) {
    case '\0':
        return;
    case '\n':
        p += 1;
        count = 0;
        goto flush;
    default:
        if (roffp + 1 == END_OF(roffbuf)) {
            *roffp = *p++;
            count = count_previous_non_blank_chars(roffp);
        flush:
            roffp[-count] = '\0';
            prt(roffbuf, roffpline, 0);
            roffpline += 1;

            memcpy(roffbuf, roffp - count + 1, count);
            roffp = roffbuf + count;
        } else {
            *roffp++ = *p++;
        }
        goto loop;
    }
}

inline static uint8_t count_previous_non_blank_chars(const char *from) {
    uint8_t offset = 0;
    while (from[-offset] != ' ') {
        offset += 1;
    }
    return offset;
}