rust-toolchain.toml.save

// Tested for N=32; could be bugs in the loop bounds for other N
// returns bytes written, like fwrite: N means no error, 0 means error in all fwrites
size_t LongNumPrint( uint8_t *num, size_t N)
{
    // caller can print a name if it wants

    const int revbufsize = 8192;      // 8kiB on the stack should be fine
    alignas(32) char revbuf[revbufsize];

    if (N<32) {
        // TODO: maybe use a smaller revbuf for this case to avoid touching new stack pages
        ASCIIrev32B(revbuf, num);   // the data we want is at the *end* of a 32-byte reverse
        return fwrite(revbuf+32-N, 1, N, stdout);
    }

    size_t bytes_written = 0;
    const uint8_t *inp = num+N;  // start with last 32 bytes of num[]
    do {
        size_t chunksize = (inp - num >= revbufsize) ? revbufsize : inp - num;

        const uint8_t *inp_stop = inp - chunksize + 32;   // leave one full vector for the end
        uint8_t *outp = revbuf;
        while (inp > inp_stop) {        // may run 0 times
            inp -= 32;
            ASCIIrev32B(outp, inp);
            outp += 32;
        }
        // reverse first (lowest address) 32 bytes of this chunk of num
        // into last 32 bytes of this chunk of revbuf
        // if chunksize%32 != 0 this will overlap, which is fine.
        ASCIIrev32B(revbuf + chunksize - 32, inp_stop - 32);
        bytes_written += fwrite(revbuf, 1, chunksize, stdout);
        inp = inp_stop - 32;
    } while ( inp > num );

    return bytes_written;
    // caller can putchar('\n') if it wants
}