| // Read either "dog", "hound", or "hounddog".
// If "dog" is found, return 1.
// If "hound" is found, return 2.
// If "hounddog" is found, return 3.
// If none of these are found, return -1.
int my_scan(streambuf* sb)
{
streammarker fence(sb);
char buffer[20];
// Try reading "hounddog":
if (sb->sgetn(buffer, 8) == 8
&& strncmp(buffer, "hounddog", 8) == 0)
return 3;
// No, no "hounddog": Back up to 'fence'
sb->seekmark(fence); //
// ... and try reading "dog":
if (sb->sgetn(buffer, 3) == 3
&& strncmp(buffer, "dog", 3) == 0)
return 1;
// No, no "dog" either: Back up to 'fence'
sb->seekmark(fence); //
// ... and try reading "hound":
if (sb->sgetn(buffer, 5) == 5
&& strncmp(buffer, "hound", 5) == 0)
return 2;
// No, no "hound" either: Back up and signal failure.
sb->seekmark(fence); // Backup to 'fence'
return -1;
}
|