"gd_get_frame" function takes too long to execute

[leHeix]

The gd_get_frame function takes more than one second to finish execution, which is considerably slow compared to other GIF decoders and nearly unusable in a runtime where performance is a key point.

gifdec/gifdec.c

Lines 464 to 482 in 54ab6c8

	int
	gd_get_frame(gd_GIF *gif)
	{
	char sep;
	dispose(gif);
	read(gif->fd, &sep, 1);
	while (sep != ',') {
	if (sep == ';')
	return 0;
	if (sep == '!')
	read_ext(gif);
	else return -1;
	read(gif->fd, &sep, 1);
	}
	if (read_image(gif) == -1)
	return -1;
	return 1;
	}

GIF used:

[sam20908]

The gd_get_frame function takes more than one second to finish execution, which is considerably slow compared to other GIF decoders and nearly unusable in a runtime where performance is a key point.

You know any other GIF libraries that are performant?

[Baker7]

I noticed this too.

This is because the decoder accesses all data by reading it from disk via "read" instead of pulling it into memory.

There are file access calls everywhere.

Functionally, this doesn't matter and I find this project excellent -- however the access speed for getting to the data beyond the first couple of frames is slow due to all the disk access.

Thank you for writing this! The code is great, simple and very portable and minimal.

I am using this in https://www.moddb.com/mods/zircon-engine

I myself am probably going to need to convert all file access reads to memory reads to get the speed upgraded.

[erhoof]

@leHeix I have a small solution for that
@Baker7
Works way faster (like x3)

#28