[FFmpeg-cvslog] Add a protocol handler for AES CBC decryption with PKCS7 padding

[Reimar Döffinger]

On Sun, Apr 24, 2011 at 03:50:08AM +0200, Martin Storsjö wrote:
> +    // We avoid using the last block until we've found EOF,
> +    // since we'll remove PKCS7 padding at the end. So make
> +    // sure we've got at least 2 blocks, so we can decrypt
> +    // at least one.
> +    while (c->indata - c->indata_used < 2*BLOCKSIZE) {
> +        int n = ffurl_read(c->hd, c->inbuffer + c->indata,
> +                           sizeof(c->inbuffer) - c->indata);
> +        if (n <= 0) {
> +            c->eof = 1;

Huh? That doesn't necessarily indicate EOF to my knowledge.
Of course doing it correct means a risk of very high CPU usage,
so this would have to copy or reuse retry_transfer_wrapper
from avio.c

> +    if (c->indata_used >= sizeof(c->inbuffer)/2) {
> +        memmove(c->inbuffer, c->inbuffer + c->indata_used,
> +                c->indata - c->indata_used);

Why memmove? I see no way those memory ranges could overlap.

> +    if (c->hd)
> +        ffurl_close(c->hd);
> +    av_free(c->aes);
> +    av_free(c->key);
> +    av_free(c->iv);

Why not av_freep?