[FFmpeg-devel] [PATCH] Handling special characters in a URL.

[Stefano Sabatini]

On date Monday 2013-02-04 01:25:01 +0530, Senthilnathan Maadasamy encoded:
> Implements Percent Encoding of URLs based on RFC 3986.
> Fixes Ticket 2031
> 
> Signed-off-by: Senthilnathan M <senthilnathan.maadasamy at gmail.com>
> ---
>  libavformat/avformat.h |    9 +++++++++
>  libavformat/utils.c    |   28 ++++++++++++++++++++++++++++
>  2 files changed, 37 insertions(+)
> 
> diff --git a/libavformat/avformat.h b/libavformat/avformat.h
> index 8330c6b..1b1d86e 100644
> --- a/libavformat/avformat.h
> +++ b/libavformat/avformat.h
> @@ -1963,6 +1963,15 @@ int av_index_search_timestamp(AVStream *st, int64_t
> timestamp, int flags);
>  int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
>                         int size, int distance, int flags);
> 
> +/**
> + * Percent encodes parts of a URL string based on RFC 3986.  Encodes the
> + * component string in place.

Percent encode ... . Encode ...

> + *
> + * @param component portion of a URL (e.g. protocol, hostname, path)

> + * @param allowed These extra permissible characters do not get encoded

string containing the extra-permissible characters which must not be encoded
?

Also mention that it may be NULL.

> + * @param comp_size the size of the component buffer
> + */

> +void av_url_percent_encode(char *component, const char *allowed, int
> comp_size);

comp_size -> component_size (comp is usually read as "compressed")

also it could be a size_t
 
>  /**
>   * Split a URL string into components.
> diff --git a/libavformat/utils.c b/libavformat/utils.c
> index 97d6558..a51b867 100644
> --- a/libavformat/utils.c
> +++ b/libavformat/utils.c
> @@ -3751,6 +3751,32 @@ void av_pkt_dump_log2(void *avcl, int level,
> AVPacket *pkt, int dump_payload,
>      pkt_dump_internal(avcl, NULL, level, pkt, dump_payload, st->time_base);
>  }
> 
> +void av_url_percent_encode(char *component, const char *allowed, int
> comp_size)

you could make use of a return value to give added information
(e.g. an error code or the size of the encoded string)

Also I dislike the fact that the function is destructive and there is
no way to check that the encoded string was truncated.

For example it could be:
size_t av_url_percent_encode(char *dst, const char *src, const char *allowed, int dst_size)

Note also that you could make the function internal so you have not to
worry about a public interface.

> +{
> +    char enc[MAX_URL_SIZE], c;
> +    const char *src = component;
> +    int enc_len = 0;

> +
> +    if (!src) return;
> +
> +    while (c = *src) {
> +        if (isalnum(c)

> +            || c == '-' || c == '.' || c == '_' || c == '~' || c == '%'

nit: strchr("-._~%", c) ?

> +            || (allowed && strchr(allowed, c))) {
> +            if (enc_len+1 >= MAX_URL_SIZE) break;
> +            enc[enc_len] = c;
> +            enc_len++;
> +        } else {
> +            if (enc_len+3 >= MAX_URL_SIZE) break;
> +            snprintf(&enc[enc_len], 4, "%%%02x", c);
> +            enc_len+=3;
> +        }
> +        src++;
> +    }
> +    enc[enc_len] = '\0';
> +    av_strlcpy(component, enc, comp_size);
> +}
> +

[...]
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