The $Id$ keywords were used in Subversion where they can be substituted
with filename, last revision number change, last changed date, and last
user who changed it.
In Git this functionality is different and can be done with Git attribute
ident. These need to be defined manually for each file in the
.gitattributes file and are afterwards replaced with 40-character
hexadecimal blob object name which is based only on the particular file
contents.
This patch simplifies handling of $Id$ keywords by removing them since
they are not used anymore.
Some JFIF images contain empty APP segments, i.e. those which consist
only of the marker bytes and the length, but without actual content.
It appears to be doubtful to have empty APP segments, but we should
apply the robustness principle, and accept these, instead of simply
failing in this case.
We choose to add empty APP segments to $imageinfo with an empty string
as value, instead of NULL, or even to omit these segments altogether.
This patch also fixes the potential issue that php_stream_read() might
not read the supposed number of bytes, which could result in garbage to
be added to the read value.
Finally, an official media type for Windows BMP files has been
registered with the IANA, so we change `getimagesize.phpt()` and
related functions to report this media type instead of `image/x-ms-bmp`.
Both lossless and lossy WebP can have an alpha channel, but this is
somewhat hard to detect. Furthermore, it is not clear whether an alpha
channel should be counted for getimagesize(). Therefore we remove the
`channel` element from the result array.
We add WebP support for getimagesize(), getimagesizefromstring)(),
image_type_to_extension() and image_type_to_mime_type(). For now we
care only about the simple lossy WebP format (VP8) and ignore the
lossless (VP8L) and extended (VP8X) formats. We use image/webp as MIME
type as it appears to be pretty common, even though it is not yet
registered with IANA.
Relevant specifications:
* <https://developers.google.com/speed/webp/docs/riff_container>
* <https://tools.ietf.org/html/rfc6386>
getimagesize() is rather strict about the length of the marker payload data,
and fails if there are extraneous bytes before the next marker. Only a very
special case reported in bug #13213 is catered to.
libjpeg is rather resilient to such corrupted JPEG files, and raises a
recoverable error in this case. Other image processors also accept such
JPEG files, so we adapt getimagesize() to skip (but warn about) such
extraneous bytes.
Very large WBMP (width or height greater than 2**31-1) cause an overflow and
circumvent the size limitation of 2048x2048 px. Very small WBMP (less than 12
bytes) cause a read error and are not recognized. This patch fixes both bugs.
there are multiple issues with this code
- php_stream_read() returns an unsigned val, so is >= 0
- if it read less than sizeof(a) bytes, the function operates on garbage
- result->channels is an unsigned val, so >= 0
