if the %pdf version header comment is offset from the start of the file the cross reference offsets will also be wrong by that amount. this change updates the cross reference location logic to use the offset from the located version header.
some documents declare stream objects without an endobj marker at the end of the stream. if a new obj token is encountered after reading a stream we reset the scanner to the object number token and return the stream.
don't cache objects parsed if their offset doesn't match the cross-reference offset, unless the object was parsed by a brute-force search operation. this is because 1 object may lie in 2 streams, 1 valid and 1 invalid. If the invalid stream is parsed first for another object then the valid stream will never be read.
some objects may be defined in more than one stream. parsing both streams would overwrite the object in the cache. to prevent this we avoid overwriting the existing object in the cache if it has the expected offset from the cross reference table.
to make the project more useful and expose more usable classes we're rearchitecting in the following way. code used to read fonts from external file formats like truetype, adobe font metrics (afm) and adobe type 1 fonts are moving to a new project which doesn't reference most of the pdf logic. the shared logic is moving to a new flat-structured project called core. this is a sort-of onion type architecture, with core being the... core, fonts being the next layer of the onion, pdfpig itself the next. this will then support additional libraries/projects as outer layers of the onion as well as releasing standalone version of the font library as pdfbox does with fontbox.
* while the pdf specification says stream data should follow a newline following a stream operator some files have only a carriage return following the stream operator.
* since comment tokens may appear inside an array or dictionary we ignore them if they occur here since they will break interpretation of the dictionary or array contents.
support both xobject and inline images. adds unsupported filters so that exceptions are only thrown when accessing lazily evaluated image.bytes property rather than when opening the page.
treat all warnings as errors.
an inline image in a pdf content stream starts with the bi tag, then id declares the start of image data and ei the end. attempting to parse the bytes after the id tag as usual resulted in errors. this change adds special case handling for inline images.
