// $Revision: 1.1 $ /* HTFormat: The format manager in the WWW Library MANAGE DIFFERENT DOCUMENT FORMATS Here we describe the functions of the HTFormat module which handles conversion between different data representations. (In MIME parlance, a representation is known as a content-type. In WWW the term "format" is often used as it is shorter). This module is implemented by HTFormat.c . This hypertext document is used to generate the HTFormat.h include file. Part of the WWW library . Preamble */ #ifndef HTFORMAT_H #define HTFORMAT_H #include "HTUtils.h" #include "HTStream.h" #include "HTAtom.h" #include "HTList.h" #ifdef SHORT_NAMES #define HTOutputSource HTOuSour #define HTOutputBinary HTOuBina #endif typedef struct _HTContentDescription { char * filename; HTAtom * content_type; HTAtom * content_language; HTAtom * content_encoding; int content_length; float quality; } HTContentDescription; PUBLIC void HTAcceptEncoding PARAMS((HTList * list, char * enc, float quality)); PUBLIC void HTAcceptLanguage PARAMS((HTList * list, char * lang, float quality)); PUBLIC BOOL HTRank PARAMS((HTList * possibilities, HTList * accepted_content_types, HTList * accepted_content_languages, HTList * accepted_content_encodings)); /* HT Input Socket: Buffering for network in This routines provide simple character input from sockets. These are used for parsing input in arbitrary IP protocols (Gopher, NNTP, FTP). */ #define INPUT_BUFFER_SIZE 4096 /* Tradeoff spped vs memory*/ typedef struct _socket_buffer { char input_buffer[INPUT_BUFFER_SIZE]; char * input_pointer; char * input_limit; int input_file_number; } HTInputSocket; /* CREATE INPUT BUFFER AND SET FILE NUMBER */ extern HTInputSocket* HTInputSocket_new PARAMS((int file_number)); /* GET NEXT CHARACTER FROM BUFFER */ extern char HTInputSocket_getCharacter PARAMS((HTInputSocket* isoc)); /* READ BLOCK FROM INPUT SOCKET Read *len characters and return a buffer (don't free) containing *len characters ( *len may have changed). Buffer is not NULL-terminated. */ extern char * HTInputSocket_getBlock PARAMS((HTInputSocket * isoc, int * len)); /* FREE INPUT SOCKET BUFFER */ extern void HTInputSocket_free PARAMS((HTInputSocket * isoc)); PUBLIC char * HTInputSocket_getLine PARAMS((HTInputSocket * isoc)); PUBLIC char * HTInputSocket_getUnfoldedLine PARAMS((HTInputSocket * isoc)); PUBLIC char * HTInputSocket_getStatusLine PARAMS((HTInputSocket * isoc)); PUBLIC BOOL HTInputSocket_seemsBinary PARAMS((HTInputSocket * isoc)); /* The HTFormat type We use the HTAtom object for holding representations. This allows faster manipulation (comparison and copying) that if we stayed with strings. The following have to be defined in advance of the other include files because of circular references. */ typedef HTAtom * HTFormat; #include "HTAccess.h" /* Required for HTRequest definition */ /* These macros (which used to be constants) define some basic internally referenced representations. INTERNAL ONES The www/xxx ones are of course not MIME standard. star/star is an output format which leaves the input untouched. It is useful for diagnostics, and for users who want to see the original, whatever it is. */ #define WWW_SOURCE HTAtom_for("*/*") /* Whatever it was originally*/ /* www/present represents the user's perception of the document. If you convert to www/present, you present the material to the user. */ #define WWW_PRESENT HTAtom_for("www/present") /* The user's perception */ /* The message/rfc822 format means a MIME message or a plain text message with no MIME header. This is what is returned by an HTTP server. */ #define WWW_MIME HTAtom_for("www/mime") /* A MIME message */ /* www/print is like www/present except it represents a printed copy. */ #define WWW_PRINT HTAtom_for("www/print") /* A printed copy */ /* www/unknown is a really unknown type. Some default action is appropriate. */ #define WWW_UNKNOWN HTAtom_for("www/unknown") /* MIME ONES (A FEW) These are regular MIME types. HTML is assumed to be added by the W3 code. application/octet-stream was mistakenly application/binary in earlier libwww versions (pre 2.11). */ #define WWW_PLAINTEXT HTAtom_for("text/plain") #define WWW_POSTSCRIPT HTAtom_for("application/postscript") #define WWW_RICHTEXT HTAtom_for("application/rtf") #define WWW_AUDIO HTAtom_for("audio/basic") #define WWW_HTML HTAtom_for("text/html") #define WWW_BINARY HTAtom_for("application/octet-stream") /* We must include the following file after defining HTFormat, to which it makes reference. The HTEncoding type */ typedef HTAtom* HTEncoding; /* The following are values for the MIME types: */ #define WWW_ENC_7BIT HTAtom_for("7bit") #define WWW_ENC_8BIT HTAtom_for("8bit") #define WWW_ENC_BINARY HTAtom_for("binary") /* We also add */ #define WWW_ENC_COMPRESS HTAtom_for("compress") #include "HTAnchor.h" /* The HTPresentation and HTConverter types This HTPresentation structure represents a possible conversion algorithm from one format to annother. It includes a pointer to a conversion routine. The conversion routine returns a stream to which data should be fed. See also HTStreamStack which scans the list of registered converters and calls one. See the initialisation module for a list of conversion routines. */ typedef struct _HTPresentation HTPresentation; typedef HTStream * HTConverter PARAMS(( HTRequest * request, void * param, HTFormat input_format, HTFormat output_format, HTStream * output_stream)); struct _HTPresentation { HTAtom* rep; /* representation name atomized */ HTAtom* rep_out; /* resulting representation */ HTConverter *converter; /* The routine to gen the stream stack */ char * command; /* MIME-format string */ float quality; /* Between 0 (bad) and 1 (good) */ float secs; float secs_per_byte; }; /* A global list of converters is kept by this module. It is also scanned by modules which want to know the set of formats supported. for example. Note there is also an additional list associated with each request . */ extern HTList * HTConversions ; /* HTSetPresentation: Register a system command to present a format ON ENTRY, rep is the MIME - style format name command is the MAILCAP - style command Template quality A degradation faction 0..1 maxbytes A limit on the length acceptable as input (0 infinite) maxsecs A limit on the time user will wait (0 for infinity) */ extern void HTSetPresentation PARAMS(( HTList * conversions, CONST char * representation, CONST char * command, float quality, float secs, float secs_per_byte )); /* HTSetConversion: Register a converstion routine ON ENTRY, rep_in is the content-type input rep_out is the resulting content-type converter is the routine to make the stream to do it */ extern void HTSetConversion PARAMS(( HTList * conversions, CONST char * rep_in, CONST char * rep_out, HTConverter * converter, float quality, float secs, float secs_per_byte )); /* HTStreamStack: Create a stack of streams This is the routine which actually sets up the conversion. It currently checks only for direct conversions, but multi-stage conversions are forseen. It takes a stream into which the output should be sent in the final format, builds the conversion stack, and returns a stream into which the data in the input format should be fed. The anchor is passed because hypertxet objects load information into the anchor object which represents them. */ extern HTStream * HTStreamStack PARAMS(( HTFormat format_in, HTRequest * request)); /* HTStackValue: Find the cost of a filter stack Must return the cost of the same stack which HTStreamStack would set up. ON ENTRY, format_in The fomat of the data to be converted format_out The format required initial_value The intrinsic "value" of the data before conversion on a scale from 0 to 1 length The number of bytes expected in the input format */ extern float HTStackValue PARAMS(( HTList * conversions, HTFormat format_in, HTFormat format_out, float initial_value, long int length)); #define NO_VALUE_FOUND -1e20 /* returned if none found */ /* HTCopy: Copy a socket to a stream This is used by the protocol engines to send data down a stream, typically one which has been generated by HTStreamStack. Returns the number of bytes transferred. */ extern int HTCopy PARAMS(( int file_number, HTStream* sink)); /* HTFileCopy: Copy a file to a stream This is used by the protocol engines to send data down a stream, typically one which has been generated by HTStreamStack. It is currently called by HTParseFile */ extern void HTFileCopy PARAMS(( FILE* fp, HTStream* sink)); /* HTCopyNoCR: Copy a socket to a stream, stripping CR characters. It is slower than HTCopy . */ extern void HTCopyNoCR PARAMS(( int file_number, HTStream* sink)); /* HTParseSocket: Parse a socket given its format This routine is called by protocol modules to load an object. uses HTStreamStack and the copy routines above. Returns HT_LOADED if succesful, <0 if not. */ extern int HTParseSocket PARAMS(( HTFormat format_in, int file_number, HTRequest * request)); /* HTParseFile: Parse a File through a file pointer This routine is called by protocols modules to load an object. uses HTStreamStack and HTFileCopy . Returns HT_LOADED if succesful, <0 if not. */ extern int HTParseFile PARAMS(( HTFormat format_in, FILE *fp, HTRequest * request)); /* HTNetToText: Convert Net ASCII to local representation This is a filter stream suitable for taking text from a socket and passing it into a stream which expects text in the local C representation. It does ASCII and newline conversion. As usual, pass its output stream to it when creating it. */ extern HTStream * HTNetToText PARAMS ((HTStream * sink)); /* HTFormatInit: Set up default presentations and conversions These are defined in HTInit.c or HTSInit.c if these have been replaced. If you don't call this routine, and you don't define any presentations, then this routine will automatically be called the first time a conversion is needed. However, if you explicitly add some conversions (eg using HTLoadRules) then you may want also to explicitly call this to get the defaults as well. */ extern void HTFormatInit PARAMS((HTList * conversions)); /* HTFormatInitNIM: Set up default presentations and conversions This is a slightly different version of HTFormatInit, but without any conversions that might use third party programs. This is intended for Non Interactive Mode. */ extern void HTFormatInitNIM PARAMS((HTList * conversions)); /* HTFormatDelete: Remove presentations and conversions Deletes the list from HTFormatInit or HTFormatInitNIM */ extern void HTFormatDelete PARAMS((HTList * conversions)); /* Epilogue */ extern BOOL HTOutputSource; /* Flag: shortcut parser */ #endif /* end */