pipe.h

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/*  
 *      Pipe.h - NT MCHAR Pipe wrapper for MAXScript
 *
 *          Copyright (c) John Wainwright 1996
 *
 */

#pragma once

#include "Strings.h"
class FileStream;

#define PIPE_BUF_SIZE   512

// The undelivered data in the pipe is held in a linked list of
// buffers, pointed into by read and write cursors.  
// A side list is kept if writers supply info about sourcing files.
// This is provided to readers like the compiler to add source
// tags to generated code.  

class src_info                      
{
public:
    src_info*    next;          // next marker
    MCHAR*       start;         // source start character in buffer chain
    Value*       file;          // source file name if any
    unsigned int offset;        // starting offset into source
    unsigned int linenumber;    // line number in the source

    //Constructor / Destructor
    src_info();
    ~src_info();
};

// Collectable::flags3 - bit 0 set if have attempted to load resource file
class Pipe : public CharStream  
{
private:
    unsigned int read_source_offset; // running reader offset in source
    CRITICAL_SECTION pipe_update;   // for syncing pipe updates
public:
    MCHAR*      write_buffer;       // pipe buffers & cursors
    MCHAR*      write_cursor;
    MCHAR*      read_buffer;
    MCHAR*      read_cursor;
    int         ungetch_count;

    HANDLE      pipe_event;         // for signalling data ready
    HANDLE      restart_event;      // used to restart a stopped pipe
    bool        waiting;            // reader is waiting for data
    bool        stopped;            // pipe reading is blocked

    FileStream* log;                // log stream if non-NULL

    src_info*   markers;            // marker list...
    src_info*   marker_tail;        
    MCHAR*      next_source_start;  // upcoming marker starting character
    Value*      write_source_file;  // current write source file, used to determine source change
    unsigned int write_source_offset;// running writer offset

    MCHAR       lastCharacterOfLastBuffer;  // used when looking back one character from current read cursor,
                                            // and read cursor is at the beginning of the read buffer

                Pipe();
                ~Pipe();
                
#   define      is_pipe(v) ((DbgVerify(!is_sourcepositionwrapper(v)), (v))->tag == INTERNAL_PIPE_TAG)
    void        collect();
    void        gc_trace();

    MCHAR       get_char();
    void        unget_char(MCHAR c);
    MCHAR       peek_char();
    int         at_eos();
    unsigned int pos(); // Gets the current position in the stream
    unsigned int line(); // Gets the current line number
    void        rewind();
    void        flush_to_eol();
    void        flush_to_eobuf();

    void        put_char(const MCHAR c, Value* source_file = NULL, unsigned int offset = 0, unsigned int line = 1);
    void        put_str(const MCHAR* str, Value* source_file = NULL, unsigned int  offset = 0, unsigned int line = 1);
    void        put_buf(const MCHAR* str, UINT count, Value* source_file = NULL, unsigned int offset = 0, unsigned int line = 1);
    void        new_write_buffer();
    void        check_write_source_change(Value* file, unsigned int offset, unsigned int line, int new_len);
    void        read_source_change();
    void        clear_source();
    void        stop();
    void        go();

    const MCHAR*        puts(const MCHAR* str);
    int         printf(const MCHAR *format, ...);
    void        flag_eos(); // sets the end of script marker in the pipe's stream

    void        log_to(FileStream* log);
    void        close_log();
    CharStream* get_log() { return log; }
};