// On-screen Display (ie. console)
// for the Build Engine
// by Jonathon Fowler (jonof@edgenetwk.com)

#include "build.h"
#include "osd.h"
#include "compat.h"
#include "baselayer.h"
#include "cache1d.h"

symbol_t *symbols = NULL;
static symbol_t *addnewsymbol(const char *name);
static symbol_t *findsymbol(const char *name, symbol_t *startingat);
static symbol_t *findexactsymbol(const char *name);

// static int _validate_osdlines(void *);

static int _internal_osdfunc_listsymbols(const osdfuncparm_t *);
static int _internal_osdfunc_help(const osdfuncparm_t *);
static int _internal_osdfunc_alias(const osdfuncparm_t *);
// static int _internal_osdfunc_dumpbuildinfo(const osdfuncparm_t *);
// static int _internal_osdfunc_setrendermode(const osdfuncparm_t *);

static int white=-1;			// colour of white (used by default display routines)
static void _internal_drawosdchar(int, int, char, int, int);
static void _internal_drawosdstr(int, int, char*, int, int, int);
static void _internal_drawosdcursor(int,int,int,int);
static int _internal_getcolumnwidth(int);
static int _internal_getrowheight(int);
static void _internal_clearbackground(int,int);
static int _internal_gettime(void);
static void _internal_onshowosd(int);

// history display
static char osdtext[TEXTSIZE];
static char osdfmt[TEXTSIZE];
static char osdversionstring[32];
static int  osdversionstringlen;
static int  osdversionstringshade;
static int  osdversionstringpal;
static int  osdpos=0;			// position next character will be written at
static int  osdlines=1;			// # lines of text in the buffer
static int  osdrows=20;			// # lines of the buffer that are visible
static int  osdrowscur=-1;
static int  osdscroll=0;
static int  osdcols=60;			// width of onscreen display in text columns
static int  osdmaxrows=20;		// maximum number of lines which can fit on the screen
static int  osdmaxlines=TEXTSIZE/60;	// maximum lines which can fit in the buffer
static char osdvisible=0;		// onscreen display visible?
static char osdinput=0;         // capture input?
static int  osdhead=0; 			// topmost visible line number
static BFILE *osdlog=NULL;		// log filehandle
static char osdinited=0;		// text buffer initialized?
static int  osdkey=0x29;		        // tilde shows the osd
static int  keytime=0;
static int osdscrtime = 0;

// command prompt editing
#define EDITLENGTH 511
static int  osdovertype=0;		// insert (0) or overtype (1)
static char osdeditbuf[EDITLENGTH+1];	// editing buffer
static char osdedittmp[EDITLENGTH+1];	// editing buffer temporary workspace
static int  osdeditlen=0;		// length of characters in edit buffer
static int  osdeditcursor=0;		// position of cursor in edit buffer
static int  osdeditshift=0;		// shift state
static int  osdeditcontrol=0;		// control state
static int  osdeditcaps=0;		// capslock
static int  osdeditwinstart=0;
static int  osdeditwinend=60-1-3;
#define editlinewidth (osdcols-1-3)

// command processing
#define HISTORYDEPTH 32
static int  osdhistorypos=-1;		// position we are at in the history buffer
static char osdhistorybuf[HISTORYDEPTH][EDITLENGTH+1];	// history strings
static int  osdhistorysize=0;		// number of entries in history
static int  osdhistorytotal=0;      // number of total history entries

// execution buffer
// the execution buffer works from the command history
static int  osdexeccount=0;		// number of lines from the head of the history buffer to execute

// maximal log line count
static int logcutoff=120000;
static int linecnt;
static int osdexecscript=0;

// presentation parameters
static int  osdpromptshade=0;
static int  osdpromptpal=0;
static int  osdeditshade=0;
static int  osdeditpal=0;
static int  osdtextshade=0;
static int  osdtextpal=0;
/* static int  osdcursorshade=0;
static int  osdcursorpal=0; */

// application callbacks
static void (*drawosdchar)(int, int, char, int, int) = _internal_drawosdchar;
static void (*drawosdstr)(int, int, char*, int, int, int) = _internal_drawosdstr;
static void (*drawosdcursor)(int, int, int, int) = _internal_drawosdcursor;
static int (*getcolumnwidth)(int) = _internal_getcolumnwidth;
static int (*getrowheight)(int) = _internal_getrowheight;
static void (*clearbackground)(int,int) = _internal_clearbackground;
static int (*gettime)(void) = _internal_gettime;
static void (*onshowosd)(int) = _internal_onshowosd;

const char *stripcolorcodes(const char *t)
{
    int i = 0;
    static char colstrip[1024];

    while (*t)
    {
        if (*t == '^' && isdigit(*(t+1)))
        {
            t += 2;
            if (isdigit(*t))
                t++;
            continue;
        }
        colstrip[i] = *t;
        i++,t++;
    }
    colstrip[i] = '\0';
    return(colstrip);
}

int OSD_Exec(const char *szScript)
{
    FILE* fp = fopenfrompath(szScript, "r");

    if (fp != NULL)
    {
        char line[255];

        OSD_Printf("Executing \"%s\"\n", szScript);
        osdexecscript++;
        while (fgets(line ,sizeof(line)-1, fp) != NULL)
            OSD_Dispatch(strtok(line,"\r\n"));
        osdexecscript--;
        fclose(fp);
        return 0;
    }
    return 1;
}

static int _internal_osdfunc_exec(const osdfuncparm_t *parm)
{
    char fn[BMAX_PATH];

    if (parm->numparms != 1) return OSDCMD_SHOWHELP;
    Bstrcpy(fn,parm->parms[0]);

    if (OSD_Exec(fn))
    {
        OSD_Printf("exec: file \"%s\" not found.\n", fn);
        return OSDCMD_OK;
    }
    return OSDCMD_OK;
}

static void _internal_drawosdchar(int x, int y, char ch, int shade, int pal)
{
    int i,j,k;
    char st[2] = { 0,0 };

    UNREFERENCED_PARAMETER(shade);
    UNREFERENCED_PARAMETER(pal);

    st[0] = ch;

    if (white<0)
    {
        // find the palette index closest to white
        k=0;
        for (i=0;i<256;i++)
        {
            j = ((int)curpalette[i].r)+((int)curpalette[i].g)+((int)curpalette[i].b);
            if (j > k) { k = j; white = i; }
        }
    }

    printext256(4+(x<<3),4+(y<<3), white, -1, st, 0);
}

static void _internal_drawosdstr(int x, int y, char *ch, int len, int shade, int pal)
{
    int i,j,k;
    char st[1024];

    UNREFERENCED_PARAMETER(shade);
    UNREFERENCED_PARAMETER(pal);

    if (len>1023) len=1023;
    memcpy(st,ch,len);
    st[len]=0;

    if (white<0)
    {
        // find the palette index closest to white
        k=0;
        for (i=0;i<256;i++)
        {
            j = ((int)curpalette[i].r)+((int)curpalette[i].g)+((int)curpalette[i].b);
            if (j > k) { k = j; white = i; }
        }
    }

    printext256(4+(x<<3),4+(y<<3), white, -1, st, 0);
}

static void _internal_drawosdcursor(int x, int y, int type, int lastkeypress)
{
    int i,j,k;
    char st[2] = { '_',0 };

    UNREFERENCED_PARAMETER(lastkeypress);

    if (type) st[0] = '#';

    if (white<0)
    {
        // find the palette index closest to white
        k=0;
        for (i=0;i<256;i++)
        {
            j = ((int)palette[i*3])+((int)palette[i*3+1])+((int)palette[i*3+2]);
            if (j > k) { k = j; white = i; }
        }
    }

    printext256(4+(x<<3),4+(y<<3)+2, white, -1, st, 0);
}

static int _internal_getcolumnwidth(int w)
{
    return w/8 - 1;
}

static int _internal_getrowheight(int w)
{
    return w/8;
}

static void _internal_clearbackground(int cols, int rows)
{
    UNREFERENCED_PARAMETER(cols);
    UNREFERENCED_PARAMETER(rows);
}

static int _internal_gettime(void)
{
    return 0;
}

static void _internal_onshowosd(int a)
{
    UNREFERENCED_PARAMETER(a);
}

////////////////////////////

static int _internal_osdfunc_alias(const osdfuncparm_t *parm)
{
    symbol_t *i;

    if (parm->numparms < 1)
    {
        int j = 0;
        OSD_Printf("Alias listing:\n");
        for (i=symbols; i!=NULL; i=i->next)
            if (i->func == (void *)OSD_ALIAS)
            {
                j++;
                OSD_Printf("     %s \"%s\"\n", i->name, i->help);
            }
        if (j == 0)
            OSD_Printf("No aliases found.\n");
        return OSDCMD_OK;
    }

    for (i=symbols; i!=NULL; i=i->next)
    {
        if (!Bstrcasecmp(parm->parms[0],i->name))
        {
            if (parm->numparms < 2)
            {
                if (i->func == (void *)OSD_ALIAS)
                    OSD_Printf("alias %s \"%s\"\n", i->name, i->help);
                else OSD_Printf("%s is a function, not an alias\n",i->name);
                return OSDCMD_OK;
            }
            if (i->func != (void *)OSD_ALIAS && i->func != (void *)OSD_UNALIASED)
            {
                OSD_Printf("Cannot override function \"%s\" with alias\n",i->name);
                return OSDCMD_OK;
            }
        }
    }

    OSD_RegisterFunction(Bstrdup(parm->parms[0]),Bstrdup(parm->parms[1]),(void *)OSD_ALIAS);
    if (!osdexecscript)
        OSD_Printf("%s\n",parm->raw);
    return OSDCMD_OK;
}

static int _internal_osdfunc_unalias(const osdfuncparm_t *parm)
{
    symbol_t *i;

    if (parm->numparms < 1)
        return OSDCMD_SHOWHELP;

    for (i=symbols; i!=NULL; i=i->next)
    {
        if (!Bstrcasecmp(parm->parms[0],i->name))
        {
            if (parm->numparms < 2)
            {
                if (i->func == (void *)OSD_ALIAS)
                {
                    OSD_Printf("Removed alias %s (\"%s\")\n", i->name, i->help);
                    i->func = (void *)OSD_UNALIASED;
                }
                else OSD_Printf("Invalid alias %s\n",i->name);
                return OSDCMD_OK;
            }
        }
    }
    OSD_Printf("Invalid alias %s\n",parm->parms[0]);
    return OSDCMD_OK;
}

static int _internal_osdfunc_vars(const osdfuncparm_t *parm)
{
    int showval = (parm->numparms < 1);

    if (!Bstrcasecmp(parm->name, "osdrows"))
    {
        if (showval) { OSD_Printf("osdrows is %d\n", osdrows); return OSDCMD_OK; }
        else
        {
            osdrows = atoi(parm->parms[0]);
            if (osdrows < 1) osdrows = 1;
            else if (osdrows > osdmaxrows) osdrows = osdmaxrows;
            if (osdrowscur!=-1)osdrowscur = osdrows;
            OSD_Printf("%s\n",parm->raw);
            return OSDCMD_OK;
        }
    }
    else if (!Bstrcasecmp(parm->name, "osdpromptshade"))
    {
        if (showval) { OSD_Printf("osdpromptshade is %d\n", osdpromptshade); return OSDCMD_OK; }
        else
        {
            osdpromptshade = atoi(parm->parms[0]);
            if (osdpromptshade < -128) osdpromptshade = -128;
            else if (osdpromptshade > 127) osdpromptshade = 127;
            OSD_Printf("%s\n",parm->raw);
            return OSDCMD_OK;
        }
    }
    else if (!Bstrcasecmp(parm->name, "osdeditshade"))
    {
        if (showval) { OSD_Printf("osdeditshade is %d\n", osdeditshade); return OSDCMD_OK; }
        else
        {
            osdeditshade = atoi(parm->parms[0]);
            if (osdeditshade < 0) osdeditshade = 0;
            else if (osdeditshade > 7) osdeditshade = 7;
            OSD_Printf("%s\n",parm->raw);
            return OSDCMD_OK;
        }
    }
    else if (!Bstrcasecmp(parm->name, "osdtextshade"))
    {
        if (showval) { OSD_Printf("osdtextshade is %d\n", osdtextshade); return OSDCMD_OK; }
        else
        {
            osdtextshade = atoi(parm->parms[0]);
            if (osdtextshade < 0) osdtextshade = 0;
            else if (osdtextshade > 7) osdtextshade = 7;
            OSD_Printf("%s\n",parm->raw);
            return OSDCMD_OK;
        }
    }

    else if (!Bstrcasecmp(parm->name, "osdpromptpal"))
    {
        if (showval) { OSD_Printf("osdpromptpal is %d\n", osdpromptpal); return OSDCMD_OK; }
        else
        {
            osdpromptpal = atoi(parm->parms[0]);
            if (osdpromptpal < 0) osdpromptpal = 0;
            else if (osdpromptpal > MAXPALOOKUPS-1) osdpromptpal = MAXPALOOKUPS;
            OSD_Printf("%s\n",parm->raw);
            return OSDCMD_OK;
        }
    }
    else if (!Bstrcasecmp(parm->name, "osdeditpal"))
    {
        if (showval) { OSD_Printf("osdeditpal is %d\n", osdeditpal); return OSDCMD_OK; }
        else
        {
            osdeditpal = atoi(parm->parms[0]);
            if (osdeditpal < 0) osdeditpal = 0;
            else if (osdeditpal > MAXPALOOKUPS-1) osdeditpal = MAXPALOOKUPS;
            OSD_Printf("%s\n",parm->raw);
            return OSDCMD_OK;
        }
    }
    else if (!Bstrcasecmp(parm->name, "osdtextpal"))
    {
        if (showval) { OSD_Printf("osdtextpal is %d\n", osdtextpal); return OSDCMD_OK; }
        else
        {
            osdtextpal = atoi(parm->parms[0]);
            if (osdtextpal < 0) osdtextpal = 0;
            else if (osdtextpal > MAXPALOOKUPS-1) osdtextpal = MAXPALOOKUPS;
            OSD_Printf("%s\n",parm->raw);
            return OSDCMD_OK;
        }
    }
    else if (!Bstrcasecmp(parm->name, "logcutoff"))
    {
        if (showval) { OSD_Printf("logcutoff is %d\n", logcutoff); return OSDCMD_OK; }
        else
        {
            logcutoff = atoi(parm->parms[0]);
            OSD_Printf("%s\n",parm->raw);
            return OSDCMD_OK;
        }
    }
    return OSDCMD_SHOWHELP;
}

static int _internal_osdfunc_listsymbols(const osdfuncparm_t *parm)
{
    symbol_t *i;
    int maxwidth = 0;

    UNREFERENCED_PARAMETER(parm);

    for (i=symbols; i!=NULL; i=i->next)
        if (i->func != (void *)OSD_UNALIASED)
            maxwidth = max((unsigned)maxwidth,Bstrlen(i->name));

    if (maxwidth > 0)
    {
        int x = 0;
        maxwidth += 3;
        OSD_Printf("Symbol listing:\n");
        for (i=symbols; i!=NULL; i=i->next)
        {
            if (i->func != (void *)OSD_UNALIASED)
            {
                OSD_Printf("%-*s",maxwidth,i->name);
                x += maxwidth;
            }
            if (x > osdcols - maxwidth)
            {
                x = 0;
                OSD_Printf("\n");
            }
        }
        if (x)
            OSD_Printf("\n");
    }

    return OSDCMD_OK;
}

static int _internal_osdfunc_help(const osdfuncparm_t *parm)
{
    symbol_t *symb;

    if (parm->numparms != 1) return OSDCMD_SHOWHELP;
    symb = findexactsymbol(parm->parms[0]);
    if (!symb)
    {
        OSD_Printf("Help Error: \"%s\" is not a defined variable or function\n", parm->parms[0]);
    }
    else
    {
        OSD_Printf("%s\n", symb->help);
    }

    return OSDCMD_OK;
}

static int _internal_osdfunc_clear(const osdfuncparm_t *parm)
{
    UNREFERENCED_PARAMETER(parm);
    Bmemset(osdtext,0,sizeof(osdtext));
    Bmemset(osdfmt,osdtextpal+(osdtextshade<<5),sizeof(osdfmt));
    osdlines = 1;
    return OSDCMD_OK;
}

static int _internal_osdfunc_history(const osdfuncparm_t *parm)
{
    int i, j = 0;
    UNREFERENCED_PARAMETER(parm);
    OSD_Printf("%s\n",parm->raw);
    for (i=HISTORYDEPTH-1; i>=0;i--)
        if (osdhistorybuf[i][0])
            OSD_Printf("%4d \"%s\"\n",osdhistorytotal-osdhistorysize+(++j),osdhistorybuf[i]);
    return OSDCMD_OK;
}

////////////////////////////


//
// OSD_Cleanup() -- Cleans up the on-screen display
//
void OSD_Cleanup(void)
{
    symbol_t *s;

    for (; symbols; symbols=s)
    {
        s=symbols->next;
        Bfree(symbols);
    }

    if (osdlog) Bfclose(osdlog);
    osdlog = NULL;

    osdinited=0;
}


//
// OSD_Init() -- Initializes the on-screen display
//
void OSD_Init(void)
{
    Bmemset(osdtext, 32, TEXTSIZE);
    Bmemset(osdfmt, osdtextpal+(osdtextshade<<5), TEXTSIZE);
    osdlines=1;

    osdinited=1;

    OSD_RegisterFunction("alias","alias: creates an alias for calling multiple commands",_internal_osdfunc_alias);
    OSD_RegisterFunction("clear","clear: clears the console text buffer",_internal_osdfunc_clear);
    OSD_RegisterFunction("exec","exec <scriptfile>: executes a script", _internal_osdfunc_exec);
    OSD_RegisterFunction("help","help: displays help for the specified cvar or command; \"listsymbols\" to show all commands",_internal_osdfunc_help);
    OSD_RegisterFunction("history","history: displays the console command history",_internal_osdfunc_history);
    OSD_RegisterFunction("listsymbols","listsymbols: lists all the recognized symbols",_internal_osdfunc_listsymbols);
    OSD_RegisterFunction("logcutoff","logcutoff: sets the maximal line count of the log file",_internal_osdfunc_vars);
    OSD_RegisterFunction("osdeditpal","osdeditpal: sets the palette of the OSD input text",_internal_osdfunc_vars);
    OSD_RegisterFunction("osdeditshade","osdeditshade: sets the shade of the OSD input text",_internal_osdfunc_vars);
    OSD_RegisterFunction("osdpromptpal","osdpromptpal: sets the palette of the OSD prompt",_internal_osdfunc_vars);
    OSD_RegisterFunction("osdpromptshade","osdpromptshade: sets the shade of the OSD prompt",_internal_osdfunc_vars);
    OSD_RegisterFunction("osdrows","osdrows: sets the number of visible lines of the OSD",_internal_osdfunc_vars);
    OSD_RegisterFunction("osdtextpal","osdtextpal: sets the palette of the OSD text",_internal_osdfunc_vars);
    OSD_RegisterFunction("osdtextshade","osdtextshade: sets the shade of the OSD text",_internal_osdfunc_vars);
    OSD_RegisterFunction("unalias","unalias: removes an alias created with \"alias\"",_internal_osdfunc_unalias);

    atexit(OSD_Cleanup);
}


//
// OSD_SetLogFile() -- Sets the text file where printed text should be echoed
//
void OSD_SetLogFile(char *fn)
{
    if (osdlog) Bfclose(osdlog);
    osdlog = NULL;
    if (fn) osdlog = Bfopen(fn,"w");
    if (osdlog) setvbuf(osdlog, (char*)NULL, _IONBF, 0);
}


//
// OSD_SetFunctions() -- Sets some callbacks which the OSD uses to understand its world
//
void OSD_SetFunctions(
    void (*drawchar)(int,int,char,int,int),
    void (*drawstr)(int,int,char*,int,int,int),
    void (*drawcursor)(int,int,int,int),
    int (*colwidth)(int),
    int (*rowheight)(int),
    void (*clearbg)(int,int),
    int (*gtime)(void),
    void (*showosd)(int)
)
{
    drawosdchar = drawchar;
    drawosdstr = drawstr;
    drawosdcursor = drawcursor;
    getcolumnwidth = colwidth;
    getrowheight = rowheight;
    clearbackground = clearbg;
    gettime = gtime;
    onshowosd = showosd;

    if (!drawosdchar) drawosdchar = _internal_drawosdchar;
    if (!drawosdstr) drawosdstr = _internal_drawosdstr;
    if (!drawosdcursor) drawosdcursor = _internal_drawosdcursor;
    if (!getcolumnwidth) getcolumnwidth = _internal_getcolumnwidth;
    if (!getrowheight) getrowheight = _internal_getrowheight;
    if (!clearbackground) clearbackground = _internal_clearbackground;
    if (!gettime) gettime = _internal_gettime;
    if (!onshowosd) onshowosd = _internal_onshowosd;
}


//
// OSD_SetParameters() -- Sets the parameters for presenting the text
//
void OSD_SetParameters(
    int promptshade, int promptpal,
    int editshade, int editpal,
    int textshade, int textpal
)
{
    osdpromptshade = promptshade;
    osdpromptpal   = promptpal;
    osdeditshade   = editshade;
    osdeditpal     = editpal;
    osdtextshade   = textshade;
    osdtextpal     = textpal;
}


//
// OSD_CaptureKey() -- Sets the scancode for the key which activates the onscreen display
//
void OSD_CaptureKey(int sc)
{
    osdkey = sc;
}

//
// OSD_FindDiffPoint() -- Finds the length of the longest common prefix of 2 strings, stolen from ZDoom
//
static int OSD_FindDiffPoint(const char *str1, const char *str2)
{
    int i;

    for (i = 0; Btolower(str1[i]) == Btolower(str2[i]); i++)
        if (str1[i] == 0 || str2[i] == 0)
            break;

    return i;
}

//
// OSD_HandleKey() -- Handles keyboard input when capturing input.
// 	Returns 0 if the key was handled internally, or the scancode if it should
// 	be passed on to the game.
//

static void OSD_HistoryPrev(void)
{
    if (osdhistorypos >= osdhistorysize-1) return;

    osdhistorypos++;
    memcpy(osdeditbuf, osdhistorybuf[osdhistorypos], EDITLENGTH+1);
    osdeditlen = osdeditcursor = 0;
    while (osdeditbuf[osdeditcursor]) osdeditlen++, osdeditcursor++;
    if (osdeditcursor<osdeditwinstart)
    {
        osdeditwinend = osdeditcursor;
        osdeditwinstart = osdeditwinend-editlinewidth;

        if (osdeditwinstart<0)
            osdeditwinend-=osdeditwinstart,
            osdeditwinstart=0;
    }
    else if (osdeditcursor>=osdeditwinend)
        osdeditwinstart+=(osdeditcursor-osdeditwinend),
        osdeditwinend+=(osdeditcursor-osdeditwinend);
}

static void OSD_HistoryNext(void)
{
    if (osdhistorypos < 0) return;

    if (osdhistorypos == 0)
    {
        osdeditlen=0;
        osdeditcursor=0;
        osdeditwinstart=0;
        osdeditwinend=editlinewidth;
        osdhistorypos = -1;
        return;
    }

    osdhistorypos--;
    memcpy(osdeditbuf, osdhistorybuf[osdhistorypos], EDITLENGTH+1);
    osdeditlen = osdeditcursor = 0;
    while (osdeditbuf[osdeditcursor]) osdeditlen++, osdeditcursor++;
    if (osdeditcursor<osdeditwinstart)
    {
        osdeditwinend = osdeditcursor;
        osdeditwinstart = osdeditwinend-editlinewidth;

        if (osdeditwinstart<0)
            osdeditwinend-=osdeditwinstart,
            osdeditwinstart=0;
    }
    else if (osdeditcursor>=osdeditwinend)
        osdeditwinstart+=(osdeditcursor-osdeditwinend),
        osdeditwinend+=(osdeditcursor-osdeditwinend);
}

int OSD_HandleChar(char ch)
{
    int i,j;
    symbol_t *tabc = NULL;
    static symbol_t *lastmatch = NULL;

    if (!osdinited || !osdinput) return ch;

    if (ch != 9) lastmatch = NULL;		// tab
    if (ch == 1)  	// control a. jump to beginning of line
    {
        osdeditcursor=0;
        osdeditwinstart=0;
        osdeditwinend=editlinewidth;
    }
    else if (ch == 2)  	// control b, move one character left
    {
        if (osdeditcursor > 0) osdeditcursor--;
    }
    else if (ch == 3)  	// control c
    {
        OSD_Printf("%s\n",osdeditbuf);
        osdeditlen=0;
        osdeditcursor=0;
        osdeditwinstart=0;
        osdeditwinend=editlinewidth;
        osdeditbuf[0] = 0;
    }
    else if (ch == 5)  	// control e, jump to end of line
    {
        osdeditcursor = osdeditlen;
        osdeditwinend = osdeditcursor;
        osdeditwinstart = osdeditwinend-editlinewidth;
        if (osdeditwinstart<0)
        {
            osdeditwinstart=0;
            osdeditwinend = editlinewidth;
        }
    }
    else if (ch == 6)  	// control f, move one character right
    {
        if (osdeditcursor < osdeditlen) osdeditcursor++;
    }
    else if (ch == 8 || ch == 127)  	// control h, backspace
    {
        if (!osdeditcursor || !osdeditlen) return 0;
        if (!osdovertype)
        {
            if (osdeditcursor < osdeditlen)
                Bmemmove(osdeditbuf+osdeditcursor-1, osdeditbuf+osdeditcursor, osdeditlen-osdeditcursor);
            osdeditlen--;
        }
        osdeditcursor--;
        if (osdeditcursor<osdeditwinstart) osdeditwinstart--,osdeditwinend--;
    }
    else if (ch == 9)  	// tab
    {
        int commonsize = 512;

        if (!lastmatch)
        {
            for (i=osdeditcursor;i>0;i--) if (osdeditbuf[i-1] == ' ') break;
            for (j=0;osdeditbuf[i] != ' ' && i < osdeditlen;j++,i++)
                osdedittmp[j] = osdeditbuf[i];
            osdedittmp[j] = 0;

            if (j > 0)
            {
                tabc = findsymbol(osdedittmp, NULL);

                if (tabc && tabc->next && findsymbol(osdedittmp, tabc->next))
                {
                    symbol_t *symb=tabc;
                    int maxwidth = 0, x = 0, num = 0;

                    while (symb && symb != lastmatch)
                    {
                        int diffpt;

                        num++;

                        if (lastmatch)
                        {
                            diffpt = OSD_FindDiffPoint(symb->name,lastmatch->name);
                            if (diffpt < commonsize)
                            {
                                commonsize = diffpt;
                                //                                            OSD_Printf("commonsize %d\n",commonsize);
                            }
                        }

                        maxwidth = max((unsigned)maxwidth,Bstrlen(symb->name));
                        lastmatch = symb;
                        symb=findsymbol(osdedittmp, lastmatch->next);
                    }
                    OSD_Printf(OSDTEXT_GREEN "Found %d possible completions for '%s':\n",num,osdedittmp);
                    maxwidth += 3;
                    symb = tabc;
                    OSD_Printf("  ");
                    while (symb && (symb != lastmatch))
                    {
                        tabc = lastmatch = symb;
                        OSD_Printf("%-*s",maxwidth,symb->name);
                        symb=findsymbol(osdedittmp, lastmatch->next);
                        x += maxwidth;
                        if (x > (osdcols - maxwidth))
                        {
                            x = 0;
                            OSD_Printf("\n");
                            if (symb && (symb != lastmatch))
                                OSD_Printf("  ");
                        }
                    }
                    if (x) OSD_Printf("\n");
                }
            }
        }
        else
        {
            tabc = findsymbol(osdedittmp, lastmatch->next);
            if (!tabc && lastmatch)
                tabc = findsymbol(osdedittmp, NULL);	// wrap */
        }

        if (tabc)
        {
            for (i=osdeditcursor;i>0;i--) if (osdeditbuf[i-1] == ' ') break;
            osdeditlen = i;
            for (j=0;tabc->name[j] && osdeditlen <= EDITLENGTH
                    && (osdeditlen < commonsize);i++,j++,osdeditlen++)
                osdeditbuf[i] = tabc->name[j];
            osdeditcursor = osdeditlen;
            osdeditwinend = osdeditcursor;
            osdeditwinstart = osdeditwinend-editlinewidth;
            if (osdeditwinstart<0)
            {
                osdeditwinstart=0;
                osdeditwinend = editlinewidth;
            }

            lastmatch = tabc;
        }
    }
    else if (ch == 11)  	// control k, delete all to end of line
    {
        Bmemset(osdeditbuf+osdeditcursor,0,sizeof(osdeditbuf)-osdeditcursor);
    }
    else if (ch == 12)  	// control l, clear screen
    {
        Bmemset(osdtext,0,sizeof(osdtext));
        Bmemset(osdfmt,osdtextpal+(osdtextshade<<5),sizeof(osdfmt));
        osdlines = 1;
    }
    else if (ch == 13)  	// control m, enter
    {
        if (osdeditlen>0)
        {
            osdeditbuf[osdeditlen] = 0;
            if (Bstrcmp(osdhistorybuf[0], osdeditbuf))
            {
                Bmemmove(osdhistorybuf[1], osdhistorybuf[0], (HISTORYDEPTH-1)*(EDITLENGTH+1));
                Bmemmove(osdhistorybuf[0], osdeditbuf, EDITLENGTH+1);
                if (osdhistorysize < HISTORYDEPTH) osdhistorysize++;
                osdhistorytotal++;
                if (osdexeccount == HISTORYDEPTH)
                    OSD_Printf("Command Buffer Warning: Failed queueing command "
                    "for execution. Buffer full.\n");
                else
                    osdexeccount++;
            }
            else
            {
                if (osdexeccount == HISTORYDEPTH)
                    OSD_Printf("Command Buffer Warning: Failed queueing command "
                    "for execution. Buffer full.\n");
                else
                    osdexeccount++;
            }
            osdhistorypos=-1;
        }

        osdeditlen=0;
        osdeditcursor=0;
        osdeditwinstart=0;
        osdeditwinend=editlinewidth;
    }
    else if (ch == 14)  	// control n, next (ie. down arrow)
    {
        OSD_HistoryNext();
    }
    else if (ch == 16)  	// control p, previous (ie. up arrow)
    {
        OSD_HistoryPrev();
    }
    else if (ch == 20)  	// control t, swap previous two chars
    {
    }
    else if (ch == 21)  	// control u, delete all to beginning
    {
        if (osdeditcursor>0 && osdeditlen)
        {
            if (osdeditcursor<osdeditlen)
                Bmemmove(osdeditbuf, osdeditbuf+osdeditcursor, osdeditlen-osdeditcursor);
            osdeditlen-=osdeditcursor;
            osdeditcursor = 0;
            osdeditwinstart = 0;
            osdeditwinend = editlinewidth;
        }
    }
    else if (ch == 23)  	// control w, delete one word back
    {
        if (osdeditcursor>0 && osdeditlen>0)
        {
            i=osdeditcursor;
            while (i>0 && osdeditbuf[i-1]==32) i--;
            while (i>0 && osdeditbuf[i-1]!=32) i--;
            if (osdeditcursor<osdeditlen)
                Bmemmove(osdeditbuf+i, osdeditbuf+osdeditcursor, osdeditlen-osdeditcursor);
            osdeditlen -= (osdeditcursor-i);
            osdeditcursor = i;
            if (osdeditcursor < osdeditwinstart)
            {
                osdeditwinstart=osdeditcursor;
                osdeditwinend=osdeditwinstart+editlinewidth;
            }
        }
    }
    else if (ch >= 32)  	// text char
    {
        if (!osdovertype && osdeditlen == EDITLENGTH)	// buffer full, can't insert another char
            return 0;

        if (!osdovertype)
        {
            if (osdeditcursor < osdeditlen)
                Bmemmove(osdeditbuf+osdeditcursor+1, osdeditbuf+osdeditcursor, osdeditlen-osdeditcursor);
            osdeditlen++;
        }
        else
        {
            if (osdeditcursor == osdeditlen)
                osdeditlen++;
        }
        osdeditbuf[osdeditcursor] = ch;
        osdeditcursor++;
        if (osdeditcursor>osdeditwinend) osdeditwinstart++,osdeditwinend++;
    }
    return 0;
}

int OSD_HandleScanCode(int sc, int press)
{
    if (!osdinited) return sc;

    if (sc == osdkey)
    {
        if (press)
        {
            osdscroll = -osdscroll;
            if (osdrowscur == -1)
                osdscroll = 1;
            else if (osdrowscur == osdrows)
                osdscroll = -1;
            osdrowscur += osdscroll;
            OSD_CaptureInput(osdscroll == 1);
            osdscrtime = getticks();
        }
        return 0;//sc;
    }
    else if (!osdinput)
    {
        return sc;
    }

    if (!press)
    {
        if (sc == 42 || sc == 54) // shift
            osdeditshift = 0;
        if (sc == 29 || sc == 157)	// control
            osdeditcontrol = 0;
        return 0;//sc;
    }

    keytime = gettime();

    if (sc == 15)  		// tab
    {
    }
    else if (sc == 1)  		// escape
    {
        //        OSD_ShowDisplay(0);
        osdscroll = -1;
        osdrowscur += osdscroll;
        OSD_CaptureInput(0);
        osdscrtime = getticks();
    }
    else if (sc == 201)  	// page up
    {
        if (osdhead < osdlines-1)
            osdhead++;
    }
    else if (sc == 209)  	// page down
    {
        if (osdhead > 0)
            osdhead--;
    }
    else if (sc == 199)  	// home
    {
        if (osdeditcontrol)
        {
            osdhead = osdlines-1;
        }
        else
        {
            osdeditcursor = 0;
            osdeditwinstart = osdeditcursor;
            osdeditwinend = osdeditwinstart+editlinewidth;
        }
    }
    else if (sc == 207)  	// end
    {
        if (osdeditcontrol)
        {
            osdhead = 0;
        }
        else
        {
            osdeditcursor = osdeditlen;
            osdeditwinend = osdeditcursor;
            osdeditwinstart = osdeditwinend-editlinewidth;
            if (osdeditwinstart<0)
            {
                osdeditwinstart=0;
                osdeditwinend = editlinewidth;
            }
        }
    }
    else if (sc == 210)  	// insert
    {
        osdovertype ^= 1;
    }
    else if (sc == 203)  	// left
    {
        if (osdeditcursor>0)
        {
            if (osdeditcontrol)
            {
                while (osdeditcursor>0)
                {
                    if (osdeditbuf[osdeditcursor-1] != 32) break;
                    osdeditcursor--;
                }
                while (osdeditcursor>0)
                {
                    if (osdeditbuf[osdeditcursor-1] == 32) break;
                    osdeditcursor--;
                }
            }
            else osdeditcursor--;
        }
        if (osdeditcursor<osdeditwinstart)
            osdeditwinend-=(osdeditwinstart-osdeditcursor),
                           osdeditwinstart-=(osdeditwinstart-osdeditcursor);
    }
    else if (sc == 205)  	// right
    {
        if (osdeditcursor<osdeditlen)
        {
            if (osdeditcontrol)
            {
                while (osdeditcursor<osdeditlen)
                {
                    if (osdeditbuf[osdeditcursor] == 32) break;
                    osdeditcursor++;
                }
                while (osdeditcursor<osdeditlen)
                {
                    if (osdeditbuf[osdeditcursor] != 32) break;
                    osdeditcursor++;
                }
            }
            else osdeditcursor++;
        }
        if (osdeditcursor>=osdeditwinend)
            osdeditwinstart+=(osdeditcursor-osdeditwinend),
                             osdeditwinend+=(osdeditcursor-osdeditwinend);
    }
    else if (sc == 200)  	// up
    {
        OSD_HistoryPrev();
    }
    else if (sc == 208)  	// down
    {
        OSD_HistoryNext();
    }
    else if (sc == 42 || sc == 54)  	// shift
    {
        osdeditshift = 1;
    }
    else if (sc == 29 || sc == 157)  	// control
    {
        osdeditcontrol = 1;
    }
    else if (sc == 58)  	// capslock
    {
        osdeditcaps ^= 1;
    }
    else if (sc == 28 || sc == 156)  	// enter
    {
    }
    else if (sc == 14)  		// backspace
    {
    }
    else if (sc == 211)  	// delete
    {
        if (osdeditcursor == osdeditlen || !osdeditlen) return 0;
        if (osdeditcursor <= osdeditlen-1) Bmemmove(osdeditbuf+osdeditcursor, osdeditbuf+osdeditcursor+1, osdeditlen-osdeditcursor-1);
        osdeditlen--;
    }

    return 0;
}


//
// OSD_ResizeDisplay() -- Handles readjustment of the display when the screen resolution
// 	changes on us.
//
void OSD_ResizeDisplay(int w, int h)
{
    int newcols;
    int newmaxlines;
    char newtext[TEXTSIZE];
    char newfmt[TEXTSIZE];
    int i,j,k;

    newcols = getcolumnwidth(w);
    newmaxlines = TEXTSIZE / newcols;

    j = min(newmaxlines, osdmaxlines);
    k = min(newcols, osdcols);

    memset(newtext, 32, TEXTSIZE);
    for (i=0;i<j;i++)
    {
        memcpy(newtext+newcols*i, osdtext+osdcols*i, k);
        memcpy(newfmt+newcols*i, osdfmt+osdcols*i, k);
    }

    memcpy(osdtext, newtext, TEXTSIZE);
    memcpy(osdfmt, newfmt, TEXTSIZE);
    osdcols = newcols;
    osdmaxlines = newmaxlines;
    osdmaxrows = getrowheight(h)-2;

    if (osdrows > osdmaxrows) osdrows = osdmaxrows;

    osdpos = 0;
    osdhead = 0;
    osdeditwinstart = 0;
    osdeditwinend = editlinewidth;
    white = -1;
}


//
// OSD_CaptureInput()
//
void OSD_CaptureInput(int cap)
{
    osdinput = (cap != 0);
    osdeditcontrol = 0;
    osdeditshift = 0;

    grabmouse(osdinput == 0);
    onshowosd(osdinput);
    if (osdinput) releaseallbuttons();
    bflushchars();
}

//
// OSD_ShowDisplay() -- Shows or hides the onscreen display
//
void OSD_ShowDisplay(int onf)
{
    osdvisible = (onf != 0);
    OSD_CaptureInput(osdvisible);
}


//
// OSD_Draw() -- Draw the onscreen display
//

void OSD_Draw(void)
{
    unsigned topoffs;
    int row, lines, x, len;

    if (!osdinited) return;

    if (osdrowscur == 0)
        OSD_ShowDisplay(osdvisible ^ 1);

    if (osdrowscur == osdrows)
        osdscroll = 0;
    else
    {
        int j;

        if ((osdrowscur < osdrows && osdscroll == 1) || osdrowscur < -1)
        {
            j = (getticks()-osdscrtime);
            while (j > -1)
            {
                osdrowscur++;
                j -= 200/osdrows;
                if (osdrowscur > osdrows-1)
                    break;
            }
        }
        if ((osdrowscur > -1 && osdscroll == -1) || osdrowscur > osdrows)
        {
            j = (getticks()-osdscrtime);
            while (j > -1)
            {
                osdrowscur--;
                j -= 200/osdrows;
                if (osdrowscur < 1)
                    break;
            }
        }
        osdscrtime = getticks();
    }

    if (!osdvisible || !osdrowscur) return;

    topoffs = osdhead * osdcols;
    row = osdrowscur-1;
    lines = min(osdlines-osdhead, osdrowscur);

    begindrawing();

    clearbackground(osdcols,osdrowscur+1);

    if (osdversionstring[0])
        drawosdstr(osdcols-osdversionstringlen,osdrowscur,osdversionstring,osdversionstringlen,osdversionstringshade,osdversionstringpal);

    for (; lines>0; lines--, row--)
    {
        drawosdstr(0,row,osdtext+topoffs,osdcols,osdtextshade,osdtextpal);
        topoffs+=osdcols;
    }

    drawosdchar(2,osdrowscur,'>',osdpromptshade,osdpromptpal);
    if (osdeditcaps) drawosdchar(0,osdrowscur,'C',osdpromptshade,osdpromptpal);
    if (osdeditshift) drawosdchar(1,osdrowscur,'H',osdpromptshade,osdpromptpal);

    len = min(osdcols-1-3, osdeditlen-osdeditwinstart);
    for (x=0; x<len; x++)
        drawosdchar(3+x,osdrowscur,osdeditbuf[osdeditwinstart+x],osdeditshade<<1,osdeditpal);

    drawosdcursor(3+osdeditcursor-osdeditwinstart,osdrowscur,osdovertype,keytime);

    enddrawing();
}


//
// OSD_Printf() -- Print a string to the onscreen display
//   and write it to the log file
//

static inline void linefeed(void)
{
    Bmemmove(osdtext+osdcols, osdtext, TEXTSIZE-osdcols);
    Bmemset(osdtext, 32, osdcols);
    Bmemmove(osdfmt+osdcols, osdfmt, TEXTSIZE-osdcols);
    Bmemset(osdfmt, osdtextpal, osdcols);
    if (osdlines < osdmaxlines) osdlines++;
}

void OSD_Printf(const char *fmt, ...)
{
    char tmpstr[1024], *chp, p=osdtextpal, s=osdtextshade;
    va_list va;

    if (!osdinited) OSD_Init();

    va_start(va, fmt);
    Bvsnprintf(tmpstr, 1024, fmt, va);
    va_end(va);

    if (linecnt<logcutoff)
    {
        if (osdlog&&(!logcutoff||linecnt<logcutoff))
            Bfputs(stripcolorcodes(tmpstr), osdlog);
    }
    else if (linecnt==logcutoff)
    {
        Bfputs("\nMaximal log size reached. Logging stopped.\nSet the \"logcutoff\" console variable to a higher value if you need a longer log.\n", osdlog);
        linecnt=logcutoff+1;
    }


    for (chp = tmpstr; *chp; chp++)
    {
        if (*chp == '^' && isdigit(*(chp+1)))
        {
            char smallbuf[4];
            chp++;
            if (isdigit(*(chp+1)))
            {
                smallbuf[0] = *(chp++);
                smallbuf[1] = *(chp);
                smallbuf[2] = '\0';
                p = atol(smallbuf);
            }
            else
            {
                smallbuf[0] = *(chp);
                smallbuf[1] = '\0';
                p = atol(smallbuf);
            }
        }
        else if (*chp == '^' && Btoupper(*(chp+1)) == 'S')
        {
            chp++;
            if (isdigit(*(++chp)))
                s = *chp;
        }
        else if (*chp == '\r') osdpos=0;
        else if (*chp == '\n')
        {
            osdpos=0;
            linecnt++;
            linefeed();
        }
        else
        {
            osdtext[osdpos] = *chp;
            osdfmt[osdpos++] = p+(s<<5);
            if (osdpos == osdcols)
            {
                osdpos = 0;
                linefeed();
            }
        }
    }
}


//
// OSD_DispatchQueued() -- Executes any commands queued in the buffer
//
void OSD_DispatchQueued(void)
{
    int cmd;

    if (!osdexeccount) return;

    cmd=osdexeccount-1;
    osdexeccount=0;

    for (; cmd>=0; cmd--)
    {
        OSD_Dispatch((const char *)osdhistorybuf[cmd]);
    }
}


//
// OSD_Dispatch() -- Executes a command string
//

static char *strtoken(char *s, char **ptrptr, int *restart)
{
    char *p, *p2, *start;

    *restart = 0;
    if (!ptrptr) return NULL;

    // if s != NULL, we process from the start of s, otherwise
    // we just continue with where ptrptr points to
    if (s) p = s;
    else p = *ptrptr;

    if (!p) return NULL;

    // eat up any leading whitespace
    while (*p != 0 && *p != ';' && *p == ' ') p++;

    // a semicolon is an end of statement delimiter like a \0 is, so we signal
    // the caller to 'restart' for the rest of the string pointed at by *ptrptr
    if (*p == ';')
    {
        *restart = 1;
        *ptrptr = p+1;
        return NULL;
    }
    // or if we hit the end of the input, signal all done by nulling *ptrptr
    else if (*p == 0)
    {
        *ptrptr = NULL;
        return NULL;
    }

    if (*p == '\"')
    {
        // quoted string
        start = ++p;
        p2 = p;
        while (*p != 0)
        {
            if (*p == '\"')
            {
                p++;
                break;
            }
            else if (*p == '\\')
            {
                switch (*(++p))
                {
                case 'n':
                    *p2 = '\n'; break;
                case 'r':
                    *p2 = '\r'; break;
                default:
                    *p2 = *p; break;
                }
            }
            else
            {
                *p2 = *p;
            }
            p2++, p++;
        }
        *p2 = 0;
    }
    else
    {
        start = p;
        while (*p != 0 && *p != ';' && *p != ' ') p++;
    }

    // if we hit the end of input, signal all done by nulling *ptrptr
    if (*p == 0)
    {
        *ptrptr = NULL;
    }
    // or if we came upon a semicolon, signal caller to restart with the
    // string at *ptrptr
    else if (*p == ';')
    {
        *p = 0;
        *ptrptr = p+1;
        *restart = 1;
    }
    // otherwise, clip off the token and carry on
    else
    {
        *(p++) = 0;
        *ptrptr = p;
    }

    return start;
}

#define MAXPARMS 512
int OSD_Dispatch(const char *cmd)
{
    char *workbuf, *wp, *wtp, *state;
    char *parms[MAXPARMS];
    int  numparms, restart = 0;
    osdfuncparm_t ofp;
    symbol_t *symb;
    //int i;

    workbuf = state = Bstrdup(cmd);
    if (!workbuf) return -1;

    do
    {
        numparms = 0;
        Bmemset(parms, 0, sizeof(parms));
        wp = strtoken(state, &wtp, &restart);
        if (!wp)
        {
            state = wtp;
            continue;
        }

        if (wp[0] == '/' && wp[1] == '/') // cheap hack
        {
            free(workbuf);
            return -1;
        }

        symb = findexactsymbol(wp);
        if (!symb)
        {
            OSD_Printf(OSDTEXT_RED "Error: \"%s\" is not a valid command or cvar\n", wp);
            free(workbuf);
            return -1;
        }

        ofp.name = wp;
        while (wtp && !restart)
        {
            wp = strtoken(NULL, &wtp, &restart);
            if (wp && numparms < MAXPARMS) parms[numparms++] = wp;
        }
        ofp.numparms = numparms;
        ofp.parms    = (const char **)parms;
        ofp.raw      = cmd;
        if (symb->func == (void *)OSD_ALIAS)
            OSD_Dispatch(symb->help);
        else if (symb->func != (void *)OSD_UNALIASED)
        {
            switch (symb->func(&ofp))
            {
            case OSDCMD_OK:
                break;
            case OSDCMD_SHOWHELP:
                OSD_Printf("%s\n", symb->help);
                break;
            }
        }

        state = wtp;
    }
    while (wtp && restart);

    free(workbuf);

    return 0;
}


//
// OSD_RegisterFunction() -- Registers a new function
//
int OSD_RegisterFunction(const char *name, const char *help, int (*func)(const osdfuncparm_t*))
{
    symbol_t *symb;
    const char *cp;

    if (!osdinited) OSD_Init();

    if (!name)
    {
        OSD_Printf("OSD_RegisterFunction(): may not register a function with a null name\n");
        return -1;
    }
    if (!name[0])
    {
        OSD_Printf("OSD_RegisterFunction(): may not register a function with no name\n");
        return -1;
    }

    // check for illegal characters in name
    for (cp = name; *cp; cp++)
    {
        if ((cp == name) && (*cp >= '0') && (*cp <= '9'))
        {
            OSD_Printf("OSD_RegisterFunction(): first character of function name \"%s\" must not be a numeral\n", name);
            return -1;
        }
        if ((*cp < '0') ||
                (*cp > '9' && *cp < 'A') ||
                (*cp > 'Z' && *cp < 'a' && *cp != '_') ||
                (*cp > 'z'))
        {
            OSD_Printf("OSD_RegisterFunction(): illegal character in function name \"%s\"\n", name);
            return -1;
        }
    }

    if (!help) help = "(no description for this function)";
    if (!func)
    {
        OSD_Printf("OSD_RegisterFunction(): may not register a null function\n");
        return -1;
    }

    symb = findexactsymbol(name);
    if (symb) // allow this now for reusing an alias name
    {
        if (symb->func != (void *)OSD_ALIAS && symb->func != (void *)OSD_UNALIASED)
        {
            OSD_Printf("OSD_RegisterFunction(): \"%s\" is already defined\n", name);
            return -1;
        }
        Bfree((char *)symb->help);
        symb->help = help;
        symb->func = func;
        return 0;
    }

    symb = addnewsymbol(name);
    if (!symb)
    {
        OSD_Printf("OSD_RegisterFunction(): Failed registering function \"%s\"\n", name);
        return -1;
    }

    symb->name = name;
    symb->help = help;
    symb->func = func;

    return 0;
}

//
// OSD_SetVersionString()
//
void OSD_SetVersionString(const char *version, int shade, int pal)
{
    if (!osdinited) OSD_Init();

    Bstrcpy(osdversionstring,version);
    osdversionstringlen = Bstrlen(osdversionstring);
    osdversionstringshade = shade;
    osdversionstringpal = pal;
}

int OSD_ParsingScript(void)
{
    return osdexecscript;
}

int OSD_OSDKey(void)
{
    return osdkey;
}

char *OSD_GetTextPtr(void)
{
    return (&osdtext[0]);
}

char *OSD_GetFmtPtr(void)
{
    return (&osdfmt[0]);
}

//
// addnewsymbol() -- Allocates space for a new symbol and attaches it
//   appropriately to the lists, sorted.
//
static symbol_t *addnewsymbol(const char *name)
{
    symbol_t *newsymb, *s, *t;

    newsymb = (symbol_t *)Bmalloc(sizeof(symbol_t));
    if (!newsymb) { return NULL; }
    Bmemset(newsymb, 0, sizeof(symbol_t));

    // link it to the main chain
    if (!symbols)
    {
        symbols = newsymb;
    }
    else
    {
        if (Bstrcasecmp(name, symbols->name) <= 0)
        {
            t = symbols;
            symbols = newsymb;
            symbols->next = t;
        }
        else
        {
            s = symbols;
            while (s->next)
            {
                if (Bstrcasecmp(s->next->name, name) > 0) break;
                s=s->next;
            }
            t = s->next;
            s->next = newsymb;
            newsymb->next = t;
        }
    }

    return newsymb;
}


//
// findsymbol() -- Finds a symbol, possibly partially named
//
static symbol_t *findsymbol(const char *name, symbol_t *startingat)
{
    if (!startingat) startingat = symbols;
    if (!startingat) return NULL;

    for (; startingat; startingat=startingat->next)
        if (startingat->func != (void *)OSD_UNALIASED && !Bstrncasecmp(name, startingat->name, Bstrlen(name))) return startingat;

    return NULL;
}


//
// findexactsymbol() -- Finds a symbol, complete named
//
static symbol_t *findexactsymbol(const char *name)
{
    symbol_t *startingat;
    if (!symbols) return NULL;

    startingat = symbols;

    for (; startingat; startingat=startingat->next)
        if (!Bstrcasecmp(name, startingat->name)) return startingat;

    return NULL;
}