windows-server-2003/sdktools/vi/alloc.c

/*
 * Various allocation routines and routines returning information about
 * allocated objects.
 */

#include "stevie.h"

char *
alloc(size)
unsigned size;
{
        char    *p;             /* pointer to new storage space */

        p = malloc(size);
        if ( p == (char *)NULL ) {      /* if there is no more room... */
                emsg("Insufficient memory");
        }
        return(p);
}

char *
ralloc(char *block,unsigned newsize)
{
    char *p;

    if((p = realloc(block,newsize)) == NULL) {
        emsg("Insufficient memory");
    }
    return(p);
}

char *
strsave(string)
char    *string;
{
        return(strcpy(alloc((unsigned)(strlen(string)+1)),string));
}

void
screenalloc()
{
        /*
         * If we're changing the size of the screen, free the old arrays
         */
        if (Realscreen != NULL)
                free(Realscreen);
        if (Nextscreen != NULL)
                free(Nextscreen);

        Realscreen = malloc((unsigned)(Rows*Columns));
        Nextscreen = malloc((unsigned)(Rows*Columns));
}

/*
 * Allocate and initialize a new line structure with room for
 * 'nchars'+1 characters. We add one to nchars here to allow for
 * null termination because all the callers would just do it otherwise.
 */
LINE *
newline(nchars)
int     nchars;
{
        register LINE   *l;

        if ((l = (LINE *) alloc(sizeof(LINE))) == NULL)
                return (LINE *) NULL;

        l->s = alloc((unsigned) (nchars+1));    /* the line is empty */
        l->s[0] = NUL;
        l->size = nchars + 1;

        l->prev = (LINE *) NULL;        /* should be initialized by caller */
        l->next = (LINE *) NULL;

        return l;
}

/*
 * filealloc() - construct an initial empty file buffer
 */
void
filealloc()
{
        if ((Filemem->linep = newline(0)) == NULL) {
                fprintf(stderr,"Unable to allocate file memory!\n");
                exit(1);
        }
        if ((Filetop->linep = newline(0)) == NULL) {
                fprintf(stderr,"Unable to allocate file memory!\n");
                exit(1);
        }
        if ((Fileend->linep = newline(0)) == NULL) {
                fprintf(stderr,"Unable to allocate file memory!\n");
                exit(1);
        }
        Filemem->index = 0;
        Filetop->index = 0;
        Fileend->index = 0;

        Filetop->linep->next = Filemem->linep;  /* connect Filetop to Filemem */
        Filemem->linep->prev = Filetop->linep;

        Filemem->linep->next = Fileend->linep;  /* connect Filemem to Fileend */
        Fileend->linep->prev = Filemem->linep;

        *Curschar = *Filemem;
        *Topchar  = *Filemem;

        Filemem->linep->num = 0;
        Fileend->linep->num = 0xffff;

        clrall();               /* clear all marks */
        u_clear();              /* clear the undo buffer */
}

/*
 * freeall() - free the current buffer
 *
 * Free all lines in the current buffer.
 */
void
freeall()
{
        register LINE   *lp, *xlp;

        for (lp = Filetop->linep; lp != NULL ;lp = xlp) {
                if (lp->s != NULL)
                        free(lp->s);
                xlp = lp->next;
                free((char *)lp);
        }

        Curschar->linep = NULL;         /* clear pointers */
        Filetop->linep = NULL;
        Filemem->linep = NULL;
        Fileend->linep = NULL;

        u_clear();
        /* _heapmin(); */
}

/*
 * bufempty() - return TRUE if the buffer is empty
 */
bool_t
bufempty()
{
        return (buf1line() && Filemem->linep->s[0] == NUL);
}

/*
 * buf1line() - return TRUE if there is only one line
 */
bool_t
buf1line()
{
        return (Filemem->linep->next == Fileend->linep);
}

/*
 * lineempty() - return TRUE if the current line is empty
 */
bool_t
lineempty()
{
        return (Curschar->linep->s[0] == NUL);
}

/*
 * endofline() - return TRUE if the given position is at end of line
 *
 * This routine will probably never be called with a position resting
 * on the NUL byte, but handle it correctly in case it happens.
 */
bool_t
endofline(p)
register LNPTR   *p;
{
        return (p->linep->s[p->index] == NUL || p->linep->s[p->index+1] == NUL);
}
/*
 * canincrease(n) - returns TRUE if the current line can be increased 'n' bytes
 *
 * This routine returns immediately if the requested space is available.
 * If not, it attempts to allocate the space and adjust the data structures
 * accordingly. If everything fails it returns FALSE.
 */
bool_t
canincrease(n)
register int    n;
{
        register int    nsize;
        register char   *s;             /* pointer to new space */

        nsize = strlen(Curschar->linep->s) + 1 + n;     /* size required */

        if (nsize <= Curschar->linep->size)
                return TRUE;

        /*
         * Need to allocate more space for the string. Allow some extra
         * space on the assumption that we may need it soon. This avoids
         * excessive numbers of calls to malloc while entering new text.
         */
        if ((s = alloc((unsigned) (nsize + SLOP))) == NULL) {
                emsg("Can't add anything, file is too big!");
                State = NORMAL;
                return FALSE;
        }

        Curschar->linep->size = nsize + SLOP;
        strcpy(s, Curschar->linep->s);
        free(Curschar->linep->s);
        Curschar->linep->s = s;

        return TRUE;
}

char *
mkstr(c)
char    c;
{
        static  char    s[2];

        s[0] = c;
        s[1] = NUL;

        return s;
}