/**
 ** fdv_grx.c -- driver for GRX native font file format
 **
 ** Copyright (c) 1995 Csaba Biegl, 820 Stirrup Dr, Nashville, TN 37221
 ** [e-mail: csaba@vuse.vanderbilt.edu]
 **
 ** This file is part of the GRX graphics library.
 **
 ** The GRX graphics library is free software; you can redistribute it
 ** and/or modify it under some conditions; see the "copying.grx" file
 ** for details.
 **
 ** This library is distributed in the hope that it will be useful,
 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 **
 **/

#include <stdio.h>
#include <string.h>

#include "libgrx.h"
#include "grfontdv.h"
#include "allocate.h"
#include "fonts/fdv_grx.h"

#ifndef  SEEK_SET
#define  SEEK_SET       0
#endif

static GrFontFileHeaderGRX fhdr;
static FILE *fontfp = NULL;
static GR_int16u *wtable = NULL;
static unsigned int wtsize = 0;
static int nextch = 0;

#if BYTE_ORDER==BIG_ENDIAN
#include "ordswap.h"
static void swap_header(void)
{
    GRX_ENTER();
    _GR_swap32u(&fhdr.magic);
    _GR_swap32u(&fhdr.bmpsize);
    _GR_swap16u(&fhdr.width);
    _GR_swap16u(&fhdr.height);
    _GR_swap16u(&fhdr.minchar);
    _GR_swap16u(&fhdr.maxchar);
    _GR_swap16u(&fhdr.isfixed);
    _GR_swap16u(&fhdr.encoding);
    _GR_swap16u(&fhdr.baseline);
    _GR_swap16u(&fhdr.undwidth);
    /* no need to change fnname  && family */
    GRX_LEAVE();
}

static void swap_wtable(void)
{
    GR_int16u *wt;
    unsigned int ws;
    GRX_ENTER();
    wt = wtable;
    ws = wtsize / sizeof(GR_int16u);
    while (ws-- > 0) {
        _GR_swap16u(wt);
        ++wt;
    }
    GRX_LEAVE();
}
#endif

static void cleanup(void)
{
    GRX_ENTER();
    if(fontfp != NULL) fclose(fontfp);
    if(wtable != NULL) farfree(wtable);
    fontfp = NULL;
    wtable = NULL;
    nextch = 0;
    wtsize = 0;
    GRX_LEAVE();
}

static int openfile(char *fname)
{
    int res;
#if BYTE_ORDER==BIG_ENDIAN
    int swap;
#endif
    GRX_ENTER();
    res = FALSE;
    cleanup();
    fontfp = fopen(fname,"rb");
    if (fontfp == NULL) {
        DBGPRINTF(DBG_FONT,("fopen(\"%s\") failed\n", fname));
        goto done;
    }
    if (fread(&fhdr,sizeof(fhdr),1,fontfp) != 1) {
        DBGPRINTF(DBG_FONT,("reading header failed\n"));
        goto done;
    }
#if BYTE_ORDER==BIG_ENDIAN
    swap = 0;
    if (fhdr.magic == GRX_FONTMAGIC_SWAPPED) {
        swap = 1;
        DBGPRINTF(DBG_FONT,("swaping header byte order\n"));
        swap_header();
    }
#endif
    if (fhdr.magic != GRX_FONTMAGIC) {
        DBGPRINTF(DBG_FONT,("font magic doesn't fit: %lx != %lx\n", \
               (unsigned long)fhdr.magic,(unsigned long)GRX_FONTMAGIC));
        goto done;
    }
    if (!fhdr.isfixed) {
        wtsize = sizeof(GR_int16u) * (fhdr.maxchar - fhdr.minchar + 1);
        wtable = farmalloc(wtsize);
        if (wtable == NULL) {
            DBGPRINTF(DBG_FONT,("Allocating wtable failed\n"));
            goto done;
        }
        if (fread(wtable,wtsize,1,fontfp) != 1) {
            DBGPRINTF(DBG_FONT,("Loading wtable failed\n"));
            goto done;
        }
#if BYTE_ORDER==BIG_ENDIAN
        if (swap) {
          DBGPRINTF(DBG_FONT,("swaping wtable byte order\n"));
          swap_wtable();
        }
#endif
    }
    nextch = fhdr.minchar;
    res = TRUE;
done:
    if (!res) cleanup();
    GRX_RETURN(res);
}

static int header(GrFontHeader *hdr)
{
    int res;
    GRX_ENTER();
    res = FALSE;
    if (fontfp != NULL) {
        memcpy(hdr->name,  fhdr.fnname,sizeof(fhdr.fnname));
        memcpy(hdr->family,fhdr.family,sizeof(fhdr.family));
        hdr->name  [sizeof(fhdr.fnname)] = '\0';
        hdr->family[sizeof(fhdr.family)] = '\0';
        hdr->proportional = fhdr.isfixed ? FALSE : TRUE;
        hdr->scalable     = FALSE;
        hdr->preloaded    = FALSE;
        hdr->modified     = GR_FONTCVT_NONE;
        hdr->width        = fhdr.width;
        hdr->height       = fhdr.height;
        hdr->baseline     = fhdr.baseline;
        hdr->ulpos        = fhdr.height - fhdr.undwidth;
        hdr->ulheight     = fhdr.undwidth;
        hdr->minchar      = fhdr.minchar;
        hdr->numchars     = fhdr.maxchar - fhdr.minchar + 1;
        hdr->encoding     = 0; /* GR_FONTENC_UNKNOWN */
        if (fhdr.encoding > 0 && fhdr.encoding <= GR_FONTENC_LASTENC)
            hdr->encoding = fhdr.encoding;
        res = TRUE;
    }
    GRX_RETURN(res);
}

static int charwdt(int chr)
{
    int res;
    GRX_ENTER();
    res = -1;
    if (fontfp != NULL && chr >= fhdr.minchar && chr <= fhdr.maxchar)
       res = (fhdr.isfixed ? fhdr.width : wtable[chr - fhdr.minchar]);
    GRX_RETURN(res);
}

static int bitmap(int chr,int w,int h,char *buffer)
{
    int res;
    GRX_ENTER();
    res = FALSE;
    if ((w > 0) && (w == charwdt(chr)) && (h > 0) && (h == fhdr.height) ) {
        if(chr != nextch) {
            long fpos = sizeof(fhdr) + (fhdr.isfixed ? 0 : wtsize);
            for(nextch = fhdr.minchar; nextch != chr; nextch++) {
                fpos += ((charwdt(nextch) + 7) >> 3) * fhdr.height;
            }
            fseek(fontfp,fpos,SEEK_SET);
        }
        nextch = chr + 1;
        res = fread(buffer,(((w + 7) >> 3) * h),1,fontfp) == 1;
    }
    GRX_RETURN(res);
}

GrFontDriver _GrFontDriverGRX = {
    "GRX",                              /* driver name (doc only) */
    ".fnt",                             /* font file extension */
    FALSE,                              /* scalable */
    openfile,                           /* file open and check routine */
    header,                             /* font header reader routine */
    charwdt,                            /* character width reader routine */
    bitmap,                             /* character bitmap reader routine */
    cleanup                             /* cleanup routine */
};