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/*
 *              Copyright (c) 1998 by Lucent Technologies.
 * Permission to use, copy, modify, and distribute this software for any
 * purpose without fee is hereby granted, provided that this entire notice
 * is included in all copies of any software which is or includes a copy
 * or modification of this software.
 *
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
 * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
 */

/*
 * gdevplan9.c: gs device to generate plan9 bitmaps
 * Russ Cox <rsc@plan9.bell-labs.com>, 3/25/98 (gdevifno)
 * Updated to fit in the standard GS distribution, 5/14/98
 * Added support for true-color bitmaps, 6/7/02
 */

#include "gdevprn.h"
#include "gsparam.h"
#include "gxlum.h"
#include "gxstdio.h"
#include <stdlib.h>

#define nil ((void*)0)
enum {
        ERROR = -2
};

typedef struct WImage WImage;
typedef struct Rectangle Rectangle;
typedef struct Point Point;

struct Point {
        int x;
        int y;
};

struct Rectangle {
        Point min;
        Point max;
};
private Point ZP = { 0, 0 };

private WImage* initwriteimage(FILE *f, Rectangle r, char*, int depth);
private int writeimageblock(WImage *w, uchar *data, int ndata);
private int bytesperline(Rectangle, int);
private int rgb2cmap(int, int, int);
private long cmap2rgb(int);

#define X_DPI   100
#define Y_DPI   100

private dev_proc_map_rgb_color(plan9_rgb2cmap);
private dev_proc_map_color_rgb(plan9_cmap2rgb);
private dev_proc_open_device(plan9_open);
private dev_proc_close_device(plan9_close);
private dev_proc_print_page(plan9_print_page);
private dev_proc_put_params(plan9_put_params);
private dev_proc_get_params(plan9_get_params);

typedef struct plan9_device_s {
        gx_device_common;
        gx_prn_device_common;
        int dither;

        int ldepth;
        int lastldepth;
        int cmapcall;
} plan9_device;

enum {
        Nbits = 8,
        Bitmask = (1<<Nbits)-1,
};

private const gx_device_procs plan9_procs =
        prn_color_params_procs(plan9_open, gdev_prn_output_page, gdev_prn_close,
                plan9_rgb2cmap, plan9_cmap2rgb,
                gdev_prn_get_params, gdev_prn_put_params);
/*
                plan9_get_params, plan9_put_params);
*/


plan9_device far_data gs_plan9_device =
{ prn_device_body(plan9_device, plan9_procs, "plan9",
        DEFAULT_WIDTH_10THS, DEFAULT_HEIGHT_10THS,
        X_DPI, Y_DPI,
        0,0,0,0,        /* margins */
        3,              /* 3 = RGB, 1 = gray, 4 = CMYK */
        Nbits*3,                /* # of bits per pixel */
        (1<<Nbits)-1,           /* # of distinct gray levels. */
        (1<<Nbits)-1,           /* # of distinct color levels. */
        1<<Nbits,               /* dither gray ramp size.  used in alpha? */
        1<<Nbits,       /* dither color ramp size.  used in alpha? */
        plan9_print_page),
        1,
};

/*
 * ghostscript asks us how to convert between
 * rgb and color map entries
 */
private gx_color_index 
plan9_rgb2cmap(gx_device *dev, gx_color_value *rgb)
{
        gx_color_value r, g, b;
        int shift;
        plan9_device *idev;
        ulong red, green, blue;

        r = rgb[0];
        g = rgb[1];
        b = rgb[2];

        idev = (plan9_device*) dev;

        shift = gx_color_value_bits - Nbits;
        red = r >> shift;
        green = g >> shift;
        blue = b >> shift;

        /*
         * we keep track of what ldepth bitmap this is by watching
         * what colors gs asks for.
         * 
         * one catch: sometimes print_page gets called more than one
         * per page (for multiple copies) without cmap calls inbetween.
         * if idev->cmapcall is 0 when print_page gets called, it uses
         * the ldepth of the last page.
         */
        if(red == green && green == blue) {
                if(red == 0 || red == Bitmask)
                        ;
                else if(red == Bitmask/3 || red == 2*Bitmask/3) {
                        if(idev->ldepth < 1)
                                idev->ldepth = 1;
                } else {
                        if(idev->ldepth < 2)
                                idev->ldepth = 2;
                }
        } else
                idev->ldepth = 3;

        idev->cmapcall = 1;
        return (blue << (2*Nbits)) | (green << Nbits) | red;
}

private int 
plan9_cmap2rgb(gx_device *dev, gx_color_index color,
  gx_color_value rgb[3]) {
        int shift, i;
        plan9_device *idev;

        if((ulong)color > 0xFFFFFF)
                return_error(gs_error_rangecheck);

        idev = (plan9_device*) dev;
        shift = gx_color_value_bits - Nbits;

        rgb[2] = ((color >> (2*Nbits)) & Bitmask) << shift;
        rgb[1] = ((color >> Nbits) & Bitmask) << shift;
        rgb[0] = (color & Bitmask) << shift;

        return 0;
}

private int
plan9_put_param_int(gs_param_list *plist, gs_param_name pname, int *pv,
        int minval, int maxval, int ecode)
{
        int code, value;
        switch(code = param_read_int(plist, pname, &value)) {
        default:
                return code;

        case 1:
                return ecode;

        case 0:
                if(value < minval || value > maxval)
                        param_signal_error(plist, pname, gs_error_rangecheck);
                *pv = value;
                return (ecode < 0 ? ecode : 1);
        }
}

private int
plan9_get_params(gx_device *pdev, gs_param_list *plist)
{
        int code;
        plan9_device *idev;

        idev = (plan9_device*) pdev;
//      printf("plan9_get_params dither %d\n", idev->dither);

        if((code = gdev_prn_get_params(pdev, plist)) < 0
         || (code = param_write_int(plist, "Dither", &idev->dither)) < 0)
                return code;
//      printf("getparams: dither=%d\n", idev->dither);
        return code;
}

private int
plan9_put_params(gx_device * pdev, gs_param_list * plist)
{
        int code;
        int dither;
        plan9_device *idev;

//      printf("plan9_put_params\n");

        idev = (plan9_device*)pdev;
        dither = idev->dither;

        code = plan9_put_param_int(plist, "Dither", &dither, 0, 1, 0);
        if(code < 0)
                return code;

        idev->dither = dither;
        return 0;
}
/*
 * plan9_open() is supposed to initialize the device.
 * there's not much to do.
 */
extern void init_p9color(void); /* in gdevifno.c */
private int
plan9_open(gx_device *dev)
{
        int code;
        plan9_device *idev;

        idev = (plan9_device*) dev;
        idev->cmapcall = 0;
        idev->ldepth = 0;

//      printf("plan9_open gs_plan9_device.dither = %d idev->dither = %d\n",
//              gs_plan9_device.dither, idev->dither);
        init_p9color();

        return gdev_prn_open(dev);
}

/*
 * plan9_print_page() is called once for each page
 * (actually once for each copy of each page, but we won't
 * worry about that).
 */
private int
plan9_print_page(gx_device_printer *pdev, FILE *f)
{
        char *chanstr;
        uchar *buf;     /* [8192*3*8/Nbits] BUG: malloc this */
        uchar *p;
        WImage *w;
        int bpl, y;
        int x, xmod;
        int ldepth;
        int ppb[] = {8, 4, 2, 1};       /* pixels per byte */
        int bpp[] = {1, 2, 4, 8};       /* bits per pixel */
        int gsbpl;
        int dither;
        int depth;
        ulong u;
        ushort us;
        Rectangle rect;
        plan9_device *idev;
        uchar *r;

        gsbpl = gdev_prn_raster(pdev);
        buf = gs_malloc(pdev->memory, gsbpl, 1, "plan9_print_page");

        if(buf == nil) {
                errprintf("out of memory\n");
                return_error(gs_error_Fatal);
        }

        idev = (plan9_device *) pdev;
        if(idev->cmapcall) {
                idev->lastldepth = idev->ldepth;
                idev->ldepth = 0;
                idev->cmapcall = 0;
        }
        ldepth = idev->lastldepth;
        dither = idev->dither;

        if(pdev->color_info.anti_alias.graphics_bits || pdev->color_info.anti_alias.text_bits)
                if(ldepth < 2)
                        ldepth = 2;

        chanstr = nil;
        depth = 0;
        switch(ldepth){
        case 0:
                chanstr = "k1";
                depth = 1;
                break;
        case 1:
                return_error(gs_error_Fatal);
        case 2:
                chanstr = "k4";
                depth = 4;
                break;
        case 3:
                chanstr = "r8g8b8";
                depth = 24;
                break;
        }

//      printf("plan9_print_page dither %d ldepth %d idither %d\n", dither, ldepth, gs_plan9_device.dither);
        rect.min = ZP;
        rect.max.x = pdev->width;
        rect.max.y = pdev->height;
        bpl = bytesperline(rect, depth);
        w = initwriteimage(f, rect, chanstr, depth);
        if(w == nil) {
                errprintf("initwriteimage failed\n");
                return_error(gs_error_Fatal);
        }

        /*
         * i wonder if it is faster to put the switch around the for loops
         * to save all the ldepth lookups.
         */
        for(y=0; y<pdev->height; y++) {
                gdev_prn_get_bits(pdev, y, buf, &p);
                r = p+2;
                switch(depth){
                default:
                        return_error(gs_error_Fatal);
                case 1:
                        for(x=0; x<pdev->width; x++){
                                if((x%8) == 0)
                                        p[x/8] = (*r>>4)&1;
                                else
                                        p[x/8] = (p[x/8]<<1) | (*r>>4)&1;
                                r += 3;
                        }
                        break;
                case 4:
                        for(x=0; x<pdev->width; x++){
                                if((x%2) == 0)
                                        p[x/2] = (*r>>4) & 0xF;
                                else
                                        p[x/2] = (p[x/2]<<4) | ((*r>>4)&0xF);
                                r += 3;
                        }
                        break;
                case 24:
                        break;
                }

                /* pad last byte over if we didn't fill it */
                xmod = pdev->width % ppb[ldepth];
                if(xmod && ldepth<3)
                        p[(x-1)/ppb[ldepth]] <<= ((ppb[ldepth]-xmod)*bpp[ldepth]);

                if(writeimageblock(w, p, bpl) == ERROR) {
                        gs_free(pdev->memory, buf, gsbpl, 1, "plan9_print_page");
                        return_error(gs_error_Fatal);
                }
        }
        if(writeimageblock(w, nil, 0) == ERROR) {
                gs_free(pdev->memory, buf, gsbpl, 1, "plan9_print_page");
                return_error(gs_error_Fatal);
        }

        gs_free(pdev->memory, buf, gsbpl, 1, "plan9_print_page");
        return 0;
}

/*
 * this is a modified version of the image compressor
 * from fb/bit2enc.  it is modified only in that it 
 * now compiles as part of gs.
 */

/*
 * Compressed image file parameters
 */
#define NMATCH  3               /* shortest match possible */
#define NRUN    (NMATCH+31)     /* longest match possible */
#define NMEM    1024            /* window size */
#define NDUMP   128             /* maximum length of dump */
#define NCBLOCK 6000            /* size of compressed blocks */

#define HSHIFT  3       /* HSHIFT==5 runs slightly faster, but hash table is 64x bigger */
#define NHASH   (1<<(HSHIFT*NMATCH))
#define HMASK   (NHASH-1)
#define hupdate(h, c)   ((((h)<<HSHIFT)^(c))&HMASK)

typedef struct Dump     Dump;
typedef struct Hlist Hlist;

struct Hlist{
        ulong p;
        Hlist *next, *prev;
};

struct Dump {
        int ndump;
        uchar *dumpbuf;
        uchar buf[1+NDUMP];
};

struct WImage {
        FILE *f;

        /* image attributes */
        Rectangle origr, r;
        int bpl;

        /* output buffer */
        uchar outbuf[NCBLOCK], *outp, *eout, *loutp;

        /* sliding input window */
        /*
         * ibase is the pointer to where the beginning of
         * the input "is" in memory.  whenever we "slide" the
         * buffer N bytes, what we are actually doing is 
         * decrementing ibase by N.
         * the ulongs in the Hlist structures are just
         * pointers relative to ibase.
         */
        uchar *inbuf;   /* inbuf should be at least NMEM+NRUN+NMATCH long */
        uchar *ibase;
        int minbuf;     /* size of inbuf (malloc'ed bytes) */
        int ninbuf;     /* size of inbuf (filled bytes) */
        ulong line;     /* the beginning of the line we are currently encoding,
                         * relative to inbuf (NOT relative to ibase) */

        /* raw dump buffer */
        Dump dump;

        /* hash tables */
        Hlist hash[NHASH];
        Hlist chain[NMEM], *cp;
        int h;
        int needhash;
};

private void
zerohash(WImage *w)
{
        memset(w->hash, 0, sizeof(w->hash));
        memset(w->chain, 0, sizeof(w->chain));
        w->cp=w->chain;
        w->needhash = 1;
}

private int
addbuf(WImage *w, uchar *buf, int nbuf)
{
        int n;
        if(buf == nil || w->outp+nbuf > w->eout) {
                if(w->loutp==w->outbuf){        /* can't really happen -- we checked line length above */
                        errprintf("buffer too small for line\n");
                        return ERROR;
                }
                n=w->loutp-w->outbuf;
                fprintf(w->f, "%11d %11d ", w->r.max.y, n);
                fwrite(w->outbuf, 1, n, w->f);
                w->r.min.y=w->r.max.y;
                w->outp=w->outbuf;
                w->loutp=w->outbuf;
                zerohash(w);
                return -1;
        }

        memmove(w->outp, buf, nbuf);
        w->outp += nbuf;
        return nbuf;
}

/* return 0 on success, -1 if buffer is full */
private int
flushdump(WImage *w)
{
        int n = w->dump.ndump;

        if(n == 0)
                return 0;

        w->dump.buf[0] = 0x80|(n-1);
        if((n=addbuf(w, w->dump.buf, n+1)) == ERROR)
                return ERROR;
        if(n < 0)
                return -1;
        w->dump.ndump = 0;
        return 0;
}

private void
updatehash(WImage *w, uchar *p, uchar *ep)
{
        uchar *q;
        Hlist *cp;
        Hlist *hash;
        int h;

        hash = w->hash;
        cp = w->cp;
        h = w->h;
        for(q=p; q<ep; q++) {
                if(cp->prev)
                        cp->prev->next = cp->next;
                cp->next = hash[h].next;
                cp->prev = &hash[h];
                cp->prev->next = cp;
                if(cp->next)
                        cp->next->prev = cp;
                cp->p = q - w->ibase;
                if(++cp == w->chain+NMEM)
                        cp = w->chain;
                if(&q[NMATCH] < &w->inbuf[w->ninbuf])
                        h = hupdate(h, q[NMATCH]);
        }
        w->cp = cp;
        w->h = h;
}

/*
 * attempt to process a line of input,
 * returning the number of bytes actually processed.
 *
 * if the output buffer needs to be flushed, we flush
 * the buffer and return 0.
 * otherwise we return bpl
 */
private int
gobbleline(WImage *w)
{
        int runlen, n, offs;
        uchar *eline, *es, *best, *p, *s, *t;
        Hlist *hp;
        uchar buf[2];
        int rv;

        if(w->needhash) {
                w->h = 0;
                for(n=0; n!=NMATCH; n++)
                        w->h = hupdate(w->h, w->inbuf[w->line+n]);
                w->needhash = 0;
        }
        w->dump.ndump=0;
        eline=w->inbuf+w->line+w->bpl;
        for(p=w->inbuf+w->line;p!=eline;){
                es = (eline < p+NRUN) ? eline : p+NRUN;

                best=nil;
                runlen=0;
                /* hash table lookup */
                for(hp=w->hash[w->h].next;hp;hp=hp->next){
                        /*
                         * the next block is an optimization of 
                         * for(s=p, t=w->ibase+hp->p; s<es && *s == *t; s++, t++)
                         *      ;
                         */

                        {       uchar *ss, *tt;
                                s = p+runlen;
                                t = w->ibase+hp->p+runlen;
                                for(ss=s, tt=t; ss>=p && *ss == *tt; ss--, tt--)
                                        ;
                                if(ss < p)
                                        while(s<es && *s == *t)
                                                s++, t++;
                        }

                        n = s-p;

                        if(n > runlen) {
                                runlen = n;
                                best = w->ibase+hp->p;
                                if(p+runlen == es)
                                        break;
                        }
                }

                /*
                 * if we didn't find a long enough run, append to 
                 * the raw dump buffer
                 */
                if(runlen<NMATCH){
                        if(w->dump.ndump==NDUMP) {
                                if((rv = flushdump(w)) == ERROR)
                                        return ERROR;
                                if(rv < 0)
                                        return 0;
                        }
                        w->dump.dumpbuf[w->dump.ndump++]=*p;
                        runlen=1;
                }else{
                /*
                 * otherwise, assuming the dump buffer is empty,
                 * add the compressed rep.
                 */
                        if((rv = flushdump(w)) == ERROR)
                                return ERROR;
                        if(rv < 0)
                                return 0;
                        offs=p-best-1;
                        buf[0] = ((runlen-NMATCH)<<2)|(offs>>8);
                        buf[1] = offs&0xff;
                        if(addbuf(w, buf, 2) < 0)
                                return 0;
                }

                /*
                 * add to hash tables what we just encoded
                 */
                updatehash(w, p, p+runlen);
                p += runlen;
        }

        if((rv = flushdump(w)) == ERROR)
                return ERROR;
        if(rv < 0)
                return 0;
        w->line += w->bpl;
        w->loutp=w->outp;
        w->r.max.y++;
        return w->bpl;
}

private uchar*
shiftwindow(WImage *w, uchar *data, uchar *edata)
{
        int n, m;

        /* shift window over */
        if(w->line > NMEM) {
                n = w->line-NMEM;
                memmove(w->inbuf, w->inbuf+n, w->ninbuf-n);
                w->line -= n;
                w->ibase -= n;
                w->ninbuf -= n;
        }

        /* fill right with data if available */
        if(w->minbuf > w->ninbuf && edata > data) {
                m = w->minbuf - w->ninbuf;
                if(edata-data < m)
                        m = edata-data;
                memmove(w->inbuf+w->ninbuf, data, m);
                data += m;
                w->ninbuf += m;
        }

        return data;
}

private WImage*
initwriteimage(FILE *f, Rectangle r, char *chanstr, int depth)
{
        WImage *w;
        int n, bpl;

        bpl = bytesperline(r, depth);
        if(r.max.y <= r.min.y || r.max.x <= r.min.x || bpl <= 0) {
                errprintf("bad rectangle, ldepth");
                return nil;
        }

        n = NMEM+NMATCH+NRUN+bpl*2;
        w = malloc(n+sizeof(*w));
        if(w == nil)
                return nil;
        w->inbuf = (uchar*) &w[1];
        w->ibase = w->inbuf;
        w->line = 0;
        w->minbuf = n;
        w->ninbuf = 0;
        w->origr = r;
        w->r = r;
        w->r.max.y = w->r.min.y;
        w->eout = w->outbuf+sizeof(w->outbuf);
        w->outp = w->loutp = w->outbuf;
        w->bpl = bpl;
        w->f = f;
        w->dump.dumpbuf = w->dump.buf+1;
        w->dump.ndump = 0;
        zerohash(w);

        fprintf(f, "compressed\n%11s %11d %11d %11d %11d ",
                chanstr, r.min.x, r.min.y, r.max.x, r.max.y);
        return w;
}

private int
writeimageblock(WImage *w, uchar *data, int ndata)
{
        uchar *edata;

        if(data == nil) {       /* end of data, flush everything */
                while(w->line < w->ninbuf)
                        if(gobbleline(w) == ERROR)
                                return ERROR;
                addbuf(w, nil, 0);
                if(w->r.min.y != w->origr.max.y) {
                        errprintf("not enough data supplied to writeimage\n");
                }
                free(w);
                return 0;
        }

        edata = data+ndata;
        data = shiftwindow(w, data, edata);
        while(w->ninbuf >= w->line+w->bpl+NMATCH) {
                if(gobbleline(w) == ERROR)
                        return ERROR;
                data = shiftwindow(w, data, edata);
        }
        if(data != edata) {
                fprintf(w->f, "data != edata.  uh oh\n");
                return ERROR; /* can't happen */
        }
        return 0;
}

/*
 * functions from the Plan9/Brazil drawing libraries 
 */
static
int
unitsperline(Rectangle r, int d, int bitsperunit)
{
        ulong l, t;

        if(d <= 0 || d > 32)    /* being called wrong.  d is image depth. */
                abort();

        if(r.min.x >= 0){
                l = (r.max.x*d+bitsperunit-1)/bitsperunit;
                l -= (r.min.x*d)/bitsperunit;
        }else{                  /* make positive before divide */
                t = (-r.min.x*d+bitsperunit-1)/bitsperunit;
                l = t+(r.max.x*d+bitsperunit-1)/bitsperunit;
        }
        return l;
}

int
wordsperline(Rectangle r, int d)
{
        return unitsperline(r, d, 8*sizeof(ulong));
}

int
bytesperline(Rectangle r, int d)
{
        return unitsperline(r, d, 8);
}