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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.
 */

/*
 * gdevifno.c: gs device to generate inferno bitmaps
 * Russ Cox <rsc@plan9.bell-labs.com>, 3/25/98
 * Updated to fit in the standard GS distribution, 5/14/98
 */

#include "gdevprn.h"
#include "gsparam.h"
#include "gxlum.h"
#include <stdlib.h>
#undef printf

#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, int ldepth);
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(inferno_rgb2cmap);
private dev_proc_map_color_rgb(inferno_cmap2rgb);
private dev_proc_open_device(inferno_open);
private dev_proc_close_device(inferno_close);
private dev_proc_print_page(inferno_print_page);
private dev_proc_put_params(inferno_put_params);
private dev_proc_get_params(inferno_get_params);

typedef struct inferno_device_s {
        gx_device_common;
        gx_prn_device_common;
        int dither;

        int ldepth;
        int lastldepth;
        int cmapcall;
} inferno_device;

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

private const gx_device_procs inferno_procs =
        prn_color_params_procs(inferno_open, gdev_prn_output_page, gdev_prn_close,
                inferno_rgb2cmap, inferno_cmap2rgb,
                gdev_prn_get_params, gdev_prn_put_params);
/*
                inferno_get_params, inferno_put_params);
*/


inferno_device far_data gs_inferno_device =
{ prn_device_body(inferno_device, inferno_procs, "inferno",
        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? */
        inferno_print_page),
        1,
};

/*
 * ghostscript asks us how to convert between
 * rgb and color map entries
 */
private gx_color_index 
inferno_rgb2cmap(gx_device *dev, gx_color_value rgb[3]) {
        int shift;
        inferno_device *idev;
        ulong red, green, blue;

        idev = (inferno_device*) dev;

        shift = gx_color_value_bits - Nbits;
        red = rgb[0] >> shift;
        green = rgb[1] >> shift;
        blue = rgb[2] >> 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 
inferno_cmap2rgb(gx_device *dev, gx_color_index color,
  gx_color_value rgb[3]) {
        int shift, i;
        inferno_device *idev;

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

        idev = (inferno_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
inferno_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
inferno_get_params(gx_device *pdev, gs_param_list *plist)
{
        int code;
        inferno_device *idev;

        idev = (inferno_device*) pdev;
//      printf("inferno_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
inferno_put_params(gx_device * pdev, gs_param_list * plist)
{
        int code;
        int dither;
        inferno_device *idev;

        printf("inferno_put_params\n");

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

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

        idev->dither = dither;
        return 0;
}

/*
 * dithering tables courtesy of john hobby
 */
/* The following constants and tables define the mapping from fine-grained RGB
   triplets to 8-bit values based on the standard Plan 9 color map.
*/
#define Rlevs   16              /* number of levels to cut red value into */
#define Glevs   16
#define Blevs   16
#define Mlevs   16
#define Rfactor 1               /* multiple of red level in p9color[] index */
#define Gfactor Rlevs
#define Bfactor (Rlevs*Glevs)
                        
ulong p9color[Rlevs*Glevs*Blevs];       /* index blue most sig, red least sig */

void init_p9color(void)         /* init at run time since p9color[] is so big */
{
        int r, g, b, o;
        ulong* cur = p9color;
        for (b=0; b<16; b++) {
            for (g=0; g<16; g++) {
                int m0 = (b>g) ? b : g;
                for (r=0; r<16; r++) {
                    int V, M, rM, gM, bM, m;
                    int m1 = (r>m0) ? r : m0;
                    V=m1&3; M=(m1-V)<<1;
                    if (m1==0) m1=1;
                    m = m1 << 3;
                    rM=r*M; gM=g*M; bM=b*M;
                    *cur = 0;
                    for (o=7*m1; o>0; o-=2*m1) {
                        int rr=(rM+o)/m, gg=(gM+o)/m, bb=(bM+o)/m;
                        int ij = (rr<<6) + (V<<4) + ((V-rr+(gg<<2)+bb)&15);
                        *cur = (*cur << 8) + 255-ij;
                    }
                    cur++;
                }
            }
        }
}

/*
 * inferno_open() is supposed to initialize the device.
 * there's not much to do.
 */
private int
inferno_open(gx_device *dev)
{
        int code;
        inferno_device *idev;

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

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

        return gdev_prn_open(dev);
}

/*
 * inferno_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
inferno_print_page(gx_device_printer *pdev, FILE *f)
{
        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;
        ulong u;
        ushort us;
        Rectangle rect;
        inferno_device *idev;
        ulong r, g, b;

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

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

        idev = (inferno_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;

//      printf("inferno_print_page dither %d ldepth %d idither %d\n", dither, ldepth, gs_inferno_device.dither);
        rect.min = ZP;
        rect.max.x = pdev->width;
        rect.max.y = pdev->height;
        bpl = bytesperline(rect, ldepth);
        w = initwriteimage(f, rect, ldepth);
        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);
                for(x=0; x<pdev->width; x++) {
                        b = p[3*x];
                        g = p[3*x+1];
                        r = p[3*x+2];
                        us = ((b>>4) << 8) | ((g>>4) << 4) | (r>>4);
                        switch(ldepth) {
                        case 3:
                                if(1 || dither){
                                        u = p9color[us];
                                        /* the ulong in p9color is a 2x2 matrix.  pull the entry
                                         * u[x%2][y%2], more or less.
                                         */
                                        p[x] = u >> (8*((y%2)+2*(x%2)));
                                } else {
                                        p[x] = rgb2cmap(r, g, b);
                                }
                                break;
                        case 2:
                                us = ~us;
                                if((x%2) == 0)
                                        p[x/2] = us & 0xf;
                                else
                                        p[x/2] = (p[x/2]<<4)|(us&0xf);
                                break;
                        case 1:
                                return_error(gs_error_Fatal);
                        case 0:
                                us = ~us;
                                if((x%8) == 0)
                                        p[x/8] = us & 0x1;
                                else
                                        p[x/8] = (p[x/8]<<1)|(us&0x1);
                                break;
                        }
                }

                /* pad last byte over if we didn't fill it */
                xmod = pdev->width % ppb[ldepth];
                if(xmod)
                        p[(x-1)/ppb[ldepth]] <<= ((ppb[ldepth]-xmod)*bpp[ldepth]);
                if(writeimageblock(w, p, bpl) == ERROR) {
                        gs_free(pdev->memory, buf, gsbpl, 1, "inferno_print_page");
                        return_error(gs_error_Fatal);
                }
        }
        if(writeimageblock(w, nil, 0) == ERROR) {
                gs_free(pdev->memory, buf, gsbpl, 1, "inferno_print_page");
                return_error(gs_error_Fatal);
        }

        gs_free(pdev->memory, buf, gsbpl, 1, "inferno_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, int ldepth)
{
        WImage *w;
        int n, bpl;

        bpl = bytesperline(r, ldepth);
        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%11d %11d %11d %11d %11d ",
                ldepth, 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 
 */
private int
bytesperline(Rectangle r, int ld)
{
        ulong ws, l, t;
        int bits = 8;

        ws = bits>>ld;  /* pixels per unit */
        if(r.min.x >= 0){
                l = (r.max.x+ws-1)/ws;
                l -= r.min.x/ws;
        }else{                  /* make positive before divide */
                t = (-r.min.x)+ws-1;
                t = (t/ws)*ws;
                l = (t+r.max.x+ws-1)/ws;
        }
        return l;
}

private int
rgb2cmap(int cr, int cg, int cb)
{
        int r, g, b, v, cv;

        if(cr < 0)
                cr = 0;
        else if(cr > 255)
                cr = 255;
        if(cg < 0)
                cg = 0;
        else if(cg > 255)
                cg = 255;
        if(cb < 0)
                cb = 0;
        else if(cb > 255)
                cb = 255;
        r = cr>>6;
        g = cg>>6;
        b = cb>>6;
        cv = cr;
        if(cg > cv)
                cv = cg;
        if(cb > cv)
                cv = cb;
        v = (cv>>4)&3;
        return 255-((((r<<2)+v)<<4)+(((g<<2)+b+v-r)&15));
}

/*
 * go the other way; not currently used.
 *
private long
cmap2rgb(int c)
{
        int j, num, den, r, g, b, v, rgb;

        c = 255-c;
        r = c>>6;
        v = (c>>4)&3;
        j = (c-v+r)&15;
        g = j>>2;
        b = j&3;
        den=r;
        if(g>den)
                den=g;
        if(b>den)
                den=b;
        if(den==0) {
                v *= 17;
                rgb = (v<<16)|(v<<8)|v;
        }
        else{
                num=17*(4*den+v);
                rgb = ((r*num/den)<<16)|((g*num/den)<<8)|(b*num/den);
        }
        return rgb;
}
 *
 *
 */