/*
 *		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.
 */

/*
 * 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
 * Comments edited for automatic TOC generation, 11/4/99
 */

#include "gdevprn.h"
#include "gsparam.h"

#define nil ((void*)0)

/*
 * ERROR
 * is used to go up the stack and
 * eventually return_error(gs_error_Fatal) to gs.
 */
#define 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;
};
static const Point ZP = { 0, 0 };

static WImage* initwriteimage(gp_file *f, Rectangle r, int ldepth, gs_memory_t *mem);
static int writeimageblock(WImage *w, uchar *data, int ndata, gs_memory_t *mem);
static int bytesperline(Rectangle, int);
static int rgb2cmap(int, int, int);
/* static long cmap2rgb(int); */ /* not currently used */

void init_p9color(ulong *p9color);

#define X_DPI	100
#define Y_DPI	100

static dev_proc_map_rgb_color(inferno_rgb2cmap);
static dev_proc_map_color_rgb(inferno_cmap2rgb);
static dev_proc_open_device(inferno_open);
static dev_proc_close_device(inferno_close);
static dev_proc_print_page(inferno_print_page);

typedef struct inferno_device_s {
        gx_device_common;
        gx_prn_device_common;
        int ldepth;
        int lastldepth;
        int color, gray;
        int cmapcall;
        int nbits;
        ulong *p9color;	/* index blue most sig, red least sig */
} inferno_device;

/* structure descriptor for the garbage collector */
/* we must use the final version because gx_device_common requires
   a finalisation call, but such procedures aren't inherited. */
gs_private_st_suffix_add1_final(st_inferno_device, inferno_device,
        "inferno_device", inferno_device_enum_ptrs, inferno_device_reloc_ptrs,
                          gx_device_finalize, st_device_printer, p9color);

static const gx_device_procs inferno_procs =
        prn_color_params_procs(inferno_open, gdev_prn_output_page, inferno_close,
                inferno_rgb2cmap, inferno_cmap2rgb,
                gdev_prn_get_params, gdev_prn_put_params);

inferno_device far_data gs_inferno_device =
{ prn_device_stype_body(inferno_device, inferno_procs, "inferno",
        &st_inferno_device,
        DEFAULT_WIDTH_10THS, DEFAULT_HEIGHT_10THS,
        X_DPI, Y_DPI,
        0,0,0,0,	/* margins */
        3,		/* 3 = RGB, 1 = gray, 4 = CMYK */
        16,		/* # of bits per pixel -- 16 is easier to handle than 12 */
        255,		/* # of distinct gray levels.  >=31 to fool gs into asking us*/
        255,		/* # of distinct color levels.  >= 31 to fool gs */
        0,		/* dither gray ramp size.  hopefully not used */
        0,    		/* dither color ramp size.  hopefully not used */
        inferno_print_page)
};

/*
 * ghostscript asks us how to convert between
 * rgb and color map entries
 */
static gx_color_index
inferno_rgb2cmap(gx_device *dev, const gx_color_value cv[]) {
        int shift;
        inferno_device *bdev = (inferno_device*) dev;
        int nbits = bdev->nbits;
        int mask = (1<<nbits)-1;
        gx_color_value red, green, blue;

        red = cv[0]; green = cv[1]; blue = cv[2];
        /* make the colors the size we want */
        if(gx_color_value_bits > nbits) {
                shift = gx_color_value_bits - nbits;
                red >>= shift;
                green >>= shift;
                blue >>= shift;
        } else if(gx_color_value_bits < nbits) {
                shift = nbits - gx_color_value_bits;
                red <<= shift;
                green <<= shift;
                blue <<= shift;
        }

        /* mask them off to be just nbits */
        red   &= mask;
        green &= mask;
        blue  &= mask;

        /*
         * 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 bdev->cmapcall is 0 when print_page gets called, it uses
         * the ldepth of the last page.
         */
        if(red == green && green == blue && red != 0 && red != mask) {
                if(red == 5 || red == 10) {
                        if(bdev->ldepth < 1)
                                bdev->ldepth = 1;
                } else {
                        if(bdev->ldepth < 2)
                                bdev->ldepth = 2;
                }
        } else
                bdev->ldepth = 3;

        bdev->cmapcall = 1;
        return ((((blue<<4)|green)<<4)|red);
}

static int
inferno_cmap2rgb(gx_device *dev, gx_color_index color,
  gx_color_value rgb[3]) {
        int shift, i;
        inferno_device *bdev = (inferno_device*) dev;
        int nbits = bdev->nbits;
        int mask = (1<<nbits)-1;

        if((int)color < 0 || (int)color > 255)
                return_error(gs_error_rangecheck);

        rgb[2] = (color >> (2*nbits)) & mask;
        rgb[1] = (color >> nbits) & mask;
        rgb[0] = color & mask;
        if(gx_color_value_bits > nbits) {
                shift = gx_color_value_bits - nbits;
                for(i=0; i<3; i++)
                        rgb[i] <<= shift;
        } else if(gx_color_value_bits < nbits) {
                shift = nbits - gx_color_value_bits;
                for(i=0; i<3; i++)
                        rgb[i] >>= shift;
        }

        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 e cp9color[] index */
#define Gfactor Rlevs
#define Bfactor	(Rlevs*Glevs)
#define p9color_size (sizeof(ulong)*Rlevs*Glevs*Blevs)

void init_p9color(ulong *p9color)	/* 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.
 */
static int
inferno_open(gx_device *dev)
{
        inferno_device *bdev = (inferno_device*) dev;
        bdev->color = bdev->gray = 0;
        bdev->cmapcall = 0;
        bdev->ldepth = 3;
        bdev->nbits = 4;	/* 4 bits per color per pixel (12 bpp, then we dither) */
                                /* if you change this, change the entry in gs_inferno_device */
        bdev->p9color = (ulong *)gs_alloc_bytes(bdev->memory, p9color_size, "plan 9 colour cube");
        if (bdev->p9color == NULL)
                return_error(gs_error_VMerror);
        init_p9color(bdev->p9color);
        return gdev_prn_open(dev);
}

/*
 * inferno_close() is called at the end, once everything
 * is finished.  we have nothing to do.
 */
static int
inferno_close(gx_device *dev)
{
        inferno_device *bdev = (inferno_device*) dev;
        int code;

        gs_free_object(dev->memory, bdev->p9color, "plan 9 colour cube");

        code = gdev_prn_close(dev);
        if(code < 0)
                return_error(code);
        return 0;
}

/*
 * inferno_print_page() is called once for each page
 * (actually once for each copy of each page, but we won't
 * worry about that).
 */
static int
inferno_print_page(gx_device_printer *pdev, gp_file *f)
{
        uchar *buf;
        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;
        ulong u;
        ushort us;

        inferno_device *bdev = (inferno_device *) pdev;
        Rectangle r;

        gsbpl = gdev_prn_raster(pdev);
        if(gsbpl > 16384) {	/* == 8192 dots across */
                emprintf(pdev->memory, "bitmap far too wide for inferno\n");
                return_error(gs_error_Fatal);
        }

        if(bdev->cmapcall) {
                bdev->lastldepth = bdev->ldepth;
                bdev->ldepth = 0;
                bdev->cmapcall = 0;
        }
        ldepth = bdev->lastldepth;

        r.min = ZP;
        r.max.x = pdev->width;
        r.max.y = pdev->height;
        bpl = bytesperline(r, ldepth);
        w = initwriteimage(f, r, ldepth, bdev->memory);
        if(w == nil) {
                emprintf(pdev->memory, "initwriteimage failed\n");
                return_error(gs_error_Fatal);
        }

        buf = gs_alloc_bytes(bdev->memory, gsbpl, "inferno line buffer");
        if(buf == NULL) {
                emprintf(pdev->memory, "couldn't allocate line buffer\n");
                return_error(gs_error_VMerror);
        }

        /*
         * 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++) {
                        us = (p[2*x]<<8) | p[2*x+1];

                        switch(ldepth) {
                        case 3:
                                if(0){
                                        int r, g, b;
                                        r = us & 0xf;
                                        g = (us>>4)&0xf;
                                        b = (us>>8)&0xf;
                                        r<<=4;
                                        g<<=4;
                                        b<<=4;
                                        p[x] = rgb2cmap(r,g,b);
                                }
                                if(1){
                                        if (us >= p9color_size)
                                            return_error(gs_error_rangecheck);
                                        u = bdev->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)));
                                }
                                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 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, bdev->memory) == ERROR) {
                        gs_free_object(bdev->memory, buf, "inferno line buffer");
                        /* w leaks here */
                        return_error(gs_error_Fatal);
                }
        }
        gs_free_object(bdev->memory, buf, "inferno line buffer");
        if(writeimageblock(w, nil, 0, bdev->memory) == ERROR) {
                return_error(gs_error_Fatal);
        }

        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.
 * some updates have been made to use dynamic memory.
 */

/*
 * 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 {
        gp_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;
};

static 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;
}

static 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 */
                        eprintf("buffer too small for line\n");
                        return ERROR;
                }
                n=w->loutp-w->outbuf;
                gp_fprintf(w->f, "%11d %11d ", w->r.max.y, n);
                gp_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 */
static 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;
}

static 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
 */
static 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;
}

static 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;
}

static WImage*
initwriteimage(gp_file *f, Rectangle r, int ldepth, gs_memory_t *mem)
{
        WImage *w;
        int n, bpl;

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

        n = NMEM+NMATCH+NRUN+bpl*2;
        w = (WImage*)gs_alloc_bytes(mem, n+sizeof(*w), "inferno image");
        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);

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

static int
writeimageblock(WImage *w, uchar *data, int ndata, gs_memory_t *mem)
{
        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) {
                        emprintf(mem, "not enough data supplied to writeimage\n");
                }
                gs_free_object(mem, w, "inferno image");
                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) {
                gp_fprintf(w->f, "data != edata.  uh oh\n");
                return ERROR; /* can't happen */
        }
        return 0;
}

/*
 * functions from the Plan9/Brazil drawing libraries
 */
static 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;
}

static 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.
 *
static 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;
}
 *
 *
 */
