/* Copyright (C) 1997, 2000 Aladdin Enterprises.  All rights reserved.
  
  This file is part of AFPL Ghostscript.
  
  AFPL Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author or
  distributor accepts any responsibility for the consequences of using it, or
  for whether it serves any particular purpose or works at all, unless he or
  she says so in writing.  Refer to the Aladdin Free Public License (the
  "License") for full details.
  
  Every copy of AFPL Ghostscript must include a copy of the License, normally
  in a plain ASCII text file named PUBLIC.  The License grants you the right
  to copy, modify and redistribute AFPL Ghostscript, but only under certain
  conditions described in the License.  Among other things, the License
  requires that the copyright notice and this notice be preserved on all
  copies.
*/

/*$Id$ */
/* Image processing streams for PostScript and PDF writers */
#include "gx.h"
#include "memory_.h"
#include "gserrors.h"
#include "gxdcconv.h"
#include "gdevpsds.h"

/* ---------------- Convert between 1/2/4/12 and 8 bits ---------------- */

gs_private_st_simple(st_1248_state, stream_1248_state, "stream_1248_state");

/* Initialize an expansion or reduction stream. */
int
s_1248_init(stream_1248_state *ss, int Columns, int samples_per_pixel)
{
    ss->samples_per_row = Columns * samples_per_pixel;
    return ss->template->init((stream_state *)ss);
}

/* Initialize the state. */
private int
s_1_init(stream_state * st)
{
    stream_1248_state *const ss = (stream_1248_state *) st;

    ss->left = ss->samples_per_row;
    ss->bits_per_sample = 1;
    return 0;
}
private int
s_2_init(stream_state * st)
{
    stream_1248_state *const ss = (stream_1248_state *) st;

    ss->left = ss->samples_per_row;
    ss->bits_per_sample = 2;
    return 0;
}
private int
s_4_init(stream_state * st)
{
    stream_1248_state *const ss = (stream_1248_state *) st;

    ss->left = ss->samples_per_row;
    ss->bits_per_sample = 4;
    return 0;
}
private int
s_12_init(stream_state * st)
{
    stream_1248_state *const ss = (stream_1248_state *) st;

    ss->left = ss->samples_per_row;
    ss->bits_per_sample = 12;	/* not needed */
    return 0;
}

/* Process one buffer. */
#define BEGIN_1248\
	stream_1248_state * const ss = (stream_1248_state *)st;\
	const byte *p = pr->ptr;\
	const byte *rlimit = pr->limit;\
	byte *q = pw->ptr;\
	byte *wlimit = pw->limit;\
	uint left = ss->left;\
	int status;\
	int n
#define END_1248\
	pr->ptr = p;\
	pw->ptr = q;\
	ss->left = left;\
	return status

/* N-to-8 expansion */
#define FOREACH_N_8(in, nout)\
	status = 0;\
	for ( ; p < rlimit; left -= n, q += n, ++p ) {\
	  byte in = p[1];\
	  n = min(left, nout);\
	  if ( wlimit - q < n ) {\
	    status = 1;\
	    break;\
	  }\
	  switch ( n ) {\
	    case 0: left = ss->samples_per_row; --p; continue;
#define END_FOREACH_N_8\
	  }\
	}
private int
s_N_8_process(stream_state * st, stream_cursor_read * pr,
	      stream_cursor_write * pw, bool last)
{
    BEGIN_1248;

    switch (ss->bits_per_sample) {

	case 1:{
		FOREACH_N_8(in, 8)
	case 8:
		q[8] = (byte) - (in & 1);
	case 7:
		q[7] = (byte) - ((in >> 1) & 1);
	case 6:
		q[6] = (byte) - ((in >> 2) & 1);
	case 5:
		q[5] = (byte) - ((in >> 3) & 1);
	case 4:
		q[4] = (byte) - ((in >> 4) & 1);
	case 3:
		q[3] = (byte) - ((in >> 5) & 1);
	case 2:
		q[2] = (byte) - ((in >> 6) & 1);
	case 1:
		q[1] = (byte) - (in >> 7);
		END_FOREACH_N_8;
	    }
	    break;

	case 2:{
		static const byte b2[4] =
		{0x00, 0x55, 0xaa, 0xff};

		FOREACH_N_8(in, 4)
	case 4:
		q[4] = b2[in & 3];
	case 3:
		q[3] = b2[(in >> 2) & 3];
	case 2:
		q[2] = b2[(in >> 4) & 3];
	case 1:
		q[1] = b2[in >> 6];
		END_FOREACH_N_8;
	    }
	    break;

	case 4:{
		static const byte b4[16] =
		{
		    0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
		    0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff
		};

		FOREACH_N_8(in, 2)
	case 2:
		q[2] = b4[in & 0xf];
	case 1:
		q[1] = b4[in >> 4];
		END_FOREACH_N_8;
	    }
	    break;

	default:
	    return ERRC;
    }

    END_1248;
}

/* 12-to-8 "expansion" */
private int
s_12_8_process(stream_state * st, stream_cursor_read * pr,
	       stream_cursor_write * pw, bool last)
{
    BEGIN_1248;

    n = ss->samples_per_row;	/* misuse n to avoid a compiler warning */
    status = 0;
    for (; rlimit - p >= 2; ++q) {
	if (q >= wlimit) {
	    status = 1;
	    break;
	}
	if (left == 0)
	    left = n;
	if ((n - left) & 1) {
	    q[1] = (byte)((p[1] << 4) | (p[2] >> 4));
	    p += 2, --left;
	} else {
	    q[1] = *++p;
	    if (!--left)
		++p;
	}
    }

    END_1248;
}


/* 8-to-N reduction */
#define FOREACH_8_N(out, nin)\
	byte out;\
	status = 1;\
	for ( ; q < wlimit; left -= n, p += n, ++q ) {\
	  n = min(left, nin);\
	  if ( rlimit - p < n ) {\
	    status = 0;\
	    break;\
	  }\
	  out = 0;\
	  switch ( n ) {\
	    case 0: left = ss->samples_per_row; --q; continue;
#define END_FOREACH_8_N\
	    q[1] = out;\
	  }\
	}
private int
s_8_N_process(stream_state * st, stream_cursor_read * pr,
	      stream_cursor_write * pw, bool last)
{
    BEGIN_1248;

    switch (ss->bits_per_sample) {

	case 1:{
		FOREACH_8_N(out, 8)
	case 8:
		out = p[8] >> 7;
	case 7:
		out |= (p[7] >> 7) << 1;
	case 6:
		out |= (p[6] >> 7) << 2;
	case 5:
		out |= (p[5] >> 7) << 3;
	case 4:
		out |= (p[4] >> 7) << 4;
	case 3:
		out |= (p[3] >> 7) << 5;
	case 2:
		out |= (p[2] >> 7) << 6;
	case 1:
		out |= p[1] & 0x80;
		END_FOREACH_8_N;
	    }
	    break;

	case 2:{
		FOREACH_8_N(out, 4)
	case 4:
		out |= p[4] >> 6;
	case 3:
		out |= (p[3] >> 6) << 2;
	case 2:
		out |= (p[2] >> 6) << 4;
	case 1:
		out |= p[1] & 0xc0;
		END_FOREACH_8_N;
	    }
	    break;

	case 4:{
		FOREACH_8_N(out, 2)
	case 2:
		out |= p[2] >> 4;
	case 1:
		out |= p[1] & 0xf0;
		END_FOREACH_8_N;
	    }
	    break;

	default:
	    return ERRC;
    }

    END_1248;
}

const stream_template s_1_8_template = {
    &st_1248_state, s_1_init, s_N_8_process, 1, 8
};
const stream_template s_2_8_template = {
    &st_1248_state, s_2_init, s_N_8_process, 1, 4
};
const stream_template s_4_8_template = {
    &st_1248_state, s_4_init, s_N_8_process, 1, 2
};
const stream_template s_12_8_template = {
    &st_1248_state, s_12_init, s_12_8_process, 1, 2
};

const stream_template s_8_1_template = {
    &st_1248_state, s_1_init, s_8_N_process, 8, 1
};
const stream_template s_8_2_template = {
    &st_1248_state, s_2_init, s_8_N_process, 4, 1
};
const stream_template s_8_4_template = {
    &st_1248_state, s_4_init, s_8_N_process, 2, 1
};

/* ---------------- Color space conversion ---------------- */

/* ------ Convert CMYK to RGB ------ */

private_st_C2R_state();

/* Initialize a CMYK => RGB conversion stream. */
int
s_C2R_init(stream_C2R_state *ss, const gs_imager_state *pis)
{
    ss->pis = pis;
    return 0;
}

/* Set default parameter values (actually, just clear pointers). */
private void
s_C2R_set_defaults(stream_state * st)
{
    stream_C2R_state *const ss = (stream_C2R_state *) st;

    ss->pis = 0;
}

/* Process one buffer. */
private int
s_C2R_process(stream_state * st, stream_cursor_read * pr,
	      stream_cursor_write * pw, bool last)
{
    stream_C2R_state *const ss = (stream_C2R_state *) st;
    const byte *p = pr->ptr;
    const byte *rlimit = pr->limit;
    byte *q = pw->ptr;
    byte *wlimit = pw->limit;

    for (; rlimit - p >= 4 && wlimit - q >= 3; p += 4, q += 3) {
	byte bc = p[1], bm = p[2], by = p[3], bk = p[4];
	frac rgb[3];

	color_cmyk_to_rgb(byte2frac(bc), byte2frac(bm), byte2frac(by),
			  byte2frac(bk), ss->pis, rgb);
	q[1] = frac2byte(rgb[0]);
	q[2] = frac2byte(rgb[1]);
	q[3] = frac2byte(rgb[2]);
    }
    pr->ptr = p;
    pw->ptr = q;
    return (rlimit - p < 4 ? 0 : 1);
}

const stream_template s_C2R_template = {
    &st_C2R_state, 0 /*NULL */ , s_C2R_process, 4, 3, 0, s_C2R_set_defaults
};

/* ------ Convert any color space to Indexed ------ */

private_st_IE_state();
private
ENUM_PTRS_WITH(ie_state_enum_ptrs, stream_IE_state *st) return 0;
case 0: return ENUM_OBJ(st->Decode);
case 1: return ENUM_BYTESTRING(&st->Table);
ENUM_PTRS_END
private
RELOC_PTRS_WITH(ie_state_reloc_ptrs, stream_IE_state *st)
{
    RELOC_VAR(st->Decode);
    RELOC_BYTESTRING_VAR(st->Table);
}
RELOC_PTRS_END

/* Set defaults. */
private void
s_IE_set_defaults(stream_state * st)
{
    stream_IE_state *const ss = (stream_IE_state *) st;

    ss->Decode = 0;		/* clear pointers */
    gs_bytestring_from_string(&ss->Table, 0, 0);
}

/* Initialize the state. */
private int
s_IE_init(stream_state * st)
{
    stream_IE_state *const ss = (stream_IE_state *) st;
    int key_index = (1 << ss->BitsPerIndex) * ss->NumComponents;
    int i;

    if (ss->Table.data == 0 || ss->Table.size < key_index)
	return ERRC;		/****** WRONG ******/
    /* Initialize Table with default values. */
    memset(ss->Table.data, 0, ss->NumComponents);
    ss->Table.data[ss->Table.size - 1] = 0;
    for (i = 0; i < countof(ss->hash_table); ++i)
	ss->hash_table[i] = key_index;
    ss->next_index = 0;
    ss->in_bits_left = 0;
    ss->next_component = 0;
    ss->byte_out = 1;
    ss->x = 0;
    return 0;
}

/* Process a buffer. */
private int
s_IE_process(stream_state * st, stream_cursor_read * pr,
	     stream_cursor_write * pw, bool last)
{
    stream_IE_state *const ss = (stream_IE_state *) st;
    /* Constant values from the state */
    const int bpc = ss->BitsPerComponent;
    const int num_components = ss->NumComponents;
    const int end_index = (1 << ss->BitsPerIndex) * num_components;
    byte *const table = ss->Table.data;
    byte *const key = table + end_index;
    /* Dynamic values from the state */
    uint byte_in = ss->byte_in;
    int in_bits_left = ss->in_bits_left;
    int next_component = ss->next_component;
    uint byte_out = ss->byte_out;
    /* Other dynamic values */
    const byte *p = pr->ptr;
    const byte *rlimit = pr->limit;
    byte *q = pw->ptr;
    byte *wlimit = pw->limit;
    int status = 0;

    for (;;) {
	uint hash, reprobe;
	int i, index;

	/* Check for a filled output byte. */
	if (byte_out >= 0x100) {
	    if (q >= wlimit) {
		status = 1;
		break;
	    }
	    *++q = (byte)byte_out;
	    byte_out = 1;
	}
	/* Acquire a complete input value. */
	while (next_component < num_components) {
	    const float *decode = &ss->Decode[next_component * 2];
	    int sample;

	    if (in_bits_left == 0) {
		if (p >= rlimit)
		    goto out;
		byte_in = *++p;
		in_bits_left = 8;
	    }
	    /* An input sample can never span a byte boundary. */
	    in_bits_left -= bpc;
	    sample = (byte_in >> in_bits_left) & ((1 << bpc) - 1);
	    /* Scale the sample according to Decode. */
	    sample = (int)((decode[0] +
			    (sample / (float)((1 << bpc) - 1) *
			     (decode[1] - decode[0]))) * 255 + 0.5);
	    key[next_component++] =
		(sample < 0 ? 0 : sample > 255 ? 255 : (byte)sample);
	}
	/* Look up the input value. */
	for (hash = 0, i = 0; i < num_components; ++i)
	    hash = hash + 23 * key[i];  /* adhoc */
	reprobe = (hash / countof(ss->hash_table)) | 137;  /* adhoc */
	for (hash %= countof(ss->hash_table);
	     memcmp(table + ss->hash_table[hash], key, num_components);
	     hash = (hash + reprobe) % countof(ss->hash_table)
	     )
	    DO_NOTHING;
	index = ss->hash_table[hash];
	if (index == end_index) {
	    /* The match was on an empty entry. */
	    if (ss->next_index == end_index) {
		/* Too many different values. */
		status = ERRC;
		break;
	    }
	    ss->hash_table[hash] = index = ss->next_index;
	    ss->next_index += num_components;
	    memcpy(table + index, key, num_components);
	}
	byte_out = (byte_out << ss->BitsPerIndex) + index / num_components;
	next_component = 0;
	if (++(ss->x) == ss->Width) {
	    /* Handle input and output padding. */
	    in_bits_left = 0;
	    if (byte_out != 1)
		while (byte_out < 0x100)
		    byte_out <<= 1;
	    ss->x = 0;
	}
    }
out:
    pr->ptr = p;
    pw->ptr = q;
    ss->byte_in = byte_in;
    ss->in_bits_left = in_bits_left;
    ss->next_component = next_component;
    ss->byte_out = byte_out;
    /* For simplicity, always update the record of the table size. */
    ss->Table.data[ss->Table.size - 1] =
	(ss->next_index == 0 ? 0 :
	 ss->next_index / ss->NumComponents - 1);
    return status;
}

const stream_template s_IE_template = {
    &st_IE_state, s_IE_init, s_IE_process, 1, 1,
    0 /* NULL */, s_IE_set_defaults
};

#if 0

/* Test code */
void
test_IE(void)
{
    const stream_template *const template = &s_IE_template;
    stream_IE_state state;
    stream_state *const ss = (stream_state *)&state;
    static const float decode[6] = {1, 0, 1, 0, 1, 0};
    static const byte in[] = {
	/*
	 * Each row is 3 pixels x 3 components x 4 bits.  Processing the
	 * first two rows doesn't cause an error; processing all 3 rows
	 * does.
	 */
	0x12, 0x35, 0x67, 0x9a, 0xb0,
	0x56, 0x7d, 0xef, 0x12, 0x30,
	0x88, 0x88, 0x88, 0x88, 0x80
    };
    byte table[3 * 5];
    int n;

    template->set_defaults(ss);
    state.BitsPerComponent = 4;
    state.NumComponents = 3;
    state.Width = 3;
    state.BitsPerIndex = 2;
    state.Decode = decode;
    gs_bytestring_from_bytes(&state.Table, table, 0, sizeof(table));
    for (n = 10; n <= 15; n += 5) {
	stream_cursor_read r;
	stream_cursor_write w;
	byte out[100];
	int status;

	s_IE_init(ss);
	r.ptr = in; --r.ptr;
	r.limit = r.ptr + n;
	w.ptr = out; --w.ptr;
	w.limit = w.ptr + sizeof(out);
	memset(table, 0xcc, sizeof(table));
	memset(out, 0xff, sizeof(out));
	dprintf1("processing %d bytes\n", n);
	status = template->process(ss, &r, &w, true);
	dprintf3("%d bytes read, %d bytes written, status = %d\n",
		 (int)(r.ptr + 1 - in), (int)(w.ptr + 1 - out), status);
	debug_dump_bytes(table, table + sizeof(table), "table");
	debug_dump_bytes(out, w.ptr + 1, "out");
    }
}

#endif

/* ---------------- Downsampling ---------------- */

/* Return the number of samples after downsampling. */
int
s_Downsample_size_out(int size_in, int factor, bool pad)
{
    return ((pad ? size_in + factor - 1 : size_in) / factor);
}

private void
s_Downsample_set_defaults(register stream_state * st)
{
    stream_Downsample_state *const ss = (stream_Downsample_state *)st;

    s_Downsample_set_defaults_inline(ss);
}

/* ------ Subsample ------ */

gs_private_st_simple(st_Subsample_state, stream_Subsample_state,
		     "stream_Subsample_state");

/* Initialize the state. */
private int
s_Subsample_init(stream_state * st)
{
    stream_Subsample_state *const ss = (stream_Subsample_state *) st;

    ss->x = ss->y = 0;
    return 0;
}

/* Process one buffer. */
private int
s_Subsample_process(stream_state * st, stream_cursor_read * pr,
		    stream_cursor_write * pw, bool last)
{
    stream_Subsample_state *const ss = (stream_Subsample_state *) st;
    const byte *p = pr->ptr;
    const byte *rlimit = pr->limit;
    byte *q = pw->ptr;
    byte *wlimit = pw->limit;
    int spp = ss->Colors;
    int width = ss->WidthIn, height = ss->HeightIn;
    int xf = ss->XFactor, yf = ss->YFactor;
    int xf2 = xf / 2, yf2 = yf / 2;
    int xlimit = (width / xf) * xf, ylimit = (height / yf) * yf;
    int xlast =
	(ss->padX && xlimit < width ? xlimit + (width % xf) / 2 : -1);
    int ylast =
	(ss->padY && ylimit < height ? ylimit + (height % yf) / 2 : -1);
    int x = ss->x, y = ss->y;
    int status = 0;

    if_debug4('w', "[w]subsample: x=%d, y=%d, rcount=%ld, wcount=%ld\n",
	      x, y, (long)(rlimit - p), (long)(wlimit - q));
    for (; rlimit - p >= spp; p += spp) {
	if (((y % yf == yf2 && y < ylimit) || y == ylast) &&
	    ((x % xf == xf2 && x < xlimit) || x == xlast)
	    ) {
	    if (wlimit - q < spp) {
		status = 1;
		break;
	    }
	    memcpy(q + 1, p + 1, spp);
	    q += spp;
	}
	if (++x == width)
	    x = 0, ++y;
    }
    if_debug5('w',
	      "[w]subsample: x'=%d, y'=%d, read %ld, wrote %ld, status = %d\n",
	      x, y, (long)(p - pr->ptr), (long)(q - pw->ptr), status);
    pr->ptr = p;
    pw->ptr = q;
    ss->x = x, ss->y = y;
    return status;
}

const stream_template s_Subsample_template = {
    &st_Subsample_state, s_Subsample_init, s_Subsample_process, 4, 4,
    0 /* NULL */, s_Downsample_set_defaults
};

/* ------ Average ------ */

private_st_Average_state();

/* Set default parameter values (actually, just clear pointers). */
private void
s_Average_set_defaults(stream_state * st)
{
    stream_Average_state *const ss = (stream_Average_state *) st;

    s_Downsample_set_defaults(st);
    /* Clear pointers */
    ss->sums = 0;
}

/* Initialize the state. */
private int
s_Average_init(stream_state * st)
{
    stream_Average_state *const ss = (stream_Average_state *) st;

    ss->sum_size =
	ss->Colors * ((ss->WidthIn + ss->XFactor - 1) / ss->XFactor);
    ss->copy_size = ss->sum_size -
	(ss->padX || (ss->WidthIn % ss->XFactor == 0) ? 0 : ss->Colors);
    ss->sums =
	(uint *)gs_alloc_byte_array(st->memory, ss->sum_size,
				    sizeof(uint), "Average sums");
    if (ss->sums == 0)
	return ERRC;	/****** WRONG ******/
    memset(ss->sums, 0, ss->sum_size * sizeof(uint));
    return s_Subsample_init(st);
}

/* Release the state. */
private void
s_Average_release(stream_state * st)
{
    stream_Average_state *const ss = (stream_Average_state *) st;

    gs_free_object(st->memory, ss->sums, "Average sums");
}

/* Process one buffer. */
private int
s_Average_process(stream_state * st, stream_cursor_read * pr,
		  stream_cursor_write * pw, bool last)
{
    stream_Average_state *const ss = (stream_Average_state *) st;
    const byte *p = pr->ptr;
    const byte *rlimit = pr->limit;
    byte *q = pw->ptr;
    byte *wlimit = pw->limit;
    int spp = ss->Colors;
    int width = ss->WidthIn;
    int xf = ss->XFactor, yf = ss->YFactor;
    int x = ss->x, y = ss->y;
    uint *sums = ss->sums;
    int status = 0;

top:
    if (y == yf || (last && p >= rlimit && ss->padY && y != 0)) {
	/* We're copying averaged values to the output. */
	int ncopy = min(ss->copy_size - x, wlimit - q);

	if (ncopy) {
	    int scale = xf * y;

	    while (--ncopy >= 0)
		*++q = (byte) (sums[x++] / scale);
	}
	if (x < ss->copy_size) {
	    status = 1;
	    goto out;
	}
	/* Done copying. */
	x = y = 0;
	memset(sums, 0, ss->sum_size * sizeof(uint));
    }
    while (rlimit - p >= spp) {
	uint *bp = sums + x / xf * spp;
	int i;

	for (i = spp; --i >= 0;)
	    *bp++ += *++p;
	if (++x == width) {
	    x = 0;
	    ++y;
	    goto top;
	}
    }
out:
    pr->ptr = p;
    pw->ptr = q;
    ss->x = x, ss->y = y;
    return status;
}

const stream_template s_Average_template = {
    &st_Average_state, s_Average_init, s_Average_process, 4, 4,
    s_Average_release, s_Average_set_defaults
};