% pdfcolorstack.w
% 
% Copyright 2009-2010 Taco Hoekwater <taco@@luatex.org>

% This file is part of LuaTeX.

% LuaTeX is free software; you can redistribute it and/or modify it under
% the terms of the GNU General Public License as published by the Free
% Software Foundation; either version 2 of the License, or (at your
% option) any later version.

% LuaTeX 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.  See the GNU Lesser General Public
% License for more details.

% You should have received a copy of the GNU General Public License along
% with LuaTeX; if not, see <http://www.gnu.org/licenses/>. 

@ @c
#include "ptexlib.h"

static const char _svn_version[] =
    "$Id: pdfcolorstack.w 3891 2010-09-14 23:02:24Z hhenkel $"
    "$URL: http://foundry.supelec.fr/svn/luatex/tags/beta-0.70.1/source/texk/web2c/luatexdir/pdf/pdfcolorstack.w $";


@* Color Stack and Matrix Transformation Support.


@ In the following array and especially stack data structures are used.

They have the following properties:

    \item{-} They automatically grow dynamically.
    \item{-} The size never decreases.
    \item{-} The variable with name ending in "size" contains the number how many
      entries the data structure can hold.
    \item{-} The variable with name ending in "used" contains the number of
      actually used entries.
    \item{-} Memory of strings in stack entries must be allocated and
      freed if the stack is cleared.


@ Color Stack 
@c
#define MAX_COLORSTACKS 32768
/* The colorstack number is stored in two bytes (info field of the node) */
/* Condition (newcolorstack): |MAX_COLORSTACKS mod STACK_INCREMENT = 0| */

#define COLOR_DEFAULT "0 g 0 G"
/* |literal_mode|s, see pdftex.web */
#define SET_ORIGIN 0
#define DIRECT_PAGE 1
#define DIRECT_ALWAYS 2

typedef struct {
    char **page_stack;
    char **form_stack;
    char *page_current;
    char *form_current;
    char *form_init;
    int page_size;
    int form_size;
    int page_used;
    int form_used;
    int literal_mode;
    boolean page_start;
} colstack_type;

static colstack_type *colstacks = NULL;
static int colstacks_size = 0;
static int colstacks_used = 0;

@ Initialization is done, if the color stacks are used,
    |init_colorstacks()| is defined as macro to avoid unnecessary
    procedure calls.
@c
#define init_colorstacks() if (colstacks_size == 0) colstacks_first_init();

static void colstacks_first_init(void)
{
    colstacks_size = STACK_INCREMENT;
    colstacks = xtalloc((unsigned) colstacks_size, colstack_type);
    colstacks_used = 1;
    colstacks[0].page_stack = NULL;
    colstacks[0].form_stack = NULL;
    colstacks[0].page_size = 0;
    colstacks[0].form_size = 0;
    colstacks[0].page_used = 0;
    colstacks[0].form_used = 0;
    colstacks[0].page_current = xstrdup(COLOR_DEFAULT);
    colstacks[0].form_current = xstrdup(COLOR_DEFAULT);
    colstacks[0].form_init = xstrdup(COLOR_DEFAULT);
    colstacks[0].literal_mode = DIRECT_ALWAYS;
    colstacks[0].page_start = true;
}

@ @c
int colorstackused(void)
{
    init_colorstacks();
    return colstacks_used;
}

@  |newcolorstack()|
    A new color stack is setup with the given parameters.
    The stack number is returned or -1 in case of error (no room).
@c
int newcolorstack(int s, int literal_mode, boolean page_start)
{
    colstack_type *colstack;
    int colstack_num;
    char *str;

    init_colorstacks();

    /* make room */
    if (colstacks_used == MAX_COLORSTACKS) {
        return -1;
    }
    if (colstacks_used == colstacks_size) {
        colstacks_size += STACK_INCREMENT;
        /* If |(MAX_COLORSTACKS mod STACK_INCREMENT = 0)| then we don't
           need to check the case that size overruns |MAX_COLORSTACKS|. */
        colstacks =
            xreallocarray(colstacks, colstack_type, (unsigned) colstacks_size);
    }
    /* claim new color stack */
    colstack_num = colstacks_used++;
    colstack = &colstacks[colstack_num];
    /* configure the new color stack */
    colstack->page_stack = NULL;
    colstack->form_stack = NULL;
    colstack->page_size = 0;
    colstack->page_used = 0;
    colstack->form_size = 0;
    colstack->form_used = 0;
    colstack->literal_mode = literal_mode;
    colstack->page_start = page_start;
    str = makecstring(s);
    if (*str == 0) {
        colstack->page_current = NULL;
        colstack->form_current = NULL;
        colstack->form_init = NULL;
    } else {
        colstack->page_current = xstrdup(str);
        colstack->form_current = xstrdup(str);
        colstack->form_init = xstrdup(str);
    }
    free(str);
    return colstack_num;
}

@ @c
#define get_colstack(n) (&colstacks[n])

@ Puts a string on top of the string pool and updates |pool_ptr|. 
@c
static void put_cstring_on_str_pool(char *str)
{
    int save_selector = selector;
    selector = new_string;
    if (str == NULL || *str == 0) {
        return;
    }
    tprint(str);
    selector = save_selector;
}

@ @c
static int colorstackset(int colstack_no, str_number s)
{
    colstack_type *colstack = get_colstack(colstack_no);

    if (global_shipping_mode == SHIPPING_PAGE) {
        xfree(colstack->page_current);
        colstack->page_current = makecstring(s);
    } else {
        xfree(colstack->form_current);
        colstack->form_current = makecstring(s);
    }
    return colstack->literal_mode;
}

@ @c
int colorstackcurrent(int colstack_no)
{
    colstack_type *colstack = get_colstack(colstack_no);

    if (global_shipping_mode == SHIPPING_PAGE) {
        put_cstring_on_str_pool(colstack->page_current);
    } else {
        put_cstring_on_str_pool(colstack->form_current);
    }
    return colstack->literal_mode;
}

@ @c
static int colorstackpush(int colstack_no, str_number s)
{
    colstack_type *colstack = get_colstack(colstack_no);
    char *str;
    if (global_shipping_mode == SHIPPING_PAGE) {
        if (colstack->page_used == colstack->page_size) {
            colstack->page_size += STACK_INCREMENT;
            colstack->page_stack = xretalloc(colstack->page_stack,
                                             (unsigned) colstack->page_size,
                                             char *);
        }
        colstack->page_stack[colstack->page_used++] = colstack->page_current;
        str = makecstring(s);
        if (*str == 0) {
            colstack->page_current = NULL;
        } else {
            colstack->page_current = xstrdup(str);
        }
        free(str);
    } else {
        if (colstack->form_used == colstack->form_size) {
            colstack->form_size += STACK_INCREMENT;
            colstack->form_stack = xretalloc(colstack->form_stack,
                                             (unsigned) colstack->form_size,
                                             char *);
        }
        colstack->form_stack[colstack->form_used++] = colstack->form_current;
        str = makecstring(s);
        if (*str == 0) {
            colstack->form_current = NULL;
        } else {
            colstack->form_current = xstrdup(str);
        }
        free(str);
    }
    return colstack->literal_mode;
}

@ @c
int colorstackpop(int colstack_no)
{
    colstack_type *colstack = get_colstack(colstack_no);

    if (global_shipping_mode == SHIPPING_PAGE) {
        if (colstack->page_used == 0) {
            pdftex_warn("pop empty color page stack %u",
                        (unsigned int) colstack_no);
            return colstack->literal_mode;
        }
        xfree(colstack->page_current);
        colstack->page_current = colstack->page_stack[--colstack->page_used];
        put_cstring_on_str_pool(colstack->page_current);
    } else {
        if (colstack->form_used == 0) {
            pdftex_warn("pop empty color form stack %u",
                        (unsigned int) colstack_no);
            return colstack->literal_mode;
        }
        xfree(colstack->form_current);
        colstack->form_current = colstack->form_stack[--colstack->form_used];
        put_cstring_on_str_pool(colstack->form_current);
    }
    return colstack->literal_mode;
}

@ @c
void colorstackpagestart(void)
{
    int i, j;
    colstack_type *colstack;

    if (global_shipping_mode == SHIPPING_PAGE) {
        /* see procedure |pdf_out_colorstack_startpage| */
        return;
    }

    for (i = 0; i < colstacks_used; i++) {
        colstack = &colstacks[i];
        for (j = 0; j < colstack->form_used; j++) {
            xfree(colstack->form_stack[j]);
        }
        colstack->form_used = 0;
        xfree(colstack->form_current);
        if (colstack->form_init == NULL) {
            colstack->form_current = NULL;
        } else {
            colstack->form_current = xstrdup(colstack->form_init);
        }
    }
}

@ @c
int colorstackskippagestart(int colstack_no)
{
    colstack_type *colstack = get_colstack(colstack_no);

    if (!colstack->page_start) {
        return 1;
    }
    if (colstack->page_current == NULL) {
        return 0;
    }
    if (strcmp(COLOR_DEFAULT, colstack->page_current) == 0) {
        return 2;
    }
    return 0;
}


@ @c
void pdf_out_colorstack(PDF pdf, halfword p)
{
    int old_setting;
    str_number s;
    int cmd;
    int stack_no;
    int literal_mode;
    cmd = pdf_colorstack_cmd(p);
    stack_no = pdf_colorstack_stack(p);
    literal_mode = 0;
    if (stack_no >= colorstackused()) {
        tprint_nl("");
        tprint("Color stack ");
        print_int(stack_no);
        tprint(" is not initialized for use!");
        tprint_nl("");
        return;
    }
    switch (cmd) {
    case colorstack_set:
    case colorstack_push:
        old_setting = selector;
        selector = new_string;
        show_token_list(token_link(pdf_colorstack_data(p)), null, -1);
        selector = old_setting;
        s = make_string();
        if (cmd == colorstack_set)
            literal_mode = colorstackset(stack_no, s);
        else
            literal_mode = colorstackpush(stack_no, s);
        if (str_length(s) > 0)
            pdf_literal(pdf, s, literal_mode, false);
        flush_str(s);
        return;
        break;
    case colorstack_pop:
        literal_mode = colorstackpop(stack_no);
        break;
    case colorstack_current:
        literal_mode = colorstackcurrent(stack_no);
        break;
    default:
        break;
    }
    if (cur_length > 0) {
        s = make_string();
        pdf_literal(pdf, s, literal_mode, false);
        flush_str(s);
    }
}

@ @c
void pdf_out_colorstack_startpage(PDF pdf)
{
    int i;
    int max;
    int start_status;
    int literal_mode;
    str_number s;
    i = 0;
    max = colorstackused();
    while (i < max) {
        start_status = colorstackskippagestart(i);
        if (start_status == 0) {
            literal_mode = colorstackcurrent(i);
            if (cur_length > 0) {
                s = make_string();
                pdf_literal(pdf, s, literal_mode, false);
                flush_str(s);
            }
        }
        i++;
    }
}