/* Copyright (C) 2001-2019 Artifex Software, Inc.
   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied,
   modified or distributed except as expressly authorized under the terms
   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  1305 Grant Avenue - Suite 200, Novato,
   CA 94945, U.S.A., +1(415)492-9861, for further information.
*/


/* pgparse.c */
/* HP-GL/2 parser */
#include "math_.h"
#include "stdio_.h"
#include "gdebug.h"
#include "gstypes.h"
#include "scommon.h"
#include "pgmand.h"

/* ---------------- Command definition ---------------- */

/* Register a command.  Return true if this is a redefinition. */
static bool
hpgl_register_command(hpgl_parser_state_t * pgl_parser_state,
                      byte * pindex, const hpgl_command_definition_t * pcmd)
{
    int index = pgl_parser_state->hpgl_command_next_index;
    byte prev = *pindex;

    if (prev != 0 && prev <= index &&
        pgl_parser_state->hpgl_command_list[prev] == pcmd)
        index = prev;
    else if (index != 0
             && pgl_parser_state->hpgl_command_list[index] == pcmd);
    else
        pgl_parser_state->hpgl_command_list[pgl_parser_state->
                                            hpgl_command_next_index =
                                            ++index] =
            (hpgl_command_definition_t *) pcmd;
    *pindex = index;
    return (prev != 0 && prev != index);
}

/* Define a list of commands. */
void
hpgl_define_commands(const gs_memory_t * mem,
                     const hpgl_named_command_t * pcmds,
                     hpgl_parser_state_t * pgl_parser_state)
{
    const hpgl_named_command_t *pcmd = pcmds;

    for (; pcmd->char1; ++pcmd)
#ifdef DEBUG
        if (
#endif
               hpgl_register_command(pgl_parser_state,
                                     &pgl_parser_state->hpgl_command_indices
                                     [pcmd->char1 - 'A'][pcmd->char2 - 'A'],
                                     &pcmd->defn)
#ifdef DEBUG
            )
            dmprintf2(mem, "Redefining command %c%c\n", pcmd->char1,
                      pcmd->char2);
#endif
    ;
}

/* ---------------- Parsing ---------------- */

/* Initialize the HP-GL/2 parser state. */
void
hpgl_process_init(hpgl_parser_state_t * pst)
{
    pst->first_letter = -1;
    pst->command = 0;
}

/* Process a buffer of HP-GL/2 commands. */
/* Return 0 if more input needed, 1 if ESC seen, or an error code. */
int
hpgl_process(hpgl_parser_state_t * pst, hpgl_state_t * pgls,
             stream_cursor_read * pr)
{
    const byte *p = pr->ptr;
    const byte *rlimit = pr->limit;
    int code = 0;
    jmp_buf exit_to_parser;

    /* We do this slightly naff setup of the buffer so the
     * buffer is sure to be currectly aligned - 64 bit MSVS 2010+
     * build requires the jmp_buf to be aligned to 16 bytes.
     */
    pst->exit_to_parser = &exit_to_parser;

    pst->source.limit = rlimit;
    /* Prepare to catch a longjmp indicating the argument scanner */
    /* needs more data, or encountered an error. */
    code = setjmp(*(pst->exit_to_parser));
    if (code) {
        /* The command detected an error, or we need to ask */
        /* the caller for more data.  pst->command != 0. */
        pr->ptr = pst->source.ptr;
        pst->exit_to_parser = NULL;
        if (code < 0 && code != gs_error_NeedInput) {
            pst->command = 0;   /* cancel command */
            if_debug0m('i', pgls->memory, "\n");
            return code;
        }
        return 0;
    }
    /* Check whether we're still feeding data to a command. */
  call:if (pst->command) {
        pst->source.ptr = p;
        pst->arg.next = 0;
        code = (*pst->command->proc) (pst, pgls);
        p = pst->source.ptr;
        /* cancel the command for any error other than needing
           more data */
        if (code < 0 && code != gs_error_NeedInput)
            pst->command = 0;
        if (code < 0)
            goto x;
        pst->command = 0;
        if_debug0m('i', pgls->memory, "\n");
    }
    while (p < rlimit) {
        byte next = *++p;

        if (next >= 'A' && next <= 'Z')
            next -= 'A';
        else if (next >= 'a' && next <= 'z')
            next -= 'a';
        else if (next == ESC) {
            --p;
            pst->first_letter = -1;
            code = 1;
            break;
        } else {                /* ignore everything else */
            /* Apparently this is what H-P plotters do.... */
            if (next > ' ' && next != ',')
                pst->first_letter = -1;
            continue;
        }
        if (pst->first_letter < 0) {
            pst->first_letter = next;
            continue;
        }
        {
            int index = pst->hpgl_command_indices[pst->first_letter][next];

#ifdef DEBUG
            if (gs_debug_c('i')) {
                char c = (index ? '-' : '?');

                dmprintf4(pgls->memory, "--%c%c%c%c",
                          pst->first_letter + 'A', next + 'A', c, c);
            }
#endif
            if (index == 0) {   /* anomalous, drop 1st letter */
                pst->first_letter = next;
                continue;
            }
            pst->first_letter = -1;
            pst->command = pst->hpgl_command_list[index];
            pst->phase = 0;
            pst->done = false;
            hpgl_args_init(pst);
            /*
             * Only a few commands should be executed while we're in
             * polygon mode: check for this here.  Note that we rely
             * on the garbage-skipping property of the parser to skip
             * over any following arguments.  This doesn't work for
             * the few commands with special syntax that should be
             * ignored in polygon mode (CO, DT, LB, SM); they must be
             * flagged as executable even in polygon mode, and check
             * the render_mode themselves.
             */
            {
                bool ignore_command = false;

                if ((pgls->g.polygon_mode) &&
                    !(pst->command->flags & hpgl_cdf_polygon)
                    )
                    ignore_command = true;
                else {          /* similarly if we are in lost mode we do not
                                   execute the commands that are only defined to
                                   be used when lost mode is cleared. */
                    if ((pgls->g.lost_mode == hpgl_lost_mode_entered) &&
                        (pst->command->flags & hpgl_cdf_lost_mode_cleared)
                        )
                        ignore_command = true;
                }
                /* Also, check that we have a command that can be executed
                   with the current personality.  NB reorganize me. */
                if (pgls->personality == rtl)
                    if (!(pst->command->flags & hpgl_cdf_rtl))  /* not rtl pcl only */
                        ignore_command = true;
                if ((pgls->personality == pcl5c)
                    || (pgls->personality == pcl5e))
                    if (!(pst->command->flags & hpgl_cdf_pcl))  /* not pcl rtl only */
                        ignore_command = true;
                if (ignore_command)
                    pst->command = 0;
            }
            goto call;
        }
    }
  x:pr->ptr = p;
    pst->exit_to_parser = NULL;

    /*
     * Within a macro we can't run out of data since all the data is
     * available in memory.
     */
    if (pgls->macro_level > 0 && (code == gs_error_NeedInput))
        code = gs_error_Fatal;
        
    return (code == gs_error_NeedInput ? 0 : code);
}

/*
 * Get a numeric HP-GL/2 argument from the input stream.  Return 0 if no
 * argument, a pointer to the value if an argument is present, or longjmp if
 * need more data.  Note that no errors are possible.
 */
static const hpgl_value_t *
hpgl_arg(const gs_memory_t * mem, hpgl_parser_state_t * pst)
{
    const byte *p;
    const byte *rlimit;
    hpgl_value_t *pvalue;

#define parg (&pst->arg)
    if (parg->next < parg->count) {     /* We're still replaying already-scanned arguments. */
        return &parg->scanned[parg->next++];
    }
    if (pst->done)
        return 0;
    p = pst->source.ptr;
    rlimit = pst->source.limit;
    pvalue = &parg->scanned[parg->count];
#define check_value()\
  if ( parg->have_value ) goto done

    for (; p < rlimit; ++p) {
        byte ch = p[1];

        switch (ch) {
            case '+':
                check_value();
                parg->have_value = 1;
                parg->sign = 1;
                pvalue->v_n.i = 0;
                break;
            case '-':
                check_value();
                parg->have_value = 1;
                parg->sign = -1;
                pvalue->v_n.i = 0;
                break;
            case '.':
                switch (parg->have_value) {
                    default:   /* > 1 */
                        goto out;
                    case 0:
                        pvalue->v_n.r = 0;
                        break;
                    case 1:
                    {
                       /* Strictly speaking assigning one element of union
                        * to another, overlapping element of a different size is
                        * undefined behavior, hence assign to an intermediate variable
                        */
                        double r = (double)pvalue->v_n.i;
                        pvalue->v_n.r = r;
                    }
                }
                parg->have_value = 2;
                parg->frac_scale = 1.0;
                break;
            case ';':
                pst->done = true;
                check_value();
                goto out;
            case HT:
            case LF:
            case FF:
            case CR:
                /* control charachers are ignored during parsing hpgl
                 */
                continue;
            case SP:
            case ',':
                /*
                 * The specification doesn't say what to do with extra
                 * separators; we just ignore them.
                 */
                if (!parg->have_value)
                    break;
                ++p;
              done:if (parg->sign < 0) {
                    if (parg->have_value > 1)
                        pvalue->v_n.r = -pvalue->v_n.r;
                    else
                        pvalue->v_n.i = -pvalue->v_n.i;
                }
                goto out;
            case '0':
            case '1':
            case '2':
            case '3':
            case '4':
            case '5':
            case '6':
            case '7':
            case '8':
            case '9':
                ch -= '0';
#define max_i 0x7fffffff
                switch (parg->have_value) {
                    default:   /* case 2 */
                        pvalue->v_n.r += ch / (parg->frac_scale *= 10);
                        break;
                    case 0:
                        parg->have_value = 1;
                        pvalue->v_n.i = ch;
                        break;
                    case 1:
                        if (pvalue->v_n.i >= max_i / 10 &&
                            (pvalue->v_n.i > max_i / 10 || ch > max_i % 10)
                            )
                            return NULL;
                        else
                            pvalue->v_n.i = pvalue->v_n.i * 10 + ch;
                }
                break;
            default:
                pst->done = true;
                check_value();
                goto out;
        }
    }
    /* We ran out of data before reaching a terminator. */
    pst->source.ptr = p;
    longjmp(*(pst->exit_to_parser), gs_error_NeedInput);
    /* NOTREACHED */
  out:pst->source.ptr = p;
    switch (parg->have_value) {
        case 0:                /* no argument */
            return NULL;
        case 1:                /* integer */
            if_debug1m('i', mem, "  %ld", (long)pvalue->v_n.i);
            pvalue->is_real = false;
            break;
        default /* case 2 */ : /* real */
            if_debug1m('i', mem, "  %g", pvalue->v_n.r);
            pvalue->is_real = true;
    }
    hpgl_arg_init(pst);
    parg->next = ++(parg->count);
    return pvalue;
#undef parg
}

/* Get a real argument. */
bool
hpgl_arg_real(const gs_memory_t * mem, hpgl_args_t * pargs, hpgl_real_t * pr)
{
    const hpgl_value_t *pvalue = hpgl_arg(mem, pargs);

    if (!pvalue)
        return false;
    *pr = (pvalue->is_real ? pvalue->v_n.r : pvalue->v_n.i);
    return true;
}

/* Get a clamped real argument. */
bool
hpgl_arg_c_real(const gs_memory_t * mem,
                hpgl_args_t * pargs, hpgl_real_t * pr)
{
    const hpgl_value_t *pvalue = hpgl_arg(mem, pargs);
    hpgl_real_t r;

    if (!pvalue)
        return false;
    r = (pvalue->is_real ? pvalue->v_n.r : pvalue->v_n.i);
    *pr = (r < -32768 ? -32768 : r > 32767 ? 32767 : r);
    return true;

}

/* Get an integer argument. */
bool
hpgl_arg_int(const gs_memory_t * mem, hpgl_args_t * pargs, int32 * pi)
{
    const hpgl_value_t *pvalue = hpgl_arg(mem, pargs);

    if (!pvalue)
        return false;
    *pi = (pvalue->is_real ? (int32) pvalue->v_n.r : pvalue->v_n.i);
    return true;
}

/* Get a clamped integer argument. */
bool
hpgl_arg_c_int(const gs_memory_t * mem, hpgl_args_t * pargs, int *pi)
{
    const hpgl_value_t *pvalue = hpgl_arg(mem, pargs);
    int32 i;

    if (!pvalue)
        return false;
    i = (pvalue->is_real ? (int32) pvalue->v_n.r : pvalue->v_n.i);
    *pi = (i < -32768 ? -32768 : i > 32767 ? 32767 : i);
    return true;
}

/* Get a "current units" argument. */
bool
hpgl_arg_units(const gs_memory_t * mem, hpgl_args_t * pargs, hpgl_real_t * pu)
{       /****** PROBABLY WRONG ******/
    return hpgl_arg_real(mem, pargs, pu);
}

/* initialize the HPGL command counter */
int
hpgl_init_command_index(hpgl_parser_state_t ** pgl_parser_state,
                        gs_memory_t * mem)
{
    hpgl_parser_state_t *pgst =
        (hpgl_parser_state_t *) gs_alloc_bytes(mem,
                                               sizeof(hpgl_parser_state_t),
                                               "hpgl_init_command_index");

    /* fatal */
    if (pgst == 0) {
        *pgl_parser_state = NULL;
        return -1;
    }

    pgst->exit_to_parser = NULL;
    pgst->hpgl_command_next_index = 0;
    /* NB fix me the parser should not depend on this behavior the
       previous design had these in bss which was automatically
       cleared to zero. */
    memset(pgst->hpgl_command_indices, 0, sizeof(pgst->hpgl_command_indices));
    hpgl_process_init(pgst);
    *pgl_parser_state = pgst;
    return 0;
}
