/* Copyright (C) 2018-2023 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.,  39 Mesa Street, Suite 108A, San Francisco,
   CA 94129, USA, for further information.
*/

/* Stack operations for the PDF interpreter */

#include "ghostpdf.h"
#include "pdf_types.h"
#include "pdf_int.h"
#include "pdf_stack.h"

int pdfi_pop(pdf_context *ctx, int num)
{
    int code = 0;
    if (num < 0)
        return_error(gs_error_rangecheck);

    if (pdfi_count_stack(ctx) < num) {
        code = gs_note_error(gs_error_stackunderflow);
        num = pdfi_count_stack(ctx);
        pdfi_set_warning(ctx, 0, NULL, W_PDF_STACKUNDERFLOW, "pdfi_pop", NULL);
    }
    while(num) {
        pdfi_countdown(ctx->stack_top[-1]);
        ctx->stack_top--;
        num--;
    }
    return code;
}

int pdfi_push(pdf_context *ctx, pdf_obj *o)
{
    pdf_obj **new_stack;
    uint32_t entries = 0;

    if (ctx->stack_top < ctx->stack_bot)
        ctx->stack_top = ctx->stack_bot;

    if (ctx->stack_top >= ctx->stack_limit) {
        if (ctx->stack_size >= MAX_STACK_SIZE)
            return_error(gs_error_pdf_stackoverflow);

        new_stack = (pdf_obj **)gs_alloc_bytes(ctx->memory, (ctx->stack_size + INITIAL_STACK_SIZE) * sizeof (pdf_obj *), "pdfi_push_increase_interp_stack");
        if (new_stack == NULL)
            return_error(gs_error_VMerror);

        memcpy(new_stack, ctx->stack_bot, ctx->stack_size * sizeof(pdf_obj *));
        gs_free_object(ctx->memory, ctx->stack_bot, "pdfi_push_increase_interp_stack");

        entries = pdfi_count_total_stack(ctx);

        ctx->stack_bot = new_stack;
        ctx->stack_top = ctx->stack_bot + entries;
        ctx->stack_size += INITIAL_STACK_SIZE;
        ctx->stack_limit = ctx->stack_bot + ctx->stack_size;
    }

    *ctx->stack_top = o;
    ctx->stack_top++;
    pdfi_countup(o);

    return 0;
}

int pdfi_mark_stack(pdf_context *ctx, pdf_obj_type type)
{
    pdf_obj *o;
    int code;

    if (type != PDF_ARRAY_MARK && type != PDF_DICT_MARK && type != PDF_PROC_MARK)
        return_error(gs_error_typecheck);

    code = pdfi_object_alloc(ctx, type, 0, &o);
    if (code < 0)
        return code;

    code = pdfi_push(ctx, o);
    if (code < 0)
        pdfi_free_object(o);
    return code;
}

void pdfi_clearstack(pdf_context *ctx)
{
    pdfi_pop(ctx, pdfi_count_stack(ctx));
}

int pdfi_count_to_mark(pdf_context *ctx, uint64_t *count)
{
    pdf_obj *o = ctx->stack_top[- 1];
    int index = -1;
    pdf_obj **save_bot = NULL;

    save_bot = ctx->stack_bot + ctx->current_stream_save.stack_count;

    *count = 0;
    while (&ctx->stack_top[index] >= save_bot) {
        if (pdfi_type_of(o) == PDF_ARRAY_MARK || pdfi_type_of(o) == PDF_DICT_MARK || pdfi_type_of(o) == PDF_PROC_MARK )
            return 0;
        o = ctx->stack_top[--index];
        (*count)++;
    }
    return_error(gs_error_unmatchedmark);
}

int pdfi_clear_to_mark(pdf_context *ctx)
{
    int code;
    uint64_t count;

    code = pdfi_count_to_mark(ctx, &count);
    if (code < 0)
        return code;
    return pdfi_pop(ctx, count + 1);
}

int
pdfi_destack_real(pdf_context *ctx, double *d)
{
    int code;

    if (pdfi_count_stack(ctx) < 1)
        return_error(gs_error_stackunderflow);

    code = pdfi_obj_to_real(ctx, ctx->stack_top[-1], d);
    if (code < 0) {
        pdfi_clearstack(ctx);
        return code;
    }
    pdfi_pop(ctx, 1);

    return 0;
}

int
pdfi_destack_reals(pdf_context *ctx, double *d, int n)
{
    int i, code;

    if (pdfi_count_stack(ctx) < n) {
        pdfi_clearstack(ctx);
        return_error(gs_error_stackunderflow);
    }

    for (i = 0; i < n; i++) {
        code = pdfi_obj_to_real(ctx, ctx->stack_top[i-n], &d[i]);
        if (code < 0) {
            pdfi_clearstack(ctx);
            return code;
        }
    }
    pdfi_pop(ctx, n);

    return 0;
}

int
pdfi_destack_floats(pdf_context *ctx, float *d, int n)
{
    int i, code;

    if (pdfi_count_stack(ctx) < n) {
        pdfi_clearstack(ctx);
        return_error(gs_error_stackunderflow);
    }

    for (i = 0; i < n; i++) {
        code = pdfi_obj_to_float(ctx, ctx->stack_top[i-n], &d[i]);
        if (code < 0) {
            pdfi_clearstack(ctx);
            return code;
        }
    }
    pdfi_pop(ctx, n);

    return 0;
}

int
pdfi_destack_int(pdf_context *ctx, int64_t *i)
{
    int code;

    if (pdfi_count_stack(ctx) < 1)
        return_error(gs_error_stackunderflow);

    code = pdfi_obj_to_int(ctx, ctx->stack_top[-1], i);
    if (code < 0) {
        pdfi_clearstack(ctx);
        return code;
    }
    pdfi_pop(ctx, 1);

    return 0;
}

int
pdfi_destack_ints(pdf_context *ctx, int64_t *i64, int n)
{
    int i, code;

    if (pdfi_count_stack(ctx) < n) {
        pdfi_clearstack(ctx);
        return_error(gs_error_stackunderflow);
    }

    for (i = 0; i < n; i++) {
        code = pdfi_obj_to_int(ctx, ctx->stack_top[i-n], &i64[i]);
        if (code < 0) {
            pdfi_clearstack(ctx);
            return code;
        }
    }
    pdfi_pop(ctx, n);

    return 0;
}