/*

  zip_source_window.c -- return part of lower source

  Copyright (C) 2012-2024 Dieter Baron and Thomas Klausner

  This file is part of libzip, a library to manipulate ZIP archives.

  The authors can be contacted at <info@libzip.org>

  Redistribution and use in source and binary forms, with or without

  modification, are permitted provided that the following conditions

  are met:

  1. Redistributions of source code must retain the above copyright

     notice, this list of conditions and the following disclaimer.

  2. Redistributions in binary form must reproduce the above copyright

     notice, this list of conditions and the following disclaimer in

     the documentation and/or other materials provided with the

     distribution.

  3. The names of the authors may not be used to endorse or promote

     products derived from this software without specific prior

     written permission.

  THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS

  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY

  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

  GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER

  IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR

  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN

  IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

#include <stdlib.h>

#include <string.h>

#include "zipint.h"

struct window {

    zip_uint64_t start; /* where in file we start reading */

    zip_uint64_t end;   /* where in file we stop reading */

    bool end_valid;     /* whether end is set, otherwise read until EOF */

    /* if not NULL, read file data for this file */

    zip_t *source_archive;

    zip_uint64_t source_index;

    zip_uint64_t offset; /* offset in src for next read */

    zip_stat_t stat;

    zip_uint64_t stat_invalid;

    zip_file_attributes_t attributes;

    zip_dostime_t dostime;

    bool dostime_valid;

    zip_error_t error;

    zip_int64_t supports;

    bool needs_seek;

};

static zip_int64_t window_read(zip_source_t *, void *, void *, zip_uint64_t, zip_source_cmd_t);

ZIP_EXTERN zip_source_t *

zip_source_window_create(zip_source_t *src, zip_uint64_t start, zip_int64_t len, zip_error_t *error) {

    return _zip_source_window_new(src, start, len, NULL, 0, NULL, NULL, NULL, 0, false, error);

}

zip_source_t *

_zip_source_window_new(zip_source_t *src, zip_uint64_t start, zip_int64_t length, zip_stat_t *st, zip_uint64_t st_invalid, zip_file_attributes_t *attributes, zip_dostime_t *dostime, zip_t *source_archive, zip_uint64_t source_index, bool take_ownership, zip_error_t *error) {

    zip_source_t* window_source;

    struct window *ctx;

    if (src == NULL || length < -1 || (source_archive == NULL && source_index != 0)) {

        zip_error_set(error, ZIP_ER_INVAL, 0);

        return NULL;

    }

    if (length >= 0) {

        if (start + (zip_uint64_t)length < start) {

            zip_error_set(error, ZIP_ER_INVAL, 0);

            return NULL;

        }

    }

    if ((ctx = (struct window *)malloc(sizeof(*ctx))) == NULL) {

        zip_error_set(error, ZIP_ER_MEMORY, 0);

        return NULL;

    }

    ctx->start = start;

    if (length == -1) {

        ctx->end_valid = false;

    }

    else {

        ctx->end = start + (zip_uint64_t)length;

        ctx->end_valid = true;

    }

    zip_stat_init(&ctx->stat);

    ctx->stat_invalid = st_invalid;

    if (attributes != NULL) {

        (void)memcpy_s(&ctx->attributes, sizeof(ctx->attributes), attributes, sizeof(ctx->attributes));

    }

    else {

        zip_file_attributes_init(&ctx->attributes);

    }

    if (dostime != NULL) {

        ctx->dostime = *dostime;

        ctx->dostime_valid = true;

    }

    else {

        ctx->dostime_valid = false;

    }

    ctx->source_archive = source_archive;

    ctx->source_index = source_index;

    zip_error_init(&ctx->error);

    ctx->supports = (zip_source_supports(src) & (ZIP_SOURCE_SUPPORTS_SEEKABLE | ZIP_SOURCE_SUPPORTS_REOPEN)) | (zip_source_make_command_bitmap(ZIP_SOURCE_GET_FILE_ATTRIBUTES, ZIP_SOURCE_GET_DOS_TIME, ZIP_SOURCE_SUPPORTS, ZIP_SOURCE_TELL, ZIP_SOURCE_FREE, -1));

    ctx->needs_seek = (ctx->supports & ZIP_SOURCE_MAKE_COMMAND_BITMASK(ZIP_SOURCE_SEEK)) ? true : false;

    if (st) {

        if (_zip_stat_merge(&ctx->stat, st, error) < 0) {

            free(ctx);

            return NULL;

        }

    }

    window_source = zip_source_layered_create(src, window_read, ctx, error);

    if (window_source != NULL && !take_ownership) {

        zip_source_keep(src);

    }

    return window_source;

}

int

_zip_source_set_source_archive(zip_source_t *src, zip_t *za) {

    src->source_archive = za;

    return _zip_register_source(za, src);

}

/* called by zip_discard to avoid operating on file from closed archive */

void

_zip_source_invalidate(zip_source_t *src) {

    src->source_closed = 1;

    if (zip_error_code_zip(&src->error) == ZIP_ER_OK) {

        zip_error_set(&src->error, ZIP_ER_ZIPCLOSED, 0);

    }

}

static zip_int64_t

window_read(zip_source_t *src, void *_ctx, void *data, zip_uint64_t len, zip_source_cmd_t cmd) {

    struct window *ctx;

    zip_int64_t ret;

    zip_uint64_t n, i;

    ctx = (struct window *)_ctx;

    switch (cmd) {

    case ZIP_SOURCE_CLOSE:

        return 0;

    case ZIP_SOURCE_ERROR:

        return zip_error_to_data(&ctx->error, data, len);

    case ZIP_SOURCE_FREE:

        free(ctx);

        return 0;

    case ZIP_SOURCE_OPEN:

        if (ctx->source_archive) {

            zip_uint64_t offset;

            if ((offset = _zip_file_get_offset(ctx->source_archive, ctx->source_index, &ctx->error)) == 0) {

                return -1;

            }

            if (ctx->end + offset < ctx->end) {

                /* zip archive data claims end of data past zip64 limits */

                zip_error_set(&ctx->error, ZIP_ER_INCONS, MAKE_DETAIL_WITH_INDEX(ZIP_ER_DETAIL_CDIR_ENTRY_INVALID, ctx->source_index));

                return -1;

            }

            ctx->start += offset;

            ctx->end += offset;

            ctx->source_archive = NULL;

        }

        if (!ctx->needs_seek) {

            DEFINE_BYTE_ARRAY(b, BUFSIZE);

            if (!byte_array_init(b, BUFSIZE)) {

                zip_error_set(&ctx->error, ZIP_ER_MEMORY, 0);

                return -1;

            }

            for (n = 0; n < ctx->start; n += (zip_uint64_t)ret) {

                i = (ctx->start - n > BUFSIZE ? BUFSIZE : ctx->start - n);

                if ((ret = zip_source_read(src, b, i)) < 0) {

                    zip_error_set_from_source(&ctx->error, src);

                    byte_array_fini(b);

                    return -1;

                }

                if (ret == 0) {

                    zip_error_set(&ctx->error, ZIP_ER_EOF, 0);

                    byte_array_fini(b);

                    return -1;

                }

            }

            byte_array_fini(b);

        }

        ctx->offset = ctx->start;

        return 0;

    case ZIP_SOURCE_READ:

        if (ctx->end_valid && len > ctx->end - ctx->offset) {

            len = ctx->end - ctx->offset;

        }

        if (len == 0) {

            return 0;

        }

        if (ctx->needs_seek) {

            if (zip_source_seek(src, (zip_int64_t)ctx->offset, SEEK_SET) < 0) {

                zip_error_set_from_source(&ctx->error, src);

                return -1;

            }

        }

        if ((ret = zip_source_read(src, data, len)) < 0) {

            zip_error_set(&ctx->error, ZIP_ER_EOF, 0);

            return -1;

        }

        ctx->offset += (zip_uint64_t)ret;

        if (ret == 0) {

            if (ctx->end_valid && ctx->offset < ctx->end) {

                zip_error_set(&ctx->error, ZIP_ER_EOF, 0);

                return -1;

            }

        }

        return ret;

    case ZIP_SOURCE_SEEK: {

        zip_int64_t new_offset;

        if (!ctx->end_valid) {

            zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, len, &ctx->error);

            if (args == NULL) {

                return -1;

            }

            if (args->whence == SEEK_END) {

                if (zip_source_seek(src, args->offset, args->whence) < 0) {

                    zip_error_set_from_source(&ctx->error, src);

                    return -1;

                }

                new_offset = zip_source_tell(src);

                if (new_offset < 0) {

                    zip_error_set_from_source(&ctx->error, src);

                    return -1;

                }

                if ((zip_uint64_t)new_offset < ctx->start) {

                    zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);

                    (void)zip_source_seek(src, (zip_int64_t)ctx->offset, SEEK_SET);

                    return -1;

                }

                ctx->offset = (zip_uint64_t)new_offset;

                return 0;

            }

        }

        new_offset = zip_source_seek_compute_offset(ctx->offset - ctx->start, ctx->end - ctx->start, data, len, &ctx->error);

        if (new_offset < 0) {

            return -1;

        }

        ctx->offset = (zip_uint64_t)new_offset + ctx->start;

        return 0;

    }

    case ZIP_SOURCE_STAT: {

        zip_stat_t *st;

        st = (zip_stat_t *)data;

        if (_zip_stat_merge(st, &ctx->stat, &ctx->error) < 0) {

            return -1;

        }

        if (!(ctx->stat.valid & ZIP_STAT_SIZE)) {

            if (ctx->end_valid) {

                st->valid |= ZIP_STAT_SIZE;

                st->size = ctx->end - ctx->start;

            }

            else if (st->valid & ZIP_STAT_SIZE) {

                st->size -= ctx->start;

            }

        }

        st->valid &= ~ctx->stat_invalid;

        return 0;

    }

    case ZIP_SOURCE_GET_FILE_ATTRIBUTES:

        if (len < sizeof(ctx->attributes)) {

            zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);

            return -1;

        }

        (void)memcpy_s(data, sizeof(ctx->attributes), &ctx->attributes, sizeof(ctx->attributes));

        return sizeof(ctx->attributes);

    case ZIP_SOURCE_GET_DOS_TIME:

        if (len < sizeof(ctx->dostime)) {

            zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);

            return -1;

        }

        if (ctx->dostime_valid) {

            (void)memcpy_s(data, sizeof(ctx->dostime), &ctx->dostime, sizeof(ctx->dostime));

            return sizeof(ctx->dostime);

        }

        else {

            return 0;

        }

    case ZIP_SOURCE_SUPPORTS:

        return ctx->supports;

    case ZIP_SOURCE_TELL:

        return (zip_int64_t)(ctx->offset - ctx->start);

    default:

        return zip_source_pass_to_lower_layer(src, data, len, cmd);

    }

}

void

_zip_deregister_source(zip_t *za, zip_source_t *src) {

    zip_uint64_t i;

    for (i = 0; i < za->nopen_source; i++) {

        if (za->open_source[i] == src) {

            za->open_source[i] = za->open_source[za->nopen_source - 1];

            za->nopen_source--;

            break;

        }

    }

}

int

_zip_register_source(zip_t *za, zip_source_t *src) {

    if (za->nopen_source + 1 >= za->nopen_source_alloc) {

        if (!ZIP_REALLOC(za->open_source, za->nopen_source_alloc, 10, &za->error)) {

            return -1;

        }

    }

    za->open_source[za->nopen_source++] = src;

    return 0;

}