root/ext/zip/lib/zip_source_window.c

DEFINITIONS

1. zip_source_window
2. _zip_source_window_new
3. _zip_source_set_source_archive
4. _zip_source_invalidate
5. window_read
6. _zip_deregister_source
7. _zip_register_source

   1 /*
   2   zip_source_window.c -- return part of lower source
   3   Copyright (C) 2012-2014 Dieter Baron and Thomas Klausner
   4 
   5   This file is part of libzip, a library to manipulate ZIP archives.
   6   The authors can be contacted at <libzip@nih.at>
   7 
   8   Redistribution and use in source and binary forms, with or without
   9   modification, are permitted provided that the following conditions
  10   are met:
  11   1. Redistributions of source code must retain the above copyright
  12      notice, this list of conditions and the following disclaimer.
  13   2. Redistributions in binary form must reproduce the above copyright
  14      notice, this list of conditions and the following disclaimer in
  15      the documentation and/or other materials provided with the
  16      distribution.
  17   3. The names of the authors may not be used to endorse or promote
  18      products derived from this software without specific prior
  19      written permission.
  20  
  21   THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
  22   OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  23   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24   ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
  25   DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  27   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  28   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
  29   IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  30   OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
  31   IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32 */
  33 
  34 
  35 #include <stdlib.h>
  36 #include <string.h>
  37 
  38 #include "zipint.h"
  39 
  40 struct window {
  41     zip_uint64_t start;
  42     zip_uint64_t end;
  43     zip_uint64_t offset;
  44     zip_stat_t stat;
  45     zip_error_t error;
  46     zip_int64_t supports;
  47     bool needs_seek;
  48 };
  49 
  50 static zip_int64_t window_read(zip_source_t *, void *, void *, zip_uint64_t, zip_source_cmd_t);
  51 
  52 
  53 zip_source_t *
  54 zip_source_window(zip_t *za, zip_source_t *src, zip_uint64_t start, zip_uint64_t len)
  55 {
  56     return _zip_source_window_new(src, start, len, NULL, &za->error);
  57 }
  58 
  59 
  60 zip_source_t *
  61 _zip_source_window_new(zip_source_t *src, zip_uint64_t start, zip_uint64_t length, zip_stat_t *st, zip_error_t *error)
  62 {
  63     struct window *ctx;
  64     
  65     if (src == NULL || start + length < start) {
  66         zip_error_set(error, ZIP_ER_INVAL, 0);
  67         return NULL;
  68     }
  69     
  70     if ((ctx=(struct window *)malloc(sizeof(*ctx))) == NULL) {
  71         zip_error_set(error, ZIP_ER_MEMORY, 0);
  72         return NULL;
  73     }
  74     
  75     ctx->start = start;
  76     ctx->end = start + length;
  77     zip_stat_init(&ctx->stat);
  78     zip_error_init(&ctx->error);
  79     ctx->supports = (zip_source_supports(src) & ZIP_SOURCE_SUPPORTS_SEEKABLE) | (zip_source_make_command_bitmap(ZIP_SOURCE_SUPPORTS, ZIP_SOURCE_TELL, -1));
  80     ctx->needs_seek = (ctx->supports & ZIP_SOURCE_MAKE_COMMAND_BITMASK(ZIP_SOURCE_SEEK)) ? true : false;
  81     
  82     if (st) {
  83         if (_zip_stat_merge(&ctx->stat, st, error) < 0) {
  84             free(ctx);
  85             return NULL;
  86         }
  87     }
  88     
  89     return zip_source_layered_create(src, window_read, ctx, error);
  90 }
  91 
  92 
  93 int
  94 _zip_source_set_source_archive(zip_source_t *src, zip_t *za)
  95 {
  96     src->source_archive = za;
  97     return _zip_register_source(za, src);
  98 }
  99 
 100 
 101 /* called by zip_discard to avoid operating on file from closed archive */
 102 void
 103 _zip_source_invalidate(zip_source_t *src)
 104 {
 105     src->source_closed = 1;
 106 
 107     if (zip_error_code_zip(&src->error) == ZIP_ER_OK) {
 108         zip_error_set(&src->error, ZIP_ER_ZIPCLOSED, 0);
 109     }
 110 }
 111 
 112 
 113 static zip_int64_t
 114 window_read(zip_source_t *src, void *_ctx, void *data, zip_uint64_t len, zip_source_cmd_t cmd)
 115 {
 116     struct window *ctx;
 117     zip_int64_t ret;
 118     zip_uint64_t n, i;
 119     char b[8192];
 120 
 121     ctx = (struct window *)_ctx;
 122 
 123     switch (cmd) {
 124         case ZIP_SOURCE_CLOSE:
 125             return 0;
 126             
 127         case ZIP_SOURCE_ERROR:
 128             return zip_error_to_data(&ctx->error, data, len);
 129             
 130         case ZIP_SOURCE_FREE:
 131             free(ctx);
 132             return 0;
 133 
 134         case ZIP_SOURCE_OPEN:
 135             if (!ctx->needs_seek) {
 136                 for (n=0; n<ctx->start; n+=(zip_uint64_t)ret) {
 137                     i = (ctx->start-n > sizeof(b) ? sizeof(b) : ctx->start-n);
 138                     if ((ret=zip_source_read(src, b, i)) < 0) {
 139                         _zip_error_set_from_source(&ctx->error, src);
 140                         return -1;
 141                     }
 142                     if (ret==0) {
 143                         zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
 144                         return -1;
 145                     }
 146                 }
 147                 
 148             }
 149             ctx->offset = ctx->start;
 150             return 0;
 151 
 152         case ZIP_SOURCE_READ:
 153             if (len > ctx->end - ctx->offset)
 154                 len = ctx->end - ctx->offset;
 155             
 156             if (len == 0)
 157                 return 0;
 158             
 159             if (ctx->needs_seek) {
 160                 if (zip_source_seek(src, (zip_int64_t)ctx->offset, SEEK_SET) < 0) {
 161                     _zip_error_set_from_source(&ctx->error, src);
 162                     return -1;
 163                 }
 164             }
 165             
 166             if ((ret=zip_source_read(src, data, len)) < 0) {
 167                 zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
 168                 return -1;
 169             }
 170 
 171             ctx->offset += (zip_uint64_t)ret;
 172 
 173             if (ret == 0) {
 174                 if (ctx->offset < ctx->end) {
 175                     zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
 176                     return -1;
 177                 }
 178             }
 179             return ret;
 180             
 181         case ZIP_SOURCE_SEEK:
 182         {
 183             zip_int64_t new_offset = zip_source_seek_compute_offset(ctx->offset - ctx->start, ctx->end - ctx->start, data, len, &ctx->error);
 184 
 185             if (new_offset < 0) {
 186                 return -1;
 187             }
 188             
 189             ctx->offset = (zip_uint64_t)new_offset + ctx->start;
 190             return 0;
 191         }
 192 
 193        case ZIP_SOURCE_STAT:
 194         {
 195             zip_stat_t *st;
 196             
 197             st = (zip_stat_t *)data;
 198             
 199             if (_zip_stat_merge(st, &ctx->stat, &ctx->error) < 0) {
 200                 return -1;
 201             }
 202             return 0;
 203         }
 204             
 205         case ZIP_SOURCE_SUPPORTS:
 206             return ctx->supports;
 207             
 208         case ZIP_SOURCE_TELL:
 209             return (zip_int64_t)(ctx->offset - ctx->start);
 210             
 211        default:
 212             zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);
 213             return -1;
 214     }
 215 }
 216 
 217 
 218 void
 219 _zip_deregister_source(zip_t *za, zip_source_t *src)
 220 {
 221     unsigned int i;
 222     
 223     for (i=0; i<za->nopen_source; i++) {
 224         if (za->open_source[i] == src) {
 225             za->open_source[i] = za->open_source[za->nopen_source-1];
 226             za->nopen_source--;
 227             break;
 228         }
 229     }
 230 }
 231 
 232 
 233 int
 234 _zip_register_source(zip_t *za, zip_source_t *src)
 235 {
 236     zip_source_t **open_source;
 237     
 238     if (za->nopen_source+1 >= za->nopen_source_alloc) {
 239         unsigned int n;
 240         n = za->nopen_source_alloc + 10;
 241         open_source = (zip_source_t **)realloc(za->open_source, n*sizeof(zip_source_t *));
 242         if (open_source == NULL) {
 243             zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
 244             return -1;
 245         }
 246         za->nopen_source_alloc = n;
 247         za->open_source = open_source;
 248     }
 249     
 250     za->open_source[za->nopen_source++] = src;
 251     
 252     return 0;
 253 }