• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  * jdapimin.c
3  *
4  * This file was part of the Independent JPEG Group's software:
5  * Copyright (C) 1994-1998, Thomas G. Lane.
6  * libjpeg-turbo Modifications:
7  * Copyright (C) 2016, D. R. Commander.
8  * For conditions of distribution and use, see the accompanying README.ijg
9  * file.
10  *
11  * This file contains application interface code for the decompression half
12  * of the JPEG library.  These are the "minimum" API routines that may be
13  * needed in either the normal full-decompression case or the
14  * transcoding-only case.
15  *
16  * Most of the routines intended to be called directly by an application
17  * are in this file or in jdapistd.c.  But also see jcomapi.c for routines
18  * shared by compression and decompression, and jdtrans.c for the transcoding
19  * case.
20  */
21 
22 #define JPEG_INTERNALS
23 #include "jinclude.h"
24 #include "jpeglib.h"
25 #include "jdmaster.h"
26 
27 
28 /*
29  * Initialization of a JPEG decompression object.
30  * The error manager must already be set up (in case memory manager fails).
31  */
32 
33 GLOBAL(void)
jpeg_CreateDecompress(j_decompress_ptr cinfo,int version,size_t structsize)34 jpeg_CreateDecompress (j_decompress_ptr cinfo, int version, size_t structsize)
35 {
36   int i;
37 
38   /* Guard against version mismatches between library and caller. */
39   cinfo->mem = NULL;            /* so jpeg_destroy knows mem mgr not called */
40   if (version != JPEG_LIB_VERSION)
41     ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
42   if (structsize != sizeof(struct jpeg_decompress_struct))
43     ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE,
44              (int) sizeof(struct jpeg_decompress_struct), (int) structsize);
45 
46   /* For debugging purposes, we zero the whole master structure.
47    * But the application has already set the err pointer, and may have set
48    * client_data, so we have to save and restore those fields.
49    * Note: if application hasn't set client_data, tools like Purify may
50    * complain here.
51    */
52   {
53     struct jpeg_error_mgr * err = cinfo->err;
54     void * client_data = cinfo->client_data; /* ignore Purify complaint here */
55     MEMZERO(cinfo, sizeof(struct jpeg_decompress_struct));
56     cinfo->err = err;
57     cinfo->client_data = client_data;
58   }
59   cinfo->is_decompressor = TRUE;
60 
61   /* Initialize a memory manager instance for this object */
62   jinit_memory_mgr((j_common_ptr) cinfo);
63 
64   /* Zero out pointers to permanent structures. */
65   cinfo->progress = NULL;
66   cinfo->src = NULL;
67 
68   for (i = 0; i < NUM_QUANT_TBLS; i++)
69     cinfo->quant_tbl_ptrs[i] = NULL;
70 
71   for (i = 0; i < NUM_HUFF_TBLS; i++) {
72     cinfo->dc_huff_tbl_ptrs[i] = NULL;
73     cinfo->ac_huff_tbl_ptrs[i] = NULL;
74   }
75 
76   /* Initialize marker processor so application can override methods
77    * for COM, APPn markers before calling jpeg_read_header.
78    */
79   cinfo->marker_list = NULL;
80   jinit_marker_reader(cinfo);
81 
82   /* And initialize the overall input controller. */
83   jinit_input_controller(cinfo);
84 
85   /* OK, I'm ready */
86   cinfo->global_state = DSTATE_START;
87 
88   /* The master struct is used to store extension parameters, so we allocate it
89    * here.
90    */
91   cinfo->master = (struct jpeg_decomp_master *)
92       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
93                                   sizeof(my_decomp_master));
94   MEMZERO(cinfo->master, sizeof(my_decomp_master));
95 }
96 
97 
98 /*
99  * Destruction of a JPEG decompression object
100  */
101 
102 GLOBAL(void)
jpeg_destroy_decompress(j_decompress_ptr cinfo)103 jpeg_destroy_decompress (j_decompress_ptr cinfo)
104 {
105   jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
106 }
107 
108 
109 /*
110  * Abort processing of a JPEG decompression operation,
111  * but don't destroy the object itself.
112  */
113 
114 GLOBAL(void)
jpeg_abort_decompress(j_decompress_ptr cinfo)115 jpeg_abort_decompress (j_decompress_ptr cinfo)
116 {
117   jpeg_abort((j_common_ptr) cinfo); /* use common routine */
118 }
119 
120 
121 /*
122  * Set default decompression parameters.
123  */
124 
125 LOCAL(void)
default_decompress_parms(j_decompress_ptr cinfo)126 default_decompress_parms (j_decompress_ptr cinfo)
127 {
128   /* Guess the input colorspace, and set output colorspace accordingly. */
129   /* (Wish JPEG committee had provided a real way to specify this...) */
130   /* Note application may override our guesses. */
131   switch (cinfo->num_components) {
132   case 1:
133     cinfo->jpeg_color_space = JCS_GRAYSCALE;
134     cinfo->out_color_space = JCS_GRAYSCALE;
135     break;
136 
137   case 3:
138     if (cinfo->saw_JFIF_marker) {
139       cinfo->jpeg_color_space = JCS_YCbCr; /* JFIF implies YCbCr */
140     } else if (cinfo->saw_Adobe_marker) {
141       switch (cinfo->Adobe_transform) {
142       case 0:
143         cinfo->jpeg_color_space = JCS_RGB;
144         break;
145       case 1:
146         cinfo->jpeg_color_space = JCS_YCbCr;
147         break;
148       default:
149         WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
150         cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
151         break;
152       }
153     } else {
154       /* Saw no special markers, try to guess from the component IDs */
155       int cid0 = cinfo->comp_info[0].component_id;
156       int cid1 = cinfo->comp_info[1].component_id;
157       int cid2 = cinfo->comp_info[2].component_id;
158 
159       if (cid0 == 1 && cid1 == 2 && cid2 == 3)
160         cinfo->jpeg_color_space = JCS_YCbCr; /* assume JFIF w/out marker */
161       else if (cid0 == 82 && cid1 == 71 && cid2 == 66)
162         cinfo->jpeg_color_space = JCS_RGB; /* ASCII 'R', 'G', 'B' */
163       else {
164         TRACEMS3(cinfo, 1, JTRC_UNKNOWN_IDS, cid0, cid1, cid2);
165         cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
166       }
167     }
168     /* Always guess RGB is proper output colorspace. */
169     cinfo->out_color_space = JCS_RGB;
170     break;
171 
172   case 4:
173     if (cinfo->saw_Adobe_marker) {
174       switch (cinfo->Adobe_transform) {
175       case 0:
176         cinfo->jpeg_color_space = JCS_CMYK;
177         break;
178       case 2:
179         cinfo->jpeg_color_space = JCS_YCCK;
180         break;
181       default:
182         WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
183         cinfo->jpeg_color_space = JCS_YCCK; /* assume it's YCCK */
184         break;
185       }
186     } else {
187       /* No special markers, assume straight CMYK. */
188       cinfo->jpeg_color_space = JCS_CMYK;
189     }
190     cinfo->out_color_space = JCS_CMYK;
191     break;
192 
193   default:
194     cinfo->jpeg_color_space = JCS_UNKNOWN;
195     cinfo->out_color_space = JCS_UNKNOWN;
196     break;
197   }
198 
199   /* Set defaults for other decompression parameters. */
200   cinfo->scale_num = 1;         /* 1:1 scaling */
201   cinfo->scale_denom = 1;
202   cinfo->output_gamma = 1.0;
203   cinfo->buffered_image = FALSE;
204   cinfo->raw_data_out = FALSE;
205   cinfo->dct_method = JDCT_DEFAULT;
206   cinfo->do_fancy_upsampling = TRUE;
207   cinfo->do_block_smoothing = TRUE;
208   cinfo->quantize_colors = FALSE;
209   /* We set these in case application only sets quantize_colors. */
210   cinfo->dither_mode = JDITHER_FS;
211 #ifdef QUANT_2PASS_SUPPORTED
212   cinfo->two_pass_quantize = TRUE;
213 #else
214   cinfo->two_pass_quantize = FALSE;
215 #endif
216   cinfo->desired_number_of_colors = 256;
217   cinfo->colormap = NULL;
218   /* Initialize for no mode change in buffered-image mode. */
219   cinfo->enable_1pass_quant = FALSE;
220   cinfo->enable_external_quant = FALSE;
221   cinfo->enable_2pass_quant = FALSE;
222 }
223 
224 
225 /*
226  * Decompression startup: read start of JPEG datastream to see what's there.
227  * Need only initialize JPEG object and supply a data source before calling.
228  *
229  * This routine will read as far as the first SOS marker (ie, actual start of
230  * compressed data), and will save all tables and parameters in the JPEG
231  * object.  It will also initialize the decompression parameters to default
232  * values, and finally return JPEG_HEADER_OK.  On return, the application may
233  * adjust the decompression parameters and then call jpeg_start_decompress.
234  * (Or, if the application only wanted to determine the image parameters,
235  * the data need not be decompressed.  In that case, call jpeg_abort or
236  * jpeg_destroy to release any temporary space.)
237  * If an abbreviated (tables only) datastream is presented, the routine will
238  * return JPEG_HEADER_TABLES_ONLY upon reaching EOI.  The application may then
239  * re-use the JPEG object to read the abbreviated image datastream(s).
240  * It is unnecessary (but OK) to call jpeg_abort in this case.
241  * The JPEG_SUSPENDED return code only occurs if the data source module
242  * requests suspension of the decompressor.  In this case the application
243  * should load more source data and then re-call jpeg_read_header to resume
244  * processing.
245  * If a non-suspending data source is used and require_image is TRUE, then the
246  * return code need not be inspected since only JPEG_HEADER_OK is possible.
247  *
248  * This routine is now just a front end to jpeg_consume_input, with some
249  * extra error checking.
250  */
251 
252 GLOBAL(int)
jpeg_read_header(j_decompress_ptr cinfo,boolean require_image)253 jpeg_read_header (j_decompress_ptr cinfo, boolean require_image)
254 {
255   int retcode;
256 
257   if (cinfo->global_state != DSTATE_START &&
258       cinfo->global_state != DSTATE_INHEADER)
259     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
260 
261   retcode = jpeg_consume_input(cinfo);
262 
263   switch (retcode) {
264   case JPEG_REACHED_SOS:
265     retcode = JPEG_HEADER_OK;
266     break;
267   case JPEG_REACHED_EOI:
268     if (require_image)          /* Complain if application wanted an image */
269       ERREXIT(cinfo, JERR_NO_IMAGE);
270     /* Reset to start state; it would be safer to require the application to
271      * call jpeg_abort, but we can't change it now for compatibility reasons.
272      * A side effect is to free any temporary memory (there shouldn't be any).
273      */
274     jpeg_abort((j_common_ptr) cinfo); /* sets state = DSTATE_START */
275     retcode = JPEG_HEADER_TABLES_ONLY;
276     break;
277   case JPEG_SUSPENDED:
278     /* no work */
279     break;
280   }
281 
282   return retcode;
283 }
284 
285 
286 /*
287  * Consume data in advance of what the decompressor requires.
288  * This can be called at any time once the decompressor object has
289  * been created and a data source has been set up.
290  *
291  * This routine is essentially a state machine that handles a couple
292  * of critical state-transition actions, namely initial setup and
293  * transition from header scanning to ready-for-start_decompress.
294  * All the actual input is done via the input controller's consume_input
295  * method.
296  */
297 
298 GLOBAL(int)
jpeg_consume_input(j_decompress_ptr cinfo)299 jpeg_consume_input (j_decompress_ptr cinfo)
300 {
301   int retcode = JPEG_SUSPENDED;
302 
303   /* NB: every possible DSTATE value should be listed in this switch */
304   switch (cinfo->global_state) {
305   case DSTATE_START:
306     /* Start-of-datastream actions: reset appropriate modules */
307     (*cinfo->inputctl->reset_input_controller) (cinfo);
308     /* Initialize application's data source module */
309     (*cinfo->src->init_source) (cinfo);
310     cinfo->global_state = DSTATE_INHEADER;
311     /*FALLTHROUGH*/
312   case DSTATE_INHEADER:
313     retcode = (*cinfo->inputctl->consume_input) (cinfo);
314     if (retcode == JPEG_REACHED_SOS) { /* Found SOS, prepare to decompress */
315       /* Set up default parameters based on header data */
316       default_decompress_parms(cinfo);
317       /* Set global state: ready for start_decompress */
318       cinfo->global_state = DSTATE_READY;
319     }
320     break;
321   case DSTATE_READY:
322     /* Can't advance past first SOS until start_decompress is called */
323     retcode = JPEG_REACHED_SOS;
324     break;
325   case DSTATE_PRELOAD:
326   case DSTATE_PRESCAN:
327   case DSTATE_SCANNING:
328   case DSTATE_RAW_OK:
329   case DSTATE_BUFIMAGE:
330   case DSTATE_BUFPOST:
331   case DSTATE_STOPPING:
332     retcode = (*cinfo->inputctl->consume_input) (cinfo);
333     break;
334   default:
335     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
336   }
337   return retcode;
338 }
339 
340 
341 /*
342  * Have we finished reading the input file?
343  */
344 
345 GLOBAL(boolean)
jpeg_input_complete(j_decompress_ptr cinfo)346 jpeg_input_complete (j_decompress_ptr cinfo)
347 {
348   /* Check for valid jpeg object */
349   if (cinfo->global_state < DSTATE_START ||
350       cinfo->global_state > DSTATE_STOPPING)
351     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
352   return cinfo->inputctl->eoi_reached;
353 }
354 
355 
356 /*
357  * Is there more than one scan?
358  */
359 
360 GLOBAL(boolean)
jpeg_has_multiple_scans(j_decompress_ptr cinfo)361 jpeg_has_multiple_scans (j_decompress_ptr cinfo)
362 {
363   /* Only valid after jpeg_read_header completes */
364   if (cinfo->global_state < DSTATE_READY ||
365       cinfo->global_state > DSTATE_STOPPING)
366     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
367   return cinfo->inputctl->has_multiple_scans;
368 }
369 
370 
371 /*
372  * Finish JPEG decompression.
373  *
374  * This will normally just verify the file trailer and release temp storage.
375  *
376  * Returns FALSE if suspended.  The return value need be inspected only if
377  * a suspending data source is used.
378  */
379 
380 GLOBAL(boolean)
jpeg_finish_decompress(j_decompress_ptr cinfo)381 jpeg_finish_decompress (j_decompress_ptr cinfo)
382 {
383   if ((cinfo->global_state == DSTATE_SCANNING ||
384        cinfo->global_state == DSTATE_RAW_OK) && ! cinfo->buffered_image) {
385     /* Terminate final pass of non-buffered mode */
386     if (cinfo->output_scanline < cinfo->output_height)
387       ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
388     (*cinfo->master->finish_output_pass) (cinfo);
389     cinfo->global_state = DSTATE_STOPPING;
390   } else if (cinfo->global_state == DSTATE_BUFIMAGE) {
391     /* Finishing after a buffered-image operation */
392     cinfo->global_state = DSTATE_STOPPING;
393   } else if (cinfo->global_state != DSTATE_STOPPING) {
394     /* STOPPING = repeat call after a suspension, anything else is error */
395     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
396   }
397   /* Read until EOI */
398   while (! cinfo->inputctl->eoi_reached) {
399     if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
400       return FALSE;             /* Suspend, come back later */
401   }
402   /* Do final cleanup */
403   (*cinfo->src->term_source) (cinfo);
404   /* We can use jpeg_abort to release memory and reset global_state */
405   jpeg_abort((j_common_ptr) cinfo);
406   return TRUE;
407 }
408