1 /*
   2  * Copyright (c) 1995, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 /*
  27  * This file was based upon the example.c stub file included in the
  28  * release 6 of the Independent JPEG Group's free JPEG software.
  29  * It has been updated to conform to release 6b.
  30  */
  31 
  32 /* First, if system header files define "boolean" map it to "system_boolean" */
  33 #define boolean system_boolean
  34 
  35 #include <stdio.h>
  36 #include <setjmp.h>
  37 #include <string.h>
  38 #include <stdlib.h>
  39 #include <assert.h>
  40 
  41 #include "jni.h"
  42 #include "jni_util.h"
  43 
  44 /* undo "system_boolean" hack and undef FAR since we don't use it anyway */
  45 #undef boolean
  46 #undef FAR
  47 #include <jpeglib.h>
  48 #include "jerror.h"
  49 
  50 #ifdef __APPLE__
  51 /* use setjmp/longjmp versions that do not save/restore the signal mask */
  52 #define setjmp _setjmp
  53 #define longjmp _longjmp
  54 #endif
  55 
  56 /* The method IDs we cache. Note that the last two belongs to the
  57  * java.io.InputStream class.
  58  */
  59 static jmethodID sendHeaderInfoID;
  60 static jmethodID sendPixelsByteID;
  61 static jmethodID sendPixelsIntID;
  62 static jmethodID InputStream_readID;
  63 static jmethodID InputStream_availableID;
  64 
  65 /* Initialize the Java VM instance variable when the library is
  66    first loaded */
  67 JavaVM *jvm;
  68 
  69 JNIEXPORT jint JNICALL
  70 DEF_JNI_OnLoad(JavaVM *vm, void *reserved)
  71 {
  72     jvm = vm;
  73     return JNI_VERSION_1_2;
  74 }
  75 
  76 /*
  77  * ERROR HANDLING:
  78  *
  79  * The JPEG library's standard error handler (jerror.c) is divided into
  80  * several "methods" which you can override individually.  This lets you
  81  * adjust the behavior without duplicating a lot of code, which you might
  82  * have to update with each future release.
  83  *
  84  * Our example here shows how to override the "error_exit" method so that
  85  * control is returned to the library's caller when a fatal error occurs,
  86  * rather than calling exit() as the standard error_exit method does.
  87  *
  88  * We use C's setjmp/longjmp facility to return control.  This means that the
  89  * routine which calls the JPEG library must first execute a setjmp() call to
  90  * establish the return point.  We want the replacement error_exit to do a
  91  * longjmp().  But we need to make the setjmp buffer accessible to the
  92  * error_exit routine.  To do this, we make a private extension of the
  93  * standard JPEG error handler object.  (If we were using C++, we'd say we
  94  * were making a subclass of the regular error handler.)
  95  *
  96  * Here's the extended error handler struct:
  97  */
  98 
  99 struct sun_jpeg_error_mgr {
 100   struct jpeg_error_mgr pub;    /* "public" fields */
 101 
 102   jmp_buf setjmp_buffer;        /* for return to caller */
 103 };
 104 
 105 typedef struct sun_jpeg_error_mgr * sun_jpeg_error_ptr;
 106 
 107 /*
 108  * Here's the routine that will replace the standard error_exit method:
 109  */
 110 
 111 METHODDEF(void)
 112 sun_jpeg_error_exit (j_common_ptr cinfo)
 113 {
 114   /* cinfo->err really points to a sun_jpeg_error_mgr struct */
 115   sun_jpeg_error_ptr myerr = (sun_jpeg_error_ptr) cinfo->err;
 116 
 117   /* Always display the message. */
 118   /* We could postpone this until after returning, if we chose. */
 119   /* (*cinfo->err->output_message) (cinfo); */
 120   /* For Java, we will format the message and put it in the error we throw. */
 121 
 122   /* Return control to the setjmp point */
 123   longjmp(myerr->setjmp_buffer, 1);
 124 }
 125 
 126 /*
 127  * Error Message handling
 128  *
 129  * This overrides the output_message method to send JPEG messages
 130  *
 131  */
 132 
 133 METHODDEF(void)
 134 sun_jpeg_output_message (j_common_ptr cinfo)
 135 {
 136   char buffer[JMSG_LENGTH_MAX];
 137 
 138   /* Create the message */
 139   (*cinfo->err->format_message) (cinfo, buffer);
 140 
 141   /* Send it to stderr, adding a newline */
 142   fprintf(stderr, "%s\n", buffer);
 143 }
 144 
 145 
 146 
 147 
 148 /*
 149  * INPUT HANDLING:
 150  *
 151  * The JPEG library's input management is defined by the jpeg_source_mgr
 152  * structure which contains two fields to convey the information in the
 153  * buffer and 5 methods which perform all buffer management.  The library
 154  * defines a standard input manager that uses stdio for obtaining compressed
 155  * jpeg data, but here we need to use Java to get our data.
 156  *
 157  * We need to make the Java class information accessible to the source_mgr
 158  * input routines.  We also need to store a pointer to the start of the
 159  * Java array being used as an input buffer so that it is not moved or
 160  * garbage collected while the JPEG library is using it.  To store these
 161  * things, we make a private extension of the standard JPEG jpeg_source_mgr
 162  * object.
 163  *
 164  * Here's the extended source manager struct:
 165  */
 166 
 167 struct sun_jpeg_source_mgr {
 168   struct jpeg_source_mgr pub;   /* "public" fields */
 169 
 170   jobject hInputStream;
 171   int suspendable;
 172   unsigned long remaining_skip;
 173 
 174   JOCTET *inbuf;
 175   jbyteArray hInputBuffer;
 176   size_t inbufoffset;
 177 
 178   /* More stuff */
 179   union pixptr {
 180       int               *ip;
 181       unsigned char     *bp;
 182   } outbuf;
 183   size_t outbufSize;
 184   jobject hOutputBuffer;
 185 };
 186 
 187 typedef struct sun_jpeg_source_mgr * sun_jpeg_source_ptr;
 188 
 189 /* We use Get/ReleasePrimitiveArrayCritical functions to avoid
 190  * the need to copy buffer elements.
 191  *
 192  * MAKE SURE TO:
 193  *
 194  * - carefully insert pairs of RELEASE_ARRAYS and GET_ARRAYS around
 195  *   callbacks to Java.
 196  * - call RELEASE_ARRAYS before returning to Java.
 197  *
 198  * Otherwise things will go horribly wrong. There may be memory leaks,
 199  * excessive pinning, or even VM crashes!
 200  *
 201  * Note that GetPrimitiveArrayCritical may fail!
 202  */
 203 static void RELEASE_ARRAYS(JNIEnv *env, sun_jpeg_source_ptr src)
 204 {
 205     if (src->inbuf) {
 206         if (src->pub.next_input_byte == 0) {
 207             src->inbufoffset = -1;
 208         } else {
 209             src->inbufoffset = src->pub.next_input_byte - src->inbuf;
 210         }
 211         (*env)->ReleasePrimitiveArrayCritical(env, src->hInputBuffer,
 212                                               src->inbuf, 0);
 213         src->inbuf = 0;
 214     }
 215     if (src->outbuf.ip) {
 216         (*env)->ReleasePrimitiveArrayCritical(env, src->hOutputBuffer,
 217                                               src->outbuf.ip, 0);
 218         src->outbuf.ip = 0;
 219     }
 220 }
 221 
 222 static int GET_ARRAYS(JNIEnv *env, sun_jpeg_source_ptr src)
 223 {
 224     if (src->hInputBuffer) {
 225         assert(src->inbuf == 0);
 226         src->inbuf = (JOCTET *)(*env)->GetPrimitiveArrayCritical
 227             (env, src->hInputBuffer, 0);
 228         if (src->inbuf == 0) {
 229             return 0;
 230         }
 231         if ((int)(src->inbufoffset) >= 0) {
 232             src->pub.next_input_byte = src->inbuf + src->inbufoffset;
 233         }
 234     }
 235     if (src->hOutputBuffer) {
 236         assert(src->outbuf.ip == 0);
 237         src->outbufSize = (*env)->GetArrayLength(env, src->hOutputBuffer);
 238         src->outbuf.ip = (int *)(*env)->GetPrimitiveArrayCritical
 239             (env, src->hOutputBuffer, 0);
 240         if (src->outbuf.ip == 0) {
 241             RELEASE_ARRAYS(env, src);
 242             return 0;
 243         }
 244     }
 245     return 1;
 246 }
 247 
 248 /*
 249  * Initialize source.  This is called by jpeg_read_header() before any
 250  * data is actually read.  Unlike init_destination(), it may leave
 251  * bytes_in_buffer set to 0 (in which case a fill_input_buffer() call
 252  * will occur immediately).
 253  */
 254 
 255 GLOBAL(void)
 256 sun_jpeg_init_source(j_decompress_ptr cinfo)
 257 {
 258     sun_jpeg_source_ptr src = (sun_jpeg_source_ptr) cinfo->src;
 259     src->pub.next_input_byte = 0;
 260     src->pub.bytes_in_buffer = 0;
 261 }
 262 
 263 /*
 264  * This is called whenever bytes_in_buffer has reached zero and more
 265  * data is wanted.  In typical applications, it should read fresh data
 266  * into the buffer (ignoring the current state of next_input_byte and
 267  * bytes_in_buffer), reset the pointer & count to the start of the
 268  * buffer, and return TRUE indicating that the buffer has been reloaded.
 269  * It is not necessary to fill the buffer entirely, only to obtain at
 270  * least one more byte.  bytes_in_buffer MUST be set to a positive value
 271  * if TRUE is returned.  A FALSE return should only be used when I/O
 272  * suspension is desired (this mode is discussed in the next section).
 273  */
 274 /*
 275  * Note that with I/O suspension turned on, this procedure should not
 276  * do any work since the JPEG library has a very simple backtracking
 277  * mechanism which relies on the fact that the buffer will be filled
 278  * only when it has backed out to the top application level.  When
 279  * suspendable is turned on, the sun_jpeg_fill_suspended_buffer will
 280  * do the actual work of filling the buffer.
 281  */
 282 
 283 GLOBAL(boolean)
 284 sun_jpeg_fill_input_buffer(j_decompress_ptr cinfo)
 285 {
 286     sun_jpeg_source_ptr src = (sun_jpeg_source_ptr) cinfo->src;
 287     JNIEnv *env = (JNIEnv *)JNU_GetEnv(jvm, JNI_VERSION_1_2);
 288     int ret, buflen;
 289 
 290     if (src->suspendable) {
 291         return FALSE;
 292     }
 293     if (src->remaining_skip) {
 294         src->pub.skip_input_data(cinfo, 0);
 295     }
 296     RELEASE_ARRAYS(env, src);
 297     buflen = (*env)->GetArrayLength(env, src->hInputBuffer);
 298     ret = (*env)->CallIntMethod(env, src->hInputStream, InputStream_readID,
 299                                 src->hInputBuffer, 0, buflen);
 300     if (ret > buflen) ret = buflen;
 301     if ((*env)->ExceptionOccurred(env) || !GET_ARRAYS(env, src)) {
 302         cinfo->err->error_exit((struct jpeg_common_struct *) cinfo);
 303     }
 304     if (ret <= 0) {
 305         /* Silently accept truncated JPEG files */
 306         WARNMS(cinfo, JWRN_JPEG_EOF);
 307         src->inbuf[0] = (JOCTET) 0xFF;
 308         src->inbuf[1] = (JOCTET) JPEG_EOI;
 309         ret = 2;
 310     }
 311 
 312     src->pub.next_input_byte = src->inbuf;
 313     src->pub.bytes_in_buffer = ret;
 314 
 315     return TRUE;
 316 }
 317 
 318 /*
 319  * Note that with I/O suspension turned on, the JPEG library requires
 320  * that all buffer filling be done at the top application level.  Due
 321  * to the way that backtracking works, this procedure should save all
 322  * of the data that was left in the buffer when suspension occurred and
 323  * only read new data at the end.
 324  */
 325 
 326 GLOBAL(void)
 327 sun_jpeg_fill_suspended_buffer(j_decompress_ptr cinfo)
 328 {
 329     sun_jpeg_source_ptr src = (sun_jpeg_source_ptr) cinfo->src;
 330     JNIEnv *env = (JNIEnv *)JNU_GetEnv(jvm, JNI_VERSION_1_2);
 331     size_t offset, buflen;
 332     int ret;
 333 
 334     RELEASE_ARRAYS(env, src);
 335     ret = (*env)->CallIntMethod(env, src->hInputStream,
 336                                 InputStream_availableID);
 337     if ((*env)->ExceptionOccurred(env) || !GET_ARRAYS(env, src)) {
 338         cinfo->err->error_exit((struct jpeg_common_struct *) cinfo);
 339     }
 340     if (ret < 0 || (unsigned int)ret <= src->remaining_skip) {
 341         return;
 342     }
 343     if (src->remaining_skip) {
 344         src->pub.skip_input_data(cinfo, 0);
 345     }
 346     /* Save the data currently in the buffer */
 347     offset = src->pub.bytes_in_buffer;
 348     if (src->pub.next_input_byte > src->inbuf) {
 349         memmove(src->inbuf, src->pub.next_input_byte, offset);
 350     }
 351     RELEASE_ARRAYS(env, src);
 352     buflen = (*env)->GetArrayLength(env, src->hInputBuffer) - offset;
 353     if (buflen <= 0) {
 354         if (!GET_ARRAYS(env, src)) {
 355             cinfo->err->error_exit((struct jpeg_common_struct *) cinfo);
 356         }
 357         return;
 358     }
 359     ret = (*env)->CallIntMethod(env, src->hInputStream, InputStream_readID,
 360                                 src->hInputBuffer, offset, buflen);
 361     if ((ret > 0) && ((unsigned int)ret > buflen)) ret = (int)buflen;
 362     if ((*env)->ExceptionOccurred(env) || !GET_ARRAYS(env, src)) {
 363         cinfo->err->error_exit((struct jpeg_common_struct *) cinfo);
 364     }
 365     if (ret <= 0) {
 366         /* Silently accept truncated JPEG files */
 367         WARNMS(cinfo, JWRN_JPEG_EOF);
 368         src->inbuf[offset] = (JOCTET) 0xFF;
 369         src->inbuf[offset + 1] = (JOCTET) JPEG_EOI;
 370         ret = 2;
 371     }
 372 
 373     src->pub.next_input_byte = src->inbuf;
 374     src->pub.bytes_in_buffer = ret + offset;
 375 
 376     return;
 377 }
 378 
 379 /*
 380  * Skip num_bytes worth of data.  The buffer pointer and count should
 381  * be advanced over num_bytes input bytes, refilling the buffer as
 382  * needed.  This is used to skip over a potentially large amount of
 383  * uninteresting data (such as an APPn marker).  In some applications
 384  * it may be possible to optimize away the reading of the skipped data,
 385  * but it's not clear that being smart is worth much trouble; large
 386  * skips are uncommon.  bytes_in_buffer may be zero on return.
 387  * A zero or negative skip count should be treated as a no-op.
 388  */
 389 /*
 390  * Note that with I/O suspension turned on, this procedure should not
 391  * do any I/O since the JPEG library has a very simple backtracking
 392  * mechanism which relies on the fact that the buffer will be filled
 393  * only when it has backed out to the top application level.
 394  */
 395 
 396 GLOBAL(void)
 397 sun_jpeg_skip_input_data(j_decompress_ptr cinfo, long num_bytes)
 398 {
 399     sun_jpeg_source_ptr src = (sun_jpeg_source_ptr) cinfo->src;
 400     JNIEnv *env = (JNIEnv *)JNU_GetEnv(jvm, JNI_VERSION_1_2);
 401     int ret;
 402     int buflen;
 403 
 404 
 405     if (num_bytes < 0) {
 406         return;
 407     }
 408     num_bytes += src->remaining_skip;
 409     src->remaining_skip = 0;
 410     ret = (int)src->pub.bytes_in_buffer; /* this conversion is safe, because capacity of the buffer is limited by jnit */
 411     if (ret >= num_bytes) {
 412         src->pub.next_input_byte += num_bytes;
 413         src->pub.bytes_in_buffer -= num_bytes;
 414         return;
 415     }
 416     num_bytes -= ret;
 417     if (src->suspendable) {
 418         src->remaining_skip = num_bytes;
 419         src->pub.bytes_in_buffer = 0;
 420         src->pub.next_input_byte = src->inbuf;
 421         return;
 422     }
 423 
 424     /* Note that the signature for the method indicates that it takes
 425      * and returns a long.  Casting the int num_bytes to a long on
 426      * the input should work well enough, and if we assume that the
 427      * return value for this particular method should always be less
 428      * than the argument value (or -1), then the return value coerced
 429      * to an int should return us the information we need...
 430      */
 431     RELEASE_ARRAYS(env, src);
 432     buflen =  (*env)->GetArrayLength(env, src->hInputBuffer);
 433     while (num_bytes > 0) {
 434         ret = (*env)->CallIntMethod(env, src->hInputStream,
 435                                     InputStream_readID,
 436                                     src->hInputBuffer, 0, buflen);
 437         if (ret > buflen) ret = buflen;
 438         if ((*env)->ExceptionOccurred(env)) {
 439             cinfo->err->error_exit((struct jpeg_common_struct *) cinfo);
 440         }
 441         if (ret < 0) {
 442             break;
 443         }
 444         num_bytes -= ret;
 445     }
 446     if (!GET_ARRAYS(env, src)) {
 447         cinfo->err->error_exit((struct jpeg_common_struct *) cinfo);
 448     }
 449     if (num_bytes > 0) {
 450         /* Silently accept truncated JPEG files */
 451         WARNMS(cinfo, JWRN_JPEG_EOF);
 452         src->inbuf[0] = (JOCTET) 0xFF;
 453         src->inbuf[1] = (JOCTET) JPEG_EOI;
 454         src->pub.bytes_in_buffer = 2;
 455         src->pub.next_input_byte = src->inbuf;
 456     } else {
 457         src->pub.bytes_in_buffer = -num_bytes;
 458         src->pub.next_input_byte = src->inbuf + ret + num_bytes;
 459     }
 460 }
 461 
 462 /*
 463  * Terminate source --- called by jpeg_finish_decompress() after all
 464  * data has been read.  Often a no-op.
 465  */
 466 
 467 GLOBAL(void)
 468 sun_jpeg_term_source(j_decompress_ptr cinfo)
 469 {
 470 }
 471 
 472 JNIEXPORT void JNICALL
 473 Java_sun_awt_image_JPEGImageDecoder_initIDs(JNIEnv *env, jclass cls,
 474                                             jclass InputStreamClass)
 475 {
 476     CHECK_NULL(sendHeaderInfoID = (*env)->GetMethodID(env, cls, "sendHeaderInfo",
 477                                            "(IIZZZ)Z"));
 478     CHECK_NULL(sendPixelsByteID = (*env)->GetMethodID(env, cls, "sendPixels", "([BI)Z"));
 479     CHECK_NULL(sendPixelsIntID = (*env)->GetMethodID(env, cls, "sendPixels", "([II)Z"));
 480     CHECK_NULL(InputStream_readID = (*env)->GetMethodID(env, InputStreamClass,
 481                                              "read", "([BII)I"));
 482     CHECK_NULL(InputStream_availableID = (*env)->GetMethodID(env, InputStreamClass,
 483                                                   "available", "()I"));
 484 }
 485 
 486 
 487 /*
 488  * The Windows Itanium Aug 2002 SDK generates bad code
 489  * for this routine.  Disable optimization for now.
 490  */
 491 #ifdef _M_IA64
 492 #pragma optimize ("", off)
 493 #endif
 494 
 495 JNIEXPORT void JNICALL
 496 Java_sun_awt_image_JPEGImageDecoder_readImage(JNIEnv *env,
 497                                               jobject this,
 498                                               jobject hInputStream,
 499                                               jbyteArray hInputBuffer)
 500 {
 501   /* This struct contains the JPEG decompression parameters and pointers to
 502    * working space (which is allocated as needed by the JPEG library).
 503    */
 504   struct jpeg_decompress_struct cinfo;
 505   /* We use our private extension JPEG error handler.
 506    * Note that this struct must live as long as the main JPEG parameter
 507    * struct, to avoid dangling-pointer problems.
 508    */
 509   struct sun_jpeg_error_mgr jerr;
 510   struct sun_jpeg_source_mgr jsrc;
 511 
 512   int ret;
 513   unsigned char *bp;
 514   int *ip, pixel;
 515   int grayscale;
 516   int hasalpha;
 517   int buffered_mode;
 518   int final_pass;
 519 
 520   /* Step 0: verify the inputs. */
 521 
 522   if (hInputBuffer == 0 || hInputStream == 0) {
 523     JNU_ThrowNullPointerException(env, 0);
 524     return;
 525   }
 526 
 527   jsrc.outbuf.ip = 0;
 528   jsrc.inbuf = 0;
 529 
 530   /* Step 1: allocate and initialize JPEG decompression object */
 531 
 532   /* We set up the normal JPEG error routines, then override error_exit. */
 533   cinfo.err = jpeg_std_error(&jerr.pub);
 534   jerr.pub.error_exit = sun_jpeg_error_exit;
 535 
 536   /* We need to setup our own print routines */
 537   jerr.pub.output_message = sun_jpeg_output_message;
 538 
 539   /* Establish the setjmp return context for sun_jpeg_error_exit to use. */
 540   if (setjmp(jerr.setjmp_buffer)) {
 541     /* If we get here, the JPEG code has signaled an error.
 542      * We need to clean up the JPEG object, close the input file, and return.
 543      */
 544     jpeg_destroy_decompress(&cinfo);
 545     RELEASE_ARRAYS(env, &jsrc);
 546     if (!(*env)->ExceptionOccurred(env)) {
 547         char buffer[JMSG_LENGTH_MAX];
 548         (*cinfo.err->format_message) ((struct jpeg_common_struct *) &cinfo,
 549                                       buffer);
 550         JNU_ThrowByName(env, "sun/awt/image/ImageFormatException", buffer);
 551     }
 552     return;
 553   }
 554   /* Now we can initialize the JPEG decompression object. */
 555   jpeg_create_decompress(&cinfo);
 556 
 557   /* Step 2: specify data source (eg, a file) */
 558 
 559   cinfo.src = &jsrc.pub;
 560   jsrc.hInputStream = hInputStream;
 561   jsrc.hInputBuffer = hInputBuffer;
 562   jsrc.hOutputBuffer = 0;
 563   jsrc.suspendable = FALSE;
 564   jsrc.remaining_skip = 0;
 565   jsrc.inbufoffset = -1;
 566   jsrc.pub.init_source = sun_jpeg_init_source;
 567   jsrc.pub.fill_input_buffer = sun_jpeg_fill_input_buffer;
 568   jsrc.pub.skip_input_data = sun_jpeg_skip_input_data;
 569   jsrc.pub.resync_to_restart = jpeg_resync_to_restart; /* use default method */
 570   jsrc.pub.term_source = sun_jpeg_term_source;
 571   if (!GET_ARRAYS(env, &jsrc)) {
 572     jpeg_destroy_decompress(&cinfo);
 573     return;
 574   }
 575   /* Step 3: read file parameters with jpeg_read_header() */
 576 
 577   (void) jpeg_read_header(&cinfo, TRUE);
 578   /* select buffered-image mode if it is a progressive JPEG only */
 579   buffered_mode = cinfo.buffered_image = jpeg_has_multiple_scans(&cinfo);
 580   grayscale = (cinfo.out_color_space == JCS_GRAYSCALE);
 581 #ifdef YCCALPHA
 582   hasalpha = (cinfo.out_color_space == JCS_RGBA);
 583 #else
 584   hasalpha = 0;
 585 #endif
 586   /* We can ignore the return value from jpeg_read_header since
 587    *   (a) suspension is not possible with the stdio data source, and
 588    *                                    (nor with the Java input source)
 589    *   (b) we passed TRUE to reject a tables-only JPEG file as an error.
 590    * See libjpeg.doc for more info.
 591    */
 592   RELEASE_ARRAYS(env, &jsrc);
 593   ret = (*env)->CallBooleanMethod(env, this, sendHeaderInfoID,
 594                                   cinfo.image_width, cinfo.image_height,
 595                                   grayscale, hasalpha, buffered_mode);
 596   if ((*env)->ExceptionOccurred(env) || !ret) {
 597     /* No more interest in this image... */
 598     jpeg_destroy_decompress(&cinfo);
 599     return;
 600   }
 601   /* Make a one-row-high sample array with enough room to expand to ints */
 602   if (grayscale) {
 603       jsrc.hOutputBuffer = (*env)->NewByteArray(env, cinfo.image_width);
 604   } else {
 605       jsrc.hOutputBuffer = (*env)->NewIntArray(env, cinfo.image_width);
 606   }
 607 
 608   if (jsrc.hOutputBuffer == 0 || !GET_ARRAYS(env, &jsrc)) {
 609     jpeg_destroy_decompress(&cinfo);
 610     return;
 611   }
 612 
 613   /* Step 4: set parameters for decompression */
 614 
 615   /* In this example, we don't need to change any of the defaults set by
 616    * jpeg_read_header(), so we do nothing here.
 617    */
 618   /* For the first pass for Java, we want to deal with RGB for simplicity */
 619   /* Unfortunately, the JPEG code does not automatically convert Grayscale */
 620   /* to RGB, so we have to deal with Grayscale explicitly. */
 621   if (!grayscale && !hasalpha) {
 622       cinfo.out_color_space = JCS_RGB;
 623   }
 624 
 625   /* Step 5: Start decompressor */
 626 
 627   jpeg_start_decompress(&cinfo);
 628 
 629   /* We may need to do some setup of our own at this point before reading
 630    * the data.  After jpeg_start_decompress() we have the correct scaled
 631    * output image dimensions available, as well as the output colormap
 632    * if we asked for color quantization.
 633    */
 634 
 635   /* Step 6: while (scan lines remain to be read) */
 636   /*           jpeg_read_scanlines(...); */
 637 
 638   /* Here we use the library's state variable cinfo.output_scanline as the
 639    * loop counter, so that we don't have to keep track ourselves.
 640    */
 641   if (buffered_mode) {
 642       final_pass = FALSE;
 643       cinfo.dct_method = JDCT_IFAST;
 644   } else {
 645       final_pass = TRUE;
 646   }
 647   do {
 648       if (buffered_mode) {
 649           do {
 650               sun_jpeg_fill_suspended_buffer(&cinfo);
 651               jsrc.suspendable = TRUE;
 652               ret = jpeg_consume_input(&cinfo);
 653               jsrc.suspendable = FALSE;
 654           } while (ret != JPEG_SUSPENDED && ret != JPEG_REACHED_EOI);
 655           if (ret == JPEG_REACHED_EOI) {
 656               final_pass = TRUE;
 657               cinfo.dct_method = JDCT_ISLOW;
 658           }
 659           jpeg_start_output(&cinfo, cinfo.input_scan_number);
 660       }
 661       while (cinfo.output_scanline < cinfo.output_height) {
 662           if (! final_pass) {
 663               do {
 664                   sun_jpeg_fill_suspended_buffer(&cinfo);
 665                   jsrc.suspendable = TRUE;
 666                   ret = jpeg_consume_input(&cinfo);
 667                   jsrc.suspendable = FALSE;
 668               } while (ret != JPEG_SUSPENDED && ret != JPEG_REACHED_EOI);
 669               if (ret == JPEG_REACHED_EOI) {
 670                   break;
 671               }
 672           }
 673           (void) jpeg_read_scanlines(&cinfo, (JSAMPARRAY) &(jsrc.outbuf), 1);
 674 
 675           if (grayscale) {
 676               RELEASE_ARRAYS(env, &jsrc);
 677               ret = (*env)->CallBooleanMethod(env, this, sendPixelsByteID,
 678                                               jsrc.hOutputBuffer,
 679                                               cinfo.output_scanline - 1);
 680           } else {
 681               if (hasalpha) {
 682                   ip = jsrc.outbuf.ip + jsrc.outbufSize;
 683                   bp = jsrc.outbuf.bp + jsrc.outbufSize * 4;
 684                   while (ip > jsrc.outbuf.ip) {
 685                       pixel = (*--bp) << 24;
 686                       pixel |= (*--bp);
 687                       pixel |= (*--bp) << 8;
 688                       pixel |= (*--bp) << 16;
 689                       *--ip = pixel;
 690                   }
 691               } else {
 692                   ip = jsrc.outbuf.ip + jsrc.outbufSize;
 693                   bp = jsrc.outbuf.bp + jsrc.outbufSize * 3;
 694                   while (ip > jsrc.outbuf.ip) {
 695                       pixel = (*--bp);
 696                       pixel |= (*--bp) << 8;
 697                       pixel |= (*--bp) << 16;
 698                       *--ip = pixel;
 699                   }
 700               }
 701               RELEASE_ARRAYS(env, &jsrc);
 702               ret = (*env)->CallBooleanMethod(env, this, sendPixelsIntID,
 703                                               jsrc.hOutputBuffer,
 704                                               cinfo.output_scanline - 1);
 705           }
 706           if ((*env)->ExceptionOccurred(env) || !ret ||
 707               !GET_ARRAYS(env, &jsrc)) {
 708               /* No more interest in this image... */
 709               jpeg_destroy_decompress(&cinfo);
 710               return;
 711           }
 712       }
 713       if (buffered_mode) {
 714           jpeg_finish_output(&cinfo);
 715       }
 716   } while (! final_pass);
 717 
 718   /* Step 7: Finish decompression */
 719 
 720   (void) jpeg_finish_decompress(&cinfo);
 721   /* We can ignore the return value since suspension is not possible
 722    * with the stdio data source.
 723    * (nor with the Java data source)
 724    */
 725 
 726   /* Step 8: Release JPEG decompression object */
 727 
 728   /* This is an important step since it will release a good deal of memory. */
 729   jpeg_destroy_decompress(&cinfo);
 730 
 731   /* After finish_decompress, we can close the input file.
 732    * Here we postpone it until after no more JPEG errors are possible,
 733    * so as to simplify the setjmp error logic above.  (Actually, I don't
 734    * think that jpeg_destroy can do an error exit, but why assume anything...)
 735    */
 736   /* Not needed for Java - the Java code will close the file */
 737   /* fclose(infile); */
 738 
 739   /* At this point you may want to check to see whether any corrupt-data
 740    * warnings occurred (test whether jerr.pub.num_warnings is nonzero).
 741    */
 742 
 743   /* And we're done! */
 744 
 745   RELEASE_ARRAYS(env, &jsrc);
 746   return;
 747 }
 748 #ifdef _M_IA64
 749 #pragma optimize ("", on)
 750 #endif
 751 
 752 
 753 /*
 754  * SOME FINE POINTS:
 755  *
 756  * In the above code, we ignored the return value of jpeg_read_scanlines,
 757  * which is the number of scanlines actually read.  We could get away with
 758  * this because we asked for only one line at a time and we weren't using
 759  * a suspending data source.  See libjpeg.doc for more info.
 760  *
 761  * We cheated a bit by calling alloc_sarray() after jpeg_start_decompress();
 762  * we should have done it beforehand to ensure that the space would be
 763  * counted against the JPEG max_memory setting.  In some systems the above
 764  * code would risk an out-of-memory error.  However, in general we don't
 765  * know the output image dimensions before jpeg_start_decompress(), unless we
 766  * call jpeg_calc_output_dimensions().  See libjpeg.doc for more about this.
 767  *
 768  * Scanlines are returned in the same order as they appear in the JPEG file,
 769  * which is standardly top-to-bottom.  If you must emit data bottom-to-top,
 770  * you can use one of the virtual arrays provided by the JPEG memory manager
 771  * to invert the data.  See wrbmp.c for an example.
 772  *
 773  * As with compression, some operating modes may require temporary files.
 774  * On some systems you may need to set up a signal handler to ensure that
 775  * temporary files are deleted if the program is interrupted.  See libjpeg.doc.
 776  */
--- EOF ---