jcapimin.c

00001 /*
00002  * jcapimin.c
00003  *
00004  * Copyright (C) 1994-1998, Thomas G. Lane.
00005  * Modified 2003-2010 by Guido Vollbeding.
00006  * This file is part of the Independent JPEG Group's software.
00007  * For conditions of distribution and use, see the accompanying README file.
00008  *
00009  * This file contains application interface code for the compression half
00010  * of the JPEG library.  These are the "minimum" API routines that may be
00011  * needed in either the normal full-compression case or the transcoding-only
00012  * case.
00013  *
00014  * Most of the routines intended to be called directly by an application
00015  * are in this file or in jcapistd.c.  But also see jcparam.c for
00016  * parameter-setup helper routines, jcomapi.c for routines shared by
00017  * compression and decompression, and jctrans.c for the transcoding case.
00018  */
00019 
00020 #define JPEG_INTERNALS
00021 #include "jinclude.h"
00022 #include "jpeglib.h"
00023 
00024 
00025 /*
00026  * Initialization of a JPEG compression object.
00027  * The error manager must already be set up (in case memory manager fails).
00028  */
00029 
00030 GLOBAL(void)
00031 jpeg_CreateCompress (j_compress_ptr cinfo, int version, size_t structsize)
00032 {
00033   int i;
00034 
00035   /* Guard against version mismatches between library and caller. */
00036   cinfo->mem = NULL;        /* so jpeg_destroy knows mem mgr not called */
00037   if (version != JPEG_LIB_VERSION)
00038     ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
00039   if (structsize != SIZEOF(struct jpeg_compress_struct))
00040     ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE, 
00041          (int) SIZEOF(struct jpeg_compress_struct), (int) structsize);
00042 
00043   /* For debugging purposes, we zero the whole master structure.
00044    * But the application has already set the err pointer, and may have set
00045    * client_data, so we have to save and restore those fields.
00046    * Note: if application hasn't set client_data, tools like Purify may
00047    * complain here.
00048    */
00049   {
00050     struct jpeg_error_mgr * err = cinfo->err;
00051     void * client_data = cinfo->client_data; /* ignore Purify complaint here */
00052     MEMZERO(cinfo, SIZEOF(struct jpeg_compress_struct));
00053     cinfo->err = err;
00054     cinfo->client_data = client_data;
00055   }
00056   cinfo->is_decompressor = FALSE;
00057 
00058   /* Initialize a memory manager instance for this object */
00059   jinit_memory_mgr((j_common_ptr) cinfo);
00060 
00061   /* Zero out pointers to permanent structures. */
00062   cinfo->progress = NULL;
00063   cinfo->dest = NULL;
00064 
00065   cinfo->comp_info = NULL;
00066 
00067   for (i = 0; i < NUM_QUANT_TBLS; i++) {
00068     cinfo->quant_tbl_ptrs[i] = NULL;
00069     cinfo->q_scale_factor[i] = 100;
00070   }
00071 
00072   for (i = 0; i < NUM_HUFF_TBLS; i++) {
00073     cinfo->dc_huff_tbl_ptrs[i] = NULL;
00074     cinfo->ac_huff_tbl_ptrs[i] = NULL;
00075   }
00076 
00077   /* Must do it here for emit_dqt in case jpeg_write_tables is used */
00078   cinfo->block_size = DCTSIZE;
00079   cinfo->natural_order = jpeg_natural_order;
00080   cinfo->lim_Se = DCTSIZE2-1;
00081 
00082   cinfo->script_space = NULL;
00083 
00084   cinfo->input_gamma = 1.0; /* in case application forgets */
00085 
00086   /* OK, I'm ready */
00087   cinfo->global_state = CSTATE_START;
00088 }
00089 
00090 
00091 /*
00092  * Destruction of a JPEG compression object
00093  */
00094 
00095 GLOBAL(void)
00096 jpeg_destroy_compress (j_compress_ptr cinfo)
00097 {
00098   jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
00099 }
00100 
00101 
00102 /*
00103  * Abort processing of a JPEG compression operation,
00104  * but don't destroy the object itself.
00105  */
00106 
00107 GLOBAL(void)
00108 jpeg_abort_compress (j_compress_ptr cinfo)
00109 {
00110   jpeg_abort((j_common_ptr) cinfo); /* use common routine */
00111 }
00112 
00113 
00114 /*
00115  * Forcibly suppress or un-suppress all quantization and Huffman tables.
00116  * Marks all currently defined tables as already written (if suppress)
00117  * or not written (if !suppress).  This will control whether they get emitted
00118  * by a subsequent jpeg_start_compress call.
00119  *
00120  * This routine is exported for use by applications that want to produce
00121  * abbreviated JPEG datastreams.  It logically belongs in jcparam.c, but
00122  * since it is called by jpeg_start_compress, we put it here --- otherwise
00123  * jcparam.o would be linked whether the application used it or not.
00124  */
00125 
00126 GLOBAL(void)
00127 jpeg_suppress_tables (j_compress_ptr cinfo, boolean suppress)
00128 {
00129   int i;
00130   JQUANT_TBL * qtbl;
00131   JHUFF_TBL * htbl;
00132 
00133   for (i = 0; i < NUM_QUANT_TBLS; i++) {
00134     if ((qtbl = cinfo->quant_tbl_ptrs[i]) != NULL)
00135       qtbl->sent_table = suppress;
00136   }
00137 
00138   for (i = 0; i < NUM_HUFF_TBLS; i++) {
00139     if ((htbl = cinfo->dc_huff_tbl_ptrs[i]) != NULL)
00140       htbl->sent_table = suppress;
00141     if ((htbl = cinfo->ac_huff_tbl_ptrs[i]) != NULL)
00142       htbl->sent_table = suppress;
00143   }
00144 }
00145 
00146 
00147 /*
00148  * Finish JPEG compression.
00149  *
00150  * If a multipass operating mode was selected, this may do a great deal of
00151  * work including most of the actual output.
00152  */
00153 
00154 GLOBAL(void)
00155 jpeg_finish_compress (j_compress_ptr cinfo)
00156 {
00157   JDIMENSION iMCU_row;
00158 
00159   if (cinfo->global_state == CSTATE_SCANNING ||
00160       cinfo->global_state == CSTATE_RAW_OK) {
00161     /* Terminate first pass */
00162     if (cinfo->next_scanline < cinfo->image_height)
00163       ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
00164     (*cinfo->master->finish_pass) (cinfo);
00165   } else if (cinfo->global_state != CSTATE_WRCOEFS)
00166     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
00167   /* Perform any remaining passes */
00168   while (! cinfo->master->is_last_pass) {
00169     (*cinfo->master->prepare_for_pass) (cinfo);
00170     for (iMCU_row = 0; iMCU_row < cinfo->total_iMCU_rows; iMCU_row++) {
00171       if (cinfo->progress != NULL) {
00172     cinfo->progress->pass_counter = (long) iMCU_row;
00173     cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows;
00174     (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
00175       }
00176       /* We bypass the main controller and invoke coef controller directly;
00177        * all work is being done from the coefficient buffer.
00178        */
00179       if (! (*cinfo->coef->compress_data) (cinfo, (JSAMPIMAGE) NULL))
00180     ERREXIT(cinfo, JERR_CANT_SUSPEND);
00181     }
00182     (*cinfo->master->finish_pass) (cinfo);
00183   }
00184   /* Write EOI, do final cleanup */
00185   (*cinfo->marker->write_file_trailer) (cinfo);
00186   (*cinfo->dest->term_destination) (cinfo);
00187   /* We can use jpeg_abort to release memory and reset global_state */
00188   jpeg_abort((j_common_ptr) cinfo);
00189 }
00190 
00191 
00192 /*
00193  * Write a special marker.
00194  * This is only recommended for writing COM or APPn markers.
00195  * Must be called after jpeg_start_compress() and before
00196  * first call to jpeg_write_scanlines() or jpeg_write_raw_data().
00197  */
00198 
00199 GLOBAL(void)
00200 jpeg_write_marker (j_compress_ptr cinfo, int marker,
00201            const JOCTET *dataptr, unsigned int datalen)
00202 {
00203   JMETHOD(void, write_marker_byte, (j_compress_ptr info, int val));
00204 
00205   if (cinfo->next_scanline != 0 ||
00206       (cinfo->global_state != CSTATE_SCANNING &&
00207        cinfo->global_state != CSTATE_RAW_OK &&
00208        cinfo->global_state != CSTATE_WRCOEFS))
00209     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
00210 
00211   (*cinfo->marker->write_marker_header) (cinfo, marker, datalen);
00212   write_marker_byte = cinfo->marker->write_marker_byte; /* copy for speed */
00213   while (datalen--) {
00214     (*write_marker_byte) (cinfo, *dataptr);
00215     dataptr++;
00216   }
00217 }
00218 
00219 /* Same, but piecemeal. */
00220 
00221 GLOBAL(void)
00222 jpeg_write_m_header (j_compress_ptr cinfo, int marker, unsigned int datalen)
00223 {
00224   if (cinfo->next_scanline != 0 ||
00225       (cinfo->global_state != CSTATE_SCANNING &&
00226        cinfo->global_state != CSTATE_RAW_OK &&
00227        cinfo->global_state != CSTATE_WRCOEFS))
00228     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
00229 
00230   (*cinfo->marker->write_marker_header) (cinfo, marker, datalen);
00231 }
00232 
00233 GLOBAL(void)
00234 jpeg_write_m_byte (j_compress_ptr cinfo, int val)
00235 {
00236   (*cinfo->marker->write_marker_byte) (cinfo, val);
00237 }
00238 
00239 
00240 /*
00241  * Alternate compression function: just write an abbreviated table file.
00242  * Before calling this, all parameters and a data destination must be set up.
00243  *
00244  * To produce a pair of files containing abbreviated tables and abbreviated
00245  * image data, one would proceed as follows:
00246  *
00247  *      initialize JPEG object
00248  *      set JPEG parameters
00249  *      set destination to table file
00250  *      jpeg_write_tables(cinfo);
00251  *      set destination to image file
00252  *      jpeg_start_compress(cinfo, FALSE);
00253  *      write data...
00254  *      jpeg_finish_compress(cinfo);
00255  *
00256  * jpeg_write_tables has the side effect of marking all tables written
00257  * (same as jpeg_suppress_tables(..., TRUE)).  Thus a subsequent start_compress
00258  * will not re-emit the tables unless it is passed write_all_tables=TRUE.
00259  */
00260 
00261 GLOBAL(void)
00262 jpeg_write_tables (j_compress_ptr cinfo)
00263 {
00264   if (cinfo->global_state != CSTATE_START)
00265     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
00266 
00267   /* (Re)initialize error mgr and destination modules */
00268   (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
00269   (*cinfo->dest->init_destination) (cinfo);
00270   /* Initialize the marker writer ... bit of a crock to do it here. */
00271   jinit_marker_writer(cinfo);
00272   /* Write them tables! */
00273   (*cinfo->marker->write_tables_only) (cinfo);
00274   /* And clean up. */
00275   (*cinfo->dest->term_destination) (cinfo);
00276   /*
00277    * In library releases up through v6a, we called jpeg_abort() here to free
00278    * any working memory allocated by the destination manager and marker
00279    * writer.  Some applications had a problem with that: they allocated space
00280    * of their own from the library memory manager, and didn't want it to go
00281    * away during write_tables.  So now we do nothing.  This will cause a
00282    * memory leak if an app calls write_tables repeatedly without doing a full
00283    * compression cycle or otherwise resetting the JPEG object.  However, that
00284    * seems less bad than unexpectedly freeing memory in the normal case.
00285    * An app that prefers the old behavior can call jpeg_abort for itself after
00286    * each call to jpeg_write_tables().
00287    */
00288 }