1 /*

     2  * jcapimin.c

     3  *

     4  * Copyright (C) 1994-1998, Thomas G. Lane.

     5  * This file is part of the Independent JPEG Group's software.

     6  * For conditions of distribution and use, see the accompanying README file.

     7  *

     8  * This file contains application interface code for the compression half

     9  * of the JPEG library.  These are the "minimum" API routines that may be

    10  * needed in either the normal full-compression case or the transcoding-only

    11  * case.

    12  *

    13  * Most of the routines intended to be called directly by an application

    14  * are in this file or in jcapistd.c.  But also see jcparam.c for

    15  * parameter-setup helper routines, jcomapi.c for routines shared by

    16  * compression and decompression, and jctrans.c for the transcoding case.

    17  */

    18 

    19 #define JPEG_INTERNALS

    20 #include "jinclude.h"

    21 #include "jpeglib.h"

    22 

    23 

    24 /*

    25  * Initialization of a JPEG compression object.

    26  * The error manager must already be set up (in case memory manager fails).

    27  */

    28 

    29 GLOBAL(void)

    30 jpeg_CreateCompress (j_compress_ptr cinfo, int version, size_t structsize)

    31 {

    32   int i;

    33 

    34   /* Guard against version mismatches between library and caller. */

    35   cinfo->mem = NULL;		/* so jpeg_destroy knows mem mgr not called */

    36   if (version != JPEG_LIB_VERSION)

    37     ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);

    38   if (structsize != SIZEOF(struct jpeg_compress_struct))

    39     ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE, 

    40 	     (int) SIZEOF(struct jpeg_compress_struct), (int) structsize);

    41 

    42   /* For debugging purposes, we zero the whole master structure.

    43    * But the application has already set the err pointer, and may have set

    44    * client_data, so we have to save and restore those fields.

    45    * Note: if application hasn't set client_data, tools like Purify may

    46    * complain here.

    47    */

    48   {

    49     struct jpeg_error_mgr * err = cinfo->err;

    50     void * client_data = cinfo->client_data; /* ignore Purify complaint here */

    51     MEMZERO(cinfo, SIZEOF(struct jpeg_compress_struct));

    52     cinfo->err = err;

    53     cinfo->client_data = client_data;

    54   }

    55   cinfo->is_decompressor = FALSE;

    56 

    57   /* Initialize a memory manager instance for this object */

    58   jinit_memory_mgr((j_common_ptr) cinfo);

    59 

    60   /* Zero out pointers to permanent structures. */

    61   cinfo->progress = NULL;

    62   cinfo->dest = NULL;

    63 

    64   cinfo->comp_info = NULL;

    65 

    66   for (i = 0; i < NUM_QUANT_TBLS; i++)

    67     cinfo->quant_tbl_ptrs[i] = NULL;

    68 

    69   for (i = 0; i < NUM_HUFF_TBLS; i++) {

    70     cinfo->dc_huff_tbl_ptrs[i] = NULL;

    71     cinfo->ac_huff_tbl_ptrs[i] = NULL;

    72   }

    73 

    74   cinfo->script_space = NULL;

    75 

    76   cinfo->input_gamma = 1.0;	/* in case application forgets */

    77 

    78   /* OK, I'm ready */

    79   cinfo->global_state = CSTATE_START;

    80 }

    81 

    82 

    83 /*

    84  * Destruction of a JPEG compression object

    85  */

    86 

    87 GLOBAL(void)

    88 jpeg_destroy_compress (j_compress_ptr cinfo)

    89 {

    90   jpeg_destroy((j_common_ptr) cinfo); /* use common routine */

    91 }

    92 

    93 

    94 /*

    95  * Abort processing of a JPEG compression operation,

    96  * but don't destroy the object itself.

    97  */

    98 

    99 GLOBAL(void)

   100 jpeg_abort_compress (j_compress_ptr cinfo)

   101 {

   102   jpeg_abort((j_common_ptr) cinfo); /* use common routine */

   103 }

   104 

   105 

   106 /*

   107  * Forcibly suppress or un-suppress all quantization and Huffman tables.

   108  * Marks all currently defined tables as already written (if suppress)

   109  * or not written (if !suppress).  This will control whether they get emitted

   110  * by a subsequent jpeg_start_compress call.

   111  *

   112  * This routine is exported for use by applications that want to produce

   113  * abbreviated JPEG datastreams.  It logically belongs in jcparam.c, but

   114  * since it is called by jpeg_start_compress, we put it here --- otherwise

   115  * jcparam.o would be linked whether the application used it or not.

   116  */

   117 

   118 GLOBAL(void)

   119 jpeg_suppress_tables (j_compress_ptr cinfo, boolean suppress)

   120 {

   121   int i;

   122   JQUANT_TBL * qtbl;

   123   JHUFF_TBL * htbl;

   124 

   125   for (i = 0; i < NUM_QUANT_TBLS; i++) {

   126     if ((qtbl = cinfo->quant_tbl_ptrs[i]) != NULL)

   127       qtbl->sent_table = suppress;

   128   }

   129 

   130   for (i = 0; i < NUM_HUFF_TBLS; i++) {

   131     if ((htbl = cinfo->dc_huff_tbl_ptrs[i]) != NULL)

   132       htbl->sent_table = suppress;

   133     if ((htbl = cinfo->ac_huff_tbl_ptrs[i]) != NULL)

   134       htbl->sent_table = suppress;

   135   }

   136 }

   137 

   138 

   139 /*

   140  * Finish JPEG compression.

   141  *

   142  * If a multipass operating mode was selected, this may do a great deal of

   143  * work including most of the actual output.

   144  */

   145 

   146 GLOBAL(void)

   147 jpeg_finish_compress (j_compress_ptr cinfo)

   148 {

   149   JDIMENSION iMCU_row;

   150 

   151   if (cinfo->global_state == CSTATE_SCANNING ||

   152       cinfo->global_state == CSTATE_RAW_OK) {

   153     /* Terminate first pass */

   154     if (cinfo->next_scanline < cinfo->image_height)

   155       ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);

   156     (*cinfo->master->finish_pass) (cinfo);

   157   } else if (cinfo->global_state != CSTATE_WRCOEFS)

   158     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

   159   /* Perform any remaining passes */

   160   while (! cinfo->master->is_last_pass) {

   161     (*cinfo->master->prepare_for_pass) (cinfo);

   162     for (iMCU_row = 0; iMCU_row < cinfo->total_iMCU_rows; iMCU_row++) {

   163       if (cinfo->progress != NULL) {

   164 	cinfo->progress->pass_counter = (long) iMCU_row;

   165 	cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows;

   166 	(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);

   167       }

   168       /* We bypass the main controller and invoke coef controller directly;

   169        * all work is being done from the coefficient buffer.

   170        */

   171       if (! (*cinfo->coef->compress_data) (cinfo, (JSAMPIMAGE) NULL))

   172 	ERREXIT(cinfo, JERR_CANT_SUSPEND);

   173     }

   174     (*cinfo->master->finish_pass) (cinfo);

   175   }

   176   /* Write EOI, do final cleanup */

   177   (*cinfo->marker->write_file_trailer) (cinfo);

   178   (*cinfo->dest->term_destination) (cinfo);

   179   /* We can use jpeg_abort to release memory and reset global_state */

   180   jpeg_abort((j_common_ptr) cinfo);

   181 }

   182 

   183 

   184 /*

   185  * Write a special marker.

   186  * This is only recommended for writing COM or APPn markers.

   187  * Must be called after jpeg_start_compress() and before

   188  * first call to jpeg_write_scanlines() or jpeg_write_raw_data().

   189  */

   190 

   191 GLOBAL(void)

   192 jpeg_write_marker (j_compress_ptr cinfo, int marker,

   193 		   const JOCTET *dataptr, unsigned int datalen)

   194 {

   195   JMETHOD(void, write_marker_byte, (j_compress_ptr info, int val));

   196 

   197   if (cinfo->next_scanline != 0 ||

   198       (cinfo->global_state != CSTATE_SCANNING &&

   199        cinfo->global_state != CSTATE_RAW_OK &&

   200        cinfo->global_state != CSTATE_WRCOEFS))

   201     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

   202 

   203   (*cinfo->marker->write_marker_header) (cinfo, marker, datalen);

   204   write_marker_byte = cinfo->marker->write_marker_byte;	/* copy for speed */

   205   while (datalen--) {

   206     (*write_marker_byte) (cinfo, *dataptr);

   207     dataptr++;

   208   }

   209 }

   210 

   211 /* Same, but piecemeal. */

   212 

   213 GLOBAL(void)

   214 jpeg_write_m_header (j_compress_ptr cinfo, int marker, unsigned int datalen)

   215 {

   216   if (cinfo->next_scanline != 0 ||

   217       (cinfo->global_state != CSTATE_SCANNING &&

   218        cinfo->global_state != CSTATE_RAW_OK &&

   219        cinfo->global_state != CSTATE_WRCOEFS))

   220     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

   221 

   222   (*cinfo->marker->write_marker_header) (cinfo, marker, datalen);

   223 }

   224 

   225 GLOBAL(void)

   226 jpeg_write_m_byte (j_compress_ptr cinfo, int val)

   227 {

   228   (*cinfo->marker->write_marker_byte) (cinfo, val);

   229 }

   230 

   231 

   232 /*

   233  * Alternate compression function: just write an abbreviated table file.

   234  * Before calling this, all parameters and a data destination must be set up.

   235  *

   236  * To produce a pair of files containing abbreviated tables and abbreviated

   237  * image data, one would proceed as follows:

   238  *

   239  *		initialize JPEG object

   240  *		set JPEG parameters

   241  *		set destination to table file

   242  *		jpeg_write_tables(cinfo);

   243  *		set destination to image file

   244  *		jpeg_start_compress(cinfo, FALSE);

   245  *		write data...

   246  *		jpeg_finish_compress(cinfo);

   247  *

   248  * jpeg_write_tables has the side effect of marking all tables written

   249  * (same as jpeg_suppress_tables(..., TRUE)).  Thus a subsequent start_compress

   250  * will not re-emit the tables unless it is passed write_all_tables=TRUE.

   251  */

   252 

   253 GLOBAL(void)

   254 jpeg_write_tables (j_compress_ptr cinfo)

   255 {

   256   if (cinfo->global_state != CSTATE_START)

   257     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

   258 

   259   /* (Re)initialize error mgr and destination modules */

   260   (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);

   261   (*cinfo->dest->init_destination) (cinfo);

   262   /* Initialize the marker writer ... bit of a crock to do it here. */

   263   jinit_marker_writer(cinfo);

   264   /* Write them tables! */

   265   (*cinfo->marker->write_tables_only) (cinfo);

   266   /* And clean up. */

   267   (*cinfo->dest->term_destination) (cinfo);

   268   /*

   269    * In library releases up through v6a, we called jpeg_abort() here to free

   270    * any working memory allocated by the destination manager and marker

   271    * writer.  Some applications had a problem with that: they allocated space

   272    * of their own from the library memory manager, and didn't want it to go

   273    * away during write_tables.  So now we do nothing.  This will cause a

   274    * memory leak if an app calls write_tables repeatedly without doing a full

   275    * compression cycle or otherwise resetting the JPEG object.  However, that

   276    * seems less bad than unexpectedly freeing memory in the normal case.

   277    * An app that prefers the old behavior can call jpeg_abort for itself after

   278    * each call to jpeg_write_tables().

   279    */

   280 }