00001 /*
00002  * jcmaster.c
00003  *
00004  * Copyright (C) 1991-1997, Thomas G. Lane.
00005  * This file is part of the Independent JPEG Group's software.
00006  * For conditions of distribution and use, see the accompanying README file.
00007  *
00008  * This file contains master control logic for the JPEG compressor.
00009  * These routines are concerned with parameter validation, initial setup,
00010  * and inter-pass control (determining the number of passes and the work 
00011  * to be done in each pass).
00012  */
00013 
00014 #define JPEG_INTERNALS
00015 #include "jinclude.h"
00016 #include "jpeglib.h"
00017 
00018 
00019 /* Private state */
00020 
00021 typedef enum {
00022         main_pass,              /* input data, also do first output step */
00023         huff_opt_pass,          /* Huffman code optimization pass */
00024         output_pass             /* data output pass */
00025 } c_pass_type;
00026 
00027 typedef struct {
00028   struct jpeg_comp_master pub;  /* public fields */
00029 
00030   c_pass_type pass_type;        /* the type of the current pass */
00031 
00032   int pass_number;              /* # of passes completed */
00033   int total_passes;             /* total # of passes needed */
00034 
00035   int scan_number;              /* current index in scan_info[] */
00036 } my_comp_master;
00037 
00038 typedef my_comp_master * my_master_ptr;
00039 
00040 
00041 /*
00042  * Support routines that do various essential calculations.
00043  */
00044 
00045 LOCAL(void)
00046 initial_setup (j_compress_ptr cinfo)
00047 /* Do computations that are needed before master selection phase */
00048 {
00049   int ci;
00050   jpeg_component_info *compptr;
00051   long samplesperrow;
00052   JDIMENSION jd_samplesperrow;
00053 
00054   /* Sanity check on image dimensions */
00055   if (cinfo->image_height <= 0 || cinfo->image_width <= 0
00056       || cinfo->num_components <= 0 || cinfo->input_components <= 0)
00057     ERREXIT(cinfo, JERR_EMPTY_IMAGE);
00058 
00059   /* Make sure image isn't bigger than I can handle */
00060   if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
00061       (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
00062     ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
00063 
00064   /* Width of an input scanline must be representable as JDIMENSION. */
00065   samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
00066   jd_samplesperrow = (JDIMENSION) samplesperrow;
00067   if ((long) jd_samplesperrow != samplesperrow)
00068     ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
00069 
00070   /* For now, precision must match compiled-in value... */
00071   if (cinfo->data_precision != BITS_IN_JSAMPLE)
00072     ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
00073 
00074   /* Check that number of components won't exceed internal array sizes */
00075   if (cinfo->num_components > MAX_COMPONENTS)
00076     ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
00077              MAX_COMPONENTS);
00078 
00079   /* Compute maximum sampling factors; check factor validity */
00080   cinfo->max_h_samp_factor = 1;
00081   cinfo->max_v_samp_factor = 1;
00082   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
00083        ci++, compptr++) {
00084     if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
00085         compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
00086       ERREXIT(cinfo, JERR_BAD_SAMPLING);
00087     cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
00088                                    compptr->h_samp_factor);
00089     cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
00090                                    compptr->v_samp_factor);
00091   }
00092 
00093   /* Compute dimensions of components */
00094   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
00095        ci++, compptr++) {
00096     /* Fill in the correct component_index value; don't rely on application */
00097     compptr->component_index = ci;
00098     /* For compression, we never do DCT scaling. */
00099     compptr->DCT_scaled_size = DCTSIZE;
00100     /* Size in DCT blocks */
00101     compptr->width_in_blocks = (JDIMENSION)
00102       jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
00103                     (long) (cinfo->max_h_samp_factor * DCTSIZE));
00104     compptr->height_in_blocks = (JDIMENSION)
00105       jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
00106                     (long) (cinfo->max_v_samp_factor * DCTSIZE));
00107     /* Size in samples */
00108     compptr->downsampled_width = (JDIMENSION)
00109       jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
00110                     (long) cinfo->max_h_samp_factor);
00111     compptr->downsampled_height = (JDIMENSION)
00112       jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
00113                     (long) cinfo->max_v_samp_factor);
00114     /* Mark component needed (this flag isn't actually used for compression) */
00115     compptr->component_needed = TRUE;
00116   }
00117 
00118   /* Compute number of fully interleaved MCU rows (number of times that
00119    * main controller will call coefficient controller).
00120    */
00121   cinfo->total_iMCU_rows = (JDIMENSION)
00122     jdiv_round_up((long) cinfo->image_height,
00123                   (long) (cinfo->max_v_samp_factor*DCTSIZE));
00124 }
00125 
00126 
00127 #ifdef C_MULTISCAN_FILES_SUPPORTED
00128 
00129 LOCAL(void)
00130 validate_script (j_compress_ptr cinfo)
00131 /* Verify that the scan script in cinfo->scan_info[] is valid; also
00132  * determine whether it uses progressive JPEG, and set cinfo->progressive_mode.
00133  */
00134 {
00135   const jpeg_scan_info * scanptr;
00136   int scanno, ncomps, ci, coefi, thisi;
00137   int Ss, Se, Ah, Al;
00138   boolean component_sent[MAX_COMPONENTS];
00139 #ifdef C_PROGRESSIVE_SUPPORTED
00140   int * last_bitpos_ptr;
00141   int last_bitpos[MAX_COMPONENTS][DCTSIZE2];
00142   /* -1 until that coefficient has been seen; then last Al for it */
00143 #endif
00144 
00145   if (cinfo->num_scans <= 0)
00146     ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0);
00147 
00148   /* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1;
00149    * for progressive JPEG, no scan can have this.
00150    */
00151   scanptr = cinfo->scan_info;
00152   if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) {
00153 #ifdef C_PROGRESSIVE_SUPPORTED
00154     cinfo->progressive_mode = TRUE;
00155     last_bitpos_ptr = & last_bitpos[0][0];
00156     for (ci = 0; ci < cinfo->num_components; ci++) 
00157       for (coefi = 0; coefi < DCTSIZE2; coefi++)
00158         *last_bitpos_ptr++ = -1;
00159 #else
00160     ERREXIT(cinfo, JERR_NOT_COMPILED);
00161 #endif
00162   } else {
00163     cinfo->progressive_mode = FALSE;
00164     for (ci = 0; ci < cinfo->num_components; ci++) 
00165       component_sent[ci] = FALSE;
00166   }
00167 
00168   for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) {
00169     /* Validate component indexes */
00170     ncomps = scanptr->comps_in_scan;
00171     if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN)
00172       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN);
00173     for (ci = 0; ci < ncomps; ci++) {
00174       thisi = scanptr->component_index[ci];
00175       if (thisi < 0 || thisi >= cinfo->num_components)
00176         ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
00177       /* Components must appear in SOF order within each scan */
00178       if (ci > 0 && thisi <= scanptr->component_index[ci-1])
00179         ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
00180     }
00181     /* Validate progression parameters */
00182     Ss = scanptr->Ss;
00183     Se = scanptr->Se;
00184     Ah = scanptr->Ah;
00185     Al = scanptr->Al;
00186     if (cinfo->progressive_mode) {
00187 #ifdef C_PROGRESSIVE_SUPPORTED
00188       /* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that
00189        * seems wrong: the upper bound ought to depend on data precision.
00190        * Perhaps they really meant 0..N+1 for N-bit precision.
00191        * Here we allow 0..10 for 8-bit data; Al larger than 10 results in
00192        * out-of-range reconstructed DC values during the first DC scan,
00193        * which might cause problems for some decoders.
00194        */
00195 #if BITS_IN_JSAMPLE == 8
00196 #define MAX_AH_AL 10
00197 #else
00198 #define MAX_AH_AL 13
00199 #endif
00200       if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 ||
00201           Ah < 0 || Ah > MAX_AH_AL || Al < 0 || Al > MAX_AH_AL)
00202         ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
00203       if (Ss == 0) {
00204         if (Se != 0)            /* DC and AC together not OK */
00205           ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
00206       } else {
00207         if (ncomps != 1)        /* AC scans must be for only one component */
00208           ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
00209       }
00210       for (ci = 0; ci < ncomps; ci++) {
00211         last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0];
00212         if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */
00213           ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
00214         for (coefi = Ss; coefi <= Se; coefi++) {
00215           if (last_bitpos_ptr[coefi] < 0) {
00216             /* first scan of this coefficient */
00217             if (Ah != 0)
00218               ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
00219           } else {
00220             /* not first scan */
00221             if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1)
00222               ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
00223           }
00224           last_bitpos_ptr[coefi] = Al;
00225         }
00226       }
00227 #endif
00228     } else {
00229       /* For sequential JPEG, all progression parameters must be these: */
00230       if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0)
00231         ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
00232       /* Make sure components are not sent twice */
00233       for (ci = 0; ci < ncomps; ci++) {
00234         thisi = scanptr->component_index[ci];
00235         if (component_sent[thisi])
00236           ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
00237         component_sent[thisi] = TRUE;
00238       }
00239     }
00240   }
00241 
00242   /* Now verify that everything got sent. */
00243   if (cinfo->progressive_mode) {
00244 #ifdef C_PROGRESSIVE_SUPPORTED
00245     /* For progressive mode, we only check that at least some DC data
00246      * got sent for each component; the spec does not require that all bits
00247      * of all coefficients be transmitted.  Would it be wiser to enforce
00248      * transmission of all coefficient bits??
00249      */
00250     for (ci = 0; ci < cinfo->num_components; ci++) {
00251       if (last_bitpos[ci][0] < 0)
00252         ERREXIT(cinfo, JERR_MISSING_DATA);
00253     }
00254 #endif
00255   } else {
00256     for (ci = 0; ci < cinfo->num_components; ci++) {
00257       if (! component_sent[ci])
00258         ERREXIT(cinfo, JERR_MISSING_DATA);
00259     }
00260   }
00261 }
00262 
00263 #endif /* C_MULTISCAN_FILES_SUPPORTED */
00264 
00265 
00266 LOCAL(void)
00267 select_scan_parameters (j_compress_ptr cinfo)
00268 /* Set up the scan parameters for the current scan */
00269 {
00270   int ci;
00271 
00272 #ifdef C_MULTISCAN_FILES_SUPPORTED
00273   if (cinfo->scan_info != NULL) {
00274     /* Prepare for current scan --- the script is already validated */
00275     my_master_ptr master = (my_master_ptr) cinfo->master;
00276     const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number;
00277 
00278     cinfo->comps_in_scan = scanptr->comps_in_scan;
00279     for (ci = 0; ci < scanptr->comps_in_scan; ci++) {
00280       cinfo->cur_comp_info[ci] =
00281         &cinfo->comp_info[scanptr->component_index[ci]];
00282     }
00283     cinfo->Ss = scanptr->Ss;
00284     cinfo->Se = scanptr->Se;
00285     cinfo->Ah = scanptr->Ah;
00286     cinfo->Al = scanptr->Al;
00287   }
00288   else
00289 #endif
00290   {
00291     /* Prepare for single sequential-JPEG scan containing all components */
00292     if (cinfo->num_components > MAX_COMPS_IN_SCAN)
00293       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
00294                MAX_COMPS_IN_SCAN);
00295     cinfo->comps_in_scan = cinfo->num_components;
00296     for (ci = 0; ci < cinfo->num_components; ci++) {
00297       cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
00298     }
00299     cinfo->Ss = 0;
00300     cinfo->Se = DCTSIZE2-1;
00301     cinfo->Ah = 0;
00302     cinfo->Al = 0;
00303   }
00304 }
00305 
00306 
00307 LOCAL(void)
00308 per_scan_setup (j_compress_ptr cinfo)
00309 /* Do computations that are needed before processing a JPEG scan */
00310 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
00311 {
00312   int ci, mcublks, tmp;
00313   jpeg_component_info *compptr;
00314   
00315   if (cinfo->comps_in_scan == 1) {
00316     
00317     /* Noninterleaved (single-component) scan */
00318     compptr = cinfo->cur_comp_info[0];
00319     
00320     /* Overall image size in MCUs */
00321     cinfo->MCUs_per_row = compptr->width_in_blocks;
00322     cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
00323     
00324     /* For noninterleaved scan, always one block per MCU */
00325     compptr->MCU_width = 1;
00326     compptr->MCU_height = 1;
00327     compptr->MCU_blocks = 1;
00328     compptr->MCU_sample_width = DCTSIZE;
00329     compptr->last_col_width = 1;
00330     /* For noninterleaved scans, it is convenient to define last_row_height
00331      * as the number of block rows present in the last iMCU row.
00332      */
00333     tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
00334     if (tmp == 0) tmp = compptr->v_samp_factor;
00335     compptr->last_row_height = tmp;
00336     
00337     /* Prepare array describing MCU composition */
00338     cinfo->blocks_in_MCU = 1;
00339     cinfo->MCU_membership[0] = 0;
00340     
00341   } else {
00342     
00343     /* Interleaved (multi-component) scan */
00344     if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
00345       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
00346                MAX_COMPS_IN_SCAN);
00347     
00348     /* Overall image size in MCUs */
00349     cinfo->MCUs_per_row = (JDIMENSION)
00350       jdiv_round_up((long) cinfo->image_width,
00351                     (long) (cinfo->max_h_samp_factor*DCTSIZE));
00352     cinfo->MCU_rows_in_scan = (JDIMENSION)
00353       jdiv_round_up((long) cinfo->image_height,
00354                     (long) (cinfo->max_v_samp_factor*DCTSIZE));
00355     
00356     cinfo->blocks_in_MCU = 0;
00357     
00358     for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
00359       compptr = cinfo->cur_comp_info[ci];
00360       /* Sampling factors give # of blocks of component in each MCU */
00361       compptr->MCU_width = compptr->h_samp_factor;
00362       compptr->MCU_height = compptr->v_samp_factor;
00363       compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
00364       compptr->MCU_sample_width = compptr->MCU_width * DCTSIZE;
00365       /* Figure number of non-dummy blocks in last MCU column & row */
00366       tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
00367       if (tmp == 0) tmp = compptr->MCU_width;
00368       compptr->last_col_width = tmp;
00369       tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
00370       if (tmp == 0) tmp = compptr->MCU_height;
00371       compptr->last_row_height = tmp;
00372       /* Prepare array describing MCU composition */
00373       mcublks = compptr->MCU_blocks;
00374       if (cinfo->blocks_in_MCU + mcublks > C_MAX_BLOCKS_IN_MCU)
00375         ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
00376       while (mcublks-- > 0) {
00377         cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
00378       }
00379     }
00380     
00381   }
00382 
00383   /* Convert restart specified in rows to actual MCU count. */
00384   /* Note that count must fit in 16 bits, so we provide limiting. */
00385   if (cinfo->restart_in_rows > 0) {
00386     long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
00387     cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
00388   }
00389 }
00390 
00391 
00392 /*
00393  * Per-pass setup.
00394  * This is called at the beginning of each pass.  We determine which modules
00395  * will be active during this pass and give them appropriate start_pass calls.
00396  * We also set is_last_pass to indicate whether any more passes will be
00397  * required.
00398  */
00399 
00400 METHODDEF(void)
00401 prepare_for_pass (j_compress_ptr cinfo)
00402 {
00403   my_master_ptr master = (my_master_ptr) cinfo->master;
00404 
00405   switch (master->pass_type) {
00406   case main_pass:
00407     /* Initial pass: will collect input data, and do either Huffman
00408      * optimization or data output for the first scan.
00409      */
00410     select_scan_parameters(cinfo);
00411     per_scan_setup(cinfo);
00412     if (! cinfo->raw_data_in) {
00413       (*cinfo->cconvert->start_pass) (cinfo);
00414       (*cinfo->downsample->start_pass) (cinfo);
00415       (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
00416     }
00417     (*cinfo->fdct->start_pass) (cinfo);
00418     (*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding);
00419     (*cinfo->coef->start_pass) (cinfo,
00420                                 (master->total_passes > 1 ?
00421                                  JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
00422     (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
00423     if (cinfo->optimize_coding) {
00424       /* No immediate data output; postpone writing frame/scan headers */
00425       master->pub.call_pass_startup = FALSE;
00426     } else {
00427       /* Will write frame/scan headers at first jpeg_write_scanlines call */
00428       master->pub.call_pass_startup = TRUE;
00429     }
00430     break;
00431 #ifdef ENTROPY_OPT_SUPPORTED
00432   case huff_opt_pass:
00433     /* Do Huffman optimization for a scan after the first one. */
00434     select_scan_parameters(cinfo);
00435     per_scan_setup(cinfo);
00436     if (cinfo->Ss != 0 || cinfo->Ah == 0 || cinfo->arith_code) {
00437       (*cinfo->entropy->start_pass) (cinfo, TRUE);
00438       (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
00439       master->pub.call_pass_startup = FALSE;
00440       break;
00441     }
00442     /* Special case: Huffman DC refinement scans need no Huffman table
00443      * and therefore we can skip the optimization pass for them.
00444      */
00445     master->pass_type = output_pass;
00446     master->pass_number++;
00447     /*FALLTHROUGH*/
00448 #endif
00449   case output_pass:
00450     /* Do a data-output pass. */
00451     /* We need not repeat per-scan setup if prior optimization pass did it. */
00452     if (! cinfo->optimize_coding) {
00453       select_scan_parameters(cinfo);
00454       per_scan_setup(cinfo);
00455     }
00456     (*cinfo->entropy->start_pass) (cinfo, FALSE);
00457     (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
00458     /* We emit frame/scan headers now */
00459     if (master->scan_number == 0)
00460       (*cinfo->marker->write_frame_header) (cinfo);
00461     (*cinfo->marker->write_scan_header) (cinfo);
00462     master->pub.call_pass_startup = FALSE;
00463     break;
00464   default:
00465     ERREXIT(cinfo, JERR_NOT_COMPILED);
00466   }
00467 
00468   master->pub.is_last_pass = (master->pass_number == master->total_passes-1);
00469 
00470   /* Set up progress monitor's pass info if present */
00471   if (cinfo->progress != NULL) {
00472     cinfo->progress->completed_passes = master->pass_number;
00473     cinfo->progress->total_passes = master->total_passes;
00474   }
00475 }
00476 
00477 
00478 /*
00479  * Special start-of-pass hook.
00480  * This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
00481  * In single-pass processing, we need this hook because we don't want to
00482  * write frame/scan headers during jpeg_start_compress; we want to let the
00483  * application write COM markers etc. between jpeg_start_compress and the
00484  * jpeg_write_scanlines loop.
00485  * In multi-pass processing, this routine is not used.
00486  */
00487 
00488 METHODDEF(void)
00489 pass_startup (j_compress_ptr cinfo)
00490 {
00491   cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
00492 
00493   (*cinfo->marker->write_frame_header) (cinfo);
00494   (*cinfo->marker->write_scan_header) (cinfo);
00495 }
00496 
00497 
00498 /*
00499  * Finish up at end of pass.
00500  */
00501 
00502 METHODDEF(void)
00503 finish_pass_master (j_compress_ptr cinfo)
00504 {
00505   my_master_ptr master = (my_master_ptr) cinfo->master;
00506 
00507   /* The entropy coder always needs an end-of-pass call,
00508    * either to analyze statistics or to flush its output buffer.
00509    */
00510   (*cinfo->entropy->finish_pass) (cinfo);
00511 
00512   /* Update state for next pass */
00513   switch (master->pass_type) {
00514   case main_pass:
00515     /* next pass is either output of scan 0 (after optimization)
00516      * or output of scan 1 (if no optimization).
00517      */
00518     master->pass_type = output_pass;
00519     if (! cinfo->optimize_coding)
00520       master->scan_number++;
00521     break;
00522   case huff_opt_pass:
00523     /* next pass is always output of current scan */
00524     master->pass_type = output_pass;
00525     break;
00526   case output_pass:
00527     /* next pass is either optimization or output of next scan */
00528     if (cinfo->optimize_coding)
00529       master->pass_type = huff_opt_pass;
00530     master->scan_number++;
00531     break;
00532   }
00533 
00534   master->pass_number++;
00535 }
00536 
00537 
00538 /*
00539  * Initialize master compression control.
00540  */
00541 
00542 GLOBAL(void)
00543 jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
00544 {
00545   my_master_ptr master;
00546 
00547   master = (my_master_ptr)
00548       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
00549                                   SIZEOF(my_comp_master));
00550   cinfo->master = (struct jpeg_comp_master *) master;
00551   master->pub.prepare_for_pass = prepare_for_pass;
00552   master->pub.pass_startup = pass_startup;
00553   master->pub.finish_pass = finish_pass_master;
00554   master->pub.is_last_pass = FALSE;
00555 
00556   /* Validate parameters, determine derived values */
00557   initial_setup(cinfo);
00558 
00559   if (cinfo->scan_info != NULL) {
00560 #ifdef C_MULTISCAN_FILES_SUPPORTED
00561     validate_script(cinfo);
00562 #else
00563     ERREXIT(cinfo, JERR_NOT_COMPILED);
00564 #endif
00565   } else {
00566     cinfo->progressive_mode = FALSE;
00567     cinfo->num_scans = 1;
00568   }
00569 
00570   if (cinfo->progressive_mode)  /*  TEMPORARY HACK ??? */
00571     cinfo->optimize_coding = TRUE; /* assume default tables no good for progressive mode */
00572 
00573   /* Initialize my private state */
00574   if (transcode_only) {
00575     /* no main pass in transcoding */
00576     if (cinfo->optimize_coding)
00577       master->pass_type = huff_opt_pass;
00578     else
00579       master->pass_type = output_pass;
00580   } else {
00581     /* for normal compression, first pass is always this type: */
00582     master->pass_type = main_pass;
00583   }
00584   master->scan_number = 0;
00585   master->pass_number = 0;
00586   if (cinfo->optimize_coding)
00587     master->total_passes = cinfo->num_scans * 2;
00588   else
00589     master->total_passes = cinfo->num_scans;
00590 }