1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/libs/libjpeg/jdtrans.c	Thu Sep 08 06:28:38 2011 +0300
     1.3 @@ -0,0 +1,143 @@
     1.4 +/*
     1.5 + * jdtrans.c
     1.6 + *
     1.7 + * Copyright (C) 1995-1997, Thomas G. Lane.
     1.8 + * This file is part of the Independent JPEG Group's software.
     1.9 + * For conditions of distribution and use, see the accompanying README file.
    1.10 + *
    1.11 + * This file contains library routines for transcoding decompression,
    1.12 + * that is, reading raw DCT coefficient arrays from an input JPEG file.
    1.13 + * The routines in jdapimin.c will also be needed by a transcoder.
    1.14 + */
    1.15 +
    1.16 +#define JPEG_INTERNALS
    1.17 +#include "jinclude.h"
    1.18 +#include "jpeglib.h"
    1.19 +
    1.20 +
    1.21 +/* Forward declarations */
    1.22 +LOCAL(void) transdecode_master_selection JPP((j_decompress_ptr cinfo));
    1.23 +
    1.24 +
    1.25 +/*
    1.26 + * Read the coefficient arrays from a JPEG file.
    1.27 + * jpeg_read_header must be completed before calling this.
    1.28 + *
    1.29 + * The entire image is read into a set of virtual coefficient-block arrays,
    1.30 + * one per component.  The return value is a pointer to the array of
    1.31 + * virtual-array descriptors.  These can be manipulated directly via the
    1.32 + * JPEG memory manager, or handed off to jpeg_write_coefficients().
    1.33 + * To release the memory occupied by the virtual arrays, call
    1.34 + * jpeg_finish_decompress() when done with the data.
    1.35 + *
    1.36 + * An alternative usage is to simply obtain access to the coefficient arrays
    1.37 + * during a buffered-image-mode decompression operation.  This is allowed
    1.38 + * after any jpeg_finish_output() call.  The arrays can be accessed until
    1.39 + * jpeg_finish_decompress() is called.  (Note that any call to the library
    1.40 + * may reposition the arrays, so don't rely on access_virt_barray() results
    1.41 + * to stay valid across library calls.)
    1.42 + *
    1.43 + * Returns NULL if suspended.  This case need be checked only if
    1.44 + * a suspending data source is used.
    1.45 + */
    1.46 +
    1.47 +GLOBAL(jvirt_barray_ptr *)
    1.48 +jpeg_read_coefficients (j_decompress_ptr cinfo)
    1.49 +{
    1.50 +  if (cinfo->global_state == DSTATE_READY) {
    1.51 +    /* First call: initialize active modules */
    1.52 +    transdecode_master_selection(cinfo);
    1.53 +    cinfo->global_state = DSTATE_RDCOEFS;
    1.54 +  }
    1.55 +  if (cinfo->global_state == DSTATE_RDCOEFS) {
    1.56 +    /* Absorb whole file into the coef buffer */
    1.57 +    for (;;) {
    1.58 +      int retcode;
    1.59 +      /* Call progress monitor hook if present */
    1.60 +      if (cinfo->progress != NULL)
    1.61 +	(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
    1.62 +      /* Absorb some more input */
    1.63 +      retcode = (*cinfo->inputctl->consume_input) (cinfo);
    1.64 +      if (retcode == JPEG_SUSPENDED)
    1.65 +	return NULL;
    1.66 +      if (retcode == JPEG_REACHED_EOI)
    1.67 +	break;
    1.68 +      /* Advance progress counter if appropriate */
    1.69 +      if (cinfo->progress != NULL &&
    1.70 +	  (retcode == JPEG_ROW_COMPLETED || retcode == JPEG_REACHED_SOS)) {
    1.71 +	if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) {
    1.72 +	  /* startup underestimated number of scans; ratchet up one scan */
    1.73 +	  cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows;
    1.74 +	}
    1.75 +      }
    1.76 +    }
    1.77 +    /* Set state so that jpeg_finish_decompress does the right thing */
    1.78 +    cinfo->global_state = DSTATE_STOPPING;
    1.79 +  }
    1.80 +  /* At this point we should be in state DSTATE_STOPPING if being used
    1.81 +   * standalone, or in state DSTATE_BUFIMAGE if being invoked to get access
    1.82 +   * to the coefficients during a full buffered-image-mode decompression.
    1.83 +   */
    1.84 +  if ((cinfo->global_state == DSTATE_STOPPING ||
    1.85 +       cinfo->global_state == DSTATE_BUFIMAGE) && cinfo->buffered_image) {
    1.86 +    return cinfo->coef->coef_arrays;
    1.87 +  }
    1.88 +  /* Oops, improper usage */
    1.89 +  ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
    1.90 +  return NULL;			/* keep compiler happy */
    1.91 +}
    1.92 +
    1.93 +
    1.94 +/*
    1.95 + * Master selection of decompression modules for transcoding.
    1.96 + * This substitutes for jdmaster.c's initialization of the full decompressor.
    1.97 + */
    1.98 +
    1.99 +LOCAL(void)
   1.100 +transdecode_master_selection (j_decompress_ptr cinfo)
   1.101 +{
   1.102 +  /* This is effectively a buffered-image operation. */
   1.103 +  cinfo->buffered_image = TRUE;
   1.104 +
   1.105 +  /* Entropy decoding: either Huffman or arithmetic coding. */
   1.106 +  if (cinfo->arith_code) {
   1.107 +    ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
   1.108 +  } else {
   1.109 +    if (cinfo->progressive_mode) {
   1.110 +#ifdef D_PROGRESSIVE_SUPPORTED
   1.111 +      jinit_phuff_decoder(cinfo);
   1.112 +#else
   1.113 +      ERREXIT(cinfo, JERR_NOT_COMPILED);
   1.114 +#endif
   1.115 +    } else
   1.116 +      jinit_huff_decoder(cinfo);
   1.117 +  }
   1.118 +
   1.119 +  /* Always get a full-image coefficient buffer. */
   1.120 +  jinit_d_coef_controller(cinfo, TRUE);
   1.121 +
   1.122 +  /* We can now tell the memory manager to allocate virtual arrays. */
   1.123 +  (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
   1.124 +
   1.125 +  /* Initialize input side of decompressor to consume first scan. */
   1.126 +  (*cinfo->inputctl->start_input_pass) (cinfo);
   1.127 +
   1.128 +  /* Initialize progress monitoring. */
   1.129 +  if (cinfo->progress != NULL) {
   1.130 +    int nscans;
   1.131 +    /* Estimate number of scans to set pass_limit. */
   1.132 +    if (cinfo->progressive_mode) {
   1.133 +      /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
   1.134 +      nscans = 2 + 3 * cinfo->num_components;
   1.135 +    } else if (cinfo->inputctl->has_multiple_scans) {
   1.136 +      /* For a nonprogressive multiscan file, estimate 1 scan per component. */
   1.137 +      nscans = cinfo->num_components;
   1.138 +    } else {
   1.139 +      nscans = 1;
   1.140 +    }
   1.141 +    cinfo->progress->pass_counter = 0L;
   1.142 +    cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
   1.143 +    cinfo->progress->completed_passes = 0;
   1.144 +    cinfo->progress->total_passes = 1;
   1.145 +  }
   1.146 +}