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Diffstat (limited to 'jpg/jctrans.c')
| -rw-r--r-- | jpg/jctrans.c | 382 |
1 files changed, 382 insertions, 0 deletions
diff --git a/jpg/jctrans.c b/jpg/jctrans.c new file mode 100644 index 0000000..f7d7b81 --- /dev/null +++ b/jpg/jctrans.c @@ -0,0 +1,382 @@ +/* + * jctrans.c + * + * Copyright (C) 1995-1998, Thomas G. Lane. + * Modified 2000-2011 by Guido Vollbeding. + * This file is part of the Independent JPEG Group's software. + * For conditions of distribution and use, see the accompanying README file. + * + * This file contains library routines for transcoding compression, + * that is, writing raw DCT coefficient arrays to an output JPEG file. + * The routines in jcapimin.c will also be needed by a transcoder. + */ + +#define JPEG_INTERNALS +#include "jinclude.h" +#include "jpeglib.h" + + +/* Forward declarations */ +LOCAL(void) transencode_master_selection + JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)); +LOCAL(void) transencode_coef_controller + JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)); + + +/* + * Compression initialization for writing raw-coefficient data. + * Before calling this, all parameters and a data destination must be set up. + * Call jpeg_finish_compress() to actually write the data. + * + * The number of passed virtual arrays must match cinfo->num_components. + * Note that the virtual arrays need not be filled or even realized at + * the time write_coefficients is called; indeed, if the virtual arrays + * were requested from this compression object's memory manager, they + * typically will be realized during this routine and filled afterwards. + */ + +GLOBAL(void) +jpeg_write_coefficients (j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays) +{ + if (cinfo->global_state != CSTATE_START) + ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); + /* Mark all tables to be written */ + jpeg_suppress_tables(cinfo, FALSE); + /* (Re)initialize error mgr and destination modules */ + (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo); + (*cinfo->dest->init_destination) (cinfo); + /* Perform master selection of active modules */ + transencode_master_selection(cinfo, coef_arrays); + /* Wait for jpeg_finish_compress() call */ + cinfo->next_scanline = 0; /* so jpeg_write_marker works */ + cinfo->global_state = CSTATE_WRCOEFS; +} + + +/* + * Initialize the compression object with default parameters, + * then copy from the source object all parameters needed for lossless + * transcoding. Parameters that can be varied without loss (such as + * scan script and Huffman optimization) are left in their default states. + */ + +GLOBAL(void) +jpeg_copy_critical_parameters (j_decompress_ptr srcinfo, + j_compress_ptr dstinfo) +{ + JQUANT_TBL ** qtblptr; + jpeg_component_info *incomp, *outcomp; + JQUANT_TBL *c_quant, *slot_quant; + int tblno, ci, coefi; + + /* Safety check to ensure start_compress not called yet. */ + if (dstinfo->global_state != CSTATE_START) + ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state); + /* Copy fundamental image dimensions */ + dstinfo->image_width = srcinfo->image_width; + dstinfo->image_height = srcinfo->image_height; + dstinfo->input_components = srcinfo->num_components; + dstinfo->in_color_space = srcinfo->jpeg_color_space; + dstinfo->jpeg_width = srcinfo->output_width; + dstinfo->jpeg_height = srcinfo->output_height; + dstinfo->min_DCT_h_scaled_size = srcinfo->min_DCT_h_scaled_size; + dstinfo->min_DCT_v_scaled_size = srcinfo->min_DCT_v_scaled_size; + /* Initialize all parameters to default values */ + jpeg_set_defaults(dstinfo); + /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB. + * Fix it to get the right header markers for the image colorspace. + */ + jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space); + dstinfo->data_precision = srcinfo->data_precision; + dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling; + /* Copy the source's quantization tables. */ + for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) { + if (srcinfo->quant_tbl_ptrs[tblno] != NULL) { + qtblptr = & dstinfo->quant_tbl_ptrs[tblno]; + if (*qtblptr == NULL) + *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo); + MEMCOPY((*qtblptr)->quantval, + srcinfo->quant_tbl_ptrs[tblno]->quantval, + SIZEOF((*qtblptr)->quantval)); + (*qtblptr)->sent_table = FALSE; + } + } + /* Copy the source's per-component info. + * Note we assume jpeg_set_defaults has allocated the dest comp_info array. + */ + dstinfo->num_components = srcinfo->num_components; + if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS) + ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components, + MAX_COMPONENTS); + for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info; + ci < dstinfo->num_components; ci++, incomp++, outcomp++) { + outcomp->component_id = incomp->component_id; + outcomp->h_samp_factor = incomp->h_samp_factor; + outcomp->v_samp_factor = incomp->v_samp_factor; + outcomp->quant_tbl_no = incomp->quant_tbl_no; + /* Make sure saved quantization table for component matches the qtable + * slot. If not, the input file re-used this qtable slot. + * IJG encoder currently cannot duplicate this. + */ + tblno = outcomp->quant_tbl_no; + if (tblno < 0 || tblno >= NUM_QUANT_TBLS || + srcinfo->quant_tbl_ptrs[tblno] == NULL) + ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno); + slot_quant = srcinfo->quant_tbl_ptrs[tblno]; + c_quant = incomp->quant_table; + if (c_quant != NULL) { + for (coefi = 0; coefi < DCTSIZE2; coefi++) { + if (c_quant->quantval[coefi] != slot_quant->quantval[coefi]) + ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno); + } + } + /* Note: we do not copy the source's Huffman table assignments; + * instead we rely on jpeg_set_colorspace to have made a suitable choice. + */ + } + /* Also copy JFIF version and resolution information, if available. + * Strictly speaking this isn't "critical" info, but it's nearly + * always appropriate to copy it if available. In particular, + * if the application chooses to copy JFIF 1.02 extension markers from + * the source file, we need to copy the version to make sure we don't + * emit a file that has 1.02 extensions but a claimed version of 1.01. + * We will *not*, however, copy version info from mislabeled "2.01" files. + */ + if (srcinfo->saw_JFIF_marker) { + if (srcinfo->JFIF_major_version == 1) { + dstinfo->JFIF_major_version = srcinfo->JFIF_major_version; + dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version; + } + dstinfo->density_unit = srcinfo->density_unit; + dstinfo->X_density = srcinfo->X_density; + dstinfo->Y_density = srcinfo->Y_density; + } +} + + +/* + * Master selection of compression modules for transcoding. + * This substitutes for jcinit.c's initialization of the full compressor. + */ + +LOCAL(void) +transencode_master_selection (j_compress_ptr cinfo, + jvirt_barray_ptr * coef_arrays) +{ + /* Initialize master control (includes parameter checking/processing) */ + jinit_c_master_control(cinfo, TRUE /* transcode only */); + + /* Entropy encoding: either Huffman or arithmetic coding. */ + if (cinfo->arith_code) + jinit_arith_encoder(cinfo); + else { + jinit_huff_encoder(cinfo); + } + + /* We need a special coefficient buffer controller. */ + transencode_coef_controller(cinfo, coef_arrays); + + jinit_marker_writer(cinfo); + + /* We can now tell the memory manager to allocate virtual arrays. */ + (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo); + + /* Write the datastream header (SOI, JFIF) immediately. + * Frame and scan headers are postponed till later. + * This lets application insert special markers after the SOI. + */ + (*cinfo->marker->write_file_header) (cinfo); +} + + +/* + * The rest of this file is a special implementation of the coefficient + * buffer controller. This is similar to jccoefct.c, but it handles only + * output from presupplied virtual arrays. Furthermore, we generate any + * dummy padding blocks on-the-fly rather than expecting them to be present + * in the arrays. + */ + +/* Private buffer controller object */ + +typedef struct { + struct jpeg_c_coef_controller pub; /* public fields */ + + JDIMENSION iMCU_row_num; /* iMCU row # within image */ + JDIMENSION mcu_ctr; /* counts MCUs processed in current row */ + int MCU_vert_offset; /* counts MCU rows within iMCU row */ + int MCU_rows_per_iMCU_row; /* number of such rows needed */ + + /* Virtual block array for each component. */ + jvirt_barray_ptr * whole_image; + + /* Workspace for constructing dummy blocks at right/bottom edges. */ + JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU]; +} my_coef_controller; + +typedef my_coef_controller * my_coef_ptr; + + +LOCAL(void) +start_iMCU_row (j_compress_ptr cinfo) +/* Reset within-iMCU-row counters for a new row */ +{ + my_coef_ptr coef = (my_coef_ptr) cinfo->coef; + + /* In an interleaved scan, an MCU row is the same as an iMCU row. + * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows. + * But at the bottom of the image, process only what's left. + */ + if (cinfo->comps_in_scan > 1) { + coef->MCU_rows_per_iMCU_row = 1; + } else { + if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1)) + coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor; + else + coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height; + } + + coef->mcu_ctr = 0; + coef->MCU_vert_offset = 0; +} + + +/* + * Initialize for a processing pass. + */ + +METHODDEF(void) +start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode) +{ + my_coef_ptr coef = (my_coef_ptr) cinfo->coef; + + if (pass_mode != JBUF_CRANK_DEST) + ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); + + coef->iMCU_row_num = 0; + start_iMCU_row(cinfo); +} + + +/* + * Process some data. + * We process the equivalent of one fully interleaved MCU row ("iMCU" row) + * per call, ie, v_samp_factor block rows for each component in the scan. + * The data is obtained from the virtual arrays and fed to the entropy coder. + * Returns TRUE if the iMCU row is completed, FALSE if suspended. + * + * NB: input_buf is ignored; it is likely to be a NULL pointer. + */ + +METHODDEF(boolean) +compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf) +{ + my_coef_ptr coef = (my_coef_ptr) cinfo->coef; + JDIMENSION MCU_col_num; /* index of current MCU within row */ + JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1; + JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; + int blkn, ci, xindex, yindex, yoffset, blockcnt; + JDIMENSION start_col; + JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN]; + JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU]; + JBLOCKROW buffer_ptr; + jpeg_component_info *compptr; + + /* Align the virtual buffers for the components used in this scan. */ + for (ci = 0; ci < cinfo->comps_in_scan; ci++) { + compptr = cinfo->cur_comp_info[ci]; + buffer[ci] = (*cinfo->mem->access_virt_barray) + ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index], + coef->iMCU_row_num * compptr->v_samp_factor, + (JDIMENSION) compptr->v_samp_factor, FALSE); + } + + /* Loop to process one whole iMCU row */ + for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; + yoffset++) { + for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row; + MCU_col_num++) { + /* Construct list of pointers to DCT blocks belonging to this MCU */ + blkn = 0; /* index of current DCT block within MCU */ + for (ci = 0; ci < cinfo->comps_in_scan; ci++) { + compptr = cinfo->cur_comp_info[ci]; + start_col = MCU_col_num * compptr->MCU_width; + blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width + : compptr->last_col_width; + for (yindex = 0; yindex < compptr->MCU_height; yindex++) { + if (coef->iMCU_row_num < last_iMCU_row || + yindex+yoffset < compptr->last_row_height) { + /* Fill in pointers to real blocks in this row */ + buffer_ptr = buffer[ci][yindex+yoffset] + start_col; + for (xindex = 0; xindex < blockcnt; xindex++) + MCU_buffer[blkn++] = buffer_ptr++; + } else { + /* At bottom of image, need a whole row of dummy blocks */ + xindex = 0; + } + /* Fill in any dummy blocks needed in this row. + * Dummy blocks are filled in the same way as in jccoefct.c: + * all zeroes in the AC entries, DC entries equal to previous + * block's DC value. The init routine has already zeroed the + * AC entries, so we need only set the DC entries correctly. + */ + for (; xindex < compptr->MCU_width; xindex++) { + MCU_buffer[blkn] = coef->dummy_buffer[blkn]; + MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0]; + blkn++; + } + } + } + /* Try to write the MCU. */ + if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) { + /* Suspension forced; update state counters and exit */ + coef->MCU_vert_offset = yoffset; + coef->mcu_ctr = MCU_col_num; + return FALSE; + } + } + /* Completed an MCU row, but perhaps not an iMCU row */ + coef->mcu_ctr = 0; + } + /* Completed the iMCU row, advance counters for next one */ + coef->iMCU_row_num++; + start_iMCU_row(cinfo); + return TRUE; +} + + +/* + * Initialize coefficient buffer controller. + * + * Each passed coefficient array must be the right size for that + * coefficient: width_in_blocks wide and height_in_blocks high, + * with unitheight at least v_samp_factor. + */ + +LOCAL(void) +transencode_coef_controller (j_compress_ptr cinfo, + jvirt_barray_ptr * coef_arrays) +{ + my_coef_ptr coef; + JBLOCKROW buffer; + int i; + + coef = (my_coef_ptr) + (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, + SIZEOF(my_coef_controller)); + cinfo->coef = (struct jpeg_c_coef_controller *) coef; + coef->pub.start_pass = start_pass_coef; + coef->pub.compress_data = compress_output; + + /* Save pointer to virtual arrays */ + coef->whole_image = coef_arrays; + + /* Allocate and pre-zero space for dummy DCT blocks. */ + buffer = (JBLOCKROW) + (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, + C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); + FMEMZERO((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); + for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) { + coef->dummy_buffer[i] = buffer + i; + } +} |