ref: b0a059537147237e868b4a8f07922ae8a349e55c
dir: /sys/src/cmd/gs/jpeg/jctrans.c/
/* * jctrans.c * * Copyright (C) 1995-1998, Thomas G. Lane. * 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; /* 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) { /* Although we don't actually use input_components for transcoding, * jcmaster.c's initial_setup will complain if input_components is 0. */ cinfo->input_components = 1; /* 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) { ERREXIT(cinfo, JERR_ARITH_NOTIMPL); } else { if (cinfo->progressive_mode) { #ifdef C_PROGRESSIVE_SUPPORTED jinit_phuff_encoder(cinfo); #else ERREXIT(cinfo, JERR_NOT_COMPILED); #endif } 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)); jzero_far((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; } }