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Diffstat (limited to 'media/libjpeg/jdcoefct.h')
-rw-r--r-- | media/libjpeg/jdcoefct.h | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/media/libjpeg/jdcoefct.h b/media/libjpeg/jdcoefct.h new file mode 100644 index 0000000000..9a0e780663 --- /dev/null +++ b/media/libjpeg/jdcoefct.h @@ -0,0 +1,83 @@ +/* + * jdcoefct.h + * + * This file was part of the Independent JPEG Group's software: + * Copyright (C) 1994-1997, Thomas G. Lane. + * libjpeg-turbo Modifications: + * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB + * Copyright (C) 2020, Google, Inc. + * For conditions of distribution and use, see the accompanying README.ijg + * file. + */ + +#define JPEG_INTERNALS +#include "jpeglib.h" + + +/* Block smoothing is only applicable for progressive JPEG, so: */ +#ifndef D_PROGRESSIVE_SUPPORTED +#undef BLOCK_SMOOTHING_SUPPORTED +#endif + + +/* Private buffer controller object */ + +typedef struct { + struct jpeg_d_coef_controller pub; /* public fields */ + + /* These variables keep track of the current location of the input side. */ + /* cinfo->input_iMCU_row is also used for this. */ + 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 */ + + /* The output side's location is represented by cinfo->output_iMCU_row. */ + + /* In single-pass modes, it's sufficient to buffer just one MCU. + * We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks, + * and let the entropy decoder write into that workspace each time. + * In multi-pass modes, this array points to the current MCU's blocks + * within the virtual arrays; it is used only by the input side. + */ + JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU]; + + /* Temporary workspace for one MCU */ + JCOEF *workspace; + +#ifdef D_MULTISCAN_FILES_SUPPORTED + /* In multi-pass modes, we need a virtual block array for each component. */ + jvirt_barray_ptr whole_image[MAX_COMPONENTS]; +#endif + +#ifdef BLOCK_SMOOTHING_SUPPORTED + /* When doing block smoothing, we latch coefficient Al values here */ + int *coef_bits_latch; +#define SAVED_COEFS 10 /* we save coef_bits[0..9] */ +#endif +} my_coef_controller; + +typedef my_coef_controller *my_coef_ptr; + + +LOCAL(void) +start_iMCU_row(j_decompress_ptr cinfo) +/* Reset within-iMCU-row counters for a new row (input side) */ +{ + 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 (cinfo->input_iMCU_row < (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; +} |