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427 lines
11 KiB
427 lines
11 KiB
/* |
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* png2pnm.c --- conversion from PNG-file to PGM/PPM-file |
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* copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com> |
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* |
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* This software is released under the MIT license. For conditions of |
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* distribution and use, see the LICENSE file part of this package. |
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*/ |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <fcntl.h> |
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#ifndef BOOL |
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#define BOOL unsigned char |
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#endif |
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#ifndef TRUE |
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#define TRUE (BOOL) 1 |
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#endif |
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#ifndef FALSE |
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#define FALSE (BOOL) 0 |
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#endif |
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/* make png2pnm verbose so we can find problems (needs to be before png.h) */ |
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#ifndef PNG_DEBUG |
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#define PNG_DEBUG 0 |
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#endif |
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#include "png.h" |
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/* function prototypes */ |
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int main (int argc, char *argv[]); |
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void usage (); |
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BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, |
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BOOL raw, BOOL alpha); |
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/* |
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* main |
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*/ |
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int main (int argc, char *argv[]) |
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{ |
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FILE *fp_rd = stdin; |
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FILE *fp_wr = stdout; |
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FILE *fp_al = NULL; |
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BOOL raw = TRUE; |
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BOOL alpha = FALSE; |
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int argi; |
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for (argi = 1; argi < argc; argi++) |
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{ |
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if (argv[argi][0] == '-') |
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{ |
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switch (argv[argi][1]) |
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{ |
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case 'n': |
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raw = FALSE; |
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break; |
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case 'r': |
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raw = TRUE; |
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break; |
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case 'a': |
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alpha = TRUE; |
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argi++; |
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if ((fp_al = fopen (argv[argi], "wb")) == NULL) |
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{ |
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fprintf (stderr, "PNM2PNG\n"); |
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fprintf (stderr, "Error: cannot create alpha-channel file %s\n", |
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argv[argi]); |
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exit (1); |
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} |
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break; |
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case 'h': |
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case '?': |
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usage (); |
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exit (0); |
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break; |
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default: |
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fprintf (stderr, "PNG2PNM\n"); |
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fprintf (stderr, "Error: unknown option %s\n", argv[argi]); |
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usage (); |
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exit (1); |
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break; |
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} /* end switch */ |
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} |
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else if (fp_rd == stdin) |
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{ |
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if ((fp_rd = fopen (argv[argi], "rb")) == NULL) |
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{ |
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fprintf (stderr, "PNG2PNM\n"); |
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fprintf (stderr, "Error: file %s does not exist\n", argv[argi]); |
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exit (1); |
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} |
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} |
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else if (fp_wr == stdout) |
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{ |
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if ((fp_wr = fopen (argv[argi], "wb")) == NULL) |
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{ |
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fprintf (stderr, "PNG2PNM\n"); |
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fprintf (stderr, "Error: cannot create file %s\n", argv[argi]); |
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exit (1); |
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} |
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} |
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else |
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{ |
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fprintf (stderr, "PNG2PNM\n"); |
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fprintf (stderr, "Error: too many parameters\n"); |
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usage (); |
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exit (1); |
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} |
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} /* end for */ |
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#if defined(O_BINARY) && (O_BINARY != 0) |
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/* set stdin/stdout if required to binary */ |
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if (fp_rd == stdin) |
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setmode (fileno (stdin), O_BINARY); |
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if ((raw) && (fp_wr == stdout)) |
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setmode (fileno (stdout), O_BINARY); |
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#endif |
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/* call the conversion program itself */ |
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if (png2pnm (fp_rd, fp_wr, fp_al, raw, alpha) == FALSE) |
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{ |
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fprintf (stderr, "PNG2PNM\n"); |
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fprintf (stderr, "Error: unsuccessful conversion of PNG-image\n"); |
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exit (1); |
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} |
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/* close input file */ |
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fclose (fp_rd); |
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/* close output file */ |
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fclose (fp_wr); |
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/* close alpha file */ |
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if (alpha) |
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fclose (fp_al); |
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return 0; |
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} |
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/* |
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* usage |
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*/ |
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void usage () |
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{ |
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fprintf (stderr, "PNG2PNM\n"); |
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fprintf (stderr, " by Willem van Schaik, 1999\n"); |
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fprintf (stderr, "Usage: png2pnm [options] <file>.png [<file>.pnm]\n"); |
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fprintf (stderr, " or: ... | png2pnm [options]\n"); |
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fprintf (stderr, "Options:\n"); |
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fprintf (stderr, |
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" -r[aw] write pnm-file in binary format (P4/P5/P6) (default)\n"); |
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fprintf (stderr, " -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n"); |
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fprintf (stderr, |
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" -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n"); |
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fprintf (stderr, " -h | -? print this help-information\n"); |
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} |
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/* |
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* png2pnm |
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*/ |
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BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, |
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BOOL raw, BOOL alpha) |
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{ |
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png_struct *png_ptr = NULL; |
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png_info *info_ptr = NULL; |
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png_byte buf[8]; |
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png_byte *png_pixels = NULL; |
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png_byte **row_pointers = NULL; |
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png_byte *pix_ptr = NULL; |
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png_uint_32 row_bytes; |
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png_uint_32 width; |
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png_uint_32 height; |
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int bit_depth; |
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int channels; |
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int color_type; |
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int alpha_present; |
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int row, col; |
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int ret; |
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int i; |
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long dep_16; |
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/* read and check signature in PNG file */ |
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ret = fread (buf, 1, 8, png_file); |
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if (ret != 8) |
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return FALSE; |
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ret = png_sig_cmp (buf, 0, 8); |
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if (ret != 0) |
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return FALSE; |
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/* create png and info structures */ |
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png_ptr = png_create_read_struct (png_get_libpng_ver(NULL), |
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NULL, NULL, NULL); |
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if (!png_ptr) |
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return FALSE; /* out of memory */ |
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info_ptr = png_create_info_struct (png_ptr); |
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if (!info_ptr) |
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{ |
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png_destroy_read_struct (&png_ptr, NULL, NULL); |
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return FALSE; /* out of memory */ |
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} |
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if (setjmp (png_jmpbuf (png_ptr))) |
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{ |
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png_destroy_read_struct (&png_ptr, &info_ptr, NULL); |
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return FALSE; |
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} |
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/* set up the input control for C streams */ |
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png_init_io (png_ptr, png_file); |
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png_set_sig_bytes (png_ptr, 8); /* we already read the 8 signature bytes */ |
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/* read the file information */ |
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png_read_info (png_ptr, info_ptr); |
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/* get size and bit-depth of the PNG-image */ |
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png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, |
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NULL, NULL, NULL); |
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/* set-up the transformations */ |
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/* transform paletted images into full-color rgb */ |
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if (color_type == PNG_COLOR_TYPE_PALETTE) |
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png_set_expand (png_ptr); |
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/* expand images to bit-depth 8 (only applicable for grayscale images) */ |
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if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) |
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png_set_expand (png_ptr); |
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/* transform transparency maps into full alpha-channel */ |
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if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS)) |
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png_set_expand (png_ptr); |
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#ifdef NJET |
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/* downgrade 16-bit images to 8-bit */ |
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if (bit_depth == 16) |
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png_set_strip_16 (png_ptr); |
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/* transform grayscale images into full-color */ |
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if (color_type == PNG_COLOR_TYPE_GRAY || |
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color_type == PNG_COLOR_TYPE_GRAY_ALPHA) |
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png_set_gray_to_rgb (png_ptr); |
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/* only if file has a file gamma, we do a correction */ |
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if (png_get_gAMA (png_ptr, info_ptr, &file_gamma)) |
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png_set_gamma (png_ptr, (double) 2.2, file_gamma); |
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#endif |
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/* all transformations have been registered; now update info_ptr data, |
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* get rowbytes and channels, and allocate image memory */ |
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png_read_update_info (png_ptr, info_ptr); |
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/* get the new color-type and bit-depth (after expansion/stripping) */ |
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png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, |
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NULL, NULL, NULL); |
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/* check for 16-bit files */ |
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if (bit_depth == 16) |
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{ |
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raw = FALSE; |
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#if defined(O_BINARY) && (O_BINARY != 0) |
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setmode (fileno (pnm_file), O_BINARY); |
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#endif |
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} |
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/* calculate new number of channels and store alpha-presence */ |
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if (color_type == PNG_COLOR_TYPE_GRAY) |
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channels = 1; |
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else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA) |
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channels = 2; |
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else if (color_type == PNG_COLOR_TYPE_RGB) |
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channels = 3; |
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else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
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channels = 4; |
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else |
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channels = 0; /* should never happen */ |
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alpha_present = (channels - 1) % 2; |
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/* check if alpha is expected to be present in file */ |
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if (alpha && !alpha_present) |
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{ |
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fprintf (stderr, "PNG2PNM\n"); |
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fprintf (stderr, "Error: PNG-file doesn't contain alpha channel\n"); |
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exit (1); |
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} |
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/* row_bytes is the width x number of channels x (bit-depth / 8) */ |
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row_bytes = png_get_rowbytes (png_ptr, info_ptr); |
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if ((row_bytes == 0) || |
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((size_t) height > (size_t) (-1) / (size_t) row_bytes)) |
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{ |
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/* too big */ |
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png_destroy_read_struct (&png_ptr, &info_ptr, NULL); |
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return FALSE; |
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} |
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if ((png_pixels = (png_byte *) |
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malloc ((size_t) row_bytes * (size_t) height)) == NULL) |
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{ |
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png_destroy_read_struct (&png_ptr, &info_ptr, NULL); |
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return FALSE; |
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} |
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if ((row_pointers = (png_byte **) |
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malloc ((size_t) height * sizeof (png_byte *))) == NULL) |
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{ |
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png_destroy_read_struct (&png_ptr, &info_ptr, NULL); |
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free (png_pixels); |
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return FALSE; |
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} |
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/* set the individual row_pointers to point at the correct offsets */ |
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for (i = 0; i < ((int) height); i++) |
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row_pointers[i] = png_pixels + i * row_bytes; |
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/* now we can go ahead and just read the whole image */ |
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png_read_image (png_ptr, row_pointers); |
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/* read rest of file, and get additional chunks in info_ptr - REQUIRED */ |
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png_read_end (png_ptr, info_ptr); |
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/* clean up after the read, and free any memory allocated - REQUIRED */ |
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png_destroy_read_struct (&png_ptr, &info_ptr, NULL); |
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/* write header of PNM file */ |
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if ((color_type == PNG_COLOR_TYPE_GRAY) || |
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(color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) |
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{ |
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fprintf (pnm_file, "%s\n", (raw) ? "P5" : "P2"); |
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fprintf (pnm_file, "%d %d\n", (int) width, (int) height); |
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fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L)); |
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} |
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else if ((color_type == PNG_COLOR_TYPE_RGB) || |
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(color_type == PNG_COLOR_TYPE_RGB_ALPHA)) |
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{ |
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fprintf (pnm_file, "%s\n", (raw) ? "P6" : "P3"); |
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fprintf (pnm_file, "%d %d\n", (int) width, (int) height); |
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fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L)); |
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} |
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/* write header of PGM file with alpha channel */ |
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if ((alpha) && |
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((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) || |
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(color_type == PNG_COLOR_TYPE_RGB_ALPHA))) |
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{ |
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fprintf (alpha_file, "%s\n", (raw) ? "P5" : "P2"); |
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fprintf (alpha_file, "%d %d\n", (int) width, (int) height); |
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fprintf (alpha_file, "%ld\n", ((1L << (int) bit_depth) - 1L)); |
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} |
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/* write data to PNM file */ |
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pix_ptr = png_pixels; |
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for (row = 0; row < (int) height; row++) |
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{ |
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for (col = 0; col < (int) width; col++) |
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{ |
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for (i = 0; i < (channels - alpha_present); i++) |
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{ |
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if (raw) |
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{ |
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fputc ((int) *pix_ptr++, pnm_file); |
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} |
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else |
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{ |
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if (bit_depth == 16) |
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{ |
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dep_16 = (long) *pix_ptr++; |
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fprintf (pnm_file, "%ld ", (dep_16 << 8) + ((long) *pix_ptr++)); |
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} |
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else |
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{ |
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fprintf (pnm_file, "%ld ", (long) *pix_ptr++); |
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} |
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} |
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} |
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if (alpha_present) |
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{ |
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if (!alpha) |
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{ |
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pix_ptr++; /* alpha */ |
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if (bit_depth == 16) |
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pix_ptr++; |
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} |
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else /* output alpha-channel as pgm file */ |
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{ |
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if (raw) |
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{ |
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fputc ((int) *pix_ptr++, alpha_file); |
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} |
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else |
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{ |
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if (bit_depth == 16) |
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{ |
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dep_16 = (long) *pix_ptr++; |
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fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++); |
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} |
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else |
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{ |
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fprintf (alpha_file, "%ld ", (long) *pix_ptr++); |
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} |
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} |
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} |
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} /* end if alpha_present */ |
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if (!raw) |
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if (col % 4 == 3) |
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fprintf (pnm_file, "\n"); |
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} /* end for col */ |
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if (!raw) |
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if (col % 4 != 0) |
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fprintf (pnm_file, "\n"); |
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} /* end for row */ |
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if (row_pointers != NULL) |
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free (row_pointers); |
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if (png_pixels != NULL) |
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free (png_pixels); |
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return TRUE; |
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} /* end of source */
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