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/* mgrtopbm.c - read a MGR bitmap and produce a PBM image.
Copyright information is at end of file.
You can find MGR and some MGR format test images at
ftp://sunsite.unc.edu/pub/Linux/apps/MGR/!INDEX.html
*/
#include <string.h>
#include <errno.h>
#include "pbm.h"
#include "mgr.h"
static void
interpHdrWidth(struct b_header const head,
unsigned int * const colsP) {
if (head.h_wide < ' ' || head.l_wide < ' ')
pm_error("Invalid width field in MGR header");
else {
unsigned int const maxDimension = 4095;
unsigned int const cols =
(((int)head.h_wide - ' ') << 6) + ((int)head.l_wide - ' ');
if (cols == 0 || cols > maxDimension)
pm_error("Invalid width value (%u) in MGR header", cols);
else
*colsP = cols;
}
}
static void
interpHdrHeight(struct b_header const head,
unsigned int * const rowsP) {
if (head.h_high < ' ' || head.l_high < ' ')
pm_error("Invalid height field in MGR header");
else {
unsigned int const maxDimension = 4095;
unsigned int const rows =
(((int)head.h_high - ' ') << 6) + ((int)head.l_high - ' ');
if (rows == 0 || rows > maxDimension)
pm_error("Invalid height value (%u) in MGR header", rows);
else
*rowsP = rows;
}
}
static void
readMgrHeader(FILE * const ifP,
unsigned int * const colsP,
unsigned int * const rowsP,
unsigned int * const depthP,
unsigned int * const padrightP ) {
struct b_header head;
unsigned int pad;
size_t bytesRead;
bytesRead = fread(&head, sizeof(struct old_b_header), 1, ifP);
if (bytesRead != 1)
pm_error("Unable to read 1st byte of file. "
"fread() returns errno %d (%s)",
errno, strerror(errno));
if (head.magic[0] == 'y' && head.magic[1] == 'z') {
/* new style bitmap */
size_t bytesRead;
bytesRead = fread(&head.depth,
sizeof(head) - sizeof(struct old_b_header), 1, ifP);
if (bytesRead != 1 )
pm_error("Unable to read header after 1st byte. "
"fread() returns errno %d (%s)",
errno, strerror(errno));
*depthP = (int) head.depth - ' ';
pad = 8;
} else if (head.magic[0] == 'x' && head.magic[1] == 'z') {
/* old style bitmap with 32-bit padding */
*depthP = 1;
pad = 32;
} else if (head.magic[0] == 'z' && head.magic[1] == 'z') {
/* old style bitmap with 16-bit padding */
*depthP = 1;
pad = 16;
} else if (head.magic[0] == 'z' && head.magic[1] == 'y') {
/* old style 8-bit pixmap with 16-bit padding */
*depthP = 8;
pad = 16;
} else {
pm_error("bad magic chars in MGR file: '%c%c'",
head.magic[0], head.magic[1] );
pad = 0; /* should never reach here */
}
interpHdrWidth (head, colsP);
interpHdrHeight(head, rowsP);
*padrightP = ((*colsP + pad - 1) / pad) * pad - *colsP;
}
int
main(int argc,
char * argv[]) {
FILE * ifP;
unsigned char * bitrow;
unsigned int rows, cols, depth;
unsigned int padright;
unsigned int row;
unsigned int itemCount;
const char * inputFileName;
pbm_init(&argc, argv);
if (argc-1 > 1)
pm_error("Too many arguments (%u). "
"Only argument is optional input file", argc-1);
if (argc-1 == 1)
inputFileName = argv[1];
else
inputFileName = "-";
ifP = pm_openr(inputFileName);
readMgrHeader(ifP, &cols, &rows, &depth, &padright);
if (depth != 1)
pm_error("MGR file has depth of %u, must be 1", depth);
pbm_writepbminit(stdout, cols, rows, 0);
bitrow = pbm_allocrow_packed(cols + padright);
itemCount = (cols + padright ) / 8;
for (row = 0; row < rows; ++row) {
/* The raster formats are nearly identical.
MGR may have rows padded to 16 or 32 bit boundaries.
*/
size_t bytesRead;
bytesRead = fread(bitrow, 1, itemCount, ifP);
if (bytesRead < itemCount)
pm_error("fread() failed to read mgr bitmap data");
pbm_writepbmrow_packed(stdout, bitrow, cols, 0);
}
pm_close(ifP);
pm_close(stdout);
return 0;
}
/* 2006.10 (afu)
Changed bitrow from plain to raw, read function from getc() to fread(),
write function from pbm_writepbmrow() to pbm_writepbmrow_packed().
Retired bitwise transformation functions.
NOT tested for old-style format files. Only one zz file in mgrsrc-0.69 .
*/
/*
** Copyright (C) 1989 by Jef Poskanzer.
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose and without fee is hereby granted, provided
** that the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation. This software is provided "as is" without express or
** implied warranty.
*/
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