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/* libpgm2.c - pgm utility library part 2
**
** 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.
*/
#include <string.h>
#include <errno.h>
#include "pm_c_util.h"
#include "mallocvar.h"
#include "pgm.h"
#include "libpgm.h"
void
pgm_writepgminit(FILE * const fileP,
int const cols,
int const rows,
gray const maxval,
int const forceplain) {
bool const plainFormat = forceplain || pm_plain_output;
if (maxval > PGM_OVERALLMAXVAL && !plainFormat)
pm_error("too-large maxval passed to ppm_writepgminit(): %d.\n"
"Maximum allowed by the PGM format is %d.",
maxval, PGM_OVERALLMAXVAL);
fprintf(fileP, "%c%c\n%d %d\n%d\n",
PGM_MAGIC1,
plainFormat || maxval >= 1<<16 ? PGM_MAGIC2 : RPGM_MAGIC2,
cols, rows, maxval );
#ifdef VMS
if (!plainFormat)
set_outfile_binary();
#endif
}
static void
putus(unsigned short const n,
FILE * const fileP) {
if (n >= 10)
putus(n / 10, fileP);
putc('0' + n % 10, fileP);
}
void
pgm_writerawsample(FILE * const fileP,
gray const val,
gray const maxval) {
if (maxval < 256) {
/* Samples fit in one byte, so write just one byte */
int rc;
rc = putc(val, fileP);
if (rc == EOF)
pm_error("Error writing single byte sample to file");
} else {
/* Samples are too big for one byte, so write two */
int n_written;
unsigned char outval[2];
/* We could save a few instructions if we exploited the internal
format of a gray, i.e. its endianness. Then we might be able
to skip the shifting and anding.
*/
outval[0] = val >> 8;
outval[1] = val & 0xFF;
n_written = fwrite(&outval, 2, 1, fileP);
if (n_written == 0)
pm_error("Error writing double byte sample to file");
}
}
static void
format1bpsRow(const gray * const grayrow,
unsigned int const cols,
unsigned char * const rowBuffer) {
/* single byte samples. */
unsigned int col;
unsigned int bufferCursor;
bufferCursor = 0;
for (col = 0; col < cols; ++col)
rowBuffer[bufferCursor++] = grayrow[col];
}
static void
format2bpsRow(const gray * const grayrow,
unsigned int const cols,
unsigned char * const rowBuffer) {
/* two byte samples. */
unsigned int col;
unsigned int bufferCursor;
bufferCursor = 0;
for (col = 0; col < cols; ++col) {
gray const val = grayrow[col];
rowBuffer[bufferCursor++] = val >> 8;
rowBuffer[bufferCursor++] = (unsigned char) val;
}
}
static void
writepgmrowraw(FILE * const fileP,
const gray * const grayrow,
unsigned int const cols,
gray const maxval) {
unsigned int const bytesPerSample = maxval < 256 ? 1 : 2;
unsigned int const bytesPerRow = cols * bytesPerSample;
unsigned char * rowBuffer;
ssize_t rc;
MALLOCARRAY(rowBuffer, bytesPerRow);
if (rowBuffer == NULL)
pm_error("Unable to allocate memory for row buffer "
"for %u columns", cols);
if (maxval < 256)
format1bpsRow(grayrow, cols, rowBuffer);
else
format2bpsRow(grayrow, cols, rowBuffer);
rc = fwrite(rowBuffer, 1, bytesPerRow, fileP);
if (rc < 0)
pm_error("Error writing row. fwrite() errno=%d (%s)",
errno, strerror(errno));
else if (rc != bytesPerRow)
pm_error("Error writing row. Short write of %u bytes "
"instead of %u", rc, bytesPerRow);
free(rowBuffer);
}
static void
writepgmrowplain(FILE * const fileP,
const gray * const grayrow,
unsigned int const cols,
gray const maxval) {
int col, charcount;
charcount = 0;
for (col = 0; col < cols; ++col) {
if (charcount >= 65) {
putc('\n', fileP);
charcount = 0;
} else if (charcount > 0) {
putc(' ', fileP);
++charcount;
}
#ifdef DEBUG
if (grayrow[col] > maxval)
pm_error("value out of bounds (%u > %u)", grayrow[col], maxval);
#endif /*DEBUG*/
putus((unsigned short)grayrow[col], fileP);
charcount += 3;
}
if (charcount > 0)
putc('\n', fileP);
}
void
pgm_writepgmrow(FILE * const fileP,
const gray * const grayrow,
int const cols,
gray const maxval,
int const forceplain) {
if (forceplain || pm_plain_output || maxval >= 1<<16)
writepgmrowplain(fileP, grayrow, cols, maxval);
else
writepgmrowraw(fileP, grayrow, cols, maxval);
}
void
pgm_writepgm(FILE * const fileP,
gray ** const grays,
int const cols,
int const rows,
gray const maxval,
int const forceplain) {
unsigned int row;
pgm_writepgminit(fileP, cols, rows, maxval, forceplain);
for (row = 0; row < rows; ++row)
pgm_writepgmrow(fileP, grays[row], cols, maxval, forceplain);
}
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