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/*=============================================================================
xvminitoppm
===============================================================================
Convert XV mini thumbnail image to PPM.
This replaces the program of the same name by Ingo Wilken
(Ingo.Wilken@informatik.uni-oldenburg.de), 1993.
Written by Bryan Henderson in April 2006 and contributed to the public
domain.
=============================================================================*/
#include <assert.h>
#include <string.h>
#include "pm_c_util.h"
#include "nstring.h"
#include "ppm.h"
#define BUFSIZE 256
typedef struct xvPalette {
unsigned int red[256];
unsigned int grn[256];
unsigned int blu[256];
} xvPalette;
struct cmdlineInfo {
const char * inputFileName;
};
static void
parseCommandLine(int const argc,
char * argv[],
struct cmdlineInfo * const cmdlineP) {
if (argc-1 < 1)
cmdlineP->inputFileName = "-";
else {
cmdlineP->inputFileName = argv[1];
if (argc-1 > 1)
pm_error("Too many arguments: %u. Only argument is optional "
"input file name.", argc-1);
}
}
static void
getline(FILE * const ifP,
char * const buf,
size_t const size) {
char * rc;
rc = fgets(buf, size, ifP);
if (rc == NULL) {
if (ferror(ifP))
pm_perror("read error");
else
pm_error("unexpected EOF");
}
}
static void
makeXvPalette(xvPalette * const xvPaletteP) {
unsigned int paletteIndex;
unsigned int r;
paletteIndex = 0;
for (r = 0; r < 8; ++r) {
unsigned int g;
for (g = 0; g < 8; ++g) {
unsigned int b;
for (b = 0; b < 4; ++b) {
xvPaletteP->red[paletteIndex] = (r*255)/7;
xvPaletteP->grn[paletteIndex] = (g*255)/7;
xvPaletteP->blu[paletteIndex] = (b*255)/3;
++paletteIndex;
}
}
}
}
static void
readXvHeader(FILE * const ifP,
unsigned int * const colsP,
unsigned int * const rowsP,
unsigned int * const maxvalP) {
char buf[256];
unsigned int cols, rows, maxval;
int rc;
bool endOfComments;
getline(ifP, buf, sizeof(buf));
if (!STRNEQ(buf, "P7 332", 6))
pm_error("Input is not a XV thumbnail picture. It does not "
"begin with the characters 'P7 332'.");
endOfComments = FALSE;
while (!endOfComments) {
getline(ifP, buf, sizeof(buf));
if (STRNEQ(buf, "#END_OF_COMMENTS", 16))
endOfComments = TRUE;
else if (STRNEQ(buf, "#BUILTIN", 8))
pm_error("This program does not know how to "
"convert builtin XV thumbnail pictures");
}
getline(ifP, buf, sizeof(buf));
rc = sscanf(buf, "%u %u %u", &cols, &rows, &maxval);
if (rc != 3)
pm_error("error parsing dimension info '%s'. "
"It does not consist of 3 decimal numbers.", buf);
if (maxval != 255)
pm_error("bogus XV thumbnail maxval %u. Should be 255", maxval);
}
static void
writePpm(FILE * const ifP,
const xvPalette * const xvPaletteP,
unsigned int const cols,
unsigned int const rows,
pixval const maxval,
FILE * const ofP) {
/*----------------------------------------------------------------------------
Write out the PPM image, from the XV-mini input file ifP, which is
positioned to the raster.
The raster contains indices into the palette *xvPaletteP.
-----------------------------------------------------------------------------*/
pixel * pixrow;
unsigned int row;
pixrow = ppm_allocrow(cols);
ppm_writeppminit(ofP, cols, rows, maxval, 0);
for (row = 0; row < rows; ++row) {
unsigned int col;
for (col = 0; col < cols; ++col) {
int byte;
byte = fgetc(ifP);
if (byte == EOF)
pm_error("unexpected EOF");
else {
unsigned int const paletteIndex = byte;
assert(byte > 0);
PPM_ASSIGN(pixrow[col],
xvPaletteP->red[paletteIndex],
xvPaletteP->grn[paletteIndex],
xvPaletteP->blu[paletteIndex]);
}
}
ppm_writeppmrow(ofP, pixrow, cols, maxval, 0);
}
ppm_freerow(pixrow);
}
int
main(int argc,
char * argv[]) {
struct cmdlineInfo cmdline;
FILE * ifP;
unsigned int cols, rows;
pixval maxval;
xvPalette xvPalette;
ppm_init(&argc, argv);
parseCommandLine(argc, argv, &cmdline);
ifP = pm_openr(cmdline.inputFileName);
makeXvPalette(&xvPalette);
readXvHeader(ifP, &cols, &rows, &maxval);
writePpm(ifP, &xvPalette, cols, rows, maxval, stdout);
pm_close(ifP);
return 0;
}
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