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/**************************************************************************
*
* Copyright 2011 Jose Fonseca
* Copyright 2008-2010 VMware, Inc.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
**************************************************************************/
#include <assert.h>
#include <string.h>
#include <stdint.h>
#include <stdio.h>
#include "image.hpp"
namespace image {
/**
* http://en.wikipedia.org/wiki/Netpbm_format
* http://netpbm.sourceforge.net/doc/ppm.html
*/
void
Image::writePNM(std::ostream &os, const char *comment) const {
assert(channels == 1 || channels >= 3);
os << (channels == 1 ? "P5" : "P6") << "\n";
if (comment) {
os << "#" << comment << "\n";
}
os << width << " " << height << "\n";
os << "255" << "\n";
const unsigned char *row;
if (channels == 1 || channels == 3) {
for (row = start(); row != end(); row += stride()) {
os.write((const char *)row, width*channels);
}
} else {
unsigned char *tmp = new unsigned char[width*3];
if (channels == 4) {
for (row = start(); row != end(); row += stride()) {
const uint32_t *src = (const uint32_t *)row;
uint32_t *dst = (uint32_t *)tmp;
unsigned x;
for (x = 0; x + 4 <= width; x += 4) {
/*
* It's much faster to access dwords than bytes.
*
* FIXME: Big-endian version.
*/
uint32_t rgba0 = *src++ & 0xffffff;
uint32_t rgba1 = *src++ & 0xffffff;
uint32_t rgba2 = *src++ & 0xffffff;
uint32_t rgba3 = *src++ & 0xffffff;
uint32_t rgb0 = rgba0
| (rgba1 << 24);
uint32_t rgb1 = (rgba1 >> 8)
| (rgba2 << 16);
uint32_t rgb2 = (rgba2 >> 16)
| (rgba3 << 8);
*dst++ = rgb0;
*dst++ = rgb1;
*dst++ = rgb2;
}
for (; x < width; ++x) {
tmp[x*3 + 0] = row[x*4 + 0];
tmp[x*3 + 1] = row[x*4 + 1];
tmp[x*3 + 2] = row[x*4 + 2];
}
os.write((const char *)tmp, width*3);
}
} else if (channels == 2) {
for (row = start(); row != end(); row += stride()) {
const unsigned char *src = row;
unsigned char *dst = tmp;
for (unsigned x = 0; x < width; ++x) {
*dst++ = *src++;
*dst++ = *src++;
*dst++ = 0;
}
os.write((const char *)tmp, width*3);
}
} else {
assert(0);
}
delete [] tmp;
}
}
const char *
readPNMHeader(const char *buffer, size_t bufferSize, unsigned *channels, unsigned *width, unsigned *height)
{
*channels = 0;
*width = 0;
*height = 0;
const char *currentBuffer = buffer;
const char *nextBuffer;
// parse number of channels
int scannedChannels = sscanf(currentBuffer, "P%d\n", channels);
if (scannedChannels != 1) { // validate scanning of channels
// invalid channel line
return buffer;
}
// convert channel token to number of channels
*channels = (*channels == 5) ? 1 : 3;
// advance past channel line
nextBuffer = (const char *) memchr((const void *) currentBuffer, '\n', bufferSize) + 1;
bufferSize -= nextBuffer - currentBuffer;
currentBuffer = nextBuffer;
// skip over optional comment
if (*currentBuffer == '#') {
// advance past comment line
nextBuffer = (const char *) memchr((const void *) currentBuffer, '\n', bufferSize) + 1;
bufferSize -= nextBuffer - currentBuffer;
currentBuffer = nextBuffer;
}
// parse dimensions of image
int scannedDimensions = sscanf(currentBuffer, "%d %d\n", width, height);
if (scannedDimensions != 2) { // validate scanning of dimensions
// invalid dimension line
return buffer;
}
// advance past dimension line
nextBuffer = (const char *) memchr((const void *) currentBuffer, '\n', bufferSize) + 1;
bufferSize -= nextBuffer - currentBuffer;
currentBuffer = nextBuffer;
// skip over "255\n" at end of header
nextBuffer = (const char *) memchr((const void *) currentBuffer, '\n', bufferSize) + 1;
// return start of image data
return nextBuffer;
}
} /* namespace image */
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