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/**
* @file llimagedimensionsinfo.cpp
*
* $LicenseInfo:firstyear=2002&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2010, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#include "linden_common.h"
#include "stdtypes.h"
#include "llimagejpeg.h"
#include "llimagedimensionsinfo.h"
// Value is true if one of Libjpeg's functions has encountered an error while working.
static bool sJpegErrorEncountered = false;
bool LLImageDimensionsInfo::load(const std::string& src_filename,U32 codec)
{
clean();
mSrcFilename = src_filename;
S32 file_size = 0;
apr_status_t s = mInfile.open(src_filename, LL_APR_RB, NULL, &file_size);
if (s != APR_SUCCESS)
{
setLastError("Unable to open file for reading", src_filename);
return false;
}
if (file_size == 0)
{
setLastError("File is empty",src_filename);
return false;
}
switch (codec)
{
case IMG_CODEC_BMP:
return getImageDimensionsBmp();
case IMG_CODEC_TGA:
return getImageDimensionsTga();
case IMG_CODEC_JPEG:
return getImageDimensionsJpeg();
case IMG_CODEC_PNG:
return getImageDimensionsPng();
default:
return false;
}
}
bool LLImageDimensionsInfo::getImageDimensionsBmp()
{
// Make sure the file is long enough.
const S32 DATA_LEN = 26; // BMP header (14) + DIB header size (4) + width (4) + height (4)
if (!checkFileLength(DATA_LEN))
{
llwarns << "Premature end of file" << llendl;
return false;
}
// Read BMP signature.
U8 signature[2];
mInfile.read((void*)signature, sizeof(signature)/sizeof(signature[0]));
// Make sure this is actually a BMP file.
// We only support Windows bitmaps (BM), according to LLImageBMP::updateData().
if (signature[0] != 'B' || signature[1] != 'M')
{
llwarns << "Not a BMP" << llendl;
return false;
}
// Read image dimensions.
mInfile.seek(APR_CUR, 16);
mWidth = read_reverse_s32();
mHeight = read_reverse_s32();
return true;
}
bool LLImageDimensionsInfo::getImageDimensionsTga()
{
const S32 TGA_FILE_HEADER_SIZE = 12;
// Make sure the file is long enough.
if (!checkFileLength(TGA_FILE_HEADER_SIZE + 1 /* width */ + 1 /* height */))
{
llwarns << "Premature end of file" << llendl;
return false;
}
// *TODO: Detect non-TGA files somehow.
mInfile.seek(APR_CUR,TGA_FILE_HEADER_SIZE);
mWidth = read_byte() | read_byte() << 8;
mHeight = read_byte() | read_byte() << 8;
return true;
}
bool LLImageDimensionsInfo::getImageDimensionsPng()
{
const S32 PNG_MAGIC_SIZE = 8;
// Make sure the file is long enough.
if (!checkFileLength(PNG_MAGIC_SIZE + 8 + sizeof(S32) * 2 /* width, height */))
{
llwarns << "Premature end of file" << llendl;
return false;
}
// Read PNG signature.
const U8 png_magic[PNG_MAGIC_SIZE] = {0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A};
U8 signature[PNG_MAGIC_SIZE];
mInfile.read((void*)signature, PNG_MAGIC_SIZE);
// Make sure it's a PNG file.
if (memcmp(signature, png_magic, PNG_MAGIC_SIZE) != 0)
{
llwarns << "Not a PNG" << llendl;
return false;
}
// Read image dimensions.
mInfile.seek(APR_CUR, 8 /* chunk length + chunk type */);
mWidth = read_s32();
mHeight = read_s32();
return true;
}
// Called instead of exit() if Libjpeg encounters an error.
void on_jpeg_error(j_common_ptr cinfo)
{
(void) cinfo;
sJpegErrorEncountered = true;
llwarns << "Libjpeg has encountered an error!" << llendl;
}
bool LLImageDimensionsInfo::getImageDimensionsJpeg()
{
sJpegErrorEncountered = false;
clean();
FILE *fp = fopen (mSrcFilename.c_str(), "rb");
if (fp == NULL)
{
setLastError("Unable to open file for reading", mSrcFilename);
return false;
}
/* Make sure this is a JPEG file. */
const size_t JPEG_MAGIC_SIZE = 2;
const U8 jpeg_magic[JPEG_MAGIC_SIZE] = {0xFF, 0xD8};
U8 signature[JPEG_MAGIC_SIZE];
if (fread(signature, sizeof(signature), 1, fp) != 1)
{
llwarns << "Premature end of file" << llendl;
return false;
}
if (memcmp(signature, jpeg_magic, JPEG_MAGIC_SIZE) != 0)
{
llwarns << "Not a JPEG" << llendl;
return false;
}
fseek(fp, 0, SEEK_SET); // go back to start of the file
/* Init jpeg */
jpeg_error_mgr jerr;
jpeg_decompress_struct cinfo;
cinfo.err = jpeg_std_error(&jerr);
// Call our function instead of exit() if Libjpeg encounters an error.
// This is done to avoid crash in this case (STORM-472).
cinfo.err->error_exit = on_jpeg_error;
jpeg_create_decompress (&cinfo);
jpeg_stdio_src (&cinfo, fp);
jpeg_read_header (&cinfo, TRUE);
cinfo.out_color_space = JCS_RGB;
jpeg_start_decompress (&cinfo);
mHeight = cinfo.output_width;
mHeight = cinfo.output_height;
jpeg_destroy_decompress(&cinfo);
fclose(fp);
return !sJpegErrorEncountered;
}
bool LLImageDimensionsInfo::checkFileLength(S32 min_len)
{
// Make sure the file is not shorter than min_len bytes.
// so that we don't have to check value returned by each read() or seek().
char* buf = new char[min_len];
int nread = mInfile.read(buf, min_len);
delete[] buf;
mInfile.seek(APR_SET, 0);
return nread == min_len;
}
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