179 lines
5.5 KiB
C++
179 lines
5.5 KiB
C++
/*=============================================================================
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JpgImage.cpp : JPG image file format implementation.
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Copyright (c) 2001 Crytek Studios. All Rights Reserved.
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Revision history:
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* Created by Khonich Andrey
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=============================================================================*/
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#if !defined(LINUX)
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#include "stdafx.h"
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#include "CImage.h"
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#include "JpgImage.h"
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extern "C"
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{
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#include "Jpeg6/Jpeglib.h"
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#include "Jmemsrc.c" // include buffer source input code
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}
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#include <setjmp.h>
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/* ==== Error mgmnt ==== */
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static char jpg_err_msg[256];
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struct my_error_mgr {
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struct jpeg_error_mgr pub; /* "public" fields */
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jmp_buf setjmp_buffer; /* for return to caller */
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};
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typedef struct my_error_mgr *my_error_ptr;
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static void my_error_exit (j_common_ptr cinfo)
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{
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char errmsg [256];
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/* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
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my_error_ptr myerr = (my_error_ptr) cinfo->err;
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/* Always display the message. */
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/* We could postpone this until after returning, if we chose. */
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(*cinfo->err->format_message) (cinfo,errmsg);
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strcpy (jpg_err_msg,errmsg);
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/* Return control to the setjmp point */
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longjmp(myerr->setjmp_buffer, 1);
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}
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/* ==== Constructor ==== */
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CImageJpgFile::~CImageJpgFile () {
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/* do nothing */
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}
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CImageJpgFile::CImageJpgFile (byte* ptr, long filesize) : CImageFile () {
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struct jpeg_decompress_struct cinfo;
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struct my_error_mgr jerr;
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JSAMPARRAY buffer; /* Output row buffer */
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int row_stride; /* physical row width in output buffer */
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int bufp;
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int i;
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SRGBPixel *pixels;
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m_eFormat = eIF_Jpg;
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/* ==== Step 1: allocate and initialize JPEG decompression object */
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/* We set up the normal JPEG error routines, then override error_exit. */
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cinfo.err = my_jpeg_std_error(&jerr.pub);
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jerr.pub.error_exit = my_error_exit;
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if (setjmp(jerr.setjmp_buffer)) {
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my_jpeg_destroy_decompress(&cinfo);
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mfSet_error (eIFE_BadFormat,jpg_err_msg);
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return;
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}
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/* Now we can initialize the JPEG decompression object. */
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my_jpeg_create_decompress(&cinfo);
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/* ==== Step 2: specify data source (memory buffer, in this case) */
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my_jpeg_memory_src(&cinfo, (char *)ptr, filesize);
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/* ==== Step 3: read file parameters with jpeg_read_header() */
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(void) my_jpeg_read_header(&cinfo, TRUE);
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/* ==== Step 4: set parameters for decompression */
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/* In this example, we don't need to change any of the defaults set by
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* jpeg_read_header(), so we do nothing here.
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*/
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/* ==== Step 5: Start decompressor */
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(void) my_jpeg_start_decompress(&cinfo);
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/* We may need to do some setup of our own at this point before reading
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* the data. After jpeg_start_decompress() we have the correct scaled
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* output image dimensions available, as well as the output colormap
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* if we asked for color quantization.
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* In this example, we need to make an output work buffer of the right size.
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*/
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mfSet_dimensions (cinfo.output_width, cinfo.output_height);
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mfSet_ImageSize(cinfo.output_width * cinfo.output_height * 4);
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pixels = (SRGBPixel *)mfGet_image();
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bufp = 0;
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/* JSAMPLEs per row in output buffer */
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row_stride = cinfo.output_width * cinfo.output_components;
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/* Make a one-row-high sample array that will go away when done with image */
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buffer = (*cinfo.mem->alloc_sarray)
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((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);
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/* ==== Step 6: while (scan lines remain to be read) */
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/* jpeg_read_scanlines(...); */
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/* Here we use the library's state variable cinfo.output_scanline as the
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* loop counter, so that we don't have to keep track ourselves.
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*/
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while (cinfo.output_scanline < cinfo.output_height) {
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/* jpeg_read_scanlines expects an array of pointers to scanlines.
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* Here the array is only one element long, but you could ask for
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* more than one scanline at a time if that's more convenient.
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*/
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(void) my_jpeg_read_scanlines(&cinfo, buffer, 1);
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/* Assume put_scanline_someplace wants a pointer and sample count. */
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/* put_scanline_someplace(buffer[0], row_stride); */
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if (cinfo.output_components == 1)
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{ /* grey scale */
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for (i=0;i<row_stride;i++)
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{
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pixels[bufp].red = buffer[0][i];
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pixels[bufp].green = buffer[0][i];
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pixels[bufp].blue = buffer[0][i];
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pixels[bufp].alpha = 255;
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bufp ++;
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}
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}
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else
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if (cinfo.output_components == 3)
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{ /* rgb triplets */
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for (i = 0; i < (int)cinfo.output_width; i++)
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{
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pixels[bufp].red = buffer[0][i*3+0];
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pixels[bufp].green = buffer[0][i*3+1];
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pixels[bufp].blue = buffer[0][i*3+2];
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pixels[bufp].alpha = 255;
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bufp ++;
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}
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}
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else
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{
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for (i = 0; i < (int)cinfo.output_width; i++)
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{
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pixels[bufp].red = buffer[0][i*4+0];
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pixels[bufp].green = buffer[0][i*4+1];
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pixels[bufp].blue = buffer[0][i*4+2];
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pixels[bufp].alpha = 255;
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bufp ++;
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}
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}
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}
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/* ==== Step 7: Finish decompression */
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(void) my_jpeg_finish_decompress(&cinfo);
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/* We can ignore the return value since suspension is not possible
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* with the buffer data source.
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*/
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/* ==== Step 8: Release JPEG decompression object */
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/* This is an important step since it will release a good deal of memory. */
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my_jpeg_destroy_decompress(&cinfo);
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/* At this point you may want to check to see whether any corrupt-data
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* warnings occurred (test whether jerr.pub.num_warnings is nonzero).
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*/
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/* And we're done! */
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}
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#endif |