Initial commit

neo/renderer/jpeg-6/jload.cpp

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+
+#include "../Shared/Shared.h"
+#include "..\Common\Common.h"
+
+/*
+ * Include file for users of JPEG library.
+ * You will need to have included system headers that define at least
+ * the typedefs FILE and size_t before you can include jpeglib.h.
+ * (stdio.h is sufficient on ANSI-conforming systems.)
+ * You may also wish to include "jerror.h".
+ */
+
+#include "jpeglib.h"
+
+
+int LoadJPG( const char * filename, unsigned char ** pic, int * width, int * height ) {
+    /* This struct contains the JPEG decompression parameters and pointers to
+     * working space (which is allocated as needed by the JPEG library).
+     */
+    struct jpeg_decompress_struct cinfo;
+    /* We use our private extension JPEG error handler.
+     * Note that this struct must live as long as the main JPEG parameter
+     * struct, to avoid dangling-pointer problems.
+     */
+    /* This struct represents a JPEG error handler.  It is declared separately
+     * because applications often want to supply a specialized error handler
+     * (see the second half of this file for an example).  But here we just
+     * take the easy way out and use the standard error handler, which will
+     * print a message on stderr and call exit() if compression fails.
+     * Note that this struct must live as long as the main JPEG parameter
+     * struct, to avoid dangling-pointer problems.
+     */
+    struct jpeg_error_mgr jerr;
+    /* More stuff */
+    fileHandle_t infile;    /* source file */
+    JSAMPARRAY buffer;      /* Output row buffer */
+    int row_stride;     /* physical row width in output buffer */
+    unsigned char * out;
+
+    /* In this example we want to open the input file before doing anything else,
+     * so that the setjmp() error recovery below can assume the file is open.
+     * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
+     * requires it in order to read binary files.
+     */
+
+    FS_FOpenFileRead( filename, &infile, qfalse );
+    if ( infile == 0 ) {
+        return 0;
+    }
+
+    /* Step 1: allocate and initialize JPEG decompression object */
+
+    /* We have to set up the error handler first, in case the initialization
+     * step fails.  (Unlikely, but it could happen if you are out of memory.)
+     * This routine fills in the contents of struct jerr, and returns jerr's
+     * address which we place into the link field in cinfo.
+     */
+    cinfo.err = jpeg_std_error( &jerr );
+
+    /* Now we can initialize the JPEG decompression object. */
+    jpeg_create_decompress( &cinfo );
+
+    /* Step 2: specify data source (eg, a file) */
+
+    jpeg_stdio_src( &cinfo, infile );
+
+    /* Step 3: read file parameters with jpeg_read_header() */
+
+    (void) jpeg_read_header( &cinfo, TRUE );
+    /* We can ignore the return value from jpeg_read_header since
+     *   (a) suspension is not possible with the stdio data source, and
+     *   (b) we passed TRUE to reject a tables-only JPEG file as an error.
+     * See libjpeg.doc for more info.
+     */
+
+    /* Step 4: set parameters for decompression */
+
+    /* In this example, we don't need to change any of the defaults set by
+     * jpeg_read_header(), so we do nothing here.
+     */
+
+    /* Step 5: Start decompressor */
+
+    (void) jpeg_start_decompress( &cinfo );
+    /* We can ignore the return value since suspension is not possible
+     * with the stdio data source.
+     */
+
+    /* We may need to do some setup of our own at this point before reading
+     * the data.  After jpeg_start_decompress() we have the correct scaled
+     * output image dimensions available, as well as the output colormap
+     * if we asked for color quantization.
+     * In this example, we need to make an output work buffer of the right size.
+     */
+    /* JSAMPLEs per row in output buffer */
+    row_stride = cinfo.output_width * cinfo.output_components;
+
+    out = Z_Malloc( cinfo.output_width * cinfo.output_height * cinfo.output_components );
+
+    *pic = out;
+    *width = cinfo.output_width;
+    *height = cinfo.output_height;
+
+    /* Step 6: while (scan lines remain to be read) */
+    /*           jpeg_read_scanlines(...); */
+
+    /* Here we use the library's state variable cinfo.output_scanline as the
+     * loop counter, so that we don't have to keep track ourselves.
+     */
+    while ( cinfo.output_scanline < cinfo.output_height ) {
+        /* jpeg_read_scanlines expects an array of pointers to scanlines.
+         * Here the array is only one element long, but you could ask for
+         * more than one scanline at a time if that's more convenient.
+         */
+        buffer = (JSAMPARRAY)out + ( row_stride * cinfo.output_scanline );
+        (void) jpeg_read_scanlines( &cinfo, buffer, 1 );
+    }
+
+    /* Step 7: Finish decompression */
+
+    (void) jpeg_finish_decompress( &cinfo );
+    /* We can ignore the return value since suspension is not possible
+     * with the stdio data source.
+     */
+
+    /* Step 8: Release JPEG decompression object */
+
+    /* This is an important step since it will release a good deal of memory. */
+    jpeg_destroy_decompress( &cinfo );
+
+    /* After finish_decompress, we can close the input file.
+     * Here we postpone it until after no more JPEG errors are possible,
+     * so as to simplify the setjmp error logic above.  (Actually, I don't
+     * think that jpeg_destroy can do an error exit, but why assume anything...)
+     */
+    FS_FCloseFile( infile );
+
+    /* At this point you may want to check to see whether any corrupt-data
+     * warnings occurred (test whether jerr.pub.num_warnings is nonzero).
+     */
+
+    /* And we're done! */
+    return 1;
+}
+