diff options
author | Paweł Redman <pawel.redman@gmail.com> | 2017-03-22 17:56:34 +0100 |
---|---|---|
committer | Paweł Redman <pawel.redman@gmail.com> | 2017-03-22 17:56:34 +0100 |
commit | 6a777afc079c2a8d3af3ecd2145fe8dd50567a39 (patch) | |
tree | 520f4489cebf8564ef6cb27064ceea45cbc005b3 /src/jpeg-6/jload.c |
Diffstat (limited to 'src/jpeg-6/jload.c')
-rw-r--r-- | src/jpeg-6/jload.c | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/src/jpeg-6/jload.c b/src/jpeg-6/jload.c new file mode 100644 index 0000000..29e750b --- /dev/null +++ b/src/jpeg-6/jload.c @@ -0,0 +1,145 @@ + +#include "../qcommon/q_shared.h" +#include "../qcommon/qcommon.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; +} + |