424 lines
14 KiB
C++
424 lines
14 KiB
C++
#include <cstdio>
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#include <jpeglib.h>
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#include <jerror.h>
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#include "jpeg.h"
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/*
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* jdatasrc.c
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*
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* Copyright (C) 1994-1996, Thomas G. Lane.
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* Modified 2009-2010 by Guido Vollbeding.
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* This file is part of the Independent JPEG Group's software.
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* For conditions of distribution and use, see the accompanying README file.
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*
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* This file contains decompression data source routines for the case of
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* reading JPEG data from a file (or any stdio stream). While these routines
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* are sufficient for most applications, some will want to use a different
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* source manager.
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* IMPORTANT: we assume that fread() will correctly transcribe an array of
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* JOCTETs from 8-bit-wide elements on external storage. If char is wider
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* than 8 bits on your machine, you may need to do some tweaking.
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*/
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/* this is not a core library module, so it doesn't define JPEG_INTERNALS */
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//#include "jinclude.h"
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#define JFREAD(file,buf,sizeofbuf) \
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((size_t) fread((void *) (buf), (size_t) 1, (size_t) (sizeofbuf), (file)))
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#define JFWRITE(file,buf,sizeofbuf) \
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((size_t) fwrite((const void *) (buf), (size_t) 1, (size_t) (sizeofbuf), (file)))
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/* Expanded data source object for stdio input */
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typedef struct {
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struct jpeg_source_mgr pub; /* public fields */
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jmp_buf error_jmp_buf; /* error handler for this instance */
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FILE * infile; /* source stream */
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JOCTET * buffer; /* start of buffer */
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boolean start_of_file; /* have we gotten any data yet? */
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} my_source_mgr;
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typedef my_source_mgr * my_src_ptr;
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#define INPUT_BUF_SIZE 4096 /* choose an efficiently fread'able size */
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/*
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* Initialize source --- called by jpeg_read_header
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* before any data is actually read.
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*/
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METHODDEF(void)
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my_init_source (j_decompress_ptr cinfo)
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{
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my_src_ptr src = (my_src_ptr) cinfo->src;
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/* We reset the empty-input-file flag for each image,
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* but we don't clear the input buffer.
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* This is correct behavior for reading a series of images from one source.
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*/
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src->start_of_file = TRUE;
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}
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/*
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* Fill the input buffer --- called whenever buffer is emptied.
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*
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* In typical applications, this should read fresh data into the buffer
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* (ignoring the current state of next_input_byte & bytes_in_buffer),
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* reset the pointer & count to the start of the buffer, and return TRUE
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* indicating that the buffer has been reloaded. It is not necessary to
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* fill the buffer entirely, only to obtain at least one more byte.
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*
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* There is no such thing as an EOF return. If the end of the file has been
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* reached, the routine has a choice of ERREXIT() or inserting fake data into
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* the buffer. In most cases, generating a warning message and inserting a
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* fake EOI marker is the best course of action --- this will allow the
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* decompressor to output however much of the image is there. However,
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* the resulting error message is misleading if the real problem is an empty
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* input file, so we handle that case specially.
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*
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* In applications that need to be able to suspend compression due to input
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* not being available yet, a FALSE return indicates that no more data can be
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* obtained right now, but more may be forthcoming later. In this situation,
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* the decompressor will return to its caller (with an indication of the
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* number of scanlines it has read, if any). The application should resume
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* decompression after it has loaded more data into the input buffer. Note
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* that there are substantial restrictions on the use of suspension --- see
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* the documentation.
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*
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* When suspending, the decompressor will back up to a convenient restart point
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* (typically the start of the current MCU). next_input_byte & bytes_in_buffer
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* indicate where the restart point will be if the current call returns FALSE.
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* Data beyond this point must be rescanned after resumption, so move it to
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* the front of the buffer rather than discarding it.
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*/
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METHODDEF(boolean)
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my_fill_input_buffer (j_decompress_ptr cinfo)
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{
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my_src_ptr src = (my_src_ptr) cinfo->src;
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size_t nbytes;
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nbytes = JFREAD(src->infile, src->buffer, INPUT_BUF_SIZE);
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if (nbytes == 0) {
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if (src->start_of_file) { /* Treat empty input file as fatal error */
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ERREXIT(cinfo, JERR_INPUT_EMPTY);
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}
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WARNMS(cinfo, JWRN_JPEG_EOF);
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/* Insert a fake EOI marker */
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src->buffer[0] = (JOCTET) 0xFF;
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src->buffer[1] = (JOCTET) JPEG_EOI;
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nbytes = 2;
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}
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if (src->start_of_file) {
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src->buffer[0] = (JOCTET) 0xFF;
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}
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src->pub.next_input_byte = src->buffer;
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src->pub.bytes_in_buffer = nbytes;
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src->start_of_file = FALSE;
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return TRUE;
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}
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/*
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* Skip data --- used to skip over a potentially large amount of
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* uninteresting data (such as an APPn marker).
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*
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* Writers of suspendable-input applications must note that skip_input_data
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* is not granted the right to give a suspension return. If the skip extends
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* beyond the data currently in the buffer, the buffer can be marked empty so
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* that the next read will cause a fill_input_buffer call that can suspend.
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* Arranging for additional bytes to be discarded before reloading the input
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* buffer is the application writer's problem.
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*/
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METHODDEF(void)
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my_skip_input_data (j_decompress_ptr cinfo, long num_bytes)
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{
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my_src_ptr src = (my_src_ptr) cinfo->src;
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/* Just a dumb implementation for now. Could use fseek() except
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* it doesn't work on pipes. Not clear that being smart is worth
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* any trouble anyway --- large skips are infrequent.
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*/
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if (num_bytes > 0) {
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while (num_bytes > (long) src->pub.bytes_in_buffer) {
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num_bytes -= (long) src->pub.bytes_in_buffer;
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(void) my_fill_input_buffer(cinfo);
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/* note we assume that fill_input_buffer will never return FALSE,
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* so suspension need not be handled.
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*/
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}
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src->pub.next_input_byte += (size_t) num_bytes;
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src->pub.bytes_in_buffer -= (size_t) num_bytes;
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}
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}
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/*
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* An additional method that can be provided by data source modules is the
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* resync_to_restart method for error recovery in the presence of RST markers.
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* For the moment, this source module just uses the default resync method
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* provided by the JPEG library. That method assumes that no backtracking
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* is possible.
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*/
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/*
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* Terminate source --- called by jpeg_finish_decompress
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* after all data has been read. Often a no-op.
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*
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* NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
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* application must deal with any cleanup that should happen even
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* for error exit.
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*/
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METHODDEF(void)
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my_term_source (j_decompress_ptr cinfo)
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{
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/* no work necessary here */
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}
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/*
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* Prepare for input from a stdio stream.
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* The caller must have already opened the stream, and is responsible
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* for closing it after finishing decompression.
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*/
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GLOBAL(void)
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my_jpeg_stdio_src (j_decompress_ptr cinfo, FILE * infile)
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{
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my_src_ptr src;
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/* The source object and input buffer are made permanent so that a series
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* of JPEG images can be read from the same file by calling jpeg_stdio_src
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* only before the first one. (If we discarded the buffer at the end of
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* one image, we'd likely lose the start of the next one.)
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* This makes it unsafe to use this manager and a different source
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* manager serially with the same JPEG object. Caveat programmer.
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*/
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if (cinfo->src == NULL) { /* first time for this JPEG object? */
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cinfo->src = (struct jpeg_source_mgr *)
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(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
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sizeof(my_source_mgr));
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src = (my_src_ptr) cinfo->src;
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src->buffer = (JOCTET *)
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(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
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INPUT_BUF_SIZE * sizeof(JOCTET));
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}
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src = (my_src_ptr) cinfo->src;
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src->pub.init_source = my_init_source;
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src->pub.fill_input_buffer = my_fill_input_buffer;
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src->pub.skip_input_data = my_skip_input_data;
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src->pub.resync_to_restart = jpeg_resync_to_restart; /* use default method */
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src->pub.term_source = my_term_source;
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src->infile = infile;
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src->pub.bytes_in_buffer = 0; /* forces fill_input_buffer on first read */
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src->pub.next_input_byte = NULL; /* until buffer loaded */
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}
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METHODDEF(void)
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my_error_exit (j_common_ptr cinfo)
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{
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/* Always display the message */
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(*cinfo->err->output_message) (cinfo);
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/* Let the memory manager delete any temp files before we die */
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//jpeg_destroy(cinfo);
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j_decompress_ptr dinfo = (j_decompress_ptr)cinfo;
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// longjmp (((rt_jpeg_error_mgr*)(dinfo->src))->error_jmp_buf, 1);
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longjmp ((reinterpret_cast<rt_jpeg_error_mgr*>(dinfo->src)) ->error_jmp_buf, 1);
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}
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//const char * const jpeg_std_message_table[] = {
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//#include "jerror.h"
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// NULL
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//};
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extern const char * const jpeg_std_message_table[];
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/*
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* Actual output of an error or trace message.
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* Applications may override this method to send JPEG messages somewhere
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* other than stderr.
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*
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* On Windows, printing to stderr is generally completely useless,
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* so we provide optional code to produce an error-dialog popup.
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* Most Windows applications will still prefer to override this routine,
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* but if they don't, it'll do something at least marginally useful.
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*
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* NOTE: to use the library in an environment that doesn't support the
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* C stdio library, you may have to delete the call to fprintf() entirely,
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* not just not use this routine.
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*/
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METHODDEF(void)
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output_message (j_common_ptr cinfo)
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{
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char buffer[JMSG_LENGTH_MAX];
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/* Create the message */
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(*cinfo->err->format_message) (cinfo, buffer);
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#ifdef USE_WINDOWS_MESSAGEBOX
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/* Display it in a message dialog box */
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MessageBox(GetActiveWindow(), buffer, "JPEG Library Error",
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MB_OK | MB_ICONERROR);
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#else
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/* Send it to stderr, adding a newline */
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fprintf(stderr, "%s\n", buffer);
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#endif
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}
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/*
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* Decide whether to emit a trace or warning message.
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* msg_level is one of:
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* -1: recoverable corrupt-data warning, may want to abort.
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* 0: important advisory messages (always display to user).
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* 1: first level of tracing detail.
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* 2,3,...: successively more detailed tracing messages.
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* An application might override this method if it wanted to abort on warnings
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* or change the policy about which messages to display.
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*/
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METHODDEF(void)
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emit_message (j_common_ptr cinfo, int msg_level)
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{
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struct jpeg_error_mgr * err = cinfo->err;
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if (msg_level < 0) {
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/* It's a warning message. Since corrupt files may generate many warnings,
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* the policy implemented here is to show only the first warning,
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* unless trace_level >= 3.
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*/
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if (err->num_warnings == 0 || err->trace_level >= 3) {
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(*err->output_message) (cinfo);
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}
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/* Always count warnings in num_warnings. */
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err->num_warnings++;
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} else {
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/* It's a trace message. Show it if trace_level >= msg_level. */
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if (err->trace_level >= msg_level) {
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(*err->output_message) (cinfo);
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}
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}
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}
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/*
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* Format a message string for the most recent JPEG error or message.
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* The message is stored into buffer, which should be at least JMSG_LENGTH_MAX
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* characters. Note that no '\n' character is added to the string.
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* Few applications should need to override this method.
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*/
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METHODDEF(void)
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format_message (j_common_ptr cinfo, char * buffer)
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{
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struct jpeg_error_mgr * err = cinfo->err;
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int msg_code = err->msg_code;
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const char * msgtext = NULL;
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const char * msgptr;
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char ch;
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boolean isstring;
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/* Look up message string in proper table */
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if (msg_code > 0 && msg_code <= err->last_jpeg_message) {
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msgtext = err->jpeg_message_table[msg_code];
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} else if (err->addon_message_table != NULL &&
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msg_code >= err->first_addon_message &&
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msg_code <= err->last_addon_message) {
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msgtext = err->addon_message_table[msg_code - err->first_addon_message];
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}
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/* Defend against bogus message number */
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if (msgtext == NULL) {
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err->msg_parm.i[0] = msg_code;
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msgtext = err->jpeg_message_table[0];
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}
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/* Check for string parameter, as indicated by %s in the message text */
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isstring = FALSE;
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msgptr = msgtext;
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while ((ch = *msgptr++) != '\0') {
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if (ch == '%') {
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if (*msgptr == 's') {
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isstring = TRUE;
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}
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break;
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}
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}
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/* Format the message into the passed buffer */
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if (isstring) {
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sprintf(buffer, msgtext, err->msg_parm.s);
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} else
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sprintf(buffer, msgtext,
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err->msg_parm.i[0], err->msg_parm.i[1],
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err->msg_parm.i[2], err->msg_parm.i[3],
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err->msg_parm.i[4], err->msg_parm.i[5],
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err->msg_parm.i[6], err->msg_parm.i[7]);
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}
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/*
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* Reset error state variables at start of a new image.
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* This is called during compression startup to reset trace/error
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* processing to default state, without losing any application-specific
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* method pointers. An application might possibly want to override
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* this method if it has additional error processing state.
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*/
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METHODDEF(void)
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reset_error_mgr (j_common_ptr cinfo)
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{
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cinfo->err->num_warnings = 0;
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/* trace_level is not reset since it is an application-supplied parameter */
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cinfo->err->msg_code = 0; /* may be useful as a flag for "no error" */
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}
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GLOBAL(struct jpeg_error_mgr *)
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my_jpeg_std_error (struct jpeg_error_mgr * err)
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{
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err->error_exit = my_error_exit;
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err->emit_message = emit_message;
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err->output_message = output_message;
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err->format_message = format_message;
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err->reset_error_mgr = reset_error_mgr;
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err->trace_level = 0; /* default = no tracing */
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err->num_warnings = 0; /* no warnings emitted yet */
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err->msg_code = 0; /* may be useful as a flag for "no error" */
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/* Initialize message table pointers */
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err->jpeg_message_table = jpeg_std_message_table;
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err->last_jpeg_message = (int) JMSG_LASTMSGCODE - 1;
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err->addon_message_table = NULL;
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err->first_addon_message = 0; /* for safety */
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err->last_addon_message = 0;
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return err;
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}
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