simple_image_reader.c

JPEG2000实现的源码

/*****************************************************************************/
/* Copyright 1998, Hewlett-Packard Company                                   */
/* All rights reserved                                                       */
/* File: "simple_image_reader.c"                                             */
/* Description: Simple implementation of the `image_reader' object           */
/* Author: David Taubman                                                     */
/* Affiliation: Hewlett-Packard and                                          */
/*              The University of New South Wales, Australia                 */
/* Version: VM9.0                                                            */
/* Last Revised: 18 April, 2001                                              */
/*****************************************************************************/
#include <local_services.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <image_io.h>
#include "simple_image_reader_local.h"

/* ========================================================================= */
/* ---------------------------- Internal Functions ------------------------- */
/* ========================================================================= */

/*****************************************************************************/
/* STATIC                          eat_white                                 */
/*****************************************************************************/

static void
eat_white(FILE *fp)
{
	int ch;
	
	while ((ch=getc(fp)) != EOF)
		if (ch == '#')
			do {
				ch = getc(fp);
			} while ((ch != '\n') && (ch != EOF));
		else if ((ch != ' ')  && (ch != '\t') && (ch != '\n') && (ch != '\r'))
		{
			ungetc(ch,fp);
			return;
		}
}

/*****************************************************************************/
/* STATIC                       open_image_file                              */
/*****************************************************************************/

static void
open_image_file(char *filename, image_component_ptr comp)
{
	FILE *fp;
	char magic[3];
	int cols, rows, bitdepth, is_signed = 0, lsb_first = 0;
	
	comp->filename = (char *)
		local_malloc(IMAGE_IO_MEM_KEY,strlen(filename)+1);
	strcpy(comp->filename,filename);
	comp->fp = fp = fopen(filename,"rb");
	if (fp == NULL)
		local_error("Unable to open input image file, \"%s\"!",filename);
	magic[0] = magic[1] = magic[2] = '\0';
	fread(magic,1,2,fp);
	if (strcmp(magic,"PG") == 0)
    { /* PGX file format. */
		char header[256], *ch;
		
		if ((fgets(header,255,fp) == NULL) || (strchr(header,'\n') == NULL))
			local_error("Invalid PGX header in input image, \"%s\"!",filename);
		ch = header;
		while ((*ch == ' ') || (*ch == '\t'))
			ch++;
		if (strncmp(ch,"LM",2) == 0)
			lsb_first = 1;
		else if (strncmp(ch,"ML",2) == 0)
			lsb_first = 0;
		else
			local_error("Cannot find valid byte order specifier in the "
			"PGX image file, \"%s\"!  Header line is\n\"%s\"",
			filename,header);
		ch += 2;
		while ((*ch == ' ') || (*ch == '\t'))
			ch++;
		is_signed = 0;
		if (*ch == '+')
			ch++;
		else if (*ch == '-')
        { is_signed = 1; ch++; }
		while ((*ch == ' ') || (*ch == '\t'))
			ch++;
		if ((sscanf(ch,"%d %d %d",&bitdepth,&cols,&rows) != 3) ||
			(bitdepth < 1) || (bitdepth > 32) || (cols < 1) || (rows < 1))
			local_error("Cannot find valid bit-depth, width and/or height "
			"specifiers in the PGX image file, \"%s\"!  Header "
			"line is\n\"%s\"",filename,header);
    }
	else if (strcmp(magic,"P5") == 0)
    { /* PGM file format. */
		eat_white(fp);
		if ((fscanf(fp,"%d",&cols) != 1) || (cols < 1))
			local_error("Invalid PNM header in input image, \"%s\"!",filename);
		eat_white(fp);
		if ((fscanf(fp,"%d",&rows) != 1) || (rows < 1))
			local_error("Invalid PNM header in input image, \"%s\"!",filename);
		eat_white(fp);
		if ((fscanf(fp,"%d",&bitdepth) < 1) ||
			(bitdepth > 255) || (bitdepth < 0))
			local_error("Invalid PNM header in input image, \"%s\"!",filename);
		fgetc(fp);
		bitdepth = 8;
		is_signed = 0;
		lsb_first = 0;
    }
	else
		local_error("Unrecognized image file format encountered while "
		"trying to open input image, \"%s\"!",filename);
	
	comp->rows = comp->unread_rows = rows;
	comp->cols = cols;
	comp->bitdepth = bitdepth;
	comp->is_signed = is_signed;
	if (bitdepth <= 8)
		comp->pack_bytes = 1;
	else if (bitdepth <= 16)
		comp->pack_bytes = 2;
#if (IMPLEMENTATION_PRECISION >= 32)
	else if (bitdepth <= 32)
		comp->pack_bytes = 4;
#endif /* IMPLEMENTATION_PRECISION >= 32 */
	else
		local_error("The input image, \"%s\", contains %d-bit sample "
		"values!!  Cannot support such high bit-depths "
		"with current implementation precision.  Try changing the "
		"IMPLEMENTATION_PRECISION macro in \"ifc.h\" and "
		"recompiling!",filename,bitdepth);
	comp->line_bytes = cols*comp->pack_bytes;
	comp->reverse_byte_order = 0;
	if (comp->pack_bytes > 1)
    {
		int native_lsb_first;
		
		native_lsb_first = 0;
		((std_byte *)(&native_lsb_first))[0] = 1;
		native_lsb_first = (native_lsb_first==1)?1:0;
		comp->reverse_byte_order = (lsb_first != native_lsb_first);
    }
}


/* ========================================================================= */
/* ------------------------- Interface Implementation ---------------------- */
/* ========================================================================= */

/*****************************************************************************/
/* STATIC                         __initialize                               */
/*****************************************************************************/

static void
__initialize(image_reader_ref base, int *num_components,
			 cmdl_ref cmdl)
{
/* Begin Aerospace mods (JHK) */
#define MAX_COMPONENTS 1024
/* End Aerospace mods (JHK) */
	simple_image_reader_ref self = (simple_image_reader_ref) base;
	char **params;
	int p;
	
	/* New Multi-component Input Begin */
	int pound_offset=0, colon_offset=0;  /* TJF: =0 to avoid warnings */
	int list_size = 0;
	int n, subset_p;
	char **subset_params, *subset_params_cpy = NULL, *params_cpy = NULL;
	char *pound_pos = NULL, *colon_pos = NULL, *fname = NULL;
	char **replacement_chars = NULL;
	FILE *fp;
	/* New Multi-component Input End */
	
	if ((p = cmdl->extract(cmdl,"-i",-1,&params)) <= 0)
		local_error("Must supply one or more input files via the"
			" `-i' argument!");
	self->num_components = p;
	
	/* New Multi-component Input Begin */
	if ((p == 1) && ((pound_pos = strchr(params[0], '#')) != NULL)) {
		if ((fp = fopen(params[0], "rb")) != NULL) {
			fclose(fp);
		}
		else {
			/* Set up possible list of replacement characters for #'s */
			replacement_chars = (char **) 
				local_malloc(IMAGE_IO_MEM_KEY,MAX_COMPONENTS*sizeof(char *));
			replacement_chars[0] = (char *)
				local_malloc(IMAGE_IO_MEM_KEY,MAX_COMPONENTS*5*sizeof(char));
			for (n=1;n<MAX_COMPONENTS;n++)
				replacement_chars[n] = replacement_chars[0]+5*n;
			if ((subset_p=cmdl->extract(cmdl,"-i_subset",-1,&subset_params))>0){
				if ((subset_p == 1) &&
					((colon_pos=strchr(subset_params[0],':'))!=NULL)){
					subset_params_cpy = (char *) local_malloc(IMAGE_IO_MEM_KEY, 
						strlen(subset_params[0])+1);
					memcpy(subset_params_cpy,subset_params[0],
						strlen(subset_params[0]));
					colon_offset = colon_pos - subset_params[0];
					subset_params_cpy[colon_offset] = '\0';
					for (n=atoi(subset_params_cpy); 
						n<=atoi(subset_params_cpy+colon_offset+1);n++){
						sprintf(replacement_chars[n-atoi(subset_params_cpy)],
							"%d",n);
						list_size++;
					}
				}
				else{
					list_size=subset_p;
					for (n=0;n<subset_p;n++){
						strcpy(replacement_chars[n], subset_params[n]);
					}
				}
			}
			else{
				list_size = MAX_COMPONENTS;
				for (n=0;n<MAX_COMPONENTS;n++){
/* Begin Aerospace modification for zero-based indexing (JHK) */
#ifdef ZERO_INDEXING
					sprintf(replacement_chars[n],"%d",n);
#else
					sprintf(replacement_chars[n],"%d",n+1);
#endif
/* End Aerospace modification for zero-based indexing (JHK) */
				}
			}
			
			/* Check out all files with pound character replaced with 
			replacement_chars */
			fname=(char *)local_malloc(IMAGE_IO_MEM_KEY,strlen(params[0])+5);
			params_cpy=(char *)local_malloc(IMAGE_IO_MEM_KEY,
				strlen(params[0])+1);
			memcpy(params_cpy,params[0],strlen(params[0]));
			pound_offset=pound_pos-params[0];
			params_cpy[pound_offset]='\0';
			for (n=0;n<list_size;n++) {
				sprintf(fname,"%s%s%s",params_cpy,replacement_chars[n], 
					params_cpy+pound_offset+1);
				if ((fp = fopen(fname, "rb")) != NULL) {
					fclose(fp);
				}
				else {
					break;
				}
			}
			self->num_components = n;
			if (self->num_components == 0)
				local_error("Metacharacter replacement of `#' for `-i' "
					"cannot open any files!");
		}
	}
	/* New Multi-component Input End */
	
	self->components = (image_component_ptr)local_malloc(IMAGE_IO_MEM_KEY,
		sizeof(image_component)*self->num_components);
	
	/* New Multi-component Input Begin Mods */
	for (p=0; p < self->num_components; p++)