seewbmp.c File Reference

#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>

Go to the source code of this file.

Data Structures
struct	parm

Functions
static long	get_mbi (FILE *infile)
static int	skip_mbi (FILE *infile)
static int	show_image_from_file (char *bmpname, FILE *bmpfile, long width, long height)
static void	clear_extparms (void)
static int	new_extparm (char *name, char *value)
static void	print_extparms (FILE *outfile)
static int	parse_headers (FILE *bmpfile)
static int	show_wbmp_from_file (char *bmpname, FILE *bmpfile)
int	main (int argc, char *argv[])

Variables
struct parm *	extparms = NULL

Function Documentation

clear_extparms()

static void clear_extparms ( void  )

static

Definition at line 162 of file seewbmp.c.

References extparms, free(), parm::name, parm::next, and parm::value.

Referenced by parse_headers().

                                 {
    while (extparms) {
        struct parm *tmp = extparms;
        extparms = extparms->next;
        free(tmp->name);
        free(tmp->value);
        free(tmp);
    }
}

get_mbi()

static long get_mbi ( FILE *  infile )

static

Definition at line 98 of file seewbmp.c.

References infile.

Referenced by show_wbmp_from_file().

                                  {
    int c;
    long result = 0;

    do {
        c = getc(infile);
        if (c < 0) return -1;
        result = (result << 7) | (c & 0x7f);
    } while (c & 0x80);

    return result;
}

main()

int main	(	int	argc,
		char *	argv[]
	)

Definition at line 304 of file seewbmp.c.

References show_wbmp_from_file().

                                 {
    int i;
    /* 1 means an I/O error.  No other error values are used yet. */
    int exitvalue = 0;

    if (argc > 1) {
        for (i = 1; i < argc; i++) {
            FILE *bmpfile;

            bmpfile = fopen(argv[i], "r");
            if (bmpfile) {
                if (show_wbmp_from_file(argv[i], bmpfile) < 0) {
                    /* We've already reported the error */
                    exitvalue = 1;
                }
                if (fclose(bmpfile) < 0) {
                    perror(argv[i]);
                    exitvalue = 1;
                }
            } else {
                perror(argv[i]);
                exitvalue = 1;
            }
            if (i < argc - 1) {
                /* more files follow -- separate them */
                printf("\n");
            }
        }
    } else {
        /* No files specified -- read from standard input */
        if (show_wbmp_from_file("stdin", stdin)) {
            exitvalue = 1;
        }
    }

    return exitvalue;
}

new_extparm()

static int new_extparm ( char *  name, char *  value  )

static

Definition at line 174 of file seewbmp.c.

References extparms, malloc(), name, parm::next, and parm::value.

Referenced by parse_headers().

                                                {
    struct parm *new;
    struct parm *p;
    
    /* Construct a new node */
    new = (struct parm *)malloc(sizeof(struct parm));
    if (!new)
        return -1;

    new->name = name;
    new->value = value;
    new->next = NULL;

    /* Add it to the end of the list. */
    if (!extparms) {
        extparms = new;
    } else {
        p = extparms;
        while (p->next) { 
            p = p->next;
        }
        p->next = new;
    }

    return 0;
}

parse_headers()

static int parse_headers ( FILE *  bmpfile )

static

Definition at line 209 of file seewbmp.c.

References clear_extparms(), free(), malloc(), name, new_extparm(), skip_mbi(), and parm::value.

Referenced by show_wbmp_from_file().

                                        {
    int c;
    int exttype;

    clear_extparms();

    c = getc(bmpfile);
    if (c < 0) return -1;
    if (!(c & 0x80)) {
        /* No extension headers follow */
        return 0;
    }
    exttype = (c >> 5) & 0x03;
    /* None of these headers do much at this time, but they
     * might be meaningful with later specifications */
    switch (exttype) {
        case 0: 
            /* All we know of type 0 headers is that
             * the high bit is a continuation bit.
             * That makes them exactly like an MBI. */
            if (skip_mbi(bmpfile) < 0) return -1;
            break;
        case 1: case 2:
            /* We don't know what to do with these */
            return -1;
        case 3:
            /* A sequence of parameter/value combinations */
            do {
                int namelen, valuelen;
                char *name, *value;
                c = getc(bmpfile);
                if (c < 0) return -1;

                namelen = (c >> 4) & 0x07;
                name = malloc(namelen + 1);
                if (!name) return -1;
                if (fread(name, namelen, 1, bmpfile) < (size_t) namelen)
                    return -1;

                valuelen = c & 0x0f;
                value = malloc(valuelen + 1);
                if (!value) { free(name); return -1; }
                if (fread(value, valuelen, 1, bmpfile) < (size_t) valuelen)
                    return -1;
            
                new_extparm(name, value);
            } while (c & 0x80);
            break;
    }
    return 0;
}

print_extparms()

static void print_extparms ( FILE *  outfile )

static

Definition at line 201 of file seewbmp.c.

References extparms, parm::name, parm::next, outfile, and parm::value.

Referenced by show_wbmp_from_file().

                                          {
    struct parm *p;

    for (p = extparms; p; p = p->next) {
        fprintf(outfile, "%s=%s\n", p->name, p->value);
    }
}

show_image_from_file()

static int show_image_from_file ( char *  bmpname, FILE *  bmpfile, long  width, long  height  )

static

Definition at line 126 of file seewbmp.c.

Referenced by show_wbmp_from_file().

                                     {
    long w, h;

    for (h = 0; h < height; h++) {
        /* w is incremented in its inner loop */
        for (w = 0; w < width; ) {
            int c;
            unsigned int bit;

            c = getc(bmpfile);
            if (c < 0) {
                perror(bmpname);
                return -1;
            }

            for (bit = 0x80; bit > 0 && w < width; bit >>= 1, w++) {
                putc((c & bit) ? '*' : ' ', stdout);
            }
        }
        putc('\n', stdout);
    }

    return 0;
}

show_wbmp_from_file()

static int show_wbmp_from_file ( char *  bmpname, FILE *  bmpfile  )

static

Definition at line 262 of file seewbmp.c.

References get_mbi(), parse_headers(), print_extparms(), and show_image_from_file().

Referenced by main().

                                                             {
    long typefield;
    long width, height;

    typefield = get_mbi(bmpfile);
    if (typefield < 0) {
        perror(bmpname);
        return -1;
    }

    if (parse_headers(bmpfile) < 0) {
        fprintf(stderr, "%s: format error in headers\n", bmpname);
        return -1;
    }
    
    width = get_mbi(bmpfile);
    height = get_mbi(bmpfile);
    if (width < 0 || height < 0) {
        fprintf(stderr, "%s: error reading height and width\n",
            bmpname);
        return -1;
    }

    switch (typefield) {
        case 0:
            printf("%s, %ldx%ld B/W bitmap, no compression\n",
                bmpname, width, height);
            print_extparms(stdout);
            if (show_image_from_file(bmpname, bmpfile,
                        width, height) < 0) {
                return -1;
            }
            break;
        default:
            fprintf(stderr, "%s: cannot handle level %ld wbmp\n",
                bmpname, typefield);
            return -1;
    }

    return 0;
}

skip_mbi()

static int skip_mbi ( FILE *  infile )

static

Definition at line 115 of file seewbmp.c.

References infile.

Referenced by parse_headers().

                                  {
    int c;

    do {
        c = getc(infile);
        if (c < 0) return -1;
    } while (c & 0x80);

    return 0;
}

Variable Documentation

extparms

struct parm* extparms = NULL

Definition at line 160 of file seewbmp.c.

Referenced by clear_extparms(), new_extparm(), and print_extparms().