wpng.c

game engine, which is useful for everyone who is interested in it. I hope you can enjoy it.

        fprintf(stderr, "to skip a field, hit the <Enter> key.\n");
        /* note:  just <Enter> leaves len == 1 */

        do {
            valid = TRUE;
            p = textbuf + TEXT_TITLE_OFFSET;
            fprintf(stderr, "  Title: ");
            fflush(stderr);
            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
                if (p[len-1] == '\n')
                    p[--len] = '\0';
                wpng_info.title = p;
                wpng_info.have_text |= TEXT_TITLE;
                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
                    fprintf(stderr, "    " PROGNAME " warning:  character code"
                      " %u is %sdiscouraged by the PNG\n    specification "
                      "[first occurrence was at character position #%d]\n",
                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
                      result+1);
                    fflush(stderr);
#ifdef FORBID_LATIN1_CTRL
                    wpng_info.have_text &= ~TEXT_TITLE;
                    valid = FALSE;
#else
                    if (p[result] == 27) {    /* escape character */
                        wpng_info.have_text &= ~TEXT_TITLE;
                        valid = FALSE;
                    }
#endif
                }
            }
        } while (!valid);

        do {
            valid = TRUE;
            p = textbuf + TEXT_AUTHOR_OFFSET;
            fprintf(stderr, "  Author: ");
            fflush(stderr);
            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
                if (p[len-1] == '\n')
                    p[--len] = '\0';
                wpng_info.author = p;
                wpng_info.have_text |= TEXT_AUTHOR;
                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
                    fprintf(stderr, "    " PROGNAME " warning:  character code"
                      " %u is %sdiscouraged by the PNG\n    specification "
                      "[first occurrence was at character position #%d]\n",
                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
                      result+1);
                    fflush(stderr);
#ifdef FORBID_LATIN1_CTRL
                    wpng_info.have_text &= ~TEXT_AUTHOR;
                    valid = FALSE;
#else
                    if (p[result] == 27) {    /* escape character */
                        wpng_info.have_text &= ~TEXT_AUTHOR;
                        valid = FALSE;
                    }
#endif
                }
            }
        } while (!valid);

        do {
            valid = TRUE;
            p = textbuf + TEXT_DESC_OFFSET;
            fprintf(stderr, "  Description (up to 9 lines):\n");
            for (i = 1;  i < 10;  ++i) {
                fprintf(stderr, "    [%d] ", i);
                fflush(stderr);
                if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1)
                    p += len;   /* now points at NULL; char before is newline */
                else
                    break;
            }
            if ((len = p - (textbuf + TEXT_DESC_OFFSET)) > 1) {
                if (p[-1] == '\n') {
                    p[-1] = '\0';
                    --len;
                }
                wpng_info.desc = textbuf + TEXT_DESC_OFFSET;
                wpng_info.have_text |= TEXT_DESC;
                p = textbuf + TEXT_DESC_OFFSET;
                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
                    fprintf(stderr, "    " PROGNAME " warning:  character code"
                      " %u is %sdiscouraged by the PNG\n    specification "
                      "[first occurrence was at character position #%d]\n",
                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
                      result+1);
                    fflush(stderr);
#ifdef FORBID_LATIN1_CTRL
                    wpng_info.have_text &= ~TEXT_DESC;
                    valid = FALSE;
#else
                    if (p[result] == 27) {    /* escape character */
                        wpng_info.have_text &= ~TEXT_DESC;
                        valid = FALSE;
                    }
#endif
                }
            }
        } while (!valid);

        do {
            valid = TRUE;
            p = textbuf + TEXT_COPY_OFFSET;
            fprintf(stderr, "  Copyright: ");
            fflush(stderr);
            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
                if (p[len-1] == '\n')
                    p[--len] = '\0';
                wpng_info.copyright = p;
                wpng_info.have_text |= TEXT_COPY;
                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
                    fprintf(stderr, "    " PROGNAME " warning:  character code"
                      " %u is %sdiscouraged by the PNG\n    specification "
                      "[first occurrence was at character position #%d]\n",
                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
                      result+1);
                    fflush(stderr);
#ifdef FORBID_LATIN1_CTRL
                    wpng_info.have_text &= ~TEXT_COPY;
                    valid = FALSE;
#else
                    if (p[result] == 27) {    /* escape character */
                        wpng_info.have_text &= ~TEXT_COPY;
                        valid = FALSE;
                    }
#endif
                }
            }
        } while (!valid);

        do {
            valid = TRUE;
            p = textbuf + TEXT_EMAIL_OFFSET;
            fprintf(stderr, "  E-mail: ");
            fflush(stderr);
            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
                if (p[len-1] == '\n')
                    p[--len] = '\0';
                wpng_info.email = p;
                wpng_info.have_text |= TEXT_EMAIL;
                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
                    fprintf(stderr, "    " PROGNAME " warning:  character code"
                      " %u is %sdiscouraged by the PNG\n    specification "
                      "[first occurrence was at character position #%d]\n",
                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
                      result+1);
                    fflush(stderr);
#ifdef FORBID_LATIN1_CTRL
                    wpng_info.have_text &= ~TEXT_EMAIL;
                    valid = FALSE;
#else
                    if (p[result] == 27) {    /* escape character */
                        wpng_info.have_text &= ~TEXT_EMAIL;
                        valid = FALSE;
                    }
#endif
                }
            }
        } while (!valid);

        do {
            valid = TRUE;
            p = textbuf + TEXT_URL_OFFSET;
            fprintf(stderr, "  URL: ");
            fflush(stderr);
            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
                if (p[len-1] == '\n')
                    p[--len] = '\0';
                wpng_info.url = p;
                wpng_info.have_text |= TEXT_URL;
                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
                    fprintf(stderr, "    " PROGNAME " warning:  character code"
                      " %u is %sdiscouraged by the PNG\n    specification "
                      "[first occurrence was at character position #%d]\n",
                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
                      result+1);
                    fflush(stderr);
#ifdef FORBID_LATIN1_CTRL
                    wpng_info.have_text &= ~TEXT_URL;
                    valid = FALSE;
#else
                    if (p[result] == 27) {    /* escape character */
                        wpng_info.have_text &= ~TEXT_URL;
                        valid = FALSE;
                    }
#endif
                }
            }
        } while (!valid);

#ifndef DOS_OS2_W32
        fclose(keybd);
#endif

    } else if (text) {
        fprintf(stderr, PROGNAME ":  unable to allocate memory for text\n");
        text = FALSE;
        wpng_info.have_text = 0;
    }


    /* allocate libpng stuff, initialize transformations, write pre-IDAT data */

    if ((rc = writepng_init(&wpng_info)) != 0) {
        switch (rc) {
            case 2:
                fprintf(stderr, PROGNAME
                  ":  libpng initialization problem (longjmp)\n");
                break;
            case 4:
                fprintf(stderr, PROGNAME ":  insufficient memory\n");
                break;
            case 11:
                fprintf(stderr, PROGNAME
                  ":  internal logic error (unexpected PNM type)\n");
                break;
            default:
                fprintf(stderr, PROGNAME
                  ":  unknown writepng_init() error\n");
                break;
        }
        exit(rc);
    }


    /* free textbuf, since it's a completely local variable and all text info
     * has just been written to the PNG file */

    if (text && textbuf) {
        free(textbuf);
        textbuf = NULL;
    }


    /* calculate rowbytes on basis of image type; note that this becomes much
     * more complicated if we choose to support PBM type, ASCII PNM types, or
     * 16-bit-per-sample binary data [currently not an official NetPBM type] */

    if (wpng_info.pnmtype == 5)
        rowbytes = wpng_info.width;
    else if (wpng_info.pnmtype == 6)
        rowbytes = wpng_info.width * 3;
    else /* if (wpng_info.pnmtype == 8) */
        rowbytes = wpng_info.width * 4;


    /* read and write the image, either in its entirety (if writing interlaced
     * PNG) or row by row (if non-interlaced) */

    fprintf(stderr, "Encoding image data...\n");
    fflush(stderr);

    if (wpng_info.interlaced) {
        long i;
        ulg bytes;
        ulg image_bytes = rowbytes * wpng_info.height;   /* overflow? */

        wpng_info.image_data = (uch *)malloc(image_bytes);
        wpng_info.row_pointers = (uch **)malloc(wpng_info.height*sizeof(uch *));
        if (wpng_info.image_data == NULL || wpng_info.row_pointers == NULL) {
            fprintf(stderr, PROGNAME ":  insufficient memory for image data\n");
            writepng_cleanup(&wpng_info);
            wpng_cleanup();
            exit(5);
        }
        for (i = 0;  i < wpng_info.height;  ++i)
            wpng_info.row_pointers[i] = wpng_info.image_data + i*rowbytes;
        bytes = fread(wpng_info.image_data, 1, image_bytes, wpng_info.infile);
        if (bytes != image_bytes) {
            fprintf(stderr, PROGNAME ":  expected %lu bytes, got %lu bytes\n",
              image_bytes, bytes);
            fprintf(stderr, "  (continuing anyway)\n");
        }
        if (writepng_encode_image(&wpng_info) != 0) {
            fprintf(stderr, PROGNAME
              ":  libpng problem (longjmp) while writing image data\n");
            writepng_cleanup(&wpng_info);
            wpng_cleanup();
            exit(2);
        }

    } else /* not interlaced:  write progressively (row by row) */ {
        long j;
        ulg bytes;

        wpng_info.image_data = (uch *)malloc(rowbytes);
        if (wpng_info.image_data == NULL) {
            fprintf(stderr, PROGNAME ":  insufficient memory for row data\n");
            writepng_cleanup(&wpng_info);
            wpng_cleanup();
            exit(5);
        }
        error = 0;
        for (j = wpng_info.height;  j > 0L;  --j) {
            bytes = fread(wpng_info.image_data, 1, rowbytes, wpng_info.infile);
            if (bytes != rowbytes) {
                fprintf(stderr, PROGNAME
                  ":  expected %lu bytes, got %lu bytes (row %ld)\n", rowbytes,
                  bytes, wpng_info.height-j);
                ++error;
                break;
            }
            if (writepng_encode_row(&wpng_info) != 0) {
                fprintf(stderr, PROGNAME
                  ":  libpng problem (longjmp) while writing row %ld\n",
                  wpng_info.height-j);
                ++error;
                break;
            }
        }
        if (error) {
            writepng_cleanup(&wpng_info);
            wpng_cleanup();
            exit(2);
        }
        if (writepng_encode_finish(&wpng_info) != 0) {
            fprintf(stderr, PROGNAME ":  error on final libpng call\n");
            writepng_cleanup(&wpng_info);
            wpng_cleanup();
            exit(2);
        }
    }


    /* OK, we're done (successfully):  clean up all resources and quit */

    fprintf(stderr, "Done.\n");
    fflush(stderr);

    writepng_cleanup(&wpng_info);
    wpng_cleanup();

    return 0;
}





static int wpng_isvalid_latin1(uch *p, int len)
{
    int i, result = -1;

    for (i = 0;  i < len;  ++i) {
        if (p[i] == 10 || (p[i] > 31 && p[i] < 127) || p[i] > 160)
            continue;           /* character is completely OK */
        if (result < 0 || (p[result] != 27 && p[i] == 27))
            result = i;         /* mark location of first questionable one */
    }                           /*  or of first escape character (bad) */

    return result;
}





static void wpng_cleanup(void)
{
    if (wpng_info.outfile) {
        fclose(wpng_info.outfile);
        wpng_info.outfile = NULL;
    }

    if (wpng_info.infile) {
        fclose(wpng_info.infile);
        wpng_info.infile = NULL;
    }

    if (wpng_info.image_data) {
        free(wpng_info.image_data);
        wpng_info.image_data = NULL;
    }

    if (wpng_info.row_pointers) {
        free(wpng_info.row_pointers);
        wpng_info.row_pointers = NULL;
    }
}




#ifdef DOS_OS2_W32

static char *dos_kbd_gets(char *buf, int len)
{
    int ch, count=0;

    do {
        buf[count++] = ch = getche();
    } while (ch != '\r' && count < len-1);

    buf[count--] = '\0';        /* terminate string */
    if (buf[count] == '\r')     /* Enter key makes CR, so change to newline */
        buf[count] = '\n';

    fprintf(stderr, "\n");      /* Enter key does *not* cause a newline */
    fflush(stderr);

    return buf;
}

#endif /* DOS_OS2_W32 */