[pdftex] inverse operation to \pdffiledump

[Akira Kakuto]

Hi Alexander,

> I am looking for a way to embed binary files, such as png image files, as
> hex-encoded strings into the TeX source of a document and to restore them
> on the disk just before using them.

If you admit shell escape, the following is possible:

\newwrite\grfFile
\immediate\openout\grfFile=tmp.txt
\immediate\write\grfFile{%
89504E470D0A1A0A0000000D494844520000001800000012080300000076%
32EEAC00000060504C5445423212CA9A0AF1D21A986D06D4A00AA68008E1%
BB13DAD5CB6A5312AC8E107A6A3AEAEAE2DBB012EECA1A8A62029A7A0EA5%
9A7D948A64654A0EFEE29AFEFEF27262327A623AFEE222EEC20AE2E2DABA%
8202BA8E0AC6AA12FEF2F2FEDA1A00000079EDA0BB0000002074524E53FF%
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF%
005C5C1BED00000001624B47441F050D10BD000000097048597300000048%
000000480046C96B3E00000009767041670000001A0000001200CF6BEC27%
000000CD4944415418D36D91EBB2C2200C8423D080353952DA9E4651FAFE%
6F69E8F4A2A33B933FFBCD125860560D3EB629B5D10FF32ED0B9C47026E6%
4713E2E51DF8F16A8ACA30DAD11FE0161E655A548CE470DBC0B33BAB0F53%
9DC278ED861940CF011FCCB481C908250FFD5D94C51AD84061B250C11DE0%
1F3F0042BF82C4EBEA65BD0251D27F033A29E96B622473005D9E5B10F567%
880D17D80280CEC6FDBA68565240C825BF3FB01136B0487DDB3D8F4A320A%
AB04C9354725B5444B8448E44E7FEF25D6DA93CDCE659B3E6BFFFD512FE7%
BE2090ECBAD6BE0000000049454E44AE426082%
}%
\immediate\closeout\grfFile
\immediate\write18{hex2bin tmp.txt tmp.png}
\pdfximage {tmp.png}\pdfrefximage\pdflastximage

\bye

where a source of hex2bin is

/*
 * hex2bin
 */
#include <stdio.h>
#include <stdlib.h>

int tobin(int c)
{
  int r;
  if('0' <= c && '9' >= c)
    r = c - '0';
  if('A' <= c && 'F' >= c)
    r = c - 'A' + 10;
  return r;
}

int main(int argc, char *argv[])
{
  FILE *fin, *fout;
  int  c1, c2, c;
  fin = fopen(argv[1], "rb");
  fout = fopen(argv[2], "wb");
  while(1) {
    c1 = getc(fin);
    c2 = getc(fin);
    if(c2 == EOF)
      break;
    c = tobin(c1) * 16 + tobin(c2);
    fprintf(fout, "%c", c);
  }
  fclose(fin);
  fclose(fout);
  return 0;
}