src/hash.c

   1 #include <R.h>
   2 #include <Rinternals.h>
   3 #include "sha1.h"
   4
   5 /*
   6  * This code is adapted from the 'digest.c' code in the 'digest'
   7  * package by Dirk Eddelbuettel <edd@debian.org> with contributions by
   8  * Antoine Lucas, Jarek Tuszynski, Henrik Bengtsson and Simon Urbanek
   9  */
  10
  11 SEXP sha1_object(SEXP object, SEXP skip_bytes)
  12 {
  13         char output[41];  /* SHA-1 is 40 bytes + '\0' */
  14         int i, skip;
  15         SEXP result;
  16         sha1_context ctx;
  17         unsigned char buffer[20];
  18         Rbyte *data;
  19         int nChar = length(object);
  20
  21         PROTECT(object = coerceVector(object, RAWSXP));
  22         data = RAW(object);
  23         PROTECT(skip_bytes = coerceVector(skip_bytes, INTSXP));
  24         skip = INTEGER(skip_bytes)[0];
  25
  26         if(skip > 0) {
  27                 if(skip >= nChar)
  28                         nChar = 0;
  29                 else {
  30                         nChar -= skip;
  31                         data += skip;
  32                 }
  33         }
  34         sha1_starts(&ctx);
  35         sha1_update(&ctx, (uint8 *) data, nChar);
  36         sha1_finish(&ctx, buffer);
  37
  38         for(i=0; i < 20; i++)
  39                 sprintf(output + i * 2, "%02x", buffer[i]);
  40
  41         PROTECT(result = allocVector(STRSXP, 1));
  42         SET_STRING_ELT(result, 0, mkChar(output));
  43         UNPROTECT(3);
  44
  45         return result;
  46 }
  47
  48
  49 SEXP sha1_file(SEXP filename, SEXP skip_bytes)
  50 {
  51         char output[41];  /* SHA-1 is 40 bytes + '\0' */
  52         int nChar, i, skip;
  53         FILE *fp;
  54         SEXP result;
  55         sha1_context ctx;
  56         unsigned char buf[1024];
  57         unsigned char sha1sum[20];
  58
  59         PROTECT(skip_bytes = coerceVector(skip_bytes, INTSXP));
  60         PROTECT(filename = coerceVector(filename, STRSXP));
  61
  62         skip = INTEGER(skip_bytes)[0];
  63
  64         if(!(fp = fopen(CHAR(STRING_ELT(filename, 0)), "rb")))
  65                 error("unable to open input file");
  66         if (skip > 0)
  67                 fseek(fp, skip, SEEK_SET);
  68         sha1_starts(&ctx);
  69
  70         while((nChar = fread(buf, 1, sizeof(buf), fp)) > 0)
  71                 sha1_update(&ctx, buf, nChar);
  72
  73         fclose(fp);
  74         sha1_finish(&ctx, sha1sum);
  75
  76         for(i=0; i < 20; i++)
  77                 sprintf(output + i * 2, "%02x", sha1sum[i]);
  78
  79         PROTECT(result = allocVector(STRSXP, 1));
  80         SET_STRING_ELT(result, 0, mkChar(output));
  81         UNPROTECT(3);
  82
  83         return result;
  84 }