freebsd-dev/lib/libmd/mdXhl.c
Poul-Henning Kamp 8a24546c85 Add a new entrypoint to the hashes in libmd:
char *
  FooFileChunk(const char *filename, char *buf, off_t offset, off_t length)
Which only hashes part of a file.
Implement FooFile() in terms of this function.

Submitted by:	roam
2001-03-17 10:00:50 +00:00

94 lines
2.0 KiB
C

/* mdXhl.c
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@login.dkuug.dk> wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
* ----------------------------------------------------------------------------
*
* $FreeBSD$
*
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include "mdX.h"
char *
MDXEnd(MDX_CTX *ctx, char *buf)
{
int i;
unsigned char digest[LENGTH];
static const char hex[]="0123456789abcdef";
if (!buf)
buf = malloc(2*LENGTH + 1);
if (!buf)
return 0;
MDXFinal(digest, ctx);
for (i = 0; i < LENGTH; i++) {
buf[i+i] = hex[digest[i] >> 4];
buf[i+i+1] = hex[digest[i] & 0x0f];
}
buf[i+i] = '\0';
return buf;
}
char *
MDXFile(const char *filename, char *buf)
{
return MDXFileChunk(filename, buf, 0, 0);
}
char *
MDXFileChunk(const char *filename, char *buf, off_t ofs, off_t len)
{
unsigned char buffer[BUFSIZ];
MDX_CTX ctx;
struct stat stbuf;
int f, i, e;
off_t n;
MDXInit(&ctx);
f = open(filename, O_RDONLY);
if (f < 0) return 0;
if (fstat(f, &stbuf) < 0) return 0;
if (ofs > stbuf.st_size)
ofs = stbuf.st_size;
if ((len == 0) || (len > stbuf.st_size - ofs))
len = stbuf.st_size - ofs;
if (lseek(f, ofs, SEEK_SET) < 0) return 0;
n = len;
while (n > 0) {
if (n > sizeof(buffer))
i = read(f, buffer, sizeof(buffer));
else
i = read(f, buffer, n);
if (i < 0) break;
MDXUpdate(&ctx, buffer, i);
n -= i;
}
e = errno;
close(f);
errno = e;
if (i < 0) return 0;
return MDXEnd(&ctx, buf);
}
char *
MDXData (const unsigned char *data, unsigned int len, char *buf)
{
MDX_CTX ctx;
MDXInit(&ctx);
MDXUpdate(&ctx,data,len);
return MDXEnd(&ctx, buf);
}