8a24546c85
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
94 lines
2.0 KiB
C
94 lines
2.0 KiB
C
/* mdXhl.c
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* ----------------------------------------------------------------------------
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* "THE BEER-WARE LICENSE" (Revision 42):
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* <phk@login.dkuug.dk> wrote this file. As long as you retain this notice you
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* can do whatever you want with this stuff. If we meet some day, and you think
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* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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* ----------------------------------------------------------------------------
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*
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* $FreeBSD$
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*
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "mdX.h"
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char *
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MDXEnd(MDX_CTX *ctx, char *buf)
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{
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int i;
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unsigned char digest[LENGTH];
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static const char hex[]="0123456789abcdef";
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if (!buf)
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buf = malloc(2*LENGTH + 1);
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if (!buf)
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return 0;
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MDXFinal(digest, ctx);
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for (i = 0; i < LENGTH; i++) {
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buf[i+i] = hex[digest[i] >> 4];
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buf[i+i+1] = hex[digest[i] & 0x0f];
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}
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buf[i+i] = '\0';
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return buf;
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}
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char *
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MDXFile(const char *filename, char *buf)
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{
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return MDXFileChunk(filename, buf, 0, 0);
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}
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char *
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MDXFileChunk(const char *filename, char *buf, off_t ofs, off_t len)
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{
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unsigned char buffer[BUFSIZ];
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MDX_CTX ctx;
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struct stat stbuf;
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int f, i, e;
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off_t n;
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MDXInit(&ctx);
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f = open(filename, O_RDONLY);
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if (f < 0) return 0;
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if (fstat(f, &stbuf) < 0) return 0;
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if (ofs > stbuf.st_size)
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ofs = stbuf.st_size;
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if ((len == 0) || (len > stbuf.st_size - ofs))
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len = stbuf.st_size - ofs;
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if (lseek(f, ofs, SEEK_SET) < 0) return 0;
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n = len;
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while (n > 0) {
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if (n > sizeof(buffer))
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i = read(f, buffer, sizeof(buffer));
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else
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i = read(f, buffer, n);
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if (i < 0) break;
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MDXUpdate(&ctx, buffer, i);
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n -= i;
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}
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e = errno;
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close(f);
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errno = e;
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if (i < 0) return 0;
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return MDXEnd(&ctx, buf);
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}
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char *
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MDXData (const unsigned char *data, unsigned int len, char *buf)
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{
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MDX_CTX ctx;
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MDXInit(&ctx);
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MDXUpdate(&ctx,data,len);
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return MDXEnd(&ctx, buf);
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}
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