From cf0fcea2b7ae26222f4865e9a6df53972a02f443 Mon Sep 17 00:00:00 2001
From: phk <phk@FreeBSD.org>
Date: Sat, 17 Mar 2001 10:00:50 +0000
Subject: 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
---
 lib/libmd/mdX.3 | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

(limited to 'lib/libmd/mdX.3')

diff --git a/lib/libmd/mdX.3 b/lib/libmd/mdX.3
index cc44122..412aeba 100644
--- a/lib/libmd/mdX.3
+++ b/lib/libmd/mdX.3
@@ -18,6 +18,7 @@
 .Nm MDXFinal ,
 .Nm MDXEnd ,
 .Nm MDXFile ,
+.Nm MDXFileChunk ,
 .Nm MDXData
 .Nd calculate the RSA Data Security, Inc., ``MDX'' message digest
 .Sh LIBRARY
@@ -38,6 +39,8 @@
 .Ft "char *"
 .Fn MDXFile "const char *filename" "char *buf"
 .Ft "char *"
+.Fn MDXFileChunk "const char *filename" "char *buf" "off_t offset" "off_t length"
+.Ft "char *"
 .Fn MDXData "const unsigned char *data" "unsigned int len" "char *buf"
 .Sh DESCRIPTION
 The MDX functions calculate a 128-bit cryptographic checksum (digest)
@@ -88,6 +91,23 @@ calculates the digest of a file, and uses
 .Fn MDXEnd
 to return the result.
 If the file cannot be opened, a null pointer is returned.
+.Fn MDXFileChunk
+is similar to
+.Fn MDXFile ,
+but it only calculates the digest over a byte-range of the file specified,
+starting at
+.Ar offset
+and spanning
+.Ar length
+bytes.
+If the
+.Ar length
+parameter is specified as 0, or more than the length of the remaining part
+of the file,
+.Fn MDXFileChunk
+calculates the digest from
+.Ar offset
+to the end of file.
 .Fn MDXData
 calculates the digest of a chunk of data in memory, and uses
 .Fn MDXEnd
-- 
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