New function (fcrc32) to calculate CRC32 of byte range from file stream.

src/hash/crc32.c

@@ -89,5 +89,18 @@ unsigned long crc32(char *buf, unsigned long len)
 	return(~crc);
 }
 
+unsigned long fcrc32(FILE* fp, unsigned long len)
+{
+	int	ch;
+	unsigned long l,crc=0xffffffff;
+
+	rewind(fp);
+	for(l=0;(len==0 || l<len) && !feof(fp);l++) {
+		if((ch=fgetc(fp))==EOF)
+			break;
+		crc=ucrc32(ch,crc);
+	}
+	return(~crc);
+}
 
 

src/hash/crc32.h

@@ -38,6 +38,8 @@
 #ifndef _CRC32_H_
 #define _CRC32_H_
 
+#include <stdio.h>	/* FILE */
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -45,6 +47,7 @@ extern "C" {
 extern long crc32tbl[];
 
 unsigned long crc32(char* buf, unsigned long len);
+unsigned long fcrc32(FILE* fp, unsigned long len);
 
 #ifdef __cplusplus
 }