Date: Fri, 18 Dec 2009 11:22:06 +0000 From: Nick Barnes <Nick.Barnes@pobox.com> To: Giorgos Keramidas <keramida@ceid.upatras.gr> Cc: Anton Shterenlikht <mexas@bristol.ac.uk>, freebsd-questions@freebsd.org Subject: Re: editing a binary file Message-ID: <11404.1261135326@thrush.ravenbrook.com> In-Reply-To: <87d42cve53.fsf@kobe.laptop> from Giorgos Keramidas <keramida@ceid.upatras.gr> of "Fri, 18 Dec 2009 11:13:12 %2B0200"
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If your Fortran file has the same word size and enddian-ness as your C, this simple program convert.c will strip all the record length fields. I just knocked it up now, no warranty, etc, but it works for me. Use as a pipe: $ ls convert.c test.f $ gcc -Wall -Werror -ansi -pedantic convert.c -o convert $ gfortran44 test.f -o test $ ./test $ ls -l test-output -rw-r--r-- 1 nb nb 2460 Dec 18 11:17 test-output $ ./convert < test-output > test-converted $ ls -l test-converted -rw-r--r-- 1 nb nb 2420 Dec 18 11:18 test-converted $ The code does a fair amount of checking; if you get one of the error messages, let us know. The most obvious unchecked problem is a short read, which will complain about mismatched lengths. If your Fortran has different word sizes or enddian-ness (e.g. most of the Fortran output files I use on the Clear Climate Code project <http://clearclimatecode.org/>; are generated on big-endian machines), you will need to add code to tweak the 'size' value after reading it, and when checking the record-end marker. Nick B /* convert.c: remove record length fields from Fortran output file. */ /* Nick Barnes, Ravenbrook Limited, 2009-12-18 */ #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <assert.h> int main(void) { long size; char *buf; ssize_t bytes; assert(sizeof(size) == 4); while(bytes = read(0, (void*)&size, sizeof(size))) { if (bytes < 0) { fprintf(stderr, "read() returned %ld\n", bytes); exit(1); } if (size <= 0) { fprintf(stderr, "Read bad record length %ld\n", size); exit(1); } buf = (char*)malloc(size + sizeof(size)); if (!buf) { fprintf(stderr, "Couldn't allocate buffer of %ld bytes\n", size + sizeof(size)); exit(1); } bytes = read(0, buf, size + sizeof(size)); if (bytes <= 0) { fprintf(stderr, "read() returned %ld\n", bytes); exit(1); } if ((*(long*)(buf+size)) != size) { fprintf(stderr, "Mismatched record lengths: %ld, %ld\n", size, *(long*)(buf+size)); exit(1); } write(1, buf, size); free(buf); } return 0; }
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