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New API for MD5 production: iso_md5_start(), iso_md5_compute(),

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iso_md5_clone(), iso_md5_end()
This commit is contained in:
Thomas Schmitt
2009-08-11 12:07:32 +02:00
parent 429b4cd21c
commit fd124c82d2
5 changed files with 191 additions and 53 deletions
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84
libisofs/md5.c
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@ -269,7 +269,28 @@ static int md5_final(libisofs_md5_ctx *ctx, char result[16], int flag)
return(1);
}
/** Compute a MD5 checksum from one or more calls of this function.
The first call has to be made with flag bit0 == 1. It may already submit
processing payload in data and datalen.
The last call has to be made with bit15 set. Normally bit1 will be set
too in order to receive the checksum before it gets disposed.
bit1 may only be set in the last call or together with bit2.
The combination of bit1 and bit2 may be used to get an intermediate
result without hampering an ongoing checksum computation.
@param ctx the checksum context which stores the state between calls.
It gets created with flag bit0 and disposed with bit15.
With flag bit0, *ctx has to be NULL or point to freeable
memory.
@param data the bytes to be checksummed
@param datalen the number of bytes in data
@param result returns the 16 bytes of checksum if called with bit1 set
@param flag bit0= allocate and init *ctx
bit1= transfer ctx to result
bit2= with bit 0 : clone new *ctx from data
bit15= free *ctx
*/
static
int libisofs_md5(void **ctx_in, char *data, int datalen,
char result[16], int flag)
/* *ctx has to be NULL or point to freeable memory */
@ -310,6 +331,60 @@ int libisofs_md5(void **ctx_in, char *data, int datalen,
}
/* ----------------------------------------------------------------------- */
/* Public MD5 computing facility */
/* API */
int iso_md5_start(void **md5_context)
{
int ret;
ret = libisofs_md5(md5_context, NULL, 0, NULL, 1);
if (ret <= 0)
return ISO_OUT_OF_MEM;
return 1;
}
/* API */
int iso_md5_compute(void *md5_context, char *data, int datalen)
{
int ret;
ret = libisofs_md5(&md5_context, data, datalen, NULL, 0);
if (ret <= 0)
return ISO_NULL_POINTER;
return 1;
}
/* API */
int iso_md5_clone(void *old_md5_context, void **new_md5_context)
{
int ret;
ret = libisofs_md5(new_md5_context, old_md5_context, 0, NULL, 4);
if (ret < 0)
return ISO_OUT_OF_MEM;
if (ret == 0)
return ISO_NULL_POINTER;
return 1;
}
/* API */
int iso_md5_end(void **md5_context, char result[16])
{
int ret;
ret = libisofs_md5(md5_context, NULL, 0, result, 2 | (1 << 15));
if (ret <= 0)
return ISO_NULL_POINTER;
return 1;
}
/* ----------------------------------------------------------------------- */
@ -324,6 +399,10 @@ int checksum_xinfo_func(void *data, int flag)
}
/* ----------------------------------------------------------------------- */
/* MD5 checksum image writer */
#ifdef Libisofs_with_checksumS
/*
@ -459,10 +538,9 @@ int checksum_writer_write_data(IsoImageWriter *writer)
/* Write image checksum to index 0 */
if (t->checksum_ctx != NULL) {
/* >>> rather fork a result than killing t->checksum_ctx */;
/* >>> rather clone a result than killing t->checksum_ctx */;
res = libisofs_md5(&(t->checksum_ctx), NULL, 0, t->image_md5,
2 | (1 << 15));
res = iso_md5_end(&(t->checksum_ctx), t->image_md5);
if (res > 0)
memcpy(t->checksum_buffer + 0, t->image_md5, 16);
}