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erc-c/src/objstore.c
Peter Evans d2047457e9 Use log_crit() instead of log_critical()
This change also removes the former log_critical and log_error macros.
2018-03-29 21:45:25 -05:00

105 lines
2.9 KiB
C

/*
* objstore.c
*
* The code here allows us to work with the object store, which is an
* entity that allows us to toss all of our binary data needs into a big
* glob of stuff that we can unpack and use at runtime. Examples of such
* data are bitmap fonts, ROM data, etc.
*/
#include <zlib.h>
#include "objstore.h"
#include "objstore_data.h"
/*
* This is data that we expect to find in the store_data variable that
* is defined in objstore_data.h.
*/
#define HEADER_DATA "hope"
/*
* Our object store. Just a simple struct that we pull data out from.
*/
static objstore store;
/*
* This function will set up the store variable so that it contains
* useful information rather than garbage data from the stack. It does
* so with a simply memcpy from store_data directly into store, such
* that the store data itself can be aligned for access.
*/
int
objstore_init()
{
// Oh, you're calling this again? Cool, but let's bail before we do
// anything else.
if (objstore_ready()) {
return OK;
}
// We want to input some bad header data and compare with what
// eventually should get put into there by memcmp.
store.header[0] = 'h';
store.header[1] = 'e';
store.header[2] = 'y';
store.header[3] = '\0';
memcpy(&store, store_data, sizeof(store));
// If the copy didn't work out somehow...
if (!objstore_ready()) {
log_crit("Object store initialization failed with bad data");
return ERR_BADFILE;
}
return OK;
}
/*
* This will empty out the store, which is not very _practically_
* useful, but is a bit useful when testing.
*/
void
objstore_clear()
{
memset(&store, 0, sizeof(store));
}
/*
* Return true if the object store is ready to be used.
*/
bool
objstore_ready()
{
int cmp;
// Test if the header field data is exactly equivalent to that
// defined in HEADER_DATA. Note we use memcmp(), because the header
// field is an array of just 4 bytes; strcmp() and strncmp() have an
// expectation that both pointers will be directed at NUL-terminated
// strings, which is _not_ the case for store.header (but,
// incidentally, _is_ the case for HEADER_DATA!).
cmp = memcmp(store.header, HEADER_DATA,
sizeof(store.header) / sizeof(char));
return cmp == 0;
}
/*
* Something to simplify the very simple getter functions we use for
* getting data from the object store.
*/
#define OBJSTORE_DEFN(x) \
const vm_8bit *objstore_##x() { return store.x; }
/*
* Note we have an extra semicolon on the end... this is mostly to avoid
* screwing up my indent, to be honest. But C will ignore the
* semicolons, so all is well.
*/
OBJSTORE_DEFN(apple2_peripheral_rom); // ignore docblock
OBJSTORE_DEFN(apple2_sys_rom); // ignore docblock
OBJSTORE_DEFN(apple2_sysfont); // ignore docblock
OBJSTORE_DEFN(apple2_invfont); // ignore docblock