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#include <stdio.h>
#include <stdlib.h>
#include <file/nbio.h>
struct nbio_t
{
FILE* f;
void* data;
size_t progress;
size_t len;
/*
* possible values:
* NBIO_READ, NBIO_WRITE - obvious
* -1 - currently doing nothing
* -2 - the pointer was reallocated since the last operation
*/
signed char op;
signed char mode;
};
static const char * modes[]={ "rb", "wb", "r+b", "rb", "wb", "r+b" };
struct nbio_t* nbio_open(const char * filename, unsigned mode)
{
struct nbio_t* handle = NULL;
FILE* f = fopen(filename, modes[mode]);
if (!f)
return NULL;
handle = (struct nbio_t*)malloc(sizeof(struct nbio_t));
if (!handle)
goto error;
handle->f = f;
handle->len = 0;
switch (mode)
{
case NBIO_WRITE:
case BIO_WRITE:
break;
default:
fseek(handle->f, 0, SEEK_END);
handle->len = ftell(handle->f);
break;
}
handle->mode = mode;
handle->data = malloc(handle->len);
if (handle->len && !handle->data)
goto error;
handle->progress = handle->len;
handle->op = -2;
return handle;
error:
if (handle)
{
if (handle->data)
free(handle->data);
handle->data = NULL;
free(handle);
}
handle = NULL;
fclose(f);
return NULL;
}
void nbio_begin_read(struct nbio_t* handle)
{
if (!handle)
return;
if (handle->op >= 0)
{
puts("ERROR - attempted file read operation while busy");
abort();
}
fseek(handle->f, 0, SEEK_SET);
handle->op = NBIO_READ;
handle->progress = 0;
}
void nbio_begin_write(struct nbio_t* handle)
{
if (!handle)
return;
if (handle->op >= 0)
{
puts("ERROR - attempted file write operation while busy");
abort();
}
fseek(handle->f, 0, SEEK_SET);
handle->op = NBIO_WRITE;
handle->progress = 0;
}
bool nbio_iterate(struct nbio_t* handle)
{
size_t amount = 65536;
if (!handle)
return false;
if (amount > handle->len - handle->progress)
amount = handle->len - handle->progress;
switch (handle->op)
{
case NBIO_READ:
if (handle->mode == BIO_READ)
{
amount = handle->len;
fread((char*)handle->data, 1, amount, handle->f);
}
else
fread((char*)handle->data + handle->progress, 1, amount, handle->f);
break;
case NBIO_WRITE:
if (handle->mode == BIO_WRITE)
{
size_t written = 0;
amount = handle->len;
written = fwrite((char*)handle->data, 1, amount, handle->f);
if (written != amount)
return false;
}
else
fwrite((char*)handle->data + handle->progress, 1, amount, handle->f);
break;
}
handle->progress += amount;
if (handle->progress == handle->len)
handle->op = -1;
return (handle->op < 0);
}
void nbio_resize(struct nbio_t* handle, size_t len)
{
if (!handle)
return;
if (handle->op >= 0)
{
puts("ERROR - attempted file resize operation while busy");
abort();
}
if (len < handle->len)
{
puts("ERROR - attempted file shrink operation, not implemented");
abort();
}
handle->len = len;
handle->data = realloc(handle->data, handle->len);
handle->op = -1;
handle->progress = handle->len;
}
void* nbio_get_ptr(struct nbio_t* handle, size_t* len)
{
if (!handle)
return NULL;
if (len)
*len = handle->len;
if (handle->op == -1)
return handle->data;
return NULL;
}
void nbio_cancel(struct nbio_t* handle)
{
if (!handle)
return;
handle->op = -1;
handle->progress = handle->len;
}
void nbio_free(struct nbio_t* handle)
{
if (!handle)
return;
if (handle->op >= 0)
{
puts("ERROR - attempted free() while busy");
abort();
}
fclose(handle->f);
free(handle->data);
handle->f = NULL;
handle->data = NULL;
free(handle);
}
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