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Added SDL_IOFromDynamicMem()

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Sam Lantinga 2024-03-17 17:11:20 -07:00 • committed by Ryan C. Gordon
parent 12245e4c75
commit df0f5deddf
6 changed files with 192 additions and 16 deletions
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111
src/file/SDL_iostream.c
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@ -495,17 +495,18 @@ static size_t mem_io(void *userdata, void *dst, const void *src, size_t size)
static size_t SDLCALL mem_read(void *userdata, void *ptr, size_t size, SDL_IOStatus *status)
{
const IOStreamMemData *iodata = (IOStreamMemData *) userdata;
IOStreamMemData *iodata = (IOStreamMemData *) userdata;
return mem_io(userdata, ptr, iodata->here, size);
}
static size_t SDLCALL mem_write(void *userdata, const void *ptr, size_t size, SDL_IOStatus *status)
{
const IOStreamMemData *iodata = (IOStreamMemData *) userdata;
IOStreamMemData *iodata = (IOStreamMemData *) userdata;
return mem_io(userdata, iodata->here, ptr, size);
}
static int SDLCALL mem_close(void *userdata) {
static int SDLCALL mem_close(void *userdata)
{
SDL_free(userdata);
return 0;
}
@ -731,6 +732,109 @@ SDL_IOStream *SDL_IOFromConstMem(const void *mem, size_t size)
return iostr;
}
typedef struct IOStreamDynamicMemData
{
SDL_IOStream *stream;
IOStreamMemData data;
Uint8 *end;
} IOStreamDynamicMemData;
static Sint64 SDLCALL dynamic_mem_size(void *userdata)
{
IOStreamDynamicMemData *iodata = (IOStreamDynamicMemData *) userdata;
return mem_size(&iodata->data);
}
static Sint64 SDLCALL dynamic_mem_seek(void *userdata, Sint64 offset, int whence)
{
IOStreamDynamicMemData *iodata = (IOStreamDynamicMemData *) userdata;
return mem_seek(&iodata->data, offset, whence);
}
static size_t SDLCALL dynamic_mem_read(void *userdata, void *ptr, size_t size, SDL_IOStatus *status)
{
IOStreamDynamicMemData *iodata = (IOStreamDynamicMemData *) userdata;
return mem_io(&iodata->data, ptr, iodata->data.here, size);
}
static int dynamic_mem_realloc(IOStreamDynamicMemData *iodata, size_t size)
{
size_t chunksize = (size_t)SDL_GetNumberProperty(SDL_GetIOProperties(iodata->stream), SDL_PROP_IOSTREAM_DYNAMIC_CHUNKSIZE_NUMBER, 0);
if (!chunksize) {
chunksize = 1024;
}
// We're intentionally allocating more memory than needed so it can be null terminated
size_t chunks = (((iodata->end - iodata->data.base) + size) / chunksize) + 1;
size_t length = (chunks * chunksize);
Uint8 *base = (Uint8 *)SDL_realloc(iodata->data.base, length);
if (!base) {
return -1;
}
size_t here_offset = (iodata->data.here - iodata->data.base);
size_t stop_offset = (iodata->data.stop - iodata->data.base);
iodata->data.base = base;
iodata->data.here = base + here_offset;
iodata->data.stop = base + stop_offset;
iodata->end = base + length;
return SDL_SetProperty(SDL_GetIOProperties(iodata->stream), SDL_PROP_IOSTREAM_DYNAMIC_MEMORY_POINTER, base);
}
static size_t SDLCALL dynamic_mem_write(void *userdata, const void *ptr, size_t size, SDL_IOStatus *status)
{
IOStreamDynamicMemData *iodata = (IOStreamDynamicMemData *) userdata;
if (size > (iodata->data.stop - iodata->data.here)) {
if (size > (iodata->end - iodata->data.here)) {
if (dynamic_mem_realloc(iodata, size) < 0) {
return 0;
}
}
iodata->data.stop = iodata->data.here + size;
}
return mem_io(&iodata->data, iodata->data.here, ptr, size);
}
static int SDLCALL dynamic_mem_close(void *userdata)
{
const IOStreamDynamicMemData *iodata = (IOStreamDynamicMemData *) userdata;
void *mem = SDL_GetProperty(SDL_GetIOProperties(iodata->stream), SDL_PROP_IOSTREAM_DYNAMIC_MEMORY_POINTER, NULL);
if (mem) {
SDL_free(mem);
}
SDL_free(userdata);
return 0;
}
SDL_IOStream *SDL_IOFromDynamicMem(void)
{
IOStreamDynamicMemData *iodata = (IOStreamDynamicMemData *) SDL_malloc(sizeof (*iodata));
if (!iodata) {
return NULL;
}
SDL_IOStreamInterface iface;
SDL_zero(iface);
iface.size = dynamic_mem_size;
iface.seek = dynamic_mem_seek;
iface.read = dynamic_mem_read;
iface.write = dynamic_mem_write;
iface.close = dynamic_mem_close;
iodata->data.base = NULL;
iodata->data.here = NULL;
iodata->data.stop = NULL;
iodata->end = NULL;
SDL_IOStream *iostr = SDL_OpenIO(&iface, iodata);
if (iostr) {
iodata->stream = iostr;
} else {
SDL_free(iodata);
}
return iostr;
}
SDL_IOStatus SDL_GetIOStatus(SDL_IOStream *context)
{
if (!context) {
@ -740,7 +844,6 @@ SDL_IOStatus SDL_GetIOStatus(SDL_IOStream *context)
return context->status;
}
SDL_IOStream *SDL_OpenIO(const SDL_IOStreamInterface *iface, void *userdata)
{
if (!iface) {