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rwops: Make read and write work like POSIX, not stdio.

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This simplifies some things, clarifies some things, and also allows
for the possibility of RWops that offer non-blocking i/o (although
none of the current built-in ones do, intentionally, we could add this
later if we choose, or people could provide things like network socket
RWops implementations now, etc.

Fixes #6729.
This commit is contained in:
Ryan C. Gordon
2022-12-14 15:42:54 -05:00
parent e9a9afaded
commit 72c1f73bc5
14 changed files with 196 additions and 197 deletions
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164
src/file/SDL_rwops.c
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@@ -182,20 +182,21 @@ static Sint64 SDLCALL windows_file_seek(SDL_RWops *context, Sint64 offset, int w
return windowsoffset.QuadPart;
}
static size_t SDLCALL
windows_file_read(SDL_RWops *context, void *ptr, size_t size, size_t maxnum)
static Sint64 SDLCALL
windows_file_read(SDL_RWops *context, void *ptr, Sint64 size)
{
size_t total_need;
const size_t total_need = (size_t) size;
size_t total_read = 0;
size_t read_ahead;
DWORD byte_read;
total_need = size * maxnum;
if (context == NULL || context->hidden.windowsio.h == INVALID_HANDLE_VALUE || !total_need) {
if (context == NULL || context->hidden.windowsio.h == INVALID_HANDLE_VALUE) {
return SDL_SetError("Invalid file handle");
} else if (!total_need) {
return 0;
}
if (context->hidden.windowsio.buffer.left > 0) {
void *data = (char *)context->hidden.windowsio.buffer.data +
context->hidden.windowsio.buffer.size -
@@ -206,7 +207,7 @@ windows_file_read(SDL_RWops *context, void *ptr, size_t size, size_t maxnum)
context->hidden.windowsio.buffer.left -= read_ahead;
if (read_ahead == total_need) {
return maxnum;
return size;
}
ptr = (char *)ptr + read_ahead;
total_need -= read_ahead;
@@ -216,8 +217,7 @@ windows_file_read(SDL_RWops *context, void *ptr, size_t size, size_t maxnum)
if (total_need < READAHEAD_BUFFER_SIZE) {
if (!ReadFile(context->hidden.windowsio.h, context->hidden.windowsio.buffer.data,
READAHEAD_BUFFER_SIZE, &byte_read, NULL)) {
SDL_Error(SDL_EFREAD);
return 0;
return SDL_Error(SDL_EFREAD);
}
read_ahead = SDL_min(total_need, (int)byte_read);
SDL_memcpy(ptr, context->hidden.windowsio.buffer.data, read_ahead);
@@ -226,26 +226,23 @@ windows_file_read(SDL_RWops *context, void *ptr, size_t size, size_t maxnum)
total_read += read_ahead;
} else {
if (!ReadFile(context->hidden.windowsio.h, ptr, (DWORD)total_need, &byte_read, NULL)) {
SDL_Error(SDL_EFREAD);
return 0;
return SDL_Error(SDL_EFREAD);
}
total_read += byte_read;
}
return total_read / size;
return total_read;
}
static size_t SDLCALL
windows_file_write(SDL_RWops *context, const void *ptr, size_t size,
size_t num)
static Sint64 SDLCALL
windows_file_write(SDL_RWops *context, const void *ptr, Sint64 size)
{
size_t total_bytes;
const size_t total_bytes = (size_t) size;
DWORD byte_written;
size_t nwritten;
total_bytes = size * num;
if (context == NULL || context->hidden.windowsio.h == INVALID_HANDLE_VALUE || !size || !total_bytes) {
if (context == NULL || context->hidden.windowsio.h == INVALID_HANDLE_VALUE) {
return SDL_SetError("Invalid file handle");
} else if (!total_bytes) {
return 0;
}
@@ -260,23 +257,19 @@ windows_file_write(SDL_RWops *context, const void *ptr, size_t size,
if (context->hidden.windowsio.append) {
if (SetFilePointer(context->hidden.windowsio.h, 0L, NULL, FILE_END) ==
INVALID_SET_FILE_POINTER) {
SDL_Error(SDL_EFWRITE);
return 0;
return SDL_Error(SDL_EFWRITE);
}
}
if (!WriteFile(context->hidden.windowsio.h, ptr, (DWORD)total_bytes, &byte_written, NULL)) {
SDL_Error(SDL_EFWRITE);
return 0;
return SDL_Error(SDL_EFWRITE);
}
nwritten = byte_written / size;
return nwritten;
return (Sint64) byte_written;
}
static int SDLCALL windows_file_close(SDL_RWops *context)
{
if (context) {
if (context->hidden.windowsio.h != INVALID_HANDLE_VALUE) {
CloseHandle(context->hidden.windowsio.h);
@@ -378,28 +371,28 @@ static Sint64 SDLCALL stdio_seek(SDL_RWops *context, Sint64 offset, int whence)
return SDL_Error(SDL_EFSEEK);
}
static size_t SDLCALL
stdio_read(SDL_RWops *context, void *ptr, size_t size, size_t maxnum)
static Sint64 SDLCALL
stdio_read(SDL_RWops *context, void *ptr, Sint64 size)
{
size_t nread;
nread = fread(ptr, size, maxnum, (FILE *)context->hidden.stdio.fp);
nread = fread(ptr, 1, size, (FILE *)context->hidden.stdio.fp);
if (nread == 0 && ferror((FILE *)context->hidden.stdio.fp)) {
SDL_Error(SDL_EFREAD);
return SDL_Error(SDL_EFREAD);
}
return nread;
return (Sint64) nread;
}
static size_t SDLCALL
stdio_write(SDL_RWops *context, const void *ptr, size_t size, size_t num)
static Sint64 SDLCALL
stdio_write(SDL_RWops *context, const void *ptr, Sint64 size)
{
size_t nwrote;
nwrote = fwrite(ptr, size, num, (FILE *)context->hidden.stdio.fp);
nwrote = fwrite(ptr, 1, size, (FILE *)context->hidden.stdio.fp);
if (nwrote == 0 && ferror((FILE *)context->hidden.stdio.fp)) {
SDL_Error(SDL_EFWRITE);
return SDL_Error(SDL_EFWRITE);
}
return nwrote;
return (Sint64) nwrote;
}
static int SDLCALL stdio_close(SDL_RWops *context)
@@ -469,44 +462,33 @@ static Sint64 SDLCALL mem_seek(SDL_RWops *context, Sint64 offset, int whence)
return (Sint64)(context->hidden.mem.here - context->hidden.mem.base);
}
static size_t SDLCALL
mem_read(SDL_RWops *context, void *ptr, size_t size, size_t maxnum)
static Sint64 mem_io(SDL_RWops *context, void *dst, const void *src, Sint64 size)
{
size_t total_bytes;
size_t mem_available;
total_bytes = (maxnum * size);
if (!maxnum || !size || ((total_bytes / maxnum) != size)) {
return 0;
const Sint64 mem_available = (Sint64) (context->hidden.mem.stop - context->hidden.mem.here);
if (size > mem_available) {
size = mem_available;
}
mem_available = (context->hidden.mem.stop - context->hidden.mem.here);
if (total_bytes > mem_available) {
total_bytes = mem_available;
}
SDL_memcpy(ptr, context->hidden.mem.here, total_bytes);
context->hidden.mem.here += total_bytes;
return total_bytes / size;
SDL_memcpy(dst, src, (size_t) size);
context->hidden.mem.here += size;
return size;
}
static size_t SDLCALL
mem_write(SDL_RWops *context, const void *ptr, size_t size, size_t num)
static Sint64 SDLCALL
mem_read(SDL_RWops *context, void *ptr, Sint64 size)
{
if ((context->hidden.mem.here + (num * size)) > context->hidden.mem.stop) {
num = (context->hidden.mem.stop - context->hidden.mem.here) / size;
}
SDL_memcpy(context->hidden.mem.here, ptr, num * size);
context->hidden.mem.here += num * size;
return num;
return mem_io(context, ptr, context->hidden.mem.here, size);
}
static size_t SDLCALL
mem_writeconst(SDL_RWops *context, const void *ptr, size_t size, size_t num)
static Sint64 SDLCALL
mem_write(SDL_RWops *context, const void *ptr, Sint64 size)
{
SDL_SetError("Can't write to read-only memory");
return 0;
return mem_io(context, context->hidden.mem.here, ptr, size);
}
static Sint64 SDLCALL
mem_writeconst(SDL_RWops *context, const void *ptr, Sint64 size)
{
return SDL_SetError("Can't write to read-only memory");
}
static int SDLCALL mem_close(SDL_RWops *context)
@@ -693,7 +675,7 @@ SDL_LoadFile_RW(SDL_RWops *src, size_t *datasize, int freesrc)
{
static const Sint64 FILE_CHUNK_SIZE = 1024;
Sint64 size;
size_t size_read, size_total;
Sint64 size_read, size_total;
void *data = NULL, *newdata;
if (src == NULL) {
@@ -709,7 +691,7 @@ SDL_LoadFile_RW(SDL_RWops *src, size_t *datasize, int freesrc)
size_total = 0;
for (;;) {
if ((((Sint64)size_total) + FILE_CHUNK_SIZE) > size) {
if ((size_total + FILE_CHUNK_SIZE) > size) {
size = (size_total + FILE_CHUNK_SIZE);
newdata = SDL_realloc(data, (size_t)(size + 1));
if (newdata == NULL) {
@@ -721,7 +703,7 @@ SDL_LoadFile_RW(SDL_RWops *src, size_t *datasize, int freesrc)
data = newdata;
}
size_read = SDL_RWread(src, (char *)data + size_total, 1, (size_t)(size - size_total));
size_read = SDL_RWread(src, (char *)data + size_total, size - size_total);
if (size_read == 0) {
break;
}
@@ -729,7 +711,7 @@ SDL_LoadFile_RW(SDL_RWops *src, size_t *datasize, int freesrc)
}
if (datasize) {
*datasize = size_total;
*datasize = (size_t) size_total;
}
((char *)data)[size_total] = '\0';
@@ -764,16 +746,16 @@ SDL_RWtell(SDL_RWops *context)
return context->seek(context, 0, RW_SEEK_CUR);
}
size_t
SDL_RWread(SDL_RWops *context, void *ptr, size_t size, size_t maxnum)
Sint64
SDL_RWread(SDL_RWops *context, void *ptr, Sint64 size)
{
return context->read(context, ptr, size, maxnum);
return context->read(context, ptr, size);
}
size_t
SDL_RWwrite(SDL_RWops *context, const void *ptr, size_t size, size_t num)
Sint64
SDL_RWwrite(SDL_RWops *context, const void *ptr, Sint64 size)
{
return context->write(context, ptr, size, num);
return context->write(context, ptr, size);
}
int SDL_RWclose(SDL_RWops *context)
@@ -787,7 +769,7 @@ Uint8 SDL_ReadU8(SDL_RWops *src)
{
Uint8 value = 0;
SDL_RWread(src, &value, sizeof(value), 1);
SDL_RWread(src, &value, sizeof(value));
return value;
}
@@ -796,7 +778,7 @@ SDL_ReadLE16(SDL_RWops *src)
{
Uint16 value = 0;
SDL_RWread(src, &value, sizeof(value), 1);
SDL_RWread(src, &value, sizeof(value));
return SDL_SwapLE16(value);
}
@@ -805,7 +787,7 @@ SDL_ReadBE16(SDL_RWops *src)
{
Uint16 value = 0;
SDL_RWread(src, &value, sizeof(value), 1);
SDL_RWread(src, &value, sizeof(value));
return SDL_SwapBE16(value);
}
@@ -814,7 +796,7 @@ SDL_ReadLE32(SDL_RWops *src)
{
Uint32 value = 0;
SDL_RWread(src, &value, sizeof(value), 1);
SDL_RWread(src, &value, sizeof(value));
return SDL_SwapLE32(value);
}
@@ -823,7 +805,7 @@ SDL_ReadBE32(SDL_RWops *src)
{
Uint32 value = 0;
SDL_RWread(src, &value, sizeof(value), 1);
SDL_RWread(src, &value, sizeof(value));
return SDL_SwapBE32(value);
}
@@ -832,7 +814,7 @@ SDL_ReadLE64(SDL_RWops *src)
{
Uint64 value = 0;
SDL_RWread(src, &value, sizeof(value), 1);
SDL_RWread(src, &value, sizeof(value));
return SDL_SwapLE64(value);
}
@@ -841,56 +823,56 @@ SDL_ReadBE64(SDL_RWops *src)
{
Uint64 value = 0;
SDL_RWread(src, &value, sizeof(value), 1);
SDL_RWread(src, &value, sizeof(value));
return SDL_SwapBE64(value);
}
size_t
SDL_WriteU8(SDL_RWops *dst, Uint8 value)
{
return SDL_RWwrite(dst, &value, sizeof(value), 1);
return (SDL_RWwrite(dst, &value, sizeof(value)) == sizeof(value)) ? 1 : 0;
}
size_t
SDL_WriteLE16(SDL_RWops *dst, Uint16 value)
{
const Uint16 swapped = SDL_SwapLE16(value);
return SDL_RWwrite(dst, &swapped, sizeof(swapped), 1);
return (SDL_RWwrite(dst, &swapped, sizeof(swapped)) == sizeof(swapped)) ? 1 : 0;
}
size_t
SDL_WriteBE16(SDL_RWops *dst, Uint16 value)
{
const Uint16 swapped = SDL_SwapBE16(value);
return SDL_RWwrite(dst, &swapped, sizeof(swapped), 1);
return (SDL_RWwrite(dst, &swapped, sizeof(swapped)) == sizeof(swapped)) ? 1 : 0;
}
size_t
SDL_WriteLE32(SDL_RWops *dst, Uint32 value)
{
const Uint32 swapped = SDL_SwapLE32(value);
return SDL_RWwrite(dst, &swapped, sizeof(swapped), 1);
return (SDL_RWwrite(dst, &swapped, sizeof(swapped)) == sizeof(swapped)) ? 1 : 0;
}
size_t
SDL_WriteBE32(SDL_RWops *dst, Uint32 value)
{
const Uint32 swapped = SDL_SwapBE32(value);
return SDL_RWwrite(dst, &swapped, sizeof(swapped), 1);
return (SDL_RWwrite(dst, &swapped, sizeof(swapped)) == sizeof(swapped)) ? 1 : 0;
}
size_t
SDL_WriteLE64(SDL_RWops *dst, Uint64 value)
{
const Uint64 swapped = SDL_SwapLE64(value);
return SDL_RWwrite(dst, &swapped, sizeof(swapped), 1);
return (SDL_RWwrite(dst, &swapped, sizeof(swapped)) == sizeof(swapped)) ? 1 : 0;
}
size_t
SDL_WriteBE64(SDL_RWops *dst, Uint64 value)
{
const Uint64 swapped = SDL_SwapBE64(value);
return SDL_RWwrite(dst, &swapped, sizeof(swapped), 1);
return (SDL_RWwrite(dst, &swapped, sizeof(swapped)) == sizeof(swapped)) ? 1 : 0;
}
/* vi: set ts=4 sw=4 expandtab: */