fixes in streams

ostd/ext/sdl_rwops.hh

@@ -12,19 +12,18 @@
 #include <SDL2/SDL.h>
 #endif
 
-#include "ostd/types.hh"
 #include "ostd/stream.hh"
 
 namespace ostd {
 namespace sdl {
 
 #ifdef OSTD_EXT_SDL_USE_SDL1
-using SDLRWopsOffset = int;
+using sdl_rwops_off_t = int;
 #else
-using SDLRWopsOffset = int64_t;
+using sdl_rwops_off_t = int64_t;
 #endif
 
-inline SDL_RWops *stream_to_rwops(Stream &s) {
+inline SDL_RWops *stream_to_rwops(stream &s) {
     SDL_RWops *rwr = SDL_AllocRW();
     if (!rwr) {
         return nullptr;
@@ -32,32 +31,52 @@ inline SDL_RWops *stream_to_rwops(Stream &s) {
 
     rwr->hidden.unknown.data1 = &s;
 
-    rwr->size = [](SDL_RWops *rw) -> SDLRWopsOffset {
-        Stream *is = static_cast<Stream *>(rw->hidden.unknown.data1);
-        return static_cast<SDLRWopsOffset>(is->size());
+    rwr->size = [](SDL_RWops *rw) -> sdl_rwops_off_t {
+        auto &is = *static_cast<stream *>(rw->hidden.unknown.data1);
+        try {
+            return static_cast<sdl_rwops_off_t>(is.size());
+        } catch (stream_error const &) {
+            return -1;
+        }
     };
 
-    rwr->seek = [](SDL_RWops *rw, SDLRWopsOffset pos, int whence) ->
-        SDLRWopsOffset
+    rwr->seek = [](SDL_RWops *rw, sdl_rwops_off_t pos, int whence) ->
+        sdl_rwops_off_t
     {
-        Stream *is = static_cast<Stream *>(rw->hidden.unknown.data1);
-        if (!pos && whence == SEEK_CUR) {
-            return static_cast<SDLRWopsOffset>(is->tell());
-        }
-        if (is->seek(((StreamOffset)pos, (StreamSeek)whence)) {
-            return static_cast<SDLRWopsOffset>(is->tell());
+        auto &is = *static_cast<stream *>(rw->hidden.unknown.data1);
+        try {
+            if (!pos && whence == SEEK_CUR) {
+                return static_cast<sdl_rwops_off_t(is.tell());
+            }
+            if (is->seek((stream_off_t(pos), stream_seek(whence)))) {
+                return static_cast<sdl_rwops_off_t>(is.tell());
+            }
+        } catch (stream_error const &) {
+            return -1;
         }
         return -1;
     };
 
-    rwr->read = [](SDL_RWops *rw, void *buf, size_t size, size_t nb) -> size_t {
-        Stream *is = static_cast<Stream *>(rw->hidden.unknown.data1);
-        return is->read_bytes(buf, size * nb) / size;
+    rwr->read = [](SDL_RWops *rw, void *buf, size_t size, size_t nb) ->
+        size_t
+    {
+        auto &is = *static_cast<stream *>(rw->hidden.unknown.data1);
+        try {
+            return is.read_bytes(buf, size * nb) / size;
+        } catch (stream_error const &) {
+            return 0;
+        }
     };
 
-    rwr->write = [](SDL_RWops *rw, const void *buf, size_t size, size_t nb) -> size_t {
-        Stream *is = static_cast<Stream *>(rw->hidden.unknown.data1);
-        return is->write_bytes(buf, size * nb) / size;
+    rwr->write = [](SDL_RWops *rw, void const *buf, size_t size, size_t nb) ->
+        size_t
+    {
+        stream &is = *static_cast<stream *>(rw->hidden.unknown.data1);
+        try {
+            return is->write_bytes(buf, size * nb) / size;
+        } catch (stream_error const &) {
+            return 0;
+        }
     };
 
     rwr->close = [](SDL_RWops *) -> int {

ostd/io.hh

@@ -61,7 +61,7 @@ struct OSTD_EXPORT file_stream: stream {
 
     void flush();
 
-    void read_bytes(void *buf, size_t count);
+    size_t read_bytes(void *buf, size_t count);
     void write_bytes(void const *buf, size_t count);
 
     int get_char();

ostd/stream.hh

@@ -6,6 +6,7 @@
 #ifndef OSTD_STREAM_HH
 #define OSTD_STREAM_HH
 
+#include <cerrno>
 #include <cstdlib>
 #include <type_traits>
 #include <locale>
@@ -66,18 +67,30 @@ struct stream {
         return e;
     }
 
-    virtual void seek(offset_type, stream_seek = stream_seek::SET) {}
+    virtual void seek(offset_type, stream_seek = stream_seek::SET) {
+        throw stream_error{EINVAL, std::generic_category()};
+    }
 
-    virtual offset_type tell() const { return -1; }
+    virtual offset_type tell() const {
+        throw stream_error{EINVAL, std::generic_category()};
+    }
 
-    virtual void flush() {}
+    virtual void flush() {
+        throw stream_error{EINVAL, std::generic_category()};
+    }
 
-    virtual void read_bytes(void *, size_t) {}
-    virtual void write_bytes(void const *, size_t) {}
+    virtual size_t read_bytes(void *, size_t) {
+        throw stream_error{EINVAL, std::generic_category()};
+    }
+    virtual void write_bytes(void const *, size_t) {
+        throw stream_error{EINVAL, std::generic_category()};
+    }
 
     virtual int get_char() {
         unsigned char c;
-        read_bytes(&c, 1);
+        if (!read_bytes(&c, 1)) {
+            throw stream_error{EIO, std::generic_category()};
+        }
         return c;
     }
 
@@ -150,13 +163,16 @@ struct stream {
     }
 
     template<typename T>
-    void get(T *v, size_t count) {
-        read_bytes(v, count * sizeof(T));
+    size_t get(T *v, size_t count) {
+        /* if eof was reached, at least return how many values succeeded */
+        return read_bytes(v, count * sizeof(T)) / sizeof(T);
     }
 
     template<typename T>
     void get(T &v) {
-        read_bytes(&v, sizeof(T));
+        if (read_bytes(&v, sizeof(T)) != sizeof(T)) {
+            throw stream_error{EIO, std::generic_category()};
+        }
     }
 
     template<typename T>

src/io.cc

@@ -84,10 +84,15 @@ void file_stream::flush() {
     }
 }
 
-void file_stream::read_bytes(void *buf, size_t count) {
-    if (std::fread(buf, 1, count, p_f) != count) {
+size_t file_stream::read_bytes(void *buf, size_t count) {
+    size_t readn = std::fread(buf, 1, count, p_f);
+    if (readn != count) {
+        if (std::feof(p_f) != 0) {
+            return readn;
+        }
         throw stream_error{EIO, std::generic_category()};
     }
+    return readn;
 }
 
 void file_stream::write_bytes(void const *buf, size_t count) {