diff --git a/Include/internal/pycore_bytesobject.h b/Include/internal/pycore_bytesobject.h index 99dd6bf1b912dd..6c6e2ed21e3761 100644 --- a/Include/internal/pycore_bytesobject.h +++ b/Include/internal/pycore_bytesobject.h @@ -60,93 +60,7 @@ PyAPI_FUNC(void) _PyBytes_Repeat(char* dest, Py_ssize_t len_dest, const char* src, Py_ssize_t len_src); -/* --- _PyBytesWriter ----------------------------------------------------- */ - -/* The _PyBytesWriter structure is big: it contains an embedded "stack buffer". - A _PyBytesWriter variable must be declared at the end of variables in a - function to optimize the memory allocation on the stack. */ -typedef struct { - /* bytes, bytearray or NULL (when the small buffer is used) */ - PyObject *buffer; - - /* Number of allocated size. */ - Py_ssize_t allocated; - - /* Minimum number of allocated bytes, - incremented by _PyBytesWriter_Prepare() */ - Py_ssize_t min_size; - - /* If non-zero, use a bytearray instead of a bytes object for buffer. */ - int use_bytearray; - - /* If non-zero, overallocate the buffer (default: 0). - This flag must be zero if use_bytearray is non-zero. */ - int overallocate; - - /* Stack buffer */ - int use_small_buffer; - char small_buffer[512]; -} _PyBytesWriter; - -/* Initialize a bytes writer - - By default, the overallocation is disabled. Set the overallocate attribute - to control the allocation of the buffer. - - Export _PyBytesWriter API for '_pickle' shared extension. */ -PyAPI_FUNC(void) _PyBytesWriter_Init(_PyBytesWriter *writer); - -/* Get the buffer content and reset the writer. - Return a bytes object, or a bytearray object if use_bytearray is non-zero. - Raise an exception and return NULL on error. */ -PyAPI_FUNC(PyObject *) _PyBytesWriter_Finish(_PyBytesWriter *writer, - void *str); - -/* Deallocate memory of a writer (clear its internal buffer). */ -PyAPI_FUNC(void) _PyBytesWriter_Dealloc(_PyBytesWriter *writer); - -/* Allocate the buffer to write size bytes. - Return the pointer to the beginning of buffer data. - Raise an exception and return NULL on error. */ -PyAPI_FUNC(void*) _PyBytesWriter_Alloc(_PyBytesWriter *writer, - Py_ssize_t size); - -/* Ensure that the buffer is large enough to write *size* bytes. - Add size to the writer minimum size (min_size attribute). - - str is the current pointer inside the buffer. - Return the updated current pointer inside the buffer. - Raise an exception and return NULL on error. */ -PyAPI_FUNC(void*) _PyBytesWriter_Prepare(_PyBytesWriter *writer, - void *str, - Py_ssize_t size); - -/* Resize the buffer to make it larger. - The new buffer may be larger than size bytes because of overallocation. - Return the updated current pointer inside the buffer. - Raise an exception and return NULL on error. - - Note: size must be greater than the number of allocated bytes in the writer. - - This function doesn't use the writer minimum size (min_size attribute). - - See also _PyBytesWriter_Prepare(). - */ -PyAPI_FUNC(void*) _PyBytesWriter_Resize(_PyBytesWriter *writer, - void *str, - Py_ssize_t size); - -/* Write bytes. - Raise an exception and return NULL on error. */ -PyAPI_FUNC(void*) _PyBytesWriter_WriteBytes(_PyBytesWriter *writer, - void *str, - const void *bytes, - Py_ssize_t size); - -// Export for '_testcapi' shared extension. -PyAPI_FUNC(PyBytesWriter*) _PyBytesWriter_CreateByteArray( - Py_ssize_t size); - +/* --- PyBytesWriter ------------------------------------------------------ */ struct PyBytesWriter { char small_buffer[256]; @@ -156,6 +70,9 @@ struct PyBytesWriter { int overallocate; }; +// Export for '_testcapi' shared extension +PyAPI_FUNC(PyBytesWriter*) _PyBytesWriter_CreateByteArray(Py_ssize_t size); + #ifdef __cplusplus } #endif diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c index 07237ceaa647e6..91d20cb9afa7ba 100644 --- a/Objects/bytesobject.c +++ b/Objects/bytesobject.c @@ -34,8 +34,6 @@ class bytes "PyBytesObject *" "&PyBytes_Type" #define PyBytesObject_SIZE (offsetof(PyBytesObject, ob_sval) + 1) /* Forward declaration */ -Py_LOCAL_INLINE(Py_ssize_t) _PyBytesWriter_GetSize(_PyBytesWriter *writer, - char *str); static void* _PyBytesWriter_ResizeAndUpdatePointer(PyBytesWriter *writer, Py_ssize_t size, void *data); static Py_ssize_t _PyBytesWriter_GetAllocated(PyBytesWriter *writer); @@ -3453,288 +3451,6 @@ bytes_iter(PyObject *seq) } -/* _PyBytesWriter API */ - -#ifdef MS_WINDOWS - /* On Windows, overallocate by 50% is the best factor */ -# define OVERALLOCATE_FACTOR 2 -#else - /* On Linux, overallocate by 25% is the best factor */ -# define OVERALLOCATE_FACTOR 4 -#endif - -void -_PyBytesWriter_Init(_PyBytesWriter *writer) -{ - /* Set all attributes before small_buffer to 0 */ - memset(writer, 0, offsetof(_PyBytesWriter, small_buffer)); -#ifndef NDEBUG - memset(writer->small_buffer, PYMEM_CLEANBYTE, - sizeof(writer->small_buffer)); -#endif -} - -void -_PyBytesWriter_Dealloc(_PyBytesWriter *writer) -{ - Py_CLEAR(writer->buffer); -} - -Py_LOCAL_INLINE(char*) -_PyBytesWriter_AsString(_PyBytesWriter *writer) -{ - if (writer->use_small_buffer) { - assert(writer->buffer == NULL); - return writer->small_buffer; - } - else if (writer->use_bytearray) { - assert(writer->buffer != NULL); - return PyByteArray_AS_STRING(writer->buffer); - } - else { - assert(writer->buffer != NULL); - return PyBytes_AS_STRING(writer->buffer); - } -} - -Py_LOCAL_INLINE(Py_ssize_t) -_PyBytesWriter_GetSize(_PyBytesWriter *writer, char *str) -{ - const char *start = _PyBytesWriter_AsString(writer); - assert(str != NULL); - assert(str >= start); - assert(str - start <= writer->allocated); - return str - start; -} - -#ifndef NDEBUG -Py_LOCAL_INLINE(int) -_PyBytesWriter_CheckConsistency(_PyBytesWriter *writer, char *str) -{ - const char *start, *end; - - if (writer->use_small_buffer) { - assert(writer->buffer == NULL); - } - else { - assert(writer->buffer != NULL); - if (writer->use_bytearray) - assert(PyByteArray_CheckExact(writer->buffer)); - else - assert(PyBytes_CheckExact(writer->buffer)); - assert(Py_REFCNT(writer->buffer) == 1); - } - - if (writer->use_bytearray) { - /* bytearray has its own overallocation algorithm, - writer overallocation must be disabled */ - assert(!writer->overallocate); - } - - assert(0 <= writer->allocated); - assert(0 <= writer->min_size && writer->min_size <= writer->allocated); - /* the last byte must always be null */ - start = _PyBytesWriter_AsString(writer); - assert(start[writer->allocated] == 0); - - end = start + writer->allocated; - assert(str != NULL); - assert(start <= str && str <= end); - return 1; -} -#endif - -void* -_PyBytesWriter_Resize(_PyBytesWriter *writer, void *str, Py_ssize_t size) -{ - Py_ssize_t allocated, pos; - - assert(_PyBytesWriter_CheckConsistency(writer, str)); - assert(writer->allocated < size); - - allocated = size; - if (writer->overallocate - && allocated <= (PY_SSIZE_T_MAX - allocated / OVERALLOCATE_FACTOR)) { - /* overallocate to limit the number of realloc() */ - allocated += allocated / OVERALLOCATE_FACTOR; - } - - pos = _PyBytesWriter_GetSize(writer, str); - if (!writer->use_small_buffer) { - if (writer->use_bytearray) { - if (PyByteArray_Resize(writer->buffer, allocated)) - goto error; - /* writer->allocated can be smaller than writer->buffer->ob_alloc, - but we cannot use ob_alloc because bytes may need to be moved - to use the whole buffer. bytearray uses an internal optimization - to avoid moving or copying bytes when bytes are removed at the - beginning (ex: del bytearray[:1]). */ - } - else { - if (_PyBytes_Resize(&writer->buffer, allocated)) - goto error; - } - } - else { - /* convert from stack buffer to bytes object buffer */ - assert(writer->buffer == NULL); - - if (writer->use_bytearray) - writer->buffer = PyByteArray_FromStringAndSize(NULL, allocated); - else - writer->buffer = PyBytes_FromStringAndSize(NULL, allocated); - if (writer->buffer == NULL) - goto error; - - if (pos != 0) { - char *dest; - if (writer->use_bytearray) - dest = PyByteArray_AS_STRING(writer->buffer); - else - dest = PyBytes_AS_STRING(writer->buffer); - memcpy(dest, - writer->small_buffer, - pos); - } - - writer->use_small_buffer = 0; -#ifndef NDEBUG - memset(writer->small_buffer, PYMEM_CLEANBYTE, - sizeof(writer->small_buffer)); -#endif - } - writer->allocated = allocated; - - str = _PyBytesWriter_AsString(writer) + pos; - assert(_PyBytesWriter_CheckConsistency(writer, str)); - return str; - -error: - _PyBytesWriter_Dealloc(writer); - return NULL; -} - -void* -_PyBytesWriter_Prepare(_PyBytesWriter *writer, void *str, Py_ssize_t size) -{ - Py_ssize_t new_min_size; - - assert(_PyBytesWriter_CheckConsistency(writer, str)); - assert(size >= 0); - - if (size == 0) { - /* nothing to do */ - return str; - } - - if (writer->min_size > PY_SSIZE_T_MAX - size) { - PyErr_NoMemory(); - _PyBytesWriter_Dealloc(writer); - return NULL; - } - new_min_size = writer->min_size + size; - - if (new_min_size > writer->allocated) - str = _PyBytesWriter_Resize(writer, str, new_min_size); - - writer->min_size = new_min_size; - return str; -} - -/* Allocate the buffer to write size bytes. - Return the pointer to the beginning of buffer data. - Raise an exception and return NULL on error. */ -void* -_PyBytesWriter_Alloc(_PyBytesWriter *writer, Py_ssize_t size) -{ - /* ensure that _PyBytesWriter_Alloc() is only called once */ - assert(writer->min_size == 0 && writer->buffer == NULL); - assert(size >= 0); - - writer->use_small_buffer = 1; -#ifndef NDEBUG - writer->allocated = sizeof(writer->small_buffer) - 1; - /* In debug mode, don't use the full small buffer because it is less - efficient than bytes and bytearray objects to detect buffer underflow - and buffer overflow. Use 10 bytes of the small buffer to test also - code using the smaller buffer in debug mode. - - Don't modify the _PyBytesWriter structure (use a shorter small buffer) - in debug mode to also be able to detect stack overflow when running - tests in debug mode. The _PyBytesWriter is large (more than 512 bytes), - if _Py_EnterRecursiveCall() is not used in deep C callback, we may hit a - stack overflow. */ - writer->allocated = Py_MIN(writer->allocated, 10); - /* _PyBytesWriter_CheckConsistency() requires the last byte to be 0, - to detect buffer overflow */ - writer->small_buffer[writer->allocated] = 0; -#else - writer->allocated = sizeof(writer->small_buffer); -#endif - return _PyBytesWriter_Prepare(writer, writer->small_buffer, size); -} - -PyObject * -_PyBytesWriter_Finish(_PyBytesWriter *writer, void *str) -{ - Py_ssize_t size; - PyObject *result; - - assert(_PyBytesWriter_CheckConsistency(writer, str)); - - size = _PyBytesWriter_GetSize(writer, str); - if (size == 0 && !writer->use_bytearray) { - Py_CLEAR(writer->buffer); - /* Get the empty byte string singleton */ - result = Py_GetConstant(Py_CONSTANT_EMPTY_BYTES); - } - else if (writer->use_small_buffer) { - if (writer->use_bytearray) { - result = PyByteArray_FromStringAndSize(writer->small_buffer, size); - } - else { - result = PyBytes_FromStringAndSize(writer->small_buffer, size); - } - } - else { - result = writer->buffer; - writer->buffer = NULL; - - if (size != writer->allocated) { - if (writer->use_bytearray) { - if (PyByteArray_Resize(result, size)) { - Py_DECREF(result); - return NULL; - } - } - else { - if (_PyBytes_Resize(&result, size)) { - assert(result == NULL); - return NULL; - } - } - } - } - return result; -} - -void* -_PyBytesWriter_WriteBytes(_PyBytesWriter *writer, void *ptr, - const void *bytes, Py_ssize_t size) -{ - char *str = (char *)ptr; - - str = _PyBytesWriter_Prepare(writer, str, size); - if (str == NULL) - return NULL; - - memcpy(str, bytes, size); - str += size; - - return str; -} - - void _PyBytes_Repeat(char* dest, Py_ssize_t len_dest, const char* src, Py_ssize_t len_src) @@ -3799,7 +3515,6 @@ byteswriter_allocated(PyBytesWriter *writer) # define OVERALLOCATE_FACTOR 4 #endif - static inline int byteswriter_resize(PyBytesWriter *writer, Py_ssize_t size, int resize) {