mirror of https://github.com/python/cpython.git
544 lines
11 KiB
C
544 lines
11 KiB
C
|
|
/* Buffer object implementation */
|
|
|
|
#include "Python.h"
|
|
|
|
|
|
typedef struct {
|
|
PyObject_HEAD
|
|
PyObject *b_base;
|
|
void *b_ptr;
|
|
int b_size;
|
|
int b_readonly;
|
|
long b_hash;
|
|
} PyBufferObject;
|
|
|
|
|
|
static PyObject *
|
|
_PyBuffer_FromMemory(PyObject *base, void *ptr, int size, int readonly)
|
|
{
|
|
PyBufferObject * b;
|
|
|
|
if ( size < 0 ) {
|
|
PyErr_SetString(PyExc_ValueError,
|
|
"size must be zero or positive");
|
|
return NULL;
|
|
}
|
|
|
|
b = PyObject_NEW(PyBufferObject, &PyBuffer_Type);
|
|
if ( b == NULL )
|
|
return NULL;
|
|
|
|
Py_XINCREF(base);
|
|
b->b_base = base;
|
|
b->b_ptr = ptr;
|
|
b->b_size = size;
|
|
b->b_readonly = readonly;
|
|
b->b_hash = -1;
|
|
|
|
return (PyObject *) b;
|
|
}
|
|
|
|
static PyObject *
|
|
_PyBuffer_FromObject(PyObject *base, int offset, int size,
|
|
getreadbufferproc proc, int readonly)
|
|
{
|
|
PyBufferProcs *pb = base->ob_type->tp_as_buffer;
|
|
void *p;
|
|
int count;
|
|
|
|
if ( offset < 0 ) {
|
|
PyErr_SetString(PyExc_ValueError,
|
|
"offset must be zero or positive");
|
|
return NULL;
|
|
}
|
|
|
|
if ( (*pb->bf_getsegcount)(base, NULL) != 1 )
|
|
{
|
|
PyErr_SetString(PyExc_TypeError,
|
|
"single-segment buffer object expected");
|
|
return NULL;
|
|
}
|
|
if ( (count = (*proc)(base, 0, &p)) < 0 )
|
|
return NULL;
|
|
|
|
/* apply constraints to the start/end */
|
|
if ( size == Py_END_OF_BUFFER || size < 0 )
|
|
size = count;
|
|
if ( offset > count )
|
|
offset = count;
|
|
if ( offset + size > count )
|
|
size = count - offset;
|
|
|
|
/* if the base object is another buffer, then "deref" it,
|
|
* except if the base of the other buffer is NULL
|
|
*/
|
|
if ( PyBuffer_Check(base) && (((PyBufferObject *)base)->b_base) )
|
|
base = ((PyBufferObject *)base)->b_base;
|
|
|
|
return _PyBuffer_FromMemory(base, (char *)p + offset, size, readonly);
|
|
}
|
|
|
|
|
|
PyObject *
|
|
PyBuffer_FromObject(PyObject *base, int offset, int size)
|
|
{
|
|
PyBufferProcs *pb = base->ob_type->tp_as_buffer;
|
|
|
|
if ( pb == NULL ||
|
|
pb->bf_getreadbuffer == NULL ||
|
|
pb->bf_getsegcount == NULL )
|
|
{
|
|
PyErr_SetString(PyExc_TypeError, "buffer object expected");
|
|
return NULL;
|
|
}
|
|
|
|
return _PyBuffer_FromObject(base, offset, size,
|
|
pb->bf_getreadbuffer, 1);
|
|
}
|
|
|
|
PyObject *
|
|
PyBuffer_FromReadWriteObject(PyObject *base, int offset, int size)
|
|
{
|
|
PyBufferProcs *pb = base->ob_type->tp_as_buffer;
|
|
|
|
if ( pb == NULL ||
|
|
pb->bf_getwritebuffer == NULL ||
|
|
pb->bf_getsegcount == NULL )
|
|
{
|
|
PyErr_SetString(PyExc_TypeError, "buffer object expected");
|
|
return NULL;
|
|
}
|
|
|
|
return _PyBuffer_FromObject(base, offset, size,
|
|
(getreadbufferproc)pb->bf_getwritebuffer,
|
|
0);
|
|
}
|
|
|
|
PyObject *
|
|
PyBuffer_FromMemory(void *ptr, int size)
|
|
{
|
|
return _PyBuffer_FromMemory(NULL, ptr, size, 1);
|
|
}
|
|
|
|
PyObject *
|
|
PyBuffer_FromReadWriteMemory(void *ptr, int size)
|
|
{
|
|
return _PyBuffer_FromMemory(NULL, ptr, size, 0);
|
|
}
|
|
|
|
PyObject *
|
|
PyBuffer_New(int size)
|
|
{
|
|
PyObject *o;
|
|
PyBufferObject * b;
|
|
|
|
if (size < 0) {
|
|
PyErr_SetString(PyExc_ValueError,
|
|
"size must be zero or positive");
|
|
return NULL;
|
|
}
|
|
/* PyObject_New is inlined */
|
|
o = PyObject_MALLOC(sizeof(*b) + size);
|
|
if ( o == NULL )
|
|
return PyErr_NoMemory();
|
|
b = (PyBufferObject *) PyObject_INIT(o, &PyBuffer_Type);
|
|
|
|
b->b_base = NULL;
|
|
b->b_ptr = (void *)(b + 1);
|
|
b->b_size = size;
|
|
b->b_readonly = 0;
|
|
b->b_hash = -1;
|
|
|
|
return o;
|
|
}
|
|
|
|
/* Methods */
|
|
|
|
static void
|
|
buffer_dealloc(PyBufferObject *self)
|
|
{
|
|
Py_XDECREF(self->b_base);
|
|
PyObject_DEL(self);
|
|
}
|
|
|
|
static int
|
|
buffer_compare(PyBufferObject *self, PyBufferObject *other)
|
|
{
|
|
int len_self = self->b_size;
|
|
int len_other = other->b_size;
|
|
int min_len = (len_self < len_other) ? len_self : len_other;
|
|
int cmp;
|
|
if (min_len > 0) {
|
|
cmp = memcmp(self->b_ptr, other->b_ptr, min_len);
|
|
if (cmp != 0)
|
|
return cmp;
|
|
}
|
|
return (len_self < len_other) ? -1 : (len_self > len_other) ? 1 : 0;
|
|
}
|
|
|
|
static PyObject *
|
|
buffer_repr(PyBufferObject *self)
|
|
{
|
|
char *status = self->b_readonly ? "read-only" : "read-write";
|
|
|
|
if ( self->b_base == NULL )
|
|
return PyString_FromFormat("<%s buffer ptr %p, size %d at %p>",
|
|
status,
|
|
self->b_ptr,
|
|
self->b_size,
|
|
self);
|
|
else
|
|
return PyString_FromFormat(
|
|
"<%s buffer for %p, ptr %p, size %d at %p>",
|
|
status,
|
|
self->b_base,
|
|
self->b_ptr,
|
|
self->b_size,
|
|
self);
|
|
}
|
|
|
|
static long
|
|
buffer_hash(PyBufferObject *self)
|
|
{
|
|
register int len;
|
|
register unsigned char *p;
|
|
register long x;
|
|
|
|
if ( self->b_hash != -1 )
|
|
return self->b_hash;
|
|
|
|
if ( !self->b_readonly )
|
|
{
|
|
/* ### use different wording, since this is conditional? */
|
|
PyErr_SetString(PyExc_TypeError, "unhashable type");
|
|
return -1;
|
|
}
|
|
|
|
len = self->b_size;
|
|
p = (unsigned char *) self->b_ptr;
|
|
x = *p << 7;
|
|
while (--len >= 0)
|
|
x = (1000003*x) ^ *p++;
|
|
x ^= self->b_size;
|
|
if (x == -1)
|
|
x = -2;
|
|
self->b_hash = x;
|
|
return x;
|
|
}
|
|
|
|
static PyObject *
|
|
buffer_str(PyBufferObject *self)
|
|
{
|
|
return PyString_FromStringAndSize(self->b_ptr, self->b_size);
|
|
}
|
|
|
|
/* Sequence methods */
|
|
|
|
static int
|
|
buffer_length(PyBufferObject *self)
|
|
{
|
|
return self->b_size;
|
|
}
|
|
|
|
static PyObject *
|
|
buffer_concat(PyBufferObject *self, PyObject *other)
|
|
{
|
|
PyBufferProcs *pb = other->ob_type->tp_as_buffer;
|
|
char *p1;
|
|
void *p2;
|
|
PyObject *ob;
|
|
int count;
|
|
|
|
if ( pb == NULL ||
|
|
pb->bf_getreadbuffer == NULL ||
|
|
pb->bf_getsegcount == NULL )
|
|
{
|
|
PyErr_BadArgument();
|
|
return NULL;
|
|
}
|
|
if ( (*pb->bf_getsegcount)(other, NULL) != 1 )
|
|
{
|
|
/* ### use a different exception type/message? */
|
|
PyErr_SetString(PyExc_TypeError,
|
|
"single-segment buffer object expected");
|
|
return NULL;
|
|
}
|
|
|
|
/* optimize special case */
|
|
if ( self->b_size == 0 )
|
|
{
|
|
Py_INCREF(other);
|
|
return other;
|
|
}
|
|
|
|
if ( (count = (*pb->bf_getreadbuffer)(other, 0, &p2)) < 0 )
|
|
return NULL;
|
|
|
|
/* optimize special case */
|
|
if ( count == 0 )
|
|
{
|
|
Py_INCREF(self);
|
|
return (PyObject *)self;
|
|
}
|
|
|
|
ob = PyString_FromStringAndSize(NULL, self->b_size + count);
|
|
p1 = PyString_AS_STRING(ob);
|
|
memcpy(p1, self->b_ptr, self->b_size);
|
|
memcpy(p1 + self->b_size, p2, count);
|
|
|
|
/* there is an extra byte in the string object, so this is safe */
|
|
p1[self->b_size + count] = '\0';
|
|
|
|
return ob;
|
|
}
|
|
|
|
static PyObject *
|
|
buffer_repeat(PyBufferObject *self, int count)
|
|
{
|
|
PyObject *ob;
|
|
register char *p;
|
|
void *ptr = self->b_ptr;
|
|
int size = self->b_size;
|
|
|
|
if ( count < 0 )
|
|
count = 0;
|
|
ob = PyString_FromStringAndSize(NULL, size * count);
|
|
if ( ob == NULL )
|
|
return NULL;
|
|
|
|
p = PyString_AS_STRING(ob);
|
|
while ( count-- )
|
|
{
|
|
memcpy(p, ptr, size);
|
|
p += size;
|
|
}
|
|
|
|
/* there is an extra byte in the string object, so this is safe */
|
|
*p = '\0';
|
|
|
|
return ob;
|
|
}
|
|
|
|
static PyObject *
|
|
buffer_item(PyBufferObject *self, int idx)
|
|
{
|
|
if ( idx < 0 || idx >= self->b_size )
|
|
{
|
|
PyErr_SetString(PyExc_IndexError, "buffer index out of range");
|
|
return NULL;
|
|
}
|
|
return PyString_FromStringAndSize((char *)self->b_ptr + idx, 1);
|
|
}
|
|
|
|
static PyObject *
|
|
buffer_slice(PyBufferObject *self, int left, int right)
|
|
{
|
|
if ( left < 0 )
|
|
left = 0;
|
|
if ( right < 0 )
|
|
right = 0;
|
|
if ( right > self->b_size )
|
|
right = self->b_size;
|
|
if ( left == 0 && right == self->b_size )
|
|
{
|
|
/* same as self */
|
|
Py_INCREF(self);
|
|
return (PyObject *)self;
|
|
}
|
|
if ( right < left )
|
|
right = left;
|
|
return PyString_FromStringAndSize((char *)self->b_ptr + left,
|
|
right - left);
|
|
}
|
|
|
|
static int
|
|
buffer_ass_item(PyBufferObject *self, int idx, PyObject *other)
|
|
{
|
|
PyBufferProcs *pb;
|
|
void *p;
|
|
int count;
|
|
|
|
if ( self->b_readonly ) {
|
|
PyErr_SetString(PyExc_TypeError,
|
|
"buffer is read-only");
|
|
return -1;
|
|
}
|
|
|
|
if (idx < 0 || idx >= self->b_size) {
|
|
PyErr_SetString(PyExc_IndexError,
|
|
"buffer assignment index out of range");
|
|
return -1;
|
|
}
|
|
|
|
pb = other ? other->ob_type->tp_as_buffer : NULL;
|
|
if ( pb == NULL ||
|
|
pb->bf_getreadbuffer == NULL ||
|
|
pb->bf_getsegcount == NULL )
|
|
{
|
|
PyErr_BadArgument();
|
|
return -1;
|
|
}
|
|
if ( (*pb->bf_getsegcount)(other, NULL) != 1 )
|
|
{
|
|
/* ### use a different exception type/message? */
|
|
PyErr_SetString(PyExc_TypeError,
|
|
"single-segment buffer object expected");
|
|
return -1;
|
|
}
|
|
|
|
if ( (count = (*pb->bf_getreadbuffer)(other, 0, &p)) < 0 )
|
|
return -1;
|
|
if ( count != 1 ) {
|
|
PyErr_SetString(PyExc_TypeError,
|
|
"right operand must be a single byte");
|
|
return -1;
|
|
}
|
|
|
|
((char *)self->b_ptr)[idx] = *(char *)p;
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
buffer_ass_slice(PyBufferObject *self, int left, int right, PyObject *other)
|
|
{
|
|
PyBufferProcs *pb;
|
|
void *p;
|
|
int slice_len;
|
|
int count;
|
|
|
|
if ( self->b_readonly ) {
|
|
PyErr_SetString(PyExc_TypeError,
|
|
"buffer is read-only");
|
|
return -1;
|
|
}
|
|
|
|
pb = other ? other->ob_type->tp_as_buffer : NULL;
|
|
if ( pb == NULL ||
|
|
pb->bf_getreadbuffer == NULL ||
|
|
pb->bf_getsegcount == NULL )
|
|
{
|
|
PyErr_BadArgument();
|
|
return -1;
|
|
}
|
|
if ( (*pb->bf_getsegcount)(other, NULL) != 1 )
|
|
{
|
|
/* ### use a different exception type/message? */
|
|
PyErr_SetString(PyExc_TypeError,
|
|
"single-segment buffer object expected");
|
|
return -1;
|
|
}
|
|
if ( (count = (*pb->bf_getreadbuffer)(other, 0, &p)) < 0 )
|
|
return -1;
|
|
|
|
if ( left < 0 )
|
|
left = 0;
|
|
else if ( left > self->b_size )
|
|
left = self->b_size;
|
|
if ( right < left )
|
|
right = left;
|
|
else if ( right > self->b_size )
|
|
right = self->b_size;
|
|
slice_len = right - left;
|
|
|
|
if ( count != slice_len ) {
|
|
PyErr_SetString(
|
|
PyExc_TypeError,
|
|
"right operand length must match slice length");
|
|
return -1;
|
|
}
|
|
|
|
if ( slice_len )
|
|
memcpy((char *)self->b_ptr + left, p, slice_len);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Buffer methods */
|
|
|
|
static int
|
|
buffer_getreadbuf(PyBufferObject *self, int idx, void **pp)
|
|
{
|
|
if ( idx != 0 ) {
|
|
PyErr_SetString(PyExc_SystemError,
|
|
"accessing non-existent buffer segment");
|
|
return -1;
|
|
}
|
|
*pp = self->b_ptr;
|
|
return self->b_size;
|
|
}
|
|
|
|
static int
|
|
buffer_getwritebuf(PyBufferObject *self, int idx, void **pp)
|
|
{
|
|
if ( self->b_readonly )
|
|
{
|
|
PyErr_SetString(PyExc_TypeError, "buffer is read-only");
|
|
return -1;
|
|
}
|
|
return buffer_getreadbuf(self, idx, pp);
|
|
}
|
|
|
|
static int
|
|
buffer_getsegcount(PyBufferObject *self, int *lenp)
|
|
{
|
|
if ( lenp )
|
|
*lenp = self->b_size;
|
|
return 1;
|
|
}
|
|
|
|
static int
|
|
buffer_getcharbuf(PyBufferObject *self, int idx, const char **pp)
|
|
{
|
|
if ( idx != 0 ) {
|
|
PyErr_SetString(PyExc_SystemError,
|
|
"accessing non-existent buffer segment");
|
|
return -1;
|
|
}
|
|
*pp = (const char *)self->b_ptr;
|
|
return self->b_size;
|
|
}
|
|
|
|
|
|
static PySequenceMethods buffer_as_sequence = {
|
|
(inquiry)buffer_length, /*sq_length*/
|
|
(binaryfunc)buffer_concat, /*sq_concat*/
|
|
(intargfunc)buffer_repeat, /*sq_repeat*/
|
|
(intargfunc)buffer_item, /*sq_item*/
|
|
(intintargfunc)buffer_slice, /*sq_slice*/
|
|
(intobjargproc)buffer_ass_item, /*sq_ass_item*/
|
|
(intintobjargproc)buffer_ass_slice, /*sq_ass_slice*/
|
|
};
|
|
|
|
static PyBufferProcs buffer_as_buffer = {
|
|
(getreadbufferproc)buffer_getreadbuf,
|
|
(getwritebufferproc)buffer_getwritebuf,
|
|
(getsegcountproc)buffer_getsegcount,
|
|
(getcharbufferproc)buffer_getcharbuf,
|
|
};
|
|
|
|
PyTypeObject PyBuffer_Type = {
|
|
PyObject_HEAD_INIT(&PyType_Type)
|
|
0,
|
|
"buffer",
|
|
sizeof(PyBufferObject),
|
|
0,
|
|
(destructor)buffer_dealloc, /* tp_dealloc */
|
|
0, /* tp_print */
|
|
0, /* tp_getattr */
|
|
0, /* tp_setattr */
|
|
(cmpfunc)buffer_compare, /* tp_compare */
|
|
(reprfunc)buffer_repr, /* tp_repr */
|
|
0, /* tp_as_number */
|
|
&buffer_as_sequence, /* tp_as_sequence */
|
|
0, /* tp_as_mapping */
|
|
(hashfunc)buffer_hash, /* tp_hash */
|
|
0, /* tp_call */
|
|
(reprfunc)buffer_str, /* tp_str */
|
|
PyObject_GenericGetAttr, /* tp_getattro */
|
|
0, /* tp_setattro */
|
|
&buffer_as_buffer, /* tp_as_buffer */
|
|
Py_TPFLAGS_DEFAULT, /* tp_flags */
|
|
0, /* tp_doc */
|
|
};
|