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Copy pathbufferobject.c
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557 lines (478 loc) · 11.1 KB
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/* Buffer object implementation */
#include "Python.h"
typedef struct {
PyObject_HEAD
PyObject *b_base;
void *b_ptr;
int b_size;
int b_readonly;
#ifdef CACHE_HASH
long b_hash;
#endif
} 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;
#ifdef CACHE_HASH
b->b_hash = -1;
#endif
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 */
if ( PyBuffer_Check(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;
#ifdef CACHE_HASH
b->b_hash = -1;
#endif
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 buf[300];
char *status = self->b_readonly ? "read-only" : "read-write";
if ( self->b_base == NULL )
{
sprintf(buf, "<%s buffer ptr %p, size %d at %p>",
status,
self->b_ptr,
self->b_size,
self);
}
else
{
sprintf(buf, "<%s buffer for %p, ptr %p, size %d at %p>",
status,
self->b_base,
self->b_ptr,
self->b_size,
self);
}
return PyString_FromString(buf);
}
static long
buffer_hash(PyBufferObject *self)
{
register int len;
register unsigned char *p;
register long x;
#ifdef CACHE_HASH
if ( self->b_hash != -1 )
return self->b_hash;
#endif
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;
#ifdef CACHE_HASH
self->b_hash = x;
#endif
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*/
0, /*tp_getattro*/
0, /*tp_setattro*/
&buffer_as_buffer, /*tp_as_buffer*/
Py_TPFLAGS_DEFAULT, /*tp_flags*/
0, /*tp_doc*/
};
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