Initial revision
diff --git a/Objects/stringobject.c b/Objects/stringobject.c
new file mode 100644
index 0000000..6430c0f
--- /dev/null
+++ b/Objects/stringobject.c
@@ -0,0 +1,328 @@
+/* String object implementation */
+
+#include <stdio.h>
+
+#include "PROTO.h"
+#include "object.h"
+#include "stringobject.h"
+#include "intobject.h"
+#include "objimpl.h"
+
+object *
+newsizedstringobject(str, size)
+ char *str;
+ int size;
+{
+ register stringobject *op = (stringobject *)
+ malloc(sizeof(stringobject) + size * sizeof(char));
+ if (op == NULL) {
+ errno = ENOMEM;
+ }
+ else {
+ NEWREF(op);
+ op->ob_type = &Stringtype;
+ op->ob_size = size;
+ if (str != NULL)
+ memcpy(op->ob_sval, str, size);
+ op->ob_sval[size] = '\0';
+ }
+ return (object *) op;
+}
+
+object *
+newstringobject(str)
+ char *str;
+{
+ register unsigned int size = strlen(str);
+ register stringobject *op = (stringobject *)
+ malloc(sizeof(stringobject) + size * sizeof(char));
+ if (op == NULL) {
+ errno = ENOMEM;
+ }
+ else {
+ NEWREF(op);
+ op->ob_type = &Stringtype;
+ op->ob_size = size;
+ strcpy(op->ob_sval, str);
+ }
+ return (object *) op;
+}
+
+unsigned int
+getstringsize(op)
+ register object *op;
+{
+ if (!is_stringobject(op)) {
+ errno = EBADF;
+ return -1;
+ }
+ return ((stringobject *)op) -> ob_size;
+}
+
+/*const*/ char *
+getstringvalue(op)
+ register object *op;
+{
+ if (!is_stringobject(op)) {
+ errno = EBADF;
+ return NULL;
+ }
+ return ((stringobject *)op) -> ob_sval;
+}
+
+/* Methods */
+
+static void
+stringprint(op, fp, flags)
+ stringobject *op;
+ FILE *fp;
+ int flags;
+{
+ int i;
+ char c;
+ if (flags & PRINT_RAW) {
+ fwrite(op->ob_sval, 1, (int) op->ob_size, fp);
+ return;
+ }
+ fprintf(fp, "'");
+ for (i = 0; i < op->ob_size; i++) {
+ c = op->ob_sval[i];
+ if (c == '\'' || c == '\\')
+ fprintf(fp, "\\%c", c);
+ else if (c < ' ' || c >= 0177)
+ fprintf(fp, "\\%03o", c&0377);
+ else
+ putc(c, fp);
+ }
+ fprintf(fp, "'");
+}
+
+static object *
+stringrepr(op)
+ register stringobject *op;
+{
+ /* XXX overflow? */
+ int newsize = 2 + 4 * op->ob_size * sizeof(char);
+ object *v = newsizedstringobject((char *)NULL, newsize);
+ if (v == NULL) {
+ errno = ENOMEM;
+ }
+ else {
+ register int i;
+ register char c;
+ register char *p;
+ NEWREF(v);
+ v->ob_type = &Stringtype;
+ ((stringobject *)v)->ob_size = newsize;
+ p = ((stringobject *)v)->ob_sval;
+ *p++ = '\'';
+ for (i = 0; i < op->ob_size; i++) {
+ c = op->ob_sval[i];
+ if (c == '\'' || c == '\\')
+ *p++ = '\\', *p++ = c;
+ else if (c < ' ' || c >= 0177) {
+ sprintf(p, "\\%03o", c&0377);
+ while (*p != '\0')
+ p++;
+
+ }
+ else
+ *p++ = c;
+ }
+ *p++ = '\'';
+ *p = '\0';
+ resizestring(&v, (int) (p - ((stringobject *)v)->ob_sval));
+ }
+ return v;
+}
+
+static int
+stringlength(a)
+ stringobject *a;
+{
+ return a->ob_size;
+}
+
+static object *
+stringconcat(a, bb)
+ register stringobject *a;
+ register object *bb;
+{
+ register unsigned int size;
+ register stringobject *op;
+ if (!is_stringobject(bb)) {
+ errno = EINVAL;
+ return NULL;
+ }
+#define b ((stringobject *)bb)
+ /* Optimize cases with empty left or right operand */
+ if (a->ob_size == 0) {
+ INCREF(bb);
+ return bb;
+ }
+ if (b->ob_size == 0) {
+ INCREF(a);
+ return (object *)a;
+ }
+ size = a->ob_size + b->ob_size;
+ op = (stringobject *)
+ malloc(sizeof(stringobject) + size * sizeof(char));
+ if (op == NULL) {
+ errno = ENOMEM;
+ }
+ else {
+ NEWREF(op);
+ op->ob_type = &Stringtype;
+ op->ob_size = size;
+ memcpy(op->ob_sval, a->ob_sval, (int) a->ob_size);
+ memcpy(op->ob_sval + a->ob_size, b->ob_sval, (int) b->ob_size);
+ op->ob_sval[size] = '\0';
+ }
+ return (object *) op;
+#undef b
+}
+
+static object *
+stringrepeat(a, n)
+ register stringobject *a;
+ register int n;
+{
+ register int i;
+ register unsigned int size;
+ register stringobject *op;
+ if (n < 0)
+ n = 0;
+ size = a->ob_size * n;
+ if (size == a->ob_size) {
+ INCREF(a);
+ return (object *)a;
+ }
+ op = (stringobject *)
+ malloc(sizeof(stringobject) + size * sizeof(char));
+ if (op == NULL) {
+ errno = ENOMEM;
+ }
+ else {
+ NEWREF(op);
+ op->ob_type = &Stringtype;
+ op->ob_size = size;
+ for (i = 0; i < size; i += a->ob_size)
+ memcpy(op->ob_sval+i, a->ob_sval, (int) a->ob_size);
+ op->ob_sval[size] = '\0';
+ }
+ return (object *) op;
+}
+
+/* String slice a[i:j] consists of characters a[i] ... a[j-1] */
+
+static object *
+stringslice(a, i, j)
+ register stringobject *a;
+ register int i, j; /* May be negative! */
+{
+ if (i < 0)
+ i = 0;
+ if (j < 0)
+ j = 0; /* Avoid signed/unsigned bug in next line */
+ if (j > a->ob_size)
+ j = a->ob_size;
+ if (i == 0 && j == a->ob_size) { /* It's the same as a */
+ INCREF(a);
+ return (object *)a;
+ }
+ if (j < i)
+ j = i;
+ return newsizedstringobject(a->ob_sval + i, (int) (j-i));
+}
+
+static object *
+stringitem(a, i)
+ stringobject *a;
+ register int i;
+{
+ if (i < 0 || i >= a->ob_size) {
+ errno = EDOM;
+ return NULL;
+ }
+ return stringslice(a, i, i+1);
+}
+
+static int
+stringcompare(a, b)
+ stringobject *a, *b;
+{
+ /* XXX should use memcmp on shortest size, then compare lengths */
+ return strcmp(a->ob_sval, b->ob_sval);
+}
+
+static sequence_methods string_as_sequence = {
+ stringlength, /*tp_length*/
+ stringconcat, /*tp_concat*/
+ stringrepeat, /*tp_repeat*/
+ stringitem, /*tp_item*/
+ stringslice, /*tp_slice*/
+ 0, /*tp_ass_item*/
+ 0, /*tp_ass_slice*/
+};
+
+typeobject Stringtype = {
+ OB_HEAD_INIT(&Typetype)
+ 0,
+ "string",
+ sizeof(stringobject),
+ sizeof(char),
+ free, /*tp_dealloc*/
+ stringprint, /*tp_print*/
+ 0, /*tp_getattr*/
+ 0, /*tp_setattr*/
+ stringcompare, /*tp_compare*/
+ stringrepr, /*tp_repr*/
+ 0, /*tp_as_number*/
+ &string_as_sequence, /*tp_as_sequence*/
+ 0, /*tp_as_mapping*/
+};
+
+void
+joinstring(pv, w)
+ register object **pv;
+ register object *w;
+{
+ register object *v;
+ if (*pv == NULL || w == NULL || !is_stringobject(*pv))
+ return;
+ v = stringconcat((stringobject *) *pv, w);
+ DECREF(*pv);
+ *pv = v;
+}
+
+/* The following function breaks the notion that strings are immutable:
+ it changes the size of a string. We get away with this only if there
+ is only one module referencing the object. You can also think of it
+ as creating a new string object and destroying the old one, only
+ more efficiently. In any case, don't use this if the string may
+ already be known to some other part of the code... */
+
+int
+resizestring(pv, newsize)
+ object **pv;
+ int newsize;
+{
+ register stringobject *v;
+ v = (stringobject *) *pv;
+ if (!is_stringobject(v) || v->ob_refcnt != 1) {
+ *pv = 0;
+ DECREF(v);
+ return errno = EBADF;
+ }
+ *pv = (object *)
+ realloc((char *)v,
+ sizeof(stringobject) + newsize * sizeof(char));
+ if (*pv == NULL) {
+ DECREF(v);
+ return errno = ENOMEM;
+ }
+ v = (stringobject *) *pv;
+ v->ob_size = newsize;
+ v->ob_sval[newsize] = '\0';
+ return 0;
+}