0
0
mirror of https://github.com/python/cpython.git synced 2024-11-30 18:51:15 +01:00
cpython/Parser/lexer/buffer.c
Lysandros Nikolaou 01481f2dc1
gh-104169: Refactor tokenizer into lexer and wrappers (#110684)
* The lexer, which include the actual lexeme producing logic, goes into
  the `lexer` directory.
* The wrappers, one wrapper per input mode (file, string, utf-8, and
  readline), go into the `tokenizer` directory and include logic for
  creating a lexer instance and managing the buffer for different modes.
---------

Co-authored-by: Pablo Galindo <pablogsal@gmail.com>
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
2023-10-11 15:14:44 +00:00

77 lines
2.9 KiB
C

#include "Python.h"
#include "errcode.h"
#include "state.h"
/* Traverse and remember all f-string buffers, in order to be able to restore
them after reallocating tok->buf */
void
_PyLexer_remember_fstring_buffers(struct tok_state *tok)
{
int index;
tokenizer_mode *mode;
for (index = tok->tok_mode_stack_index; index >= 0; --index) {
mode = &(tok->tok_mode_stack[index]);
mode->f_string_start_offset = mode->f_string_start - tok->buf;
mode->f_string_multi_line_start_offset = mode->f_string_multi_line_start - tok->buf;
}
}
/* Traverse and restore all f-string buffers after reallocating tok->buf */
void
_PyLexer_restore_fstring_buffers(struct tok_state *tok)
{
int index;
tokenizer_mode *mode;
for (index = tok->tok_mode_stack_index; index >= 0; --index) {
mode = &(tok->tok_mode_stack[index]);
mode->f_string_start = tok->buf + mode->f_string_start_offset;
mode->f_string_multi_line_start = tok->buf + mode->f_string_multi_line_start_offset;
}
}
/* Read a line of text from TOK into S, using the stream in TOK.
Return NULL on failure, else S.
On entry, tok->decoding_buffer will be one of:
1) NULL: need to call tok->decoding_readline to get a new line
2) PyUnicodeObject *: decoding_feof has called tok->decoding_readline and
stored the result in tok->decoding_buffer
3) PyByteArrayObject *: previous call to tok_readline_recode did not have enough room
(in the s buffer) to copy entire contents of the line read
by tok->decoding_readline. tok->decoding_buffer has the overflow.
In this case, tok_readline_recode is called in a loop (with an expanded buffer)
until the buffer ends with a '\n' (or until the end of the file is
reached): see tok_nextc and its calls to tok_reserve_buf.
*/
int
_PyLexer_tok_reserve_buf(struct tok_state *tok, Py_ssize_t size)
{
Py_ssize_t cur = tok->cur - tok->buf;
Py_ssize_t oldsize = tok->inp - tok->buf;
Py_ssize_t newsize = oldsize + Py_MAX(size, oldsize >> 1);
if (newsize > tok->end - tok->buf) {
char *newbuf = tok->buf;
Py_ssize_t start = tok->start == NULL ? -1 : tok->start - tok->buf;
Py_ssize_t line_start = tok->start == NULL ? -1 : tok->line_start - tok->buf;
Py_ssize_t multi_line_start = tok->multi_line_start - tok->buf;
_PyLexer_remember_fstring_buffers(tok);
newbuf = (char *)PyMem_Realloc(newbuf, newsize);
if (newbuf == NULL) {
tok->done = E_NOMEM;
return 0;
}
tok->buf = newbuf;
tok->cur = tok->buf + cur;
tok->inp = tok->buf + oldsize;
tok->end = tok->buf + newsize;
tok->start = start < 0 ? NULL : tok->buf + start;
tok->line_start = line_start < 0 ? NULL : tok->buf + line_start;
tok->multi_line_start = multi_line_start < 0 ? NULL : tok->buf + multi_line_start;
_PyLexer_restore_fstring_buffers(tok);
}
return 1;
}