json: Fast path for string encoding #133239
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https://gist.github.com/methane/e080ec9783db2a313f40a2b9e1837e72
Benchmark hidden because not significant (10): json_dumps: List of 256 floats, json_dumps(ensure_ascii=False): List of 256 floats, json_loads: List of 256 booleans, json_loads: List of 256 ASCII strings, json_loads: List of 256 dicts with 1 int, json_loads: Medium complex object, json_loads: Complex object, json_loads: Dict with 256 lists of 256 dicts with 1 int, json_loads: List of 256 stringsensure_ascii=False, json_loads: Complex objectensure_ascii=False |
nineteendo
commented
May 1, 2025
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| for (i = 0, output_size = 0; i < input_chars; i++) { | ||
| Py_UCS4 c = PyUnicode_READ(kind, input, i); | ||
| Py_ssize_t d; | ||
| if (S_CHAR(c)) { | ||
| d = 1; | ||
| } | ||
| else { | ||
| switch(c) { | ||
| case '\\': case '"': case '\b': case '\f': | ||
| case '\n': case '\r': case '\t': | ||
| d = 2; break; | ||
| default: | ||
| d = c >= 0x10000 ? 12 : 6; | ||
| } | ||
| } | ||
| if (output_size > PY_SSIZE_T_MAX - d) { | ||
| PyErr_SetString(PyExc_OverflowError, "string is too long to escape"); | ||
| return NULL; | ||
| } | ||
| output_size += d; | ||
| } |
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Could we rewrite this to be faster? Because that's the only difference in the fast path between both PRs.
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pyperformance (with
--enable-optimizations)jsonyx-performance-tests (with
--enable-optimizations)