[3.14] gh-132983: Refactor shared code in train_dict and finalize_dict (GH-134432) (#134442)

gh-132983: Refactor shared code in train_dict and finalize_dict (GH-134432)

Refactor shared code in train_dict and finalize_dict
(cherry picked from commit c64a214)

Co-authored-by: Emma Smith <[email protected]>

Author: miss-islington

Modules/_zstd/_zstdmodule.c

@@ -172,6 +172,49 @@ get_zstd_state(PyObject *module)
     return (_zstd_state *)state;
 }
 
+static Py_ssize_t
+calculate_samples_stats(PyBytesObject *samples_bytes, PyObject *samples_sizes,
+                    size_t **chunk_sizes)
+{
+    Py_ssize_t chunks_number;
+    Py_ssize_t sizes_sum;
+    Py_ssize_t i;
+
+    chunks_number = Py_SIZE(samples_sizes);
+    if ((size_t) chunks_number > UINT32_MAX) {
+        PyErr_Format(PyExc_ValueError,
+                        "The number of samples should be <= %u.", UINT32_MAX);
+        return -1;
+    }
+
+    /* Prepare chunk_sizes */
+    *chunk_sizes = PyMem_New(size_t, chunks_number);
+    if (*chunk_sizes == NULL) {
+        PyErr_NoMemory();
+        return -1;
+    }
+
+    sizes_sum = 0;
+    for (i = 0; i < chunks_number; i++) {
+        PyObject *size = PyTuple_GetItem(samples_sizes, i);
+        (*chunk_sizes)[i] = PyLong_AsSize_t(size);
+        if ((*chunk_sizes)[i] == (size_t)-1 && PyErr_Occurred()) {
+            PyErr_Format(PyExc_ValueError,
+                            "Items in samples_sizes should be an int "
+                            "object, with a value between 0 and %u.", SIZE_MAX);
+            return -1;
+        }
+        sizes_sum += (*chunk_sizes)[i];
+    }
+
+    if (sizes_sum != Py_SIZE(samples_bytes)) {
+        PyErr_SetString(PyExc_ValueError,
+                        "The samples size tuple doesn't match the concatenation's size.");
+        return -1;
+    }
+    return chunks_number;
+}
+
 
 /*[clinic input]
 _zstd.train_dict
@@ -192,54 +235,25 @@ _zstd_train_dict_impl(PyObject *module, PyBytesObject *samples_bytes,
                       PyObject *samples_sizes, Py_ssize_t dict_size)
 /*[clinic end generated code: output=8e87fe43935e8f77 input=d20dedb21c72cb62]*/
 {
-    // TODO(emmatyping): The preamble and suffix to this function and _finalize_dict
-    // are pretty similar. We should see if we can refactor them to share that code.
-    Py_ssize_t chunks_number;
-    size_t *chunk_sizes = NULL;
     PyObject *dst_dict_bytes = NULL;
+    size_t *chunk_sizes = NULL;
+    Py_ssize_t chunks_number;
     size_t zstd_ret;
-    Py_ssize_t sizes_sum;
-    Py_ssize_t i;
 
     /* Check arguments */
     if (dict_size <= 0) {
         PyErr_SetString(PyExc_ValueError, "dict_size argument should be positive number.");
         return NULL;
     }
 
-    chunks_number = Py_SIZE(samples_sizes);
-    if ((size_t) chunks_number > UINT32_MAX) {
-        PyErr_Format(PyExc_ValueError,
-                        "The number of samples should be <= %u.", UINT32_MAX);
+    /* Check that the samples are valid and get their sizes */
+    chunks_number = calculate_samples_stats(samples_bytes, samples_sizes,
+                                            &chunk_sizes);
+    if (chunks_number < 0)
+    {
         return NULL;
     }
 
-    /* Prepare chunk_sizes */
-    chunk_sizes = PyMem_New(size_t, chunks_number);
-    if (chunk_sizes == NULL) {
-        PyErr_NoMemory();
-        goto error;
-    }
-
-    sizes_sum = 0;
-    for (i = 0; i < chunks_number; i++) {
-        PyObject *size = PyTuple_GetItem(samples_sizes, i);
-        chunk_sizes[i] = PyLong_AsSize_t(size);
-        if (chunk_sizes[i] == (size_t)-1 && PyErr_Occurred()) {
-            PyErr_Format(PyExc_ValueError,
-                            "Items in samples_sizes should be an int "
-                            "object, with a value between 0 and %u.", SIZE_MAX);
-            goto error;
-        }
-        sizes_sum += chunk_sizes[i];
-    }
-
-    if (sizes_sum != Py_SIZE(samples_bytes)) {
-        PyErr_SetString(PyExc_ValueError,
-                        "The samples size tuple doesn't match the concatenation's size.");
-        goto error;
-    }
-
     /* Allocate dict buffer */
     dst_dict_bytes = PyBytes_FromStringAndSize(NULL, dict_size);
     if (dst_dict_bytes == NULL) {
@@ -307,48 +321,21 @@ _zstd_finalize_dict_impl(PyObject *module, PyBytesObject *custom_dict_bytes,
     PyObject *dst_dict_bytes = NULL;
     size_t zstd_ret;
     ZDICT_params_t params;
-    Py_ssize_t sizes_sum;
-    Py_ssize_t i;
 
     /* Check arguments */
     if (dict_size <= 0) {
         PyErr_SetString(PyExc_ValueError, "dict_size argument should be positive number.");
         return NULL;
     }
 
-    chunks_number = Py_SIZE(samples_sizes);
-    if ((size_t) chunks_number > UINT32_MAX) {
-        PyErr_Format(PyExc_ValueError,
-                        "The number of samples should be <= %u.", UINT32_MAX);
+    /* Check that the samples are valid and get their sizes */
+    chunks_number = calculate_samples_stats(samples_bytes, samples_sizes,
+                                            &chunk_sizes);
+    if (chunks_number < 0)
+    {
         return NULL;
     }
 
-    /* Prepare chunk_sizes */
-    chunk_sizes = PyMem_New(size_t, chunks_number);
-    if (chunk_sizes == NULL) {
-        PyErr_NoMemory();
-        goto error;
-    }
-
-    sizes_sum = 0;
-    for (i = 0; i < chunks_number; i++) {
-        PyObject *size = PyTuple_GetItem(samples_sizes, i);
-        chunk_sizes[i] = PyLong_AsSize_t(size);
-        if (chunk_sizes[i] == (size_t)-1 && PyErr_Occurred()) {
-            PyErr_Format(PyExc_ValueError,
-                            "Items in samples_sizes should be an int "
-                            "object, with a value between 0 and %u.", SIZE_MAX);
-            goto error;
-        }
-        sizes_sum += chunk_sizes[i];
-    }
-
-    if (sizes_sum != Py_SIZE(samples_bytes)) {
-        PyErr_SetString(PyExc_ValueError,
-                        "The samples size tuple doesn't match the concatenation's size.");
-        goto error;
-    }
-
     /* Allocate dict buffer */
     dst_dict_bytes = PyBytes_FromStringAndSize(NULL, dict_size);
     if (dst_dict_bytes == NULL) {