1 files changed, 171 insertions, 0 deletions
diff --git a/pcilib/py.c b/pcilib/py.c
new file mode 100644
index 0000000..2248892
--- /dev/null
+++ b/pcilib/py.c
@@ -0,0 +1,171 @@
+#include <Python.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+
+
+#include "pci.h"
+#include "pcilib.h"
+#include "py.h"
+#include "error.h"
+
+struct pcilib_py_s {
+    PyObject *main_module;
+    PyObject *global_dict;
+};
+
+int pcilib_init_py(pcilib_t *ctx) {
+    ctx->py = (pcilib_py_t*)malloc(sizeof(pcilib_py_t));
+    if (!ctx->py) return PCILIB_ERROR_MEMORY;
+
+    Py_Initialize();
+
+    ctx->py->main_module = PyImport_AddModule("__parser__");
+    if (!ctx->py->main_module)
+        return PCILIB_ERROR_FAILED;
+
+    ctx->py->global_dict = PyModule_GetDict(ctx->py->main_module);
+    if (!ctx->py->global_dict)
+        return PCILIB_ERROR_FAILED;
+
+    return 0;
+}
+
+void pcilib_free_py(pcilib_t *ctx) {
+    if (ctx->py) {
+	    // Dict and module references are borrowed
+        free(ctx->py);
+        ctx->py = NULL;
+    }
+
+    Py_Finalize();
+}
+
+/*
+static int pcilib_py_realloc_string(pcilib_t *ctx, size_t required, size_t *size, char **str) {
+    char *ptr;
+    size_t cur = *size;
+    
+    if ((required + 1) > cur) {
+        while (cur < required) cur *= 2;
+        ptr = (char*)realloc(*str, cur);
+        if (!ptr) return PCILIB_ERROR_MEMORY;
+        *size = cur;
+        *str = ptr;
+    }
+    ]
+    return 0;
+}
+*/
+
+static char *pcilib_py_parse_string(pcilib_t *ctx, const char *codestr, pcilib_value_t *value) {
+    int i;
+    int err = 0;
+    pcilib_value_t val;
+    pcilib_register_value_t regval;
+
+    char save;
+    char *reg, *cur;
+    size_t offset = 0;
+
+    size_t size;
+    char *src;
+    char *dst;
+
+    size_t max_repl = 2 + 2 * sizeof(pcilib_value_t);                               // the text representation of largest integer
+
+    if (value) {
+        err = pcilib_copy_value(ctx, &val, value);
+        if (err) return NULL;
+
+        err = pcilib_convert_value_type(ctx, &val, PCILIB_TYPE_STRING);
+        if (err) return NULL;
+
+        if (strlen(val.sval) > max_repl)
+            max_repl = strlen(val.sval);
+    }
+
+    size = ((max_repl + 1) / 3 + 1) * strlen(codestr);                          // minimum register length is 3 symbols ($a + delimiter space), it is replaces with (max_repl+1) symbols
+
+    src = strdup(codestr);
+    dst = (char*)malloc(size);                                                  // allocating maximum required space
+
+    if ((!src)||(!dst)) {
+        if (src) free(src);
+        if (dst) free(dst);
+        pcilib_error("Failed to allocate memory for string formulas");
+        return NULL;
+    }
+
+    cur = src;
+    reg = strchr(src, '$');
+    while (reg) {
+        strcpy(dst + offset, cur);
+        offset += reg - cur;
+
+            // find the end of the register name
+        reg++;
+        for (i = 0; isalnum(reg[i]); i++);
+        save = reg[i];
+        reg[i] = 0;
+
+            // determine replacement value
+        if (!strcasecmp(reg, "value")) {
+            if (!value) {
+                pcilib_error("Python formula (%s) relies on the value of register, but it is not provided", codestr);
+                err = PCILIB_ERROR_INVALID_REQUEST;
+                break;
+            }
+
+            strcpy(dst + offset, val.sval);
+        } else {
+            err = pcilib_read_register(ctx, NULL, reg, &regval);
+            if (err) break;
+
+            sprintf(dst + offset, "0x%x", regval);
+        }
+
+        offset += strlen(dst + offset);
+        reg[i] = save;
+
+            // Advance to the next register if any
+        cur = reg + i;
+        reg = strchr(cur, '$');
+    }
+
+    strcpy(dst + offset, cur);
+
+    free(src);
+
+    if (err) {
+        free(dst);
+        return NULL;
+    }
+
+    return dst;
+}
+
+int pcilib_py_eval_string(pcilib_t *ctx, const char *codestr, pcilib_value_t *value) {
+    PyGILState_STATE gstate;
+    char *code;
+    PyObject* obj;
+
+    code = pcilib_py_parse_string(ctx, codestr, value);
+    if (!code) {
+        pcilib_error("Failed to parse registers in the code: %s", codestr);
+        return PCILIB_ERROR_FAILED;
+    }
+
+    gstate = PyGILState_Ensure();
+    obj = PyRun_String(code, Py_eval_input, ctx->py->global_dict, ctx->py->global_dict);
+    PyGILState_Release(gstate);
+
+    if (!obj) {
+        pcilib_error("Failed to run the Python code: %s", code);
+        return PCILIB_ERROR_FAILED;
+    }
+
+    return pcilib_set_value_from_float(ctx, value, PyFloat_AsDouble(obj));
+}