port `base64` module from v1.x

docs/modules/base64.md

@@ -0,0 +1,12 @@
+---
+icon: package
+label: base64
+---
+
+### `base64.b64encode(b: bytes) -> bytes`
+
+Encode bytes-like object `b` using the standard Base64 alphabet.
+
+### `base64.b64decode(b: bytes) -> bytes`
+
+Decode Base64 encoded bytes-like object `b`.

include/pocketpy/interpreter/modules.h

@@ -15,6 +15,7 @@ void pk__add_module_traceback();
 void pk__add_module_enum();
 void pk__add_module_inspect();
 void pk__add_module_pickle();
+void pk__add_module_base64();
 void pk__add_module_importlib();
 
 void pk__add_module_linalg();

src/interpreter/vm.c

@@ -232,6 +232,7 @@ void VM__ctor(VM* self) {
     pk__add_module_enum();
     pk__add_module_inspect();
     pk__add_module_pickle();
+    pk__add_module_base64();
     pk__add_module_importlib();
 
     pk__add_module_conio();

src/modules/base64.c

@@ -0,0 +1,195 @@
+#include "pocketpy/interpreter/vm.h"
+#include "pocketpy/pocketpy.h"
+#include <limits.h>
+
+// https://github.com/zhicheng/base64/blob/master/base64.c
+
+const char BASE64_PAD = '=';
+const char BASE64DE_FIRST = '+';
+const char BASE64DE_LAST = 'z';
+
+/* BASE 64 encode table */
+const char base64en[] = {
+	'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
+	'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
+	'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
+	'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
+	'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
+	'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
+	'w', 'x', 'y', 'z', '0', '1', '2', '3',
+	'4', '5', '6', '7', '8', '9', '+', '/',
+};
+
+/* ASCII order for BASE 64 decode, 255 in unused character */
+const unsigned char base64de[] = {
+	/* nul, soh, stx, etx, eot, enq, ack, bel, */
+	   255, 255, 255, 255, 255, 255, 255, 255,
+
+	/*  bs,  ht,  nl,  vt,  np,  cr,  so,  si, */
+	   255, 255, 255, 255, 255, 255, 255, 255,
+
+	/* dle, dc1, dc2, dc3, dc4, nak, syn, etb, */
+	   255, 255, 255, 255, 255, 255, 255, 255,
+
+	/* can,  em, sub, esc,  fs,  gs,  rs,  us, */
+	   255, 255, 255, 255, 255, 255, 255, 255,
+
+	/*  sp, '!', '"', '#', '$', '%', '&', ''', */
+	   255, 255, 255, 255, 255, 255, 255, 255,
+
+	/* '(', ')', '*', '+', ',', '-', '.', '/', */
+	   255, 255, 255,  62, 255, 255, 255,  63,
+
+	/* '0', '1', '2', '3', '4', '5', '6', '7', */
+	    52,  53,  54,  55,  56,  57,  58,  59,
+
+	/* '8', '9', ':', ';', '<', '=', '>', '?', */
+	    60,  61, 255, 255, 255, 255, 255, 255,
+
+	/* '@', 'A', 'B', 'C', 'D', 'E', 'F', 'G', */
+	   255,   0,   1,  2,   3,   4,   5,    6,
+
+	/* 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', */
+	     7,   8,   9,  10,  11,  12,  13,  14,
+
+	/* 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', */
+	    15,  16,  17,  18,  19,  20,  21,  22,
+
+	/* 'X', 'Y', 'Z', '[', '\', ']', '^', '_', */
+	    23,  24,  25, 255, 255, 255, 255, 255,
+
+	/* '`', 'a', 'b', 'c', 'd', 'e', 'f', 'g', */
+	   255,  26,  27,  28,  29,  30,  31,  32,
+
+	/* 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', */
+	    33,  34,  35,  36,  37,  38,  39,  40,
+
+	/* 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', */
+	    41,  42,  43,  44,  45,  46,  47,  48,
+
+	/* 'x', 'y', 'z', '{', '|', '}', '~', del, */
+	    49,  50,  51, 255, 255, 255, 255, 255
+};
+
+static unsigned int
+base64_encode(const unsigned char *in, unsigned int inlen, char *out)
+{
+	int s;
+	unsigned int i;
+	unsigned int j;
+	unsigned char c;
+	unsigned char l;
+
+	s = 0;
+	l = 0;
+	for (i = j = 0; i < inlen; i++) {
+		c = in[i];
+
+		switch (s) {
+		case 0:
+			s = 1;
+			out[j++] = base64en[(c >> 2) & 0x3F];
+			break;
+		case 1:
+			s = 2;
+			out[j++] = base64en[((l & 0x3) << 4) | ((c >> 4) & 0xF)];
+			break;
+		case 2:
+			s = 0;
+			out[j++] = base64en[((l & 0xF) << 2) | ((c >> 6) & 0x3)];
+			out[j++] = base64en[c & 0x3F];
+			break;
+		}
+		l = c;
+	}
+
+	switch (s) {
+	case 1:
+		out[j++] = base64en[(l & 0x3) << 4];
+		out[j++] = BASE64_PAD;
+		out[j++] = BASE64_PAD;
+		break;
+	case 2:
+		out[j++] = base64en[(l & 0xF) << 2];
+		out[j++] = BASE64_PAD;
+		break;
+	}
+
+	out[j] = 0;
+
+	return j;
+}
+
+static unsigned int
+base64_decode(const char *in, unsigned int inlen, unsigned char *out)
+{
+	unsigned int i;
+	unsigned int j;
+	unsigned char c;
+
+	if (inlen & 0x3) {
+		return 0;
+	}
+
+	for (i = j = 0; i < inlen; i++) {
+		if (in[i] == BASE64_PAD) {
+			break;
+		}
+		if (in[i] < BASE64DE_FIRST || in[i] > BASE64DE_LAST) {
+			return 0;
+		}
+
+		c = base64de[(unsigned char)in[i]];
+		if (c == 255) {
+			return 0;
+		}
+
+		switch (i & 0x3) {
+		case 0:
+			out[j] = (c << 2) & 0xFF;
+			break;
+		case 1:
+			out[j++] |= (c >> 4) & 0x3;
+			out[j] = (c & 0xF) << 4; 
+			break;
+		case 2:
+			out[j++] |= (c >> 2) & 0xF;
+			out[j] = (c & 0x3) << 6;
+			break;
+		case 3:
+			out[j++] |= c;
+			break;
+		}
+	}
+
+	return j;
+}
+
+static bool base64_b64encode(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(1);
+    PY_CHECK_ARG_TYPE(0, tp_bytes);
+    int src_size;
+    unsigned char* src_data = py_tobytes(argv, &src_size);
+    unsigned char* dst_data = py_newbytes(py_retval(), src_size * 2);
+    int size = base64_encode(src_data, src_size, (char*)dst_data);
+    py_bytes_resize(py_retval(), size);
+    return true;
+}
+
+static bool base64_b64decode(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(1);
+    PY_CHECK_ARG_TYPE(0, tp_bytes);
+    int src_size;
+    unsigned char* src_data = py_tobytes(argv, &src_size);
+    unsigned char* dst_data = py_newbytes(py_retval(), src_size);
+    int size = base64_decode((const char*)src_data, src_size, dst_data);
+    py_bytes_resize(py_retval(), size);
+    return true;
+}
+
+void pk__add_module_base64(){
+    py_GlobalRef mod = py_newmodule("base64");
+
+    py_bindfunc(mod, "b64encode", base64_b64encode);
+    py_bindfunc(mod, "b64decode", base64_b64decode);
+}