Implement str/bytes rich comparisons.

py/obj.h

@@ -397,3 +397,4 @@ typedef struct _mp_obj_classmethod_t {
 void mp_seq_multiply(const void *items, uint item_sz, uint len, uint times, void *dest);
 bool m_seq_get_fast_slice_indexes(machine_uint_t len, mp_obj_t slice, machine_uint_t *begin, machine_uint_t *end);
 #define m_seq_copy(dest, src, len, item_sz) memcpy(dest, src, len * sizeof(item_sz))
+bool mp_seq_cmp_bytes(int op, const byte *data1, uint len1, const byte *data2, uint len2);

py/objstr.c

@@ -169,6 +169,18 @@ mp_obj_t str_binary_op(int op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
             mp_seq_multiply(lhs_data, sizeof(*lhs_data), lhs_len, n, data);
             return mp_obj_str_builder_end(s);
         }
+
+        // These 2 are never passed here, dealt with as a special case in rt_binary_op().
+        //case RT_BINARY_OP_EQUAL:
+        //case RT_BINARY_OP_NOT_EQUAL:
+        case RT_BINARY_OP_LESS:
+        case RT_BINARY_OP_LESS_EQUAL:
+        case RT_BINARY_OP_MORE:
+        case RT_BINARY_OP_MORE_EQUAL:
+            if (MP_OBJ_IS_STR(rhs_in)) {
+                GET_STR_DATA_LEN(rhs_in, rhs_data, rhs_len);
+                return MP_BOOL(mp_seq_cmp_bytes(op, lhs_data, lhs_len, rhs_data, rhs_len));
+            }
     }
 
     return MP_OBJ_NULL; // op not supported

py/sequence.c

@@ -14,6 +14,8 @@
 
 // Helpers for sequence types
 
+#define SWAP(type, var1, var2) { type t = var2; var2 = var1; var1 = t; }
+
 // Implements backend of sequence * integer operation. Assumes elements are
 // memory-adjacent in sequence.
 void mp_seq_multiply(const void *items, uint item_sz, uint len, uint times, void *dest) {
@@ -53,3 +55,39 @@ bool m_seq_get_fast_slice_indexes(machine_uint_t len, mp_obj_t slice, machine_ui
     *end = stop;
     return true;
 }
+
+// Special-case comparison function for sequences of bytes
+// Don't pass RT_BINARY_OP_NOT_EQUAL here
+bool mp_seq_cmp_bytes(int op, const byte *data1, uint len1, const byte *data2, uint len2) {
+    // Let's deal only with > & >=
+    if (op == RT_BINARY_OP_LESS || op == RT_BINARY_OP_LESS_EQUAL) {
+        SWAP(const byte*, data1, data2);
+        SWAP(uint, len1, len2);
+        if (op == RT_BINARY_OP_LESS) {
+            op = RT_BINARY_OP_MORE;
+        } else {
+            op = RT_BINARY_OP_MORE_EQUAL;
+        }
+    }
+    uint min_len = len1 < len2 ? len1 : len2;
+    int res = memcmp(data1, data2, min_len);
+    if (res < 0) {
+        return false;
+    }
+    if (res > 0) {
+        return true;
+    }
+
+    // If we had tie in the last element...
+    // ... and we have lists of different lengths...
+    if (len1 != len2) {
+        if (len1 < len2) {
+            // ... then longer list length wins (we deal only with >)
+            return false;
+        }
+    } else if (op == RT_BINARY_OP_MORE) {
+        // Otherwise, if we have strict relation, equality means failure
+        return false;
+    }
+    return true;
+}

tests/basics/string-compare.py

+print("" == "")
+print("" > "")
+print("" < "")
+print("" == "1")
+print("1" == "")
+print("" > "1")
+print("1" > "")
+print("" < "1")
+print("1" < "")
+print("" >= "1")
+print("1" >= "")
+print("" <= "1")
+print("1" <= "")
+
+print("1" == "1")
+print("1" != "1")
+print("1" == "2")
+print("1" == "10")
+
+print("1" > "1")
+print("1" > "2")
+print("2" > "1")
+print("10" > "1")
+print("1/" > "1")
+print("1" > "10")
+print("1" > "1/")
+
+print("1" < "1")
+print("2" < "1")
+print("1" < "2")
+print("1" < "10")
+print("1" < "1/")
+print("10" < "1")
+print("1/" < "1")
+
+print("1" >= "1")
+print("1" >= "2")
+print("2" >= "1")
+print("10" >= "1")
+print("1/" >= "1")
+print("1" >= "10")
+print("1" >= "1/")
+
+print("1" <= "1")
+print("2" <= "1")
+print("1" <= "2")
+print("1" <= "10")
+print("1" <= "1/")
+print("10" <= "1")
+print("1/" <= "1")