1 files changed, 101 insertions, 0 deletions
diff --git a/packages/utils/src/abi_encoder/utils/signature_parser.ts b/packages/utils/src/abi_encoder/utils/signature_parser.ts
new file mode 100644
index 000000000..315784cea
--- /dev/null
+++ b/packages/utils/src/abi_encoder/utils/signature_parser.ts
@@ -0,0 +1,101 @@
+import { DataItem } from 'ethereum-types';
+import * as _ from 'lodash';
+
+/**
+ * Returns an array of DataItem's corresponding to the input signature.
+ * A signature can be in two forms: '<DataItem.type>' or '(<DataItem1.type>, <DataItem2.type>, ...)
+ * An example of the first form would be 'address' or 'uint256'
+ * An example of the second form would be '(address, uint256)'
+ * Signatures can also include a name field, for example: 'foo address' or '(foo address, bar uint256)'
+ * @param signature of input DataItems
+ * @return DataItems derived from input signature
+ */
+export function generateDataItemsFromSignature(signature: string): DataItem[] {
+    let trimmedSignature = signature;
+    if (signature.startsWith('(')) {
+        if (!signature.endsWith(')')) {
+            throw new Error(`Failed to generate data item. Must end with ')'`);
+        }
+        trimmedSignature = signature.substr(1, signature.length - 2);
+    }
+    trimmedSignature += ',';
+    let isCurrTokenArray = false;
+    let currTokenArrayModifier = '';
+    let isParsingArrayModifier = false;
+    let currToken = '';
+    let parenCount = 0;
+    let currTokenName = '';
+    const dataItems: DataItem[] = [];
+    for (const char of trimmedSignature) {
+        // Tokenize the type string while keeping track of parentheses.
+        switch (char) {
+            case '(':
+                parenCount += 1;
+                currToken += char;
+                break;
+            case ')':
+                parenCount -= 1;
+                currToken += char;
+                break;
+            case '[':
+                if (parenCount === 0) {
+                    isParsingArrayModifier = true;
+                    isCurrTokenArray = true;
+                    currTokenArrayModifier += '[';
+                } else {
+                    currToken += char;
+                }
+                break;
+            case ']':
+                if (parenCount === 0) {
+                    isParsingArrayModifier = false;
+                    currTokenArrayModifier += ']';
+                } else {
+                    currToken += char;
+                }
+                break;
+            case ' ':
+                if (parenCount === 0) {
+                    currTokenName = currToken;
+                    currToken = '';
+                } else {
+                    currToken += char;
+                }
+                break;
+            case ',':
+                if (parenCount === 0) {
+                    // Generate new DataItem from token
+                    const components = currToken.startsWith('(') ? generateDataItemsFromSignature(currToken) : [];
+                    const isTuple = !_.isEmpty(components);
+                    const dataItem: DataItem = { name: currTokenName, type: '' };
+                    if (isTuple) {
+                        dataItem.type = 'tuple';
+                        dataItem.components = components;
+                    } else {
+                        dataItem.type = currToken;
+                    }
+                    if (isCurrTokenArray) {
+                        dataItem.type += currTokenArrayModifier;
+                    }
+                    dataItems.push(dataItem);
+                    // reset token state
+                    currTokenName = '';
+                    currToken = '';
+                    isCurrTokenArray = false;
+                    currTokenArrayModifier = '';
+                    break;
+                } else {
+                    currToken += char;
+                    break;
+                }
+            default:
+                if (isParsingArrayModifier) {
+                    currTokenArrayModifier += char;
+                } else {
+                    currToken += char;
+                }
+                break;
+        }
+    }
+    return dataItems;
+}