🐛 [placeholder-plain] Do not search for a trailer word once the xref …

…position is known fixes #209
vbuch · Feb 23, 2024 · 169910e · 169910e
1 parent 11d3364
commit 169910e
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Showing 3 changed files with 57 additions and 8 deletions.
diff --git a/packages/placeholder-plain/src/__snapshots__/readRefTable.test.js.snap b/packages/placeholder-plain/src/__snapshots__/readRefTable.test.js.snap
@@ -242,3 +242,39 @@ Object {
   "startingIndex": 0,
 }
 `;
+
+exports[`readRefTable Expects to merge correctly the refTable of resources 8`] = `
+Object {
+  "maxIndex": 27,
+  "offsets": Map {
+    1 => 15,
+    2 => 89780,
+    3 => 265,
+    4 => 302,
+    5 => 27161,
+    6 => 55428,
+    7 => 72070,
+    8 => 378,
+    9 => 592,
+    10 => 764,
+    11 => 4338,
+    12 => 89711,
+    13 => 4443,
+    14 => 26241,
+    15 => 26484,
+    16 => 26817,
+    17 => 27302,
+    18 => 54210,
+    19 => 54444,
+    20 => 55060,
+    21 => 55560,
+    22 => 71288,
+    23 => 71522,
+    24 => 71742,
+    25 => 72781,
+    26 => 89525,
+    27 => 89643,
+  },
+  "startingIndex": 0,
+}
+`;
diff --git a/packages/placeholder-plain/src/readRefTable.js b/packages/placeholder-plain/src/readRefTable.js
@@ -82,22 +82,22 @@ export const getXref = (pdf, position) => {
 };
 
 /**
- * @typedef {Map<*, *>} GetFullXrefTableReturnType
+ * @typedef {Map<number, number>} FullXrefTable
  */
 
 /**
  * @param {Buffer} pdf
- * @returns {GetFullXrefTableReturnType}
+ * @param {number} xRefPosition
+ * @returns {FullXrefTable}
  */
-export const getFullXrefTable = (pdf) => {
-    const lastTrailerPosition = getLastTrailerPosition(pdf);
-    const lastXrefTable = getXref(pdf, lastTrailerPosition);
+const getFullXref = (pdf, xRefPosition) => {
+    const lastXrefTable = getXref(pdf, xRefPosition);
 
     if (lastXrefTable.prev === undefined) {
         return lastXrefTable.xRefContent;
     }
-    const pdfWithoutLastTrailer = pdf.slice(0, lastTrailerPosition);
-    const partOfXrefTable = getFullXrefTable(pdfWithoutLastTrailer);
+
+    const partOfXrefTable = getFullXref(pdf, lastXrefTable.prev);
 
     const mergedXrefTable = new Map([
         ...partOfXrefTable,
@@ -107,11 +107,20 @@ export const getFullXrefTable = (pdf) => {
     return mergedXrefTable;
 };
 
+/**
+ * @param {Buffer} pdf
+ * @returns {FullXrefTable}
+ */
+export const getFullXrefTable = (pdf) => {
+    const lastTrailerPosition = getLastTrailerPosition(pdf);
+    return getFullXref(pdf, lastTrailerPosition);
+};
+
 /**
  * @typedef {object} ReadRefTableReturnType
  * @prop {number} startingIndex
  * @prop {number} maxIndex
- * @prop {GetFullXrefTableReturnType} offsets
+ * @prop {FullXrefTable} offsets
  */
 
 /**

diff --git a/packages/placeholder-plain/src/xrefToRefMap.js b/packages/placeholder-plain/src/xrefToRefMap.js
@@ -1,5 +1,9 @@
 import {SignPdfError} from '@signpdf/utils';
 
+/**
+ * @param {string} xrefString
+ * @returns {Map<number, number>}
+ */
 const xrefToRefMap = (xrefString) => {
     const lines = xrefString.split('\n').filter((l) => l !== '');