1 files changed, 112 insertions, 0 deletions
diff --git a/utils/patch.awk b/utils/patch.awk
new file mode 100755
index 0000000..b625d37
--- /dev/null
+++ b/utils/patch.awk
@@ -0,0 +1,112 @@
+#!/usr/bin/awk -f
+
+# Apply a diff file to an original
+# Usage: awk -f patch.awk target-file patch-file
+
+FNR == NR {
+    lines[FNR] = $0
+    next;
+}
+
+{
+    patchLines[FNR] = $0
+}
+
+END {
+    totalPatchLines=length(patchLines)
+    totalLines = length(lines)
+    patchLineIndex = 1
+
+    mode = "none"
+
+    while (patchLineIndex <= totalPatchLines) {
+        line = patchLines[patchLineIndex]
+
+        if (line ~ /^--- / || line ~ /^\+\+\+ /) {
+            patchLineIndex++
+            continue
+        }
+
+        if (line ~ /^@@ /) {
+            mode = "hunk"
+            hunkIndex++
+            patchLineIndex++
+            continue
+        }
+
+        if (mode == "hunk") {
+            while (patchLineIndex <= totalPatchLines && line ~ /^[-+ ]/ && line !~ /^--- /) {
+                sanitizedLine = substr(line, 2)
+                if (line !~ /^\+/) {
+                    hunkTotalOriginalLines[hunkIndex]++;
+                    hunkOriginalLines[hunkIndex,hunkTotalOriginalLines[hunkIndex]] = sanitizedLine
+                } 
+                if (line !~ /^-/) {
+                    hunkTotalUpdatedLines[hunkIndex]++;
+                    hunkUpdatedLines[hunkIndex,hunkTotalUpdatedLines[hunkIndex]] = sanitizedLine
+                }
+                patchLineIndex++
+                line = patchLines[patchLineIndex]
+            }
+            mode = "none"
+        } else {
+            patchLineIndex++
+        }
+    }
+
+    if (hunkIndex == 0) {
+        print "No patch" > "/dev/stderr"
+        exit 1
+    }
+
+    totalHunks = hunkIndex
+    hunkIndex = 1
+
+    # inspectHunks()
+
+    for (lineIndex = 1; lineIndex <= totalLines; lineIndex++) {
+        line = lines[lineIndex]
+        nextLineIndex = 0
+
+        if (line == hunkOriginalLines[hunkIndex,1]) {
+            nextLineIndex = lineIndex + 1
+            for (i = 2; i <= hunkTotalOriginalLines[hunkIndex]; i++) {
+                if (lines[nextLineIndex] != hunkOriginalLines[hunkIndex,i]) {
+                    nextLineIndex = 0
+                    break
+                }
+                nextLineIndex++
+            }
+        }
+        if (nextLineIndex > 0) {
+            for (i = 1; i <= hunkTotalUpdatedLines[hunkIndex]; i++) {
+                print hunkUpdatedLines[hunkIndex,i]
+            }
+            hunkIndex++
+            lineIndex = nextLineIndex -1;
+        } else {
+            print line
+        }
+    }
+
+    if (hunkIndex != totalHunks + 1) {
+        print "Failed to patch the file" > "/dev/stderr"
+        exit 1
+    }
+}
+
+function inspectHunks() {
+    print "/* Begin inspecting hunks"
+    for (i = 1; i <= totalHunks; i++) {
+        print ">>>>>> Original"
+        for (j = 1; j <= hunkTotalOriginalLines[i]; j++) {
+            print hunkOriginalLines[i,j]
+        }
+        print "======"
+        for (j = 1; j <= hunkTotalUpdatedLines[i]; j++) {
+            print hunkUpdatedLines[i,j]
+        }
+        print "<<<<<< Updated"
+    }
+    print "End inspecting hunks */\n"
+}
+\ No newline at end of file