Add API fuzzer

Author: guidovranken

fuzzer-api.cpp

@@ -0,0 +1,97 @@
+#include "baseapi.h"
+#include "leptonica/allheaders.h"
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+class BitReader {
+    private:
+        uint8_t const* data;
+        size_t size;
+        size_t shift;
+    public:
+        BitReader(const uint8_t* data, size_t size) :
+            data(data), size(size), shift(0)
+        { }
+
+        int Read(void) {
+            if ( size == 0 ) {
+                return 0;
+            }
+
+            const int ret = ((*data) >> shift) & 1;
+
+            shift++;
+            if ( shift >= 8 ) {
+                shift = 0;
+                data++;
+                size--;
+            }
+
+            return ret;
+        }
+};
+
+tesseract::TessBaseAPI *api = nullptr;
+
+extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv)
+{
+    (void)argc;
+    (void)argv;
+
+
+#ifndef TESSDATA_PREFIX
+#error TESSDATA_PREFIX must be defined
+#else
+    if ( setenv("TESSDATA_PREFIX", TESSDATA_PREFIX, 1) != 0 ) {
+        printf("Setenv failed\n");
+        abort();
+    }
+#endif
+
+    api = new tesseract::TessBaseAPI();
+    if ( api->Init(nullptr, "eng") != 0 ) {
+        printf("Cannot initialize API\n");
+        abort();
+    }
+
+    /* Silence output */
+    api->SetVariable("debug_file", "/dev/null");
+
+    return 0;
+}
+
+
+static PIX* createPix(BitReader& BR, const size_t width, const size_t height) {
+    Pix* pix = pixCreate(width, height, 1);
+
+    if ( pix == nullptr ) {
+        printf("pix creation failed\n");
+        abort();
+    }
+
+    for (size_t i = 0; i < width; i++) {
+        for (size_t j = 0; j < height; j++) {
+            pixSetPixel(pix, i, j, BR.Read());
+        }
+    }
+
+    return pix;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+    BitReader BR(data, size);
+
+    auto pix = createPix(BR, 100, 100);
+
+    api->SetImage(pix);
+
+    char* outText = api->GetUTF8Text();
+
+    pixDestroy(&pix);
+    delete[] outText;
+
+    return 0;
+}