1 files changed, 63 insertions, 0 deletions
diff --git a/tools/br_ips/ips_patch.c b/tools/br_ips/ips_patch.c
new file mode 100644
index 000000000..03780cf72
--- /dev/null
+++ b/tools/br_ips/ips_patch.c
@@ -0,0 +1,63 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+
+#ifdef _MSC_VER
+
+#define FATAL_ERROR(format, ...)          \
+do {                                      \
+    fprintf(stderr, format, __VA_ARGS__); \
+    exit(1);                              \
+} while (0)
+
+#else
+
+#define FATAL_ERROR(format, ...)            \
+do {                                        \
+    fprintf(stderr, format, ##__VA_ARGS__); \
+    exit(1);                                \
+} while (0)
+
+#endif // _MSC_VER
+
+static const char SPLASH[] = "Small IPS patch utility\n"
+                             "Created by PikalaxALT on 23 June 2019 All Rights Reserved\n";
+
+int main(int argc, char ** argv) {
+    puts(SPLASH);
+    if (argc != 4) FATAL_ERROR("usage: %s ROM PATCH OUT\n", argv[0]);
+    FILE * rom = fopen(argv[1], "rb");
+    if (rom == NULL) FATAL_ERROR("failed to open file \"%s\" for reading\n", argv[1]);
+    FILE * patch = fopen(argv[2], "rb");
+    if (patch == NULL) FATAL_ERROR("failed to open file \"%s\" for reading\n", argv[2]);
+    FILE * out = fopen(argv[3], "wb");
+    if (patch == NULL) FATAL_ERROR("failed to open file \"%s\" for writing\n", argv[3]);
+    char magic[5];
+    if (fread(magic, 1, 5, patch) != 5) FATAL_ERROR("read magic\n");
+    if (memcmp(magic, "PATCH", 5) != 0) FATAL_ERROR("malformed IPS patch\n");
+    fseek(rom, 0, SEEK_END);
+    size_t romsize = ftell(rom);
+    fseek(rom, 0, SEEK_SET);
+    char * buffer = malloc(romsize);
+    if (buffer == NULL) FATAL_ERROR("failed to allocate dest buffer\n");
+    if (fread(buffer, 1, romsize, rom) != romsize) FATAL_ERROR("read ROM\n");
+    fclose(rom);
+    while (1) {
+        uint32_t offset;
+        size_t size;
+        
+        offset = (unsigned char)getc(patch) << 16;
+        offset |= (unsigned char)getc(patch) << 8;
+        offset |= (unsigned char)getc(patch);
+        if (offset == 0x454F46) break;
+        size = (unsigned char)getc(patch) << 8;
+        size |= (unsigned char)getc(patch);
+        if (fread(buffer + offset, 1, size, patch) != size) FATAL_ERROR("read segment\n");
+    }
+    fclose(patch);
+    fwrite(buffer, 1, romsize, out);
+    fclose(out);
+    free(buffer);
+    return 0;
+}