From 210d3e2aa89e2ae0593b4e70328f399fe0e76bb5 Mon Sep 17 00:00:00 2001
From: Michael Orlitzky <michael@orlitzky.com>
Date: Sun, 6 Aug 2023 13:13:39 -0400
Subject: [PATCH] io-svg.c: clean up compiler warnings

---
 io-svg.c | 81 ++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 50 insertions(+), 31 deletions(-)

diff --git a/io-svg.c b/io-svg.c
index c08fa7d..d0c2a1b 100644
--- a/io-svg.c
+++ b/io-svg.c
@@ -1,9 +1,9 @@
-#include <stdio.h> /* fprintf, printf */
-#include <string.h> /* memcpy, memset, strstr */
+#include <string.h> /* memcpy, memset */
 
 #include <cairo.h>
 #include <gdk/gdk.h>
 #include <gdk-pixbuf/gdk-pixbuf.h> /* includes glib.h */
+#include <glib/gprintf.h>
 #include <svgtiny.h>
 
 /*
@@ -137,8 +137,10 @@ static diagram_t* svgtiny_diagram_from_buffer(char* buffer,
 
   code = svgtiny_parse(diagram, buffer, bytecount, "", width, height);
 
-  if (code != svgtiny_OK) {
-    switch (code) {
+  switch(code) {
+    case svgtiny_OK:
+      /* The one success case. */
+      return diagram;
     case svgtiny_OUT_OF_MEMORY:
       g_set_error_literal(error,
                           G_FILE_ERROR,
@@ -165,11 +167,10 @@ static diagram_t* svgtiny_diagram_from_buffer(char* buffer,
                   diagram->error_line,
                   diagram->error_message);
       break;
-    }
-    return NULL;
   }
 
-  return diagram;
+  /* All other cases above are failure */
+  return NULL;
 }
 
 /**
@@ -194,9 +195,9 @@ static cairo_t* cairo_context_from_diagram(diagram_t* diagram) {
 
   crs = cairo_surface_status(surface);
   if (crs != CAIRO_STATUS_SUCCESS) {
-    fprintf(stderr,
-            "cairo_image_surface_create failed: %s\n",
-            cairo_status_to_string(crs));
+    g_fprintf(stderr,
+              "cairo_image_surface_create failed: %s\n",
+              cairo_status_to_string(crs));
     cairo_surface_destroy(surface);
     return NULL;
   }
@@ -209,9 +210,9 @@ static cairo_t* cairo_context_from_diagram(diagram_t* diagram) {
   cairo_surface_destroy(surface);
 
   if (crs != CAIRO_STATUS_SUCCESS) {
-    fprintf(stderr,
-            "cairo_create failed: %s\n",
-            cairo_status_to_string(crs));
+    g_fprintf(stderr,
+              "cairo_create failed: %s\n",
+              cairo_status_to_string(crs));
     cairo_destroy(cr);
     return NULL;
   }
@@ -251,9 +252,9 @@ static cairo_t* cairo_context_from_diagram(diagram_t* diagram) {
   /* Check the status again just for good measure? */
   crs = cairo_status(cr);
   if (crs != CAIRO_STATUS_SUCCESS) {
-    fprintf(stderr,
-            "cairo error: %s\n",
-            cairo_status_to_string(crs));
+    g_fprintf(stderr,
+              "cairo error: %s\n",
+              cairo_status_to_string(crs));
     cairo_destroy(cr);
     return NULL;
   }
@@ -354,10 +355,9 @@ static gboolean gdk_pixbuf_load_increment(gpointer data,
                                           const guchar* buf,
                                           guint buf_size,
                                           GError** error) {
-  size_t increment = 0;
   SvgTinyContext* context = (SvgTinyContext*)data;
 
-  /* YOLO, no error checking */
+  /* YOLO, what is error checking? */
   context->svg_data = g_realloc(context->svg_data,
                                 context->svg_data_size + buf_size);
   memcpy(context->svg_data + context->svg_data_size, buf, buf_size);
@@ -426,13 +426,13 @@ static char* process_gtk_symbolic_svg_xinclude(const char* buffer,
   char* xi;
   char* xi_stop;
 
-  xi_start = strstr(buffer, XI_SIGNATURE);
+  xi_start = g_strstr_len(buffer, buf_size, XI_SIGNATURE);
   if (xi_start == NULL) {
     return NULL;
   }
 
   xi = xi_start + strlen(XI_SIGNATURE);
-  xi_stop = strstr(xi, "\"");
+  xi_stop = g_strstr_len(xi, (buffer + buf_size) - xi, "\"");
   if(xi_stop == NULL) {
     /* We found the start of an XInclude, but not the end of its
        base64-encoded data? Play it safe and do nothing. */
@@ -443,7 +443,15 @@ static char* process_gtk_symbolic_svg_xinclude(const char* buffer,
      "xi" into one */
   *xi_stop = 0;
   gsize decoded_size;
-  guchar* decoded = g_base64_decode(xi, &decoded_size);
+
+  /* All files are ASCII, right? In GTK's gdkpixbufutils.c, our base64
+   * data is encoded from a binary file stream, i.e. bytes, without
+   * any regard for what the text inside represents. Elsewhere we are
+   * pretending that gchar is a reasonable data type to use for the
+   * contents of an SVG file; here we are saying that again out loud.
+   */
+  gchar* decoded = (gchar*)g_base64_decode(xi, &decoded_size);
+  *xi_stop = '"';
 
   /* We need another round of processing to strip the <xml> and <svg>
    * elements out of "decoded", but it's simpler to just overwrite
@@ -453,9 +461,21 @@ static char* process_gtk_symbolic_svg_xinclude(const char* buffer,
    * element so much, because if one exists, it has to come before the
    * <svg>. As a result, we just need to strip everything up to the
    * leading <svg> tag. */
-  guchar* svg_open_start = strstr(decoded, "<svg ");
-  guchar* svg_open_end = strstr(svg_open_start, ">");
-  memset(decoded, ' ', (1 + (svg_open_end - decoded)));
+  gchar* svg_open_start = g_strstr_len(decoded, decoded_size, "<svg ");
+  if (svg_open_start == NULL) {
+    /* Uhhhhh */
+    g_free(decoded);
+    return NULL;
+  }
+  else {
+    gchar* svg_open_end = g_strstr_len(svg_open_start, decoded_size, ">");
+    if (svg_open_end == NULL) {
+      /* Uhhhhh */
+      g_free(decoded);
+      return NULL;
+    }
+    memset(decoded, ' ', (1 + (svg_open_end - decoded)));
+  }
 
   /* We're going to keep everything up to xi_start. If the <xi:include
    * started at, say, position three, then this would compute a size
@@ -560,14 +580,13 @@ void fill_info(GdkPixbufFormat* info) {
 int main(int argc, char** argv) {
   char* svgpath;
   char* pngpath;
-  FILE* fp;
   GError* err = NULL;
   GdkPixbuf* pb;
 
   /* Parse arguments, and maybe print usage */
   if (argc < 3) {
-    printf("Usage: %s INPUT OUTPUT\n", argv[0]);
-    printf("Convert an SVG file (INPUT) to a PNG file (OUTPUT)\n");
+    g_printf("Usage: %s INPUT OUTPUT\n", argv[0]);
+    g_printf("Convert an SVG file (INPUT) to a PNG file (OUTPUT)\n");
     return 2;
   }
 
@@ -576,10 +595,10 @@ int main(int argc, char** argv) {
 
   pb = gdk_pixbuf_new_from_file(svgpath, &err);
   if (!pb) {
-    fprintf(stderr,
-            "Error %d in gdk_pixbuf_new_from_file: %s\n",
-            err->code,
-            err->message);
+    g_fprintf(stderr,
+              "Error %d in gdk_pixbuf_new_from_file: %s\n",
+              err->code,
+              err->message);
     g_error_free(err);
     return 1;
   }
-- 
2.43.2