2 files changed, 76 insertions, 28 deletions

diff --git a/src/format/image/dbg.c b/src/format/image/dbg.c
new file mode 100644
index 0000000..56cb53b
--- /dev/null
+++ b/src/format/image/dbg.c
@@ -0,0 +1,20 @@
+#include "dbg.h"
+
+ff_result ff_set_debug_stream(FILE *stream)
+{
+    intff_debug_stream = stream;
+    intff_debug_enabled = (stream != NULL);
+    return FF_RESULT_OK;
+}
+
+ff_result ff_dprintf(const char *format, ...)
+{
+    if (!intff_debug_enabled || !intff_debug_stream) return FF_RESULT_WARN_DEBUG_DISABLED;
+
+    va_list args;
+    va_start(args, format);
+    vfprintf(intff_debug_stream, format, args);
+    va_end(args);
+
+    return FF_RESULT_OK;
+}
diff --git a/src/format/image/png.c b/src/format/image/png.c
index 1170af2..d177819 100644
--- a/src/format/image/png.c
+++ b/src/format/image/png.c
@@ -1,56 +1,84 @@
 #include "tinyff/image/png.h"
-#include "png.h"
-
-
+#include "tinyff/dbg.h"
 
 ff_result ff_png_isvalid(FILE *file)
 {
+    ff_dprintf("png: validating signature\n");
+
     char raw_sig[8];
-    if (fread(raw_sig, sizeof(char), 8, file) != 8) {
-        // Unable to read first 8 bytes
+    if (fread(raw_sig, 1, 8, file) != 8) {
+        ff_dprintf("png: failed to read signature bytes\n");
         return FF_RESULT_ERROR_INVALID_FILE;
     }
 
+    ff_dprintf(
+        "png: signature read: %02X %02X %02X %02X %02X %02X %02X %02X\n",
+        raw_sig[0], raw_sig[1], raw_sig[2], raw_sig[3],
+        raw_sig[4], raw_sig[5], raw_sig[6], raw_sig[7]
+    );
+
     if (memcmp(raw_sig, PNG_SIGNATURE, 8) != 0) {
-        // Signature did not match
+        ff_dprintf("png: signature mismatch\n");
         return FF_RESULT_ERROR_INVALID_FILE_SIGNITURE;
     }
 
+    ff_dprintf("png: signature valid\n");
     return FF_RESULT_OK;
 }
 
-ff_result ff_open_png(const char *filepath, ff_png_ctx **out_ctx) {
-    // Validate
-    
+ff_result ff_open_png(const char *filepath, ff_png_ctx **out_ctx)
+{
+    ff_dprintf("png: opening file '%s'\n", filepath);
+
     ff_png_ctx ctx;
     ctx.raw = fopen(filepath, "rb");
 
     if (!ctx.raw) {
+        ff_dprintf("png: fopen failed\n");
         return FF_RESULT_ERROR_READ_FILE_FAILURE;
     }
 
-    if (ff_png_isvalid(ctx.raw) != FF_RESULT_OK) {
-        return ff_png_isvalid(ctx.raw);
+    ff_dprintf("png: file opened successfully\n");
+
+    ff_result res = ff_png_isvalid(ctx.raw);
+    if (res != FF_RESULT_OK) {
+        ff_dprintf("png: validation failed (%d)\n", res);
+        fclose(ctx.raw);
+        return res;
     }
 
-    // This is a heavy W.I.P
-    
+    ff_dprintf("png: validation passed\n");
+
+    *out_ctx = NULL;
+    ff_dprintf("png: open_png reached WIP end\n");
+
+    return FF_RESULT_OK;
 }
 
-void ff_png_header_handler(uint8_t *data, size_t len, ff_png_ctx *ctx)
+void ff_png_header_handler(uint8_t *buf, size_t len, ff_png_ctx *ctx)
 {
-    if (len != 13) return; // Invalid length
-    printf("Width:              %d\n", get_big_endian(data));
-    printf("Height:             %d\n", get_big_endian(data + 4));
-    printf("Bit depth:          %d\n", (unsigned char)data[8]);
-    printf("Color type:         %d\n", (unsigned char)data[9]);
-    printf("Compression method: %d\n", (unsigned char)data[10]);
-    printf("Filter method:      %d\n", (unsigned char)data[11]);
-    printf("Interlace method:   %d\n", (unsigned char)data[12]);
-
-    // Store in context
-    ctx->width = get_big_endian(data);
-    ctx->height = get_big_endian(data + 4);
-    ctx->bit_depth = (unsigned char)data[8];
-    ctx->color_type = (unsigned char)data[9];
+    ff_dprintf("png: IHDR chunk received (len=%zu)\n", len);
+
+    if (len != 13) {
+        ff_dprintf("png: invalid IHDR length\n");
+        return;
+    }
+
+    uint32_t w = get_big_endian(buf);
+    uint32_t h = get_big_endian(buf + 4);
+
+    ff_dprintf("Width:              %u\n", w);
+    ff_dprintf("Height:             %u\n", h);
+    ff_dprintf("Bit depth:          %u\n", buf[8]);
+    ff_dprintf("Color type:         %u\n", buf[9]);
+    ff_dprintf("Compression method: %u\n", buf[10]);
+    ff_dprintf("Filter method:      %u\n", buf[11]);
+    ff_dprintf("Interlace method:   %u\n", buf[12]);
+
+    ctx->width = w;
+    ctx->height = h;
+    ctx->bit_depth = buf[8];
+    ctx->color_type = buf[9];
+
+    ff_dprintf("png: IHDR stored in context\n");
 }
\ No newline at end of file