From 3309f3f753ac3179237c4cb53e5e4d778e60ea89 Mon Sep 17 00:00:00 2001 From: John Whitington Date: Fri, 23 Dec 2022 16:19:40 +0000 Subject: [PATCH] more --- cpdfpng.ml | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/cpdfpng.ml b/cpdfpng.ml index 3d7813d..a4f19bd 100644 --- a/cpdfpng.ml +++ b/cpdfpng.ml @@ -16,13 +16,24 @@ let string_of_tag t = (char_of_int (i32toi (Int32.logand 0x000000FFl (Int32.shift_right t 8)))) (char_of_int (i32toi (Int32.logand 0x000000FFl t))) -let read_unsigned_4byte i = 0l +let read_unsigned_4byte i = + let a = i32ofi (i.input_byte ()) in + let b = i32ofi (i.input_byte ()) in + let c = i32ofi (i.input_byte ()) in + let d = i32ofi (i.input_byte ()) in + lor32 (lor32 (lsl32 a 24) (lsl32 b 16)) (lor32 (lsl32 c 8) d) -let read_data l i = bytes_of_string "" +let read_data l i = + let l = i32toi l in + let b = mkbytes l in + setinit i b 0 l; + b let read_chunk i = let chunklen = read_unsigned_4byte i in + Printf.printf "chunklen = %li\n" chunklen; let chunktype = read_unsigned_4byte i in + Printf.printf "chunktype = %s\n" (string_of_tag chunktype); let chunkdata = read_data chunklen i in let _ (* crc *) = read_unsigned_4byte i in (string_of_tag chunktype, chunkdata)