From: Andre Noll <maan@tuebingen.mpg.de>
Date: Mon, 9 Aug 2021 21:13:35 +0000 (+0200)
Subject: mp4: Use read/write functions from portable_io.h.
X-Git-Tag: v0.7.1~7^2~116
X-Git-Url: http://git.tue.mpg.de/?a=commitdiff_plain;h=6d87d92d6be3d9aeeda162e639ec9e25d2e0f06d;p=paraslash.git

mp4: Use read/write functions from portable_io.h.

This removes quite a bit of ugly code. In particular, atom_get_size()
is completely unnecessary and can be removed. Since there is no
function in portable_io.h to read a 24 bit integer, we have to add
read_u24_be().
---

diff --git a/mp4.c b/mp4.c
index aab39a1e..af491fc2 100644
--- a/mp4.c
+++ b/mp4.c
@@ -8,6 +8,7 @@
 #include <regex.h>
 
 #include "para.h"
+#include "portable_io.h"
 #include "string.h"
 #include "mp4.h"
 
@@ -30,34 +31,12 @@ static int32_t read_data(mp4ff_t * f, void *data, uint32_t size)
 	return result;
 }
 
-/* parse atom header size */
-static int32_t atom_get_size(const int8_t * data)
-{
-	uint32_t result;
-	uint32_t a, b, c, d;
-
-	a = (uint8_t) data[0];
-	b = (uint8_t) data[1];
-	c = (uint8_t) data[2];
-	d = (uint8_t) data[3];
-
-	result = (a << 24) | (b << 16) | (c << 8) | d;
-	return (int32_t) result;
-}
-
 static uint64_t read_int64(mp4ff_t * f)
 {
 	uint8_t data[8];
-	uint64_t result = 0;
-	int8_t i;
 
 	read_data(f, data, 8);
-
-	for (i = 0; i < 8; i++) {
-		result |= ((uint64_t) data[i]) << ((7 - i) * 8);
-	}
-
-	return result;
+	return read_u64_be(data);
 }
 
 /* comnapre 2 atom names, returns 1 for equal, 0 for unequal */
@@ -325,7 +304,7 @@ static uint64_t atom_read_header(mp4ff_t * f, uint8_t * atom_type,
 	if (ret != 8)
 		return 0;
 
-	size = atom_get_size(atom_header);
+	size = read_u32_be(atom_header);
 	*header_size = 8;
 
 	/* check for 64 bit atom size */
@@ -393,33 +372,18 @@ static uint8_t read_char(mp4ff_t * f)
 
 static uint32_t read_int24(mp4ff_t * f)
 {
-	uint32_t result;
-	uint32_t a, b, c;
 	int8_t data[4];
 
 	read_data(f, data, 3);
-	a = (uint8_t) data[0];
-	b = (uint8_t) data[1];
-	c = (uint8_t) data[2];
-
-	result = (a << 16) | (b << 8) | c;
-	return (uint32_t) result;
+	return read_u24_be(data);
 }
 
 static uint32_t read_int32(mp4ff_t * f)
 {
-	uint32_t result;
-	uint32_t a, b, c, d;
 	int8_t data[4];
 
 	read_data(f, data, 4);
-	a = (uint8_t) data[0];
-	b = (uint8_t) data[1];
-	c = (uint8_t) data[2];
-	d = (uint8_t) data[3];
-
-	result = (a << 24) | (b << 16) | (c << 8) | d;
-	return (uint32_t) result;
+	return read_u32_be(data);
 }
 
 static int32_t read_stsz(mp4ff_t * f)
@@ -546,16 +510,10 @@ static int32_t read_stco(mp4ff_t * f)
 
 static uint16_t read_int16(mp4ff_t * f)
 {
-	uint32_t result;
-	uint32_t a, b;
 	int8_t data[2];
 
 	read_data(f, data, 2);
-	a = (uint8_t) data[0];
-	b = (uint8_t) data[1];
-
-	result = (a << 8) | b;
-	return (uint16_t) result;
+	return read_u16_be(data);
 }
 
 static uint32_t read_mp4_descr_length(mp4ff_t * f)
@@ -1584,14 +1542,16 @@ static unsigned membuffer_write_atom_name(membuffer * buf, const char *data)
 
 static unsigned membuffer_write_int16(membuffer * buf, uint16_t data)
 {
-	uint8_t temp[2] = { (uint8_t) (data >> 8), (uint8_t) data };
+	uint8_t temp[2];
+
+	write_u16_be(temp, data);
 	return membuffer_write(buf, temp, 2);
 }
 
 static unsigned membuffer_write_int32(membuffer * buf, uint32_t data)
 {
-	uint8_t temp[4] = { (uint8_t) (data >> 24), (uint8_t) (data >> 16),
-		(uint8_t) (data >> 8), (uint8_t) data };
+	uint8_t temp[4];
+	write_u32_be(temp, data);
 	return membuffer_write(buf, temp, 4);
 }
 
@@ -1935,18 +1895,7 @@ uint32_t * out_size)
 
 static uint32_t fix_byte_order_32(uint32_t src)
 {
-	uint32_t result;
-	uint32_t a, b, c, d;
-	int8_t data[4];
-
-	memcpy(data, &src, sizeof (src));
-	a = (uint8_t) data[0];
-	b = (uint8_t) data[1];
-	c = (uint8_t) data[2];
-	d = (uint8_t) data[3];
-
-	result = (a << 24) | (b << 16) | (c << 8) | d;
-	return (uint32_t) result;
+	return read_u32_be(&src);
 }
 
 static uint32_t modify_moov(mp4ff_t * f, const mp4ff_metadata_t * data,
@@ -2076,19 +2025,9 @@ static int32_t write_data(mp4ff_t * f, void *data, uint32_t size)
 
 static int32_t write_int32(mp4ff_t * f, const uint32_t data)
 {
-	uint32_t result;
-	uint32_t a, b, c, d;
 	int8_t temp[4];
-
-	*(uint32_t *) temp = data;
-	a = (uint8_t) temp[0];
-	b = (uint8_t) temp[1];
-	c = (uint8_t) temp[2];
-	d = (uint8_t) temp[3];
-
-	result = (a << 24) | (b << 16) | (c << 8) | d;
-
-	return write_data(f, (uint8_t *) & result, sizeof (result));
+	write_u32_be(temp, data);
+	return write_data(f, temp, sizeof(temp));
 }
 
 static int32_t truncate_stream(mp4ff_t * f)
diff --git a/portable_io.h b/portable_io.h
index fdd4165d..81dfcf57 100644
--- a/portable_io.h
+++ b/portable_io.h
@@ -58,6 +58,11 @@ static inline uint32_t read_u32_be(const void *buf)
 	return read_portable_be(32, buf);
 }
 
+static inline uint32_t read_u24_be(const void *buf)
+{
+	return read_portable_be(24, buf);
+}
+
 static inline uint16_t read_u16_be(const void *buf)
 {
 	return read_portable_be(16, buf);