reviewed by zhengchao, propose multiple suggestions.

1 files changed, 98 insertions, 79 deletions

diff --git a/src/av_format_identify.c b/src/av_format_identify.c
index 07df489..533d554 100644
--- a/src/av_format_identify.c
+++ b/src/av_format_identify.c
@@ -1,4 +1,15 @@
 #include "av_format_identify.h"
+#include <arpa/inet.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>  
+
+#include <sys/io.h>
+#include <arpa/inet.h>
+
 
 #define FIT_TIMES 1
 #define TS_SYNC_BYTE 0x47
@@ -17,79 +28,96 @@ const char *g_mp4_box_type_all[] = { "ftyp", "pdin", "moov", "mvhd", "trak", "tk
 "schi", "iinf", "xml", "bxml", "pitm", "fiin", "paen", "fpar", "fecr", "segr", "gitn", "tsel", "meco", "mere", "uuid" };
 const int g_mp4_box_type_count = sizeof(g_mp4_box_type_all) / sizeof(char *);
 
+/*To find that whether the initial size bytes pointed to by buff satisfies the rules of MPEG-TS AV Container
+ * by supposing that its first 1 byte is sync_byte in ts header.*/
+int is_mpeg_ts_each(const char *buff, size_t size);
+/*To identify whether the whole byte stream belongs to MPEG_TS container*/
+int is_mpeg_ts(const char* buff, size_t size);
+
+
+/*To find that whether the initial size bytes pointed to by buff satisfies the rules of FLV AV Container
+ * by supposing that its first 1 byte is TagType in FLV Tag Header.*/
+int is_flv_each(const char* buff, size_t size);
+/*To identify whether the whole byte stream belongs to FLV container*/
+int is_flv(const char* buff, size_t size);
+
+/*To find that whether the initial size bytes pointed to by buff satisfies the rules of MP4 AV Container
+ * by supposing that its first 4 byte is Boxtype in Box of MP4 file.*/
+int is_mp4_each(const char* buff, size_t size);
+/*To identify whether the whole byte stream belongs to MP4 container*/
+int is_mp4(const char* buff, size_t size);
+
 
 int is_mpeg_ts_each(const char *buff, size_t size)
 {
 	int ret_ts_each = 0;
 	const char *p = buff;
 	int fit_times = 0;
-	p += TS_PKT_SIZE;
-
-	size_t  cont_cout_pre, cont_cout_aft;
+	
+	size_t  cont_cout_pre=0, cont_cout_aft=0;
 	cont_cout_pre = htonl(*(size_t *)buff) & 0x0000000f;
 
-    uint32_t pid_pre, pid_aft;
+    uint32_t pid_pre=0, pid_aft=0;
     pid_pre = ((htonl(*(uint32_t *)buff) & 0x000fff00) >> 8) + ((((htonl(*(uint32_t *)buff) & 0x00f00000) >> 20) % 2) << 12);
 
-	const char *pack_tail;
-	const char *pack_half;
-	const char *pack_quarter;
-
-	size_t whole_pack_cout;
-	size_t half_pack_cout;
-	size_t quarter_pack_cout;
+	const char *pack_tail=NULL;
+	const char *pack_half=NULL;
+	const char *pack_quarter=NULL;
 
+	size_t whole_pack_cnt=0;
+	size_t half_pack_cnt=0;
+	size_t quarter_pack_cnt=0;
+	
+	p += TS_PKT_SIZE;
 	while (p < (buff + size))
 	{
-		if (*p == TS_SYNC_BYTE)
+		if (*p != TS_SYNC_BYTE)
+		{
+			break;
+		}
+		
+		if ((p + 3) < (buff + size))
 		{
-			if ((p + 3) < (buff + size))
+            pid_aft = ((htonl(*(uint32_t *)p) & 0x000fff00) >> 8) + ((((htonl(*(uint32_t *)p) & 0x00f00000) >> 20) % 2) << 12);
+            if (pid_aft == pid_pre && pid_aft!=8191)
+            {
+            	cont_cout_aft = htonl(*(size_t *)p) & 0x0000000f;
+			    if (cont_cout_aft == (cont_cout_pre + 1) % 16)
+			    {
+				    fit_times++;
+			    }
+			    else
+			    {
+				    break;
+			    }
+            }
+            else
+            {
+                fit_times++;
+            }
+		}
+		if (fit_times >= FIT_TIMES)
+		{
+			whole_pack_cnt = size / TS_PKT_SIZE;
+			if (size % TS_PKT_SIZE == 0)
 			{
-                pid_aft = ((htonl(*(uint32_t *)p) & 0x000fff00) >> 8) + ((((htonl(*(uint32_t *)p) & 0x00f00000) >> 20) % 2) << 12);
-                if (pid_aft == pid_pre && pid_aft!=8191)
-                {
-                	cont_cout_aft = htonl(*(size_t *)p) & 0x0000000f;
-				    if (cont_cout_aft == (cont_cout_pre + 1) % 16)
-				    {
-					    fit_times++;
-				    }
-				    else
-				    {
-					    break;
-				    }
-                }
-                else
-                {
-                    fit_times++;
-                }
+				whole_pack_cnt--;
 			}
-			if (fit_times >= FIT_TIMES)
+            half_pack_cnt = whole_pack_cnt/2;
+            quarter_pack_cnt = whole_pack_cnt/4;
+            if (whole_pack_cnt < 3 || half_pack_cnt < 2 || quarter_pack_cnt < 1)
+            {
+                break;
+            }
+			pack_tail = buff + whole_pack_cnt * TS_PKT_SIZE;
+            pack_half = buff + half_pack_cnt * TS_PKT_SIZE;
+			pack_quarter = buff + quarter_pack_cnt * TS_PKT_SIZE;
+            //if (*pack_tail == TS_SYNC_BYTE && *(pack_tail - TS_PKT_SIZE) == TS_SYNC_BYTE)
+            if (*pack_tail == TS_SYNC_BYTE && *pack_half == TS_SYNC_BYTE && *pack_quarter == TS_SYNC_BYTE)
 			{
-				whole_pack_cout = size / TS_PKT_SIZE;
-				if (size % TS_PKT_SIZE == 0)
-				{
-					whole_pack_cout--;
-				}
-                half_pack_cout = whole_pack_cout/2;
-                quarter_pack_cout = whole_pack_cout/4;
-                if (whole_pack_cout < 3 || half_pack_cout < 2 || quarter_pack_cout < 1)
-                {
-                    break;
-                }
-				pack_tail = buff + whole_pack_cout * TS_PKT_SIZE;
-                pack_half = buff + half_pack_cout * TS_PKT_SIZE;
-				pack_quarter = buff + quarter_pack_cout * TS_PKT_SIZE;
-                //if (*pack_tail == TS_SYNC_BYTE && *(pack_tail - TS_PKT_SIZE) == TS_SYNC_BYTE)
-                if (*pack_tail == TS_SYNC_BYTE && *pack_half == TS_SYNC_BYTE && *pack_quarter == TS_SYNC_BYTE)
-				{
-					ret_ts_each = 1;
-					break;
-				}
+				ret_ts_each = 1;
 				break;
 			}
-		}
-		else
-		{
 			break;
 		}
 
@@ -102,32 +130,23 @@ int is_mpeg_ts_each(const char *buff, size_t size)
 
 int is_mpeg_ts(const char* buff, size_t size)
 {
-	int ret_ts = 0;
-	const char *p_each = buff;
-	int ret_ts_each;
-	while (p_each < buff + size)
+	const char *p = buff;
+	int is_ts=0;
+	while (p < buff + size)
 	{
-		p_each = memchr(p_each, TS_SYNC_BYTE, size - (p_each - buff));
-		if (p_each == NULL)
+		p = memchr(p, TS_SYNC_BYTE, size - (p - buff));
+		if (p == NULL||p + 3 >= buff + size)
 		{
 			break;
 		}
-		else if (p_each + 3 >= buff + size)
+		is_ts = is_mpeg_ts_each(p, size - (p - buff));
+		if (is_ts == 1)
 		{
 			break;
 		}
-		else
-		{
-			ret_ts_each = is_mpeg_ts_each(p_each, size - (p_each - buff));
-			if (ret_ts_each == 1)
-			{
-				ret_ts = 1;
-				break;
-			}
-			p_each++;
-		}
+		p++;		
 	}
-	return ret_ts;
+	return is_ts;
 }
 
 
@@ -152,13 +171,13 @@ int is_flv_each(const char* buff, size_t size)
 	int ret_flv_each = 0;
 	const char *p = buff;
 	int fit_times = 0;
-	size_t left;
-	size_t right = 11 + (htonl(*(size_t *)p) & 0x00ffffff);
+	uint32_t left=0;
+	uint32_t right = 11 + (htonl(*(size_t *)p) & 0x00ffffff);
 	p += (right + 4);
 
 	while (p < (buff + size))
 	{
-		left = htonl(*(size_t *)(p - 4));
+		left = htonl(*(uint32_t *)(p - 4));
 		if (right == left && (*(p) == FLV_TAG_AUDIO || *(p) == FLV_TAG_VIDEO || *(p) == FLV_TAG_SCRIPT_DATA))
 		{
 			fit_times++;
@@ -215,7 +234,7 @@ int is_flv(const char* buff, size_t size)
 
 
 
-int is_mp4_boxtype(const char *buff)
+int is_mp4_boxname_deep(const char *buff)
 {
 	int i;
 	size_t size_type_h;
@@ -264,7 +283,7 @@ int is_mp4_each(const char* buff, size_t size)
 	int ret_mp4_each = 0;
 	int ret_mp4_boxname;
 	int sig_mp4_boxtype = 0;
-	if (is_mp4_boxtype(buff) == 1)
+	if (is_mp4_boxname_deep(buff) == 1)
 	{
 		sig_mp4_boxtype = 1;
 	}
@@ -275,7 +294,7 @@ int is_mp4_each(const char* buff, size_t size)
 	p += 8;
 	while (p + 4 < (buff + size))
 	{
-		if (memcmp(p - 8, "mdat", 4) == 0 && htonl(*(size_t *)(p - 12)) == 1)
+		if (memcmp(p - 8, "mdat", 4) == 0 && htonl(*(size_t *)(p - 12)) == 1)//large size
 		{
 			p -= 8;
 			if (p + 12 < buff + size)
@@ -349,7 +368,7 @@ int is_mp4_each(const char* buff, size_t size)
 			}
 		}
 		fit_times++;
-		if (is_mp4_boxtype(p) == 1)
+		if (is_mp4_boxname_deep(p) == 1)
 		{
 			sig_mp4_boxtype++;
 		}