implemented FTE_STRINGS compliant substring behavior (FRIK_FILE feature

but upgraded by FTE_STRINGS)

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@8901 d7cf8633-e32d-0410-b094-e92efae38249

diff --git a/prvm_cmds.c b/prvm_cmds.c
index a644f1a2e3ef76e4571abfeb6c5e9079cef8d3bc..f792d63f9f43db73fa81484cfc9baea6cfb17906 100644 (file)
--- a/prvm_cmds.c
+++ b/prvm_cmds.c
@@ -2101,7 +2101,7 @@ string    substring(string s, float start, float length)
 // returns a section of a string as a tempstring
 void VM_substring(void)
 {
-       int i, start, length;
+       int start, length, slength;
        const char *s;
        char string[VM_STRINGTEMP_LENGTH];
 
@@ -2110,10 +2110,16 @@ void VM_substring(void)
        s = PRVM_G_STRING(OFS_PARM0);
        start = (int)PRVM_G_FLOAT(OFS_PARM1);
        length = (int)PRVM_G_FLOAT(OFS_PARM2);
-       for (i = 0;i < start && *s;i++, s++);
-       for (i = 0;i < (int)sizeof(string) - 1 && *s && i < length;i++, s++)
-               string[i] = *s;
-       string[i] = 0;
+       slength = strlen(s);
+       if (length < 0) // FTE_STRINGS feature
+               length += slength - start;
+       if (start < 0) // FTE_STRINGS feature
+               start += slength;
+       start = bound(0, start, slength); // consistent with php 5.2.0 but not 5.2.3
+       length = min(length, (int)sizeof(string) - 1);
+       length = min(length, slength - start);
+       memcpy(string, s + start, length);
+       string[length] = 0;
        PRVM_G_INT(OFS_RETURN) = PRVM_SetTempString(string);
 }