Mercurial > urweb
diff src/c/urweb.c @ 1388:3913cbfd72e9
String processing optimizations
author | Adam Chlipala <adam@chlipala.net> |
---|---|
date | Tue, 11 Jan 2011 14:03:54 -0500 |
parents | 64724ef86149 |
children | 9a721f0722d3 |
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--- a/src/c/urweb.c Thu Jan 06 19:26:31 2011 -0500 +++ b/src/c/urweb.c Tue Jan 11 14:03:54 2011 -0500 @@ -2133,23 +2133,48 @@ } uw_Basis_char uw_Basis_strsub(uw_context ctx, uw_Basis_string s, uw_Basis_int n) { - if (n >= 0 && n < strlen(s)) - return s[n]; - else - uw_error(ctx, FATAL, "Out-of-bounds strsub"); + while (n >= 0) { + if (*s == 0) + uw_error(ctx, FATAL, "Out-of-bounds strsub"); + + if (n == 0) + return *s; + + --n; + ++s; + } + + uw_error(ctx, FATAL, "Negative strsub bound"); } uw_Basis_string uw_Basis_strsuffix(uw_context ctx, uw_Basis_string s, uw_Basis_int n) { - if (n >= 0 && n < strlen(s)) - return &s[n]; - else - uw_error(ctx, FATAL, "Out-of-bounds strsuffix"); + while (n >= 0) { + if (*s == 0 || n == 0) + return s; + + --n; + ++s; + } + + uw_error(ctx, FATAL, "Negative strsuffix bound"); } uw_Basis_int uw_Basis_strlen(uw_context ctx, uw_Basis_string s) { return strlen(s); } +uw_Basis_bool uw_Basis_strlenGe(uw_context ctx, uw_Basis_string s, uw_Basis_int n) { + while (n > 0) { + if (*s == 0) + return uw_Basis_False; + + --n; + ++s; + } + + return uw_Basis_True; +} + uw_Basis_string uw_Basis_strchr(uw_context ctx, uw_Basis_string s, uw_Basis_char ch) { return strchr(s, ch); }