libc: Add an implementation of strtol/strtoul and export it via plugins

These were lifted from the lua plugin.

sdl, doom, puzzles updated to use the exported version

todo: lua, maybe?
also: convert uses of atoi [back] to strtol

Change-Id: I5a1ebbe8d8c99349e594ab9bbbce474e7645b4e9

firmware/libc/include/stdlib.h

@@ -58,6 +58,8 @@ void exit(int status);
 #endif
 
 int atoi (const char *str);
+unsigned long int strtoul(const char *ptr, char **endptr, int base);
+long int strtol(const char *ptr, char **endptr, int base);
 
 #ifdef __cplusplus
 }

firmware/libc/strtol.c

@@ -0,0 +1,29 @@
+#include <stdlib.h>
+#include <errno.h>
+#include <limits.h>
+#include <ctype.h>
+#include <gcc_extensions.h>
+
+#define ABS_LONG_MIN LONG_MAX
+long int strtol(const char *nptr, char **endptr, int base)
+{
+  int neg=0;
+  unsigned long int v;
+  const char*orig=nptr;
+
+  while(UNLIKELY(isspace(*nptr))) nptr++;
+
+  if (*nptr == '-' && isalnum(nptr[1])) { neg=-1; ++nptr; }
+  v=strtoul(nptr,endptr,base);
+  if (endptr && *endptr==nptr) *endptr=(char *)orig;
+  if (UNLIKELY(v>=ABS_LONG_MIN)) {
+    if (v==ABS_LONG_MIN && neg) {
+      errno=0;
+      return v;
+    }
+    errno=ERANGE;
+    return (neg?LONG_MIN:LONG_MAX);
+  }
+  return (neg?-v:v);
+}
+

firmware/libc/strtoul.c

@@ -0,0 +1,57 @@
+#include <stdlib.h>
+#include <errno.h>
+#include <ctype.h>
+#include <limits.h>
+#include <gcc_extensions.h>
+
+unsigned long int strtoul(const char *ptr, char **endptr, int base)
+{
+  int neg = 0, overflow = 0;
+  unsigned long int v=0;
+  const char* orig;
+  const char* nptr=ptr;
+
+  while(UNLIKELY(isspace(*nptr))) ++nptr;
+
+  if (*nptr == '-') { neg=1; nptr++; }
+  else if (*nptr == '+') ++nptr;
+  orig=nptr;
+  if (base==16 && nptr[0]=='0') goto skip0x;
+  if (base) {
+    register unsigned int b=base-2;
+    if (UNLIKELY(b>34)) { errno=EINVAL; return 0; }
+  } else {
+    if (*nptr=='0') {
+      base=8;
+skip0x:
+      if ((nptr[1]=='x'||nptr[1]=='X') && isxdigit(nptr[2])) {
+	nptr+=2;
+	base=16;
+      }
+    } else
+      base=10;
+  }
+  while(LIKELY(*nptr)) {
+    register unsigned char c=*nptr;
+    c=(c>='a'?c-'a'+10:c>='A'?c-'A'+10:c<='9'?c-'0':0xff);
+    if (UNLIKELY(c>=base)) break;	/* out of base */
+    {
+      register unsigned long x=(v&0xff)*base+c;
+      register unsigned long w=(v>>8)*base+(x>>8);
+      if (w>(ULONG_MAX>>8)) overflow=1;
+      v=(w<<8)+(x&0xff);
+    }
+    ++nptr;
+  }
+  if (UNLIKELY(nptr==orig)) {		/* no conversion done */
+    nptr=ptr;
+    errno=EINVAL;
+    v=0;
+  }
+  if (endptr) *endptr=(char *)nptr;
+  if (overflow) {
+    errno=ERANGE;
+    return ULONG_MAX;
+  }
+  return (neg?-v:v);
+}