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#include "strings.h"
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#ifndef NDEBUG
# define JAM_STRING_MAGIC ((char)0xcf)
# define JAM_STRING_MAGIC_SIZE 4
static void assert_invariants( string* self )
{
int i;
assert( self->size < self->capacity );
assert( ( self->capacity <= sizeof(self->opt) ) == ( self->value == self->opt ) );
assert( strlen( self->value ) == self->size );
for (i = 0; i < 4; ++i)
{
assert( self->magic[i] == JAM_STRING_MAGIC );
assert( self->value[self->capacity + i] == JAM_STRING_MAGIC );
}
}
#else
# define JAM_STRING_MAGIC_SIZE 0
# define assert_invariants(x) do {} while (0)
#endif
void string_new( string* s )
{
s->value = s->opt;
s->size = 0;
s->capacity = sizeof(s->opt);
s->opt[0] = 0;
#ifndef NDEBUG
memset(s->magic, JAM_STRING_MAGIC, sizeof(s->magic));
#endif
assert_invariants( s );
}
void string_free( string* s )
{
assert_invariants( s );
if ( s->value != s->opt )
free( s->value );
}
static void string_reserve_internal( string* self, size_t capacity )
{
if ( self->value == self->opt )
{
self->value = malloc( capacity + JAM_STRING_MAGIC_SIZE );
self->value[0] = 0;
strncat( self->value, self->opt, sizeof(self->opt) );
assert( strlen( self->value ) <= self->capacity ); /* This is a regression test */
}
else
{
self->value = realloc( self->value, capacity + JAM_STRING_MAGIC_SIZE );
}
#ifndef NDEBUG
memcpy( self->value + capacity, self->magic, JAM_STRING_MAGIC_SIZE );
#endif
self->capacity = capacity;
}
void string_reserve( string* self, size_t capacity )
{
assert_invariants( self );
if ( capacity <= self->capacity )
return;
string_reserve_internal( self, capacity );
assert_invariants( self );
}
static void extend_full( string* self, char* start, char *finish )
{
size_t new_size = self->capacity + ( finish - start );
size_t new_capacity = self->capacity;
size_t old_size = self->capacity;
while ( new_capacity < new_size + 1)
new_capacity <<= 1;
string_reserve_internal( self, new_capacity );
memcpy( self->value + old_size, start, new_size - old_size );
self->value[new_size] = 0;
self->size = new_size;
}
void string_append( string* self, char* rhs )
{
char* p = self->value + self->size;
char* end = self->value + self->capacity;
assert_invariants( self );
while ( *rhs && p != end)
*p++ = *rhs++;
if ( p != end )
{
*p = 0;
self->size = p - self->value;
}
else
{
extend_full( self, rhs, rhs + strlen(rhs) );
}
assert_invariants( self );
}
void string_append_range( string* self, char* start, char* finish )
{
char* p = self->value + self->size;
char* end = self->value + self->capacity;
assert_invariants( self );
while ( p != end && start != finish )
*p++ = *start++;
if ( p != end )
{
*p = 0;
self->size = p - self->value;
}
else
{
extend_full( self, start, finish );
}
assert_invariants( self );
}
void string_copy( string* s, char* rhs )
{
string_new( s );
string_append( s, rhs );
}
void string_truncate( string* self, size_t n )
{
assert_invariants( self );
assert( n <= self->capacity );
self->value[self->size = n] = 0;
assert_invariants( self );
}
void string_pop_back( string* self )
{
string_truncate( self, self->size - 1 );
}
void string_push_back( string* self, char x )
{
string_append_range( self, &x, &x + 1 );
}
char string_back( string* self )
{
assert_invariants( self );
return self->value[self->size - 1];
}
#ifndef NDEBUG
void string_unit_test()
{
string s[1];
int i;
char buffer[sizeof(s->opt) * 2 + 2];
int limit = sizeof(buffer) > 254 ? 254 : sizeof(buffer);
string_new(s);
for (i = 0; i < limit; ++i)
{
string_push_back( s, (char)(i + 1) );
};
for (i = 0; i < limit; ++i)
{
assert( i < s->size );
assert( s->value[i] == (char)(i + 1));
}
string_free(s);
}
#endif
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