stringbuf.c
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/*
stringbuf: mimicking a bit of C++ to more safely handle strings
copyright 2006-10 by the mpg123 project - free software under the terms of the LGPL 2.1
see COPYING and AUTHORS files in distribution or http://mpg123.org
initially written by Thomas Orgis
*/
#include "mpg123lib_intern.h"
#include "config.h"
#include "mpg123.h"
#include "compat.h"
#include <string.h>
#include "debug.h"
void attribute_align_arg mpg123_init_string(mpg123_string* sb)
{
/* Handing in NULL here is a fatal mistake and rightfully so. */
sb->p = NULL;
sb->size = 0;
sb->fill = 0;
}
void attribute_align_arg mpg123_free_string(mpg123_string* sb)
{
if(!sb)
return;
if(sb->p != NULL) free(sb->p);
mpg123_init_string(sb);
}
int attribute_align_arg mpg123_grow_string(mpg123_string* sb, size_t new)
{
if(!sb)
return 0;
if(sb->size < new) return mpg123_resize_string(sb, new);
else return 1;
}
int attribute_align_arg mpg123_resize_string(mpg123_string* sb, size_t new)
{
if(!sb)
return 0;
debug3("resizing string pointer %p from %lu to %lu", (void*) sb->p, (unsigned long)sb->size, (unsigned long)new);
if(new == 0)
{
if(sb->size && sb->p != NULL) free(sb->p);
mpg123_init_string(sb);
return 1;
}
if(sb->size != new)
{
char* t;
debug("really!");
t = (char*) safe_realloc(sb->p, new*sizeof(char));
debug1("safe_realloc returned %p", (void*) t);
if(t != NULL)
{
sb->p = t;
sb->size = new;
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if(sb->size < sb->fill)
{
// Cut short the existing data, properly.
sb->fill = sb->size;
sb->p[sb->fill-1] = 0;
}
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return 1;
}
else return 0;
}
else return 1; /* success */
}
int attribute_align_arg mpg123_copy_string(mpg123_string* from, mpg123_string* to)
{
size_t fill;
char *text;
debug2("called copy_string with %p -> %p", (void*)from, (void*)to);
if(to == NULL)
return 0;
if(from == NULL)
{
fill = 0;
text = NULL;
}
else
{
fill = from->fill;
text = from->p;
}
if(mpg123_resize_string(to, fill))
{
if(fill) /* Avoid memcpy(NULL, NULL, 0) */
memcpy(to->p, text, fill);
to->fill = fill;
return 1;
}
else return 0;
}
int attribute_align_arg mpg123_add_string(mpg123_string* sb, const char* stuff)
{
debug1("adding %s", stuff);
return mpg123_add_substring(sb, stuff, 0, stuff ? strlen(stuff) : 0);
}
int attribute_align_arg mpg123_add_substring(mpg123_string *sb, const char *stuff, size_t from, size_t count)
{
debug("adding a substring");
if(!sb || !stuff)
return 0;
if(sb->fill) /* includes zero byte... */
{
if( (SIZE_MAX - sb->fill >= count) /* Avoid overflow. */
&& (sb->size >= sb->fill+count || mpg123_grow_string(sb, sb->fill+count)) )
{
memcpy(sb->p+sb->fill-1, stuff+from, count);
sb->fill += count;
sb->p[sb->fill-1] = 0; /* Terminate! */
}
else return 0;
}
else
{
if( count < SIZE_MAX && mpg123_grow_string(sb, count+1) )
{
memcpy(sb->p, stuff+from, count);
sb->fill = count+1;
sb->p[sb->fill-1] = 0; /* Terminate! */
}
else return 0;
}
return 1;
}
int attribute_align_arg mpg123_set_substring(mpg123_string* sb, const char* stuff, size_t from, size_t count)
{
if(!sb)
return 0;
sb->fill = 0;
return mpg123_add_substring(sb, stuff, from, count);
}
int attribute_align_arg mpg123_set_string(mpg123_string* sb, const char* stuff)
{
if(!sb)
return 0;
sb->fill = 0;
return mpg123_add_string(sb, stuff);
}
size_t attribute_align_arg mpg123_strlen(mpg123_string *sb, int utf8)
{
size_t i;
size_t bytelen;
/* Notions of empty string. If there's only a single character, it has to be the trailing zero, and if the first is the trailing zero anyway, we got empty. */
if(!sb || sb->fill < 2 || sb->p[0] == 0) return 0;
/* Find the first non-null character from the back.
We already established that the first character is non-null
That at fill-2 has to be null, though. */
for(i=sb->fill-2; i>0; --i)
if(sb->p[i] != 0) break;
/* For simple byte strings, we are done now. */
bytelen = i+1;
if(!utf8) return bytelen;
else
{
/* Work out the actual count of UTF8 bytes.
This employs no particular encoding error checking. */
size_t len = 0;
for(i=0; i<bytelen; ++i)
{
/* Every byte that is not a continuation byte ( 0xc0 == 10xx xxxx ) stands for a character. */
if((sb->p[i] & 0xc0) != 0x80) len++;
}
return len;
}
}
int attribute_align_arg mpg123_chomp_string(mpg123_string *sb)
{
ssize_t i;
if(!sb || !sb->fill) return 0;
/* Ensure that it is zero-terminated. */
sb->p[sb->fill-1] = 0;
for(i=sb->fill-2; i>=0; --i)
{
char *c = sb->p+i;
/* Stop at the first proper character. */
if(*c && *c != '\r' && *c != '\n') break;
else *c = 0;
}
/* initial fill at least 1, so i at least -1,
+2 means nothing happened for fill=1 .
With i=0, we got one non-null character, fill shall be 2
to accomodate the trailing zero. */
sb->fill = (size_t)i+2;
return 1;
}