mirrors/janet
1
0
Fork 0
mirror of https://github.com/janet-lang/janet synced 2024-11-28 19:19:53 +00:00
Code Issues 1 Releases Wiki Activity

Added string/format function (snprintf like)

Browse Source
This commit is contained in:
J.-F. Cap 2019-02-16 03:29:04 +01:00
parent ec02d55145
commit a6f022a73d
1 changed files with 148 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

148
src/core/string.c
View File

@ -21,6 +21,7 @@
*/
#include <string.h>
#include <ctype.h>
#ifndef JANET_AMALG
#include <janet/janet.h>
@ -501,6 +502,148 @@ static Janet cfun_string_pretty(int32_t argc, Janet *argv) {
return janet_wrap_buffer(buffer);
}
/*
* code adapted from lua/lstrlib.c http://lua.org
*/
#define MAX_ITEM 256
#define FMT_FLAGS "-+ #0"
#define MAX_FORMAT 32
static const char *scanformat(const char *strfrmt, char *form,char width[3], char precision[3]) {
const char *p = strfrmt;
memset(width, '\0', 3);
memset(precision, '\0', 3);
while (*p != '\0' && strchr(FMT_FLAGS, *p) != NULL)
p++; /* skip flags */
if ((size_t) (p - strfrmt) >= sizeof(FMT_FLAGS) / sizeof(char))
janet_panic("invalid format (repeated flags)");
if (isdigit((int) (*p)))
width[0] = *p++; /* skip width */
if (isdigit((int) (*p)))
width[1] = *p++; /* (2 digits at most) */
if (*p == '.') {
p++;
if (isdigit((int) (*p)))
precision[0] = *p++; /* skip precision */
if (isdigit((int) (*p)))
precision[1] = *p++; /* (2 digits at most) */
}
if (isdigit((int) (*p)))
janet_panic("invalid format (width or precision too long)");
*(form++) = '%';
memcpy(form, strfrmt, ((p - strfrmt) + 1) * sizeof(char));
form += (p - strfrmt) + 1;
*form = '\0';
return p;
}
static Janet cfun_string_format(int32_t argc, Janet * argv) {
janet_arity(argc, 2, -1);
JanetBuffer *b = janet_getbuffer(argv, 0);
const char *strfrmt = (const char *) janet_getstring(argv, 1);
size_t sfl = strlen(strfrmt);
const char *strfrmt_end = strfrmt + sfl;
int32_t arg = 1;
while (strfrmt < strfrmt_end) {
if (*strfrmt != '%')
janet_buffer_push_u8(b, (uint8_t) * strfrmt++);
else if (*++strfrmt == '%')
janet_buffer_push_u8(b, (uint8_t) * strfrmt++); /* %% */
else { /* format item */
char form[MAX_FORMAT],item[MAX_ITEM];
char width[3], precision[3];
int nb = 0; /* number of bytes in added item */
if (++arg >= argc)
janet_panic("no enough value for format");
strfrmt = scanformat(strfrmt, form, width, precision);
switch (*strfrmt++) {
case 'c':
{
nb = snprintf(item, MAX_ITEM, form, (int)
janet_getinteger(argv, arg));
break;
}
case 'd':
case 'i':
case 'o':
case 'u':
case 'x':
case 'X':
{
int32_t n = janet_getinteger(argv, arg);
nb = snprintf(item, MAX_ITEM, form, n);
break;
}
case 'a':
case 'A':
case 'e':
case 'E':
case 'f':
case 'g':
case 'G':
{
double d = janet_getnumber(argv, arg);
nb = snprintf(item, MAX_ITEM, form, d);
break;
}
case 's':
{
const uint8_t *s = janet_getstring(argv, arg);
size_t l = janet_string_length(s);
if (form[2] == '\0')
janet_buffer_push_bytes(b, s, l);
else {
if (l != strlen((const char *) s))
janet_panic("string contains zeros");
if (!strchr(form, '.') && l >= 100) {
janet_panic
("no precision and string is too long to be formatted");
} else {
nb = snprintf(item, MAX_ITEM, form, s);
}
}
break;
}
case 'V':
{
janet_to_string_b(b, argv[arg]);
break;
}
case 'v':
{
janet_description_b(b, argv[arg]);
break;
}
case 'p': /* janet pretty , precision = depth */
{
int depth = atoi(precision);
if (depth < 1)
depth = 4;
janet_pretty(b, depth, argv[arg]);
break;
}
default:
{ /* also treat cases 'nLlh' */
janet_panicf("invalid conversion '%s' to 'format'",
form);
}
}
if (nb >= MAX_ITEM)
janet_panicf("format buffer overflow", form);
if (nb > 0)
janet_buffer_push_bytes(b, (uint8_t *) item, nb);
}
}
return janet_wrap_buffer(b);
}
static const JanetReg string_cfuns[] = {
{
"string/slice", cfun_string_slice,
@ -614,6 +757,11 @@ static const JanetReg string_cfuns[] = {
"Pretty prints a value to a buffer. Optionally allows setting max "
"recursion depth, as well as writing to a buffer. Returns the buffer.")
},
{ "string/format", cfun_string_format,
JDOC("(string/format buffer format & values)\n\n"
"Similar to snprintf, but specialized for operating with janet"
"...")
},
{NULL, NULL, NULL}
};