#include "devs_internal.h"

static int numvalue(char c) {

if ('0' <= c && c <= '9')

return c - '0';

c |= 0x20;

if ('a' <= c && c <= 'z')

return c - 'a' + 10;

return -1;

}

#define WR(c) \

do { \

char tmp = (c); \

if (numskip == 0) { \

if (dp < dstlen) \

dst[dp] = tmp; \

dp++; \

} else \

numskip--; \

} while (0)

size_t devs_strformat(devs_ctx_t *ctx, const char *fmt, size_t fmtlen, char *dst, size_t dstlen,

value_t *args, size_t numargs, size_t numskip) {

size_t fp = 0;

size_t dp = 0;

if (dstlen)

dst[0] = 0; // in case numskip prevents us from writing anything

while (fp <= fmtlen) {

char c = fp == fmtlen ? (fp++, 0) : fmt[fp++];

if (c != '{' || fp >= fmtlen) {

// if we see "}}" we treat it as a single "}"

if (c == '}' && fp < fmtlen && fmt[fp] == '}')

fp++;

goto write_c;

}

c = fmt[fp++];

if (c == '{')

goto write_c;

int pos = numvalue(c);

if (pos < 0) {

c = '!';

goto write_c;

}

size_t nextp = fp;

while (nextp < fmtlen && fmt[nextp] != '}')

nextp++;

int precision = -1;

if (fp < nextp)

precision = numvalue(fmt[fp++]);

fp = nextp + 1;

if (pos >= (int)numargs) {

c = '?';

goto write_c;

}

if (precision < 0)

precision = 6;

unsigned sz;

const char *s;

value_t v = args[pos];

char buf[64];

if (devs_is_number(v)) {

jd_print_double(buf, devs_value_to_double(ctx, args[pos]), precision + 1);

s = buf;

sz = strlen(buf);

} else {

value_t tmp = devs_value_to_string(ctx, v);

// note that tmp is not pinned, it may go away at next allocation, but we only use it

// down below

s = devs_string_get_utf8(ctx, tmp, &sz);

}

while (sz--)

WR(*s++);

continue;

write_c:

WR(c);

}

if (dstlen)

dst[dstlen - 1] = 0; // in case we overflow

return dp;

}