feat: crypto.c

.gitignore

@@ -0,0 +1,60 @@
+# Created by https://www.toptal.com/developers/gitignore/api/c
+# Edit at https://www.toptal.com/developers/gitignore?templates=c
+
+### C ###
+# Prerequisites
+*.d
+
+# Object files
+*.o
+*.ko
+*.obj
+*.elf
+
+# Linker output
+*.ilk
+*.map
+*.exp
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Libraries
+*.lib
+*.a
+*.la
+*.lo
+
+# Shared objects (inc. Windows DLLs)
+*.dll
+*.so
+*.so.*
+*.dylib
+
+# Executables
+*.exe
+*.out
+*.app
+*.i*86
+*.x86_64
+*.hex
+
+# Debug files
+*.dSYM/
+*.su
+*.idb
+*.pdb
+
+# Kernel Module Compile Results
+*.mod*
+*.cmd
+.tmp_versions/
+modules.order
+Module.symvers
+Mkfile.old
+dkms.conf
+
+# End of https://www.toptal.com/developers/gitignore/api/c
+config.h
+crypto

Makefile

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+CFLAGS	=	-Wall -Wpedantic -Wextra
+LDFLAGS	=	-lcurl
+
+SRC		=	crypto.c
+
+OBJ		=	$(SRC:.c=.o)
+
+.PHONY:		all clean re debug
+
+all:		crypto
+
+$(OBJ):		config.h
+
+config.h:
+	cp config.def.h $@
+
+crypto:	$(OBJ)
+	$(CC) -o $@ $(LDFLAGS) $(OBJ)
+
+clean:
+	$(RM) $(OBJ)
+	$(RM) crypto
+
+re:			clean all
+
+debug:		CFLAGS+=-g3
+debug:		re

README.md

@@ -1,2 +1,25 @@
 # crypto
+Get your current holding in crypto from Binance in your own currency.
 
+Makefile inspired from suckless
+
+## Dependencies
+### Arch
+```console
+# pacman -S curl
+```
+
+### Debian 11+
+```console
+# apt-get install libcurl4-dev
+```
+
+## How-To
+```console
+$ make
+```
+Set your settings in config.h
+```console
+$ make
+$ ./crypto.sh
+```

config.def.h

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+#define CUR "$"
+
+struct wallet_s {
+    char *from;
+    char *to;
+    float value;
+} WALLET[] = {
+    {"BTC",  "USDT", 1.00000000},
+    {0},
+};

crypto.c

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+#include <curl/curl.h>
+#include <errno.h>
+#include <error.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/param.h>
+#include "config.h"
+
+#define BUF_SIZE 1024
+
+// [{"symbol":"BTCUSDT","price":"69420.69420"}]
+static int get_next_symbol(char* buf, float* price)
+{
+    static const char output[] = "\"symbol\":\"%*[^\"]\",\"price\":\"%f\"";
+    char* tmp = strtok(buf, "{");
+
+    if (!tmp) {
+        return 1;
+    }
+    tmp = strtok(0, "}");
+    if (!tmp) {
+        return 1;
+    }
+    return !sscanf(tmp, output, price);
+}
+
+static size_t write_callback(char *response, size_t s, size_t n, void *buf)
+{
+    size_t size = s * n;
+
+    return snprintf(buf, MIN(size, BUF_SIZE), response);
+}
+
+static char* build_url(void)
+{
+    static const char base[] =
+        "https://api.binance.com/api/v3/ticker/price?symbols=[";
+    size_t s = sizeof base;
+    char* url;
+
+    for (size_t i = 0; WALLET[i].to; i++) {
+        s += strlen(WALLET[i].from) + strlen(WALLET[i].to) + 3; // ["SYMBOL",]
+    }
+    url = malloc(s);
+    if (!url) {
+        return 0;
+    }
+    strcpy(url, base);
+    for (size_t i = 0; WALLET[i].to; i++) {
+        strcat(strcat(strcat(strcat(
+            url,
+            "\""),
+            WALLET[i].from),
+            WALLET[i].to),
+            "\","
+        );
+    }
+    url[strlen(url) - 1] = ']';
+    return url;
+}
+
+static CURL* init_curl(char* response)
+{
+    char* url = build_url();
+    CURL* curl = curl_easy_init();
+
+
+    if (!url || !curl) {
+        free(url);
+        curl_easy_cleanup(curl);
+        return 0;
+    }
+    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);
+    curl_easy_setopt(curl, CURLOPT_WRITEDATA, response);
+    curl_easy_setopt(curl, CURLOPT_URL, url);
+    curl_easy_perform(curl);
+    free(url);
+    return curl;
+}
+
+int main(void)
+{
+    char response[BUF_SIZE];
+    CURL* curl = init_curl(response);
+    int err;
+    float price, current;
+    float sum = 0;
+
+    if (!curl) {
+        error(1, errno, "cannot init curl");
+    }
+    err = get_next_symbol(response, &price);
+    for (size_t i = 0; !err && WALLET[i].to; i++) {
+        current = price * WALLET[i].value;
+        printf("%s=%.2f" CUR " ", WALLET[i].from, current);
+        sum += current;
+        err = get_next_symbol(0, &price);
+    }
+    printf("TOT=%.2f" CUR "\n", sum);
+    curl_easy_cleanup(curl);
+    return 0;
+}